tris/recoll
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity
recoll/src/doc/user/usermanual.xml

7239 lines
328 KiB
XML
Raw Blame History

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
<!ENTITY RCL "<application>Recoll</application>">
<!ENTITY RCLAPPS "<ulink url='http://www.recoll.org/pages/features.html#doctypes'>http://www.recoll.org/pages/features.html</ulink>">
<!ENTITY RCLVERSION "1.29">
<!ENTITY XAP "<application>Xapian</application>">
<!ENTITY WIN "<application>Windows</application>">
<!ENTITY LIN "<application>Unix</application>-like systems">
<!ENTITY FAQS "https://www.lesbonscomptes.com/recoll/faqsandhowtos/">
<!ENTITY RCLCONF SYSTEM "recoll.conf.xml">
]>
<book lang="en">
<!-- A nice overview of docbook elements:
https://tdg.docbook.org/tdg/4.5/ch02.html#ch02-logdiv -->
<bookinfo>
<title>Recoll user manual</title>
<author>
<firstname>Jean-Francois</firstname>
<surname>Dockes</surname>
<affiliation>
<address><email>jfd@recoll.org</email></address>
</affiliation>
</author>
<copyright>
<year>2005-2020</year>
<holder role="mailto:jfd@recoll.org">Jean-Francois Dockes</holder>
</copyright>
<abstract>
<para><literal>Permission is granted to copy, distribute and/or
modify this document under the terms of the GNU Free Documentation
License, Version 1.3 or any later version published by the Free
Software Foundation; with no Invariant Sections, no Front-Cover
Texts, and no Back-Cover Texts. A copy of the license can be
found at the following
location: <ulink url="http://www.gnu.org/licenses/fdl.html">GNU
web site</ulink>.</literal></para>
<para>This document introduces full text search notions
and describes the installation and use of the &RCL;
application. This version describes &RCL; &RCLVERSION;.</para>
</abstract>
</bookinfo>
<chapter id="RCL.INTRODUCTION">
<title>Introduction</title>
<para>This document introduces full text search notions
and describes the installation and use of the &RCL;
application. It is updated for &RCL; &RCLVERSION;.</para>
<para>&RCL; was for a long time dedicated to Unix-like systems. It
was only lately (2015) ported to
<application>MS-Windows</application>. Many references in this
manual, especially file locations, are specific to Unix, and not
valid on &WIN;, where some described features are also not available.
The manual will be progressively updated. Until this happens, on
&WIN;, most references to shared files can be translated by looking
under the Recoll installation directory (Typically <filename>C:/Program
Files (x86)/Recoll</filename>, esp. anything referenced
in <filename>/usr/share</filename> in this document will be found int
the <filename>Share</filename> subdirectory). The user configuration is
stored by default under <filename>AppData/Local/Recoll</filename>
inside the user directory, along with the index itself.</para>
<sect1 id="RCL.INTRODUCTION.TRYIT">
<title>Giving it a try</title>
<para>If you do not like reading manuals (who does?) but
wish to give &RCL; a try, just
<link linkend="RCL.INSTALL.BINARY">install</link> the application
and start the <command>recoll</command> graphical user
interface (GUI), which will ask permission to index your home
directory, allowing you to search immediately after
indexing completes.</para>
<para>Do not do this if your home directory contains a huge
number of documents and you do not want to wait or are very
short on disk space. In this case, you may first want to customize
the <link linkend="RCL.INDEXING.CONFIG">configuration</link>
to restrict the indexed area (shortcut: from the
<command>recoll</command> GUI go to:
<menuchoice>
<guimenu>Preferences</guimenu>
<guimenuitem>Indexing configuration</guimenuitem>
</menuchoice>, then adjust the <guilabel>Top
directories</guilabel> section).</para>
<para>On &LIN;, you may need to install the
appropriate
<link linkend="RCL.INSTALL.EXTERNAL">supporting applications</link>
for document types that need them (for
example <application>antiword</application> for
<application>Microsoft Word</application> files).
The &RCL; for &WIN; package is self-contained and includes
most useful auxiliary programs.</para>
</sect1>
<sect1 id="RCL.INTRODUCTION.SEARCH">
<title>Full text search</title>
<para>&RCL; is a full text search application, which means that it
finds your data by content rather than by external attributes
(like the file name). You specify words
(terms) which should or should not appear in the text you are
looking for, and receive in return a list of matching
documents, ordered so that the most
<emphasis>relevant</emphasis> documents will appear
first.</para>
<para>You do not need to remember in what file or email message you
stored a given piece of information. You just ask for related
terms, and the tool will return a list of documents where
these terms are prominent, in a similar way to Internet search
engines.</para>
<para>Full text search applications try to determine which
documents are most relevant to the search terms you
provide. Computer algorithms for determining relevance can be
very complex, and in general are inferior to the power of the
human mind to rapidly determine relevance. The quality of
relevance guessing is probably the most important aspect when
evaluating a search application. &RCL; relies on the &XAP;
probabilistic information retrieval library to determine
relevance.</para>
<para>In many cases, you are looking for all the forms of a
word, including plurals, different tenses for a verb, or terms
derived from the same root or <emphasis>stem</emphasis>
(example: <replaceable>floor, floors, floored,
flooring...</replaceable>). Queries are usually automatically
expanded to all such related terms (words that reduce to the
same stem). This can be prevented for searching for a specific
form.</para>
<para>Stemming, by itself, does not accommodate for misspellings or
phonetic searches. A full text search application may also support
this form of approximation. For example, a search for
<replaceable>aliterattion</replaceable> returning no result might
propose <replaceable>alliteration, alteration, alterations, or
altercation</replaceable> as possible replacement terms. &RCL; bases
its suggestions on the actual index contents, so that suggestions may
be made for words which would not appear in a standard dictionary.</para>
</sect1>
<sect1 id="RCL.INTRODUCTION.RECOLL">
<title>Recoll overview</title>
<para>&RCL; uses the
<ulink url="http://www.xapian.org">&XAP;</ulink> information retrieval
library as its storage and retrieval engine. &XAP; is a very
mature package using <ulink
url="http://www.xapian.org/docs/intro_ir.html">a sophisticated
probabilistic ranking model</ulink>.</para>
<para>The &XAP; library manages an index database which
describes where terms appear in your document files. It
efficiently processes the complex queries which are produced by
the &RCL; query expansion mechanism, and is in charge of the
all-important relevance computation task.</para>
<para>&RCL; provides the mechanisms and interface to get data
into and out of the index. This includes translating the many
possible document formats into pure text, handling term
variations (using &XAP; stemmers), and spelling approximations
(using the <application>aspell</application> speller),
interpreting user queries and presenting results.</para>
<para>In a shorter way, &RCL; does the dirty footwork, &XAP;
deals with the intelligent parts of the process.</para>
<para>The &XAP; index can be big (roughly the size of the original
document set), but it is not a document archive. &RCL; can only
display documents that still exist at the place from which they were
indexed.</para>
<para>&RCL; stores all internal data in <application>Unicode
UTF-8</application> format, and it can index many types of files
with different character sets, encodings, and languages into the
same index. It can process documents embedded inside other
documents (for example a PDF document stored inside a Zip
archive sent as an email attachment...), down to an arbitrary
depth.</para>
<para>Stemming is the process by which &RCL; reduces words to
their radicals so that searching does not depend, for example, on a
word being singular or plural (floor, floors), or on a verb tense
(flooring, floored). Because the mechanisms used for stemming
depend on the specific grammatical rules for each language, there
is a separate &XAP; stemmer module for most common languages where
stemming makes sense.</para>
<para>&RCL; stores the unstemmed versions of terms in the main index
and uses auxiliary databases for term expansion (one for each
stemming language), which means that you can switch stemming
languages between searches, or add a language without needing a
full reindex.</para>
<para>Storing documents written in different languages in the same
index is possible, and commonly done. In this situation, you can
specify several stemming languages for the index. </para>
<para>&RCL; currently makes no attempt at automatic language
recognition, which means that the stemmer will sometimes be applied
to terms from other languages with potentially strange results. In
practise, even if this introduces possibilities of confusion, this
approach has been proven quite useful, and it is much less
cumbersome than separating your documents according to what
language they are written in.</para>
<para>By default, &RCL; strips most accents and
diacritics from terms, and converts them to lower case before
either storing them in the index or searching for them. As a
consequence, it is impossible to search for a particular
capitalization of a term (<literal>US</literal> /
<literal>us</literal>), or to discriminate two terms based on
diacritics (<literal>sake</literal> / <literal>saké</literal>,
<literal>mate</literal> / <literal>maté</literal>).</para>
<para>&RCL; can optionally store the raw terms, without accent
stripping or case conversion. In this configuration, default searches
will behave as before, but it is possible to perform searches
sensitive to case and diacritics. This is described in more detail in
the section about
<link linkend="RCL.INDEXING.CONFIG.SENS">index case and diacritics sensitivity</link>.
</para>
<para>&RCL; uses many parameters to define exactly what to index,
and how to classify and decode the source documents. These are kept
in <link linkend="RCL.INDEXING.CONFIG">configuration files</link>. A
default configuration is copied into a standard location (usually
something like <filename>/usr/share/recoll/examples</filename>)
during installation. The default values set by the configuration
files in this directory may be overridden by values set inside your
personal configuration. With the default configuration, &RCL; will
index your home directory with generic parameters. Most common
parameters can be set by using
configuration menus in the <command>recoll</command> GUI. Some less
common parameters can only be set by editing the text files (the
new values will be preserved by the GUI).</para>
<para>The <link linkend="RCL.INDEXING.PERIODIC.EXEC">indexing process</link>
is started automatically (after asking permission), the
first time you execute the <command>recoll</command> GUI. Indexing
can also be performed by executing the <command>recollindex</command>
command. &RCL; indexing is multithreaded by default when appropriate
hardware resources are available, and can perform in parallel
multiple tasks for text extraction, segmentation and index
updates.</para>
<para><link linkend="RCL.SEARCH">Searches</link> are usually
performed inside the <command>recoll</command> GUI, which has many
options to help you find what you are looking for. However, there
are other ways to query the index:
<itemizedlist>
<listitem><para>A
<link linkend="RCL.SEARCH.COMMANDLINE">command line interface</link>.
</para></listitem>
<listitem><para>A
<link linkend="RCL.PROGRAM.PYTHONAPI"><application>Python</application> programming interface</link>
</para></listitem>
<listitem><para>A <link linkend="RCL.SEARCH.KIO"><application>KDE</application> KIO slave module</link>.
</para></listitem>
<listitem><para>A Ubuntu Unity
<ulink url="https://www.lesbonscomptes.com/recoll/pages/download.html">Scope</ulink>
module.</para></listitem>
<listitem><para>A Gnome Shell
<ulink url="https://www.lesbonscomptes.com/recoll/pages/download.html">Search Provider</ulink>.
</para></listitem>
<listitem><para>A
<ulink url="https://framagit.org/medoc92/recollwebui">Web interface</ulink>.
</para></listitem>
</itemizedlist>
</para>
</sect1>
</chapter>
<chapter id="RCL.INDEXING">
<title>Indexing</title>
<sect1 id="RCL.INDEXING.INTRODUCTION">
<title>Introduction</title>
<para>Indexing is the process by which the set of documents is
analyzed and the data entered into the database. &RCL;
indexing is normally incremental: documents will only be
processed if they have been modified since the last run. On
the first execution, all documents will need processing. A
full index build can be forced later by specifying an option
to the indexing command (<command>recollindex</command>
<option>-z</option> or <option>-Z</option>).</para>
<para><command>recollindex</command> skips files which caused an
error during a previous pass. This is a performance optimization, and
the command line option <option>-k</option> can be set to retry
failed files, for example after updating an input handler.</para>
<para>The following sections give an overview of different
aspects of the indexing processes and configuration, with links
to detailed sections.</para>
<para>Depending on your data, temporary files may be needed during
indexing, some of them possibly quite big. You can use the
<envar>RECOLL_TMPDIR</envar> or <envar>TMPDIR</envar> environment
variables to determine where they are created (the default is to
use <filename>/tmp</filename>). Using <envar>TMPDIR</envar> has
the nice property that it may also be taken into account by
auxiliary commands executed by <command>recollindex</command>.</para>
<sect2 id="RCL.INDEXING.INTRODUCTION.MODES">
<title>Indexing modes</title>
<para>&RCL; indexing can be performed along two main modes:</para>
<itemizedlist>
<listitem>
<formalpara><title>
<link linkend="RCL.INDEXING.PERIODIC">Periodic (or batch) indexing</link>
</title> <para><command>recollindex</command> is executed at
discrete times. On &LIN;, the typical usage is to have a
nightly run
<link linkend="RCL.INDEXING.PERIODIC.AUTOMAT">
programmed</link>
into your <command>cron</command> file. On &WIN;, this is
the only mode available, and the Windows Task Scheduler can
be used to run indexing. In both cases, the GUI includes an
easy interface to the system batch scheduler.</para>
</formalpara>
</listitem>
<listitem>
<formalpara><title>
<link linkend="RCL.INDEXING.MONITOR">Real time indexing</link>
</title>
<para>(Only available on &LIN;). <command>recollindex</command> runs
permanently as a daemon and uses a file system alteration monitor
(e.g. <application>inotify</application>) to detect file
changes. New or updated files are indexed at once. Monitoring a
big file system tree can consume
significant system resources. </para>
</formalpara>
</listitem>
</itemizedlist>
<simplesect><title>&LIN;: choosing an indexing mode</title>
<para>The choice between the two methods is mostly a matter of
preference, and they can be combined by setting up multiple
indexes (ie: use periodic indexing on a big documentation
directory, and real time indexing on a small home
directory), or, with &RCL; 1.24 and newer, by
<link linkend="RCL.INDEXING.MONITOR">configuring the index so that only a subset of the tree will be monitored.</link>
</para>
<para>The choice of method and the parameters used can be
configured from the <command>recoll</command> GUI:
<menuchoice>
<guimenu>Preferences</guimenu>
<guimenuitem>Indexing schedule</guimenuitem>
</menuchoice> dialog.
</para>
</simplesect>
</sect2>
<sect2 id="RCL.INDEXING.INTRODUCTION.CONFIG">
<title>Configurations, multiple indexes</title>
<para>&RCL; supports defining multiple indexes, each defined by its
own configuration directory. A configuration directory contains
<link linkend="RCL.INDEXING.CONFIG">several files</link> which
describe what should be indexed and how.</para>
<para>When <command>recoll</command> or
<command>recollindex</command> is first executed, it creates a
default configuration directory. This configuration is the one used
for indexing and querying when no specific configuration is
specified. It is located in <filename>$HOME/.recoll/</filename> for
&LIN; and <filename>%LOCALAPPDATA%\Recoll</filename> on &WIN;
(typically
<filename>C:\Users\[me]\Appdata\Local\Recoll</filename>).</para>
<para>All configuration parameters have defaults, defined in
system-wide files. Without further customisation, the default
configuration will process your complete home directory, with a
reasonable set of defaults. It can be adjusted to process a
different area of the file system, select files in different ways,
and many other things.</para>
<para>In some cases, it may be useful to create additional
configuration directories, for example, to separate personal and
shared indexes, or to take advantage of the organization of your
data to improve search precision.</para>
<para>In order to do this, you would create an empty directory in a
location of your choice, and then instruct
<command>recoll</command> or <command>recollindex</command> to use
it by setting either a command line option (<literal>-c</literal>
<replaceable>/some/directory</replaceable>), or an environment
variable
(<envar>RECOLL_CONFDIR</envar>=<replaceable>/some/directory</replaceable>).
Any modification performed by the commands (e.g. configuration
customisation or searches by <command>recoll</command> or index
creation by <command>recollindex</command>) would then apply to the
new directory and not to the default one.</para>
<para>Once multiple indexes are created, you can use each of them
separately by setting the <literal>-c</literal> option or the
<envar>RECOLL_CONFDIR</envar> environment variable when starting a
command, to select the desired index.</para>
<para>It is also possible to instruct one configuration to
query one or several other indexes in addition to its own, by using
the <guimenuitem>External index</guimenuitem> function in the
<command>recoll</command> GUI, or some other functions in the
command line and programming tools.</para>
<para>A plausible usage scenario for the multiple index feature
would be for a system administrator to set up a central index for
shared data, that you choose to search or not in addition to your
personal data. Of course, there are other possibilities. for
example, there are many cases where you know the subset of files
that should be searched, and where narrowing the search can improve
the results. You can achieve approximately the same effect with the
directory filter in advanced search, but multiple indexes may have
better performance and may be worth the trouble in some
cases.</para>
<para>A more advanced use case would be to use multiple index to
improve indexing performance, by updating several indexes in
parallel (using multiple CPU cores and disks, or possibly several
machines), and then merging them, or querying them in
parallel.</para>
<para>See the section about
<link linkend="RCL.INDEXING.CONFIG.MULTIPLE">configuring multiple indexes</link>
for more detail</para>
</sect2>
<sect2>
<title>Document types</title>
<para>&RCL; knows about quite a few different document
types. The parameters for document types recognition and
processing are set in <link linkend="RCL.INDEXING.CONFIG">
configuration files</link>.
</para>
<para>Most file types, like HTML or word processing files, only hold
one document. Some file types, like email folders or zip
archives, can hold many individually indexed documents, which may
themselves be compound ones. Such hierarchies can go quite
deep, and &RCL; can process, for example, a
<application>LibreOffice</application>
document stored as an attachment to an email message inside an
email folder archived in a zip file...</para>
<para><command>recollindex</command> processes plain text, HTML,
OpenDocument (Open/LibreOffice), email formats, and a few others
internally.</para>
<para>Other file types (ie: postscript, pdf, ms-word, rtf ...)
need external applications for preprocessing. The list is in the
<link linkend="RCL.INSTALL.EXTERNAL">installation</link>
section. After every indexing operation, &RCL; updates a list of
commands that would be needed for indexing existing files
types. This list can be displayed by selecting the menu option
<menuchoice>
<guimenu>File</guimenu>
<guimenuitem>Show Missing Helpers</guimenuitem>
</menuchoice>
in the <command>recoll</command> GUI. It is stored in the
<filename>missing</filename> text file inside the configuration
directory.</para>
<para>After installing a missing handler, you may need to
tell <command>recollindex</command>
to retry the failed files, by adding option <literal>-k</literal>
to the command line, or by using the GUI
<menuchoice>
<guimenu>File</guimenu>
<guimenuitem>Special indexing</guimenuitem>
</menuchoice> menu. This is because <command>recollindex</command>,
in its default operation mode, will not retry files which caused an
error during an earlier pass. In special cases, it may be useful to
reset the data for a category of files before indexing. See
the <command>recollindex</command> manual page. If your index is
not too big, it may be simpler to just reset it.</para>
<para>By default, &RCL; will try to index any file type that
it has a way to read. This is sometimes not desirable, and
there are ways to either exclude some types, or on the
contrary define a positive list of types to be
indexed. In the latter case, any type not in the list will
be ignored.</para>
<para>Excluding files by name can be done by adding wildcard name
patterns to the
<link linkend="RCL.INSTALL.CONFIG.RECOLLCONF.SKIPPEDNAMES">
skippedNames</link>
list, which can be done from the GUI Index configuration
menu. Excluding by type can be done by setting the
<link linkend="RCL.INSTALL.CONFIG.RECOLLCONF.EXCLUDEDMIMETYPES">
excludedmimetypes</link>
list in the configuration file (1.20 and later). This can be
redefined for subdirectories.</para>
<para>You can also define an exclusive list of MIME types to be
indexed (no others will be indexed), by setting
the <link linkend="RCL.INSTALL.CONFIG.RECOLLCONF.INDEXEDMIMETYPES">
indexedmimetypes</link>
configuration variable. Example:<programlisting>
indexedmimetypes = text/html application/pdf
</programlisting>
It is possible to redefine this parameter for
subdirectories. Example:<programlisting>
[/path/to/my/dir]
indexedmimetypes = application/pdf
</programlisting>
(When using sections like this, don't forget that they remain
in effect until the end of the file or another section
indicator).
</para>
<para><literal>excludedmimetypes</literal> or
<literal>indexedmimetypes</literal>, can be set either by editing
the <link linkend="RCL.INSTALL.CONFIG.RECOLLCONF">configuration file (<filename>recoll.conf</filename>)</link>
for the index, or by using the GUI index configuration tool.</para>
<note><title>Note about MIME types</title>
<para>When editing the <literal>indexedmimetypes</literal>
or <literal>excludedmimetypes</literal> lists, you should use the
MIME values listed in the <filename>mimemap</filename> file
or in Recoll result lists in preference to <literal>file -i</literal>
output: there are a number of differences. The
<literal>file -i</literal> output should only be used for files
without extensions, or for which the extension is not listed in
<filename>mimemap</filename></para></note>
</sect2>
<sect2>
<title>Indexing failures</title>
<para>Indexing may fail for some documents, for a number of
reasons: a helper program may be missing, the document may be
corrupt, we may fail to uncompress a file because no file
system space is available, etc.</para>
<para>The &RCL; indexer in versions 1.21 and later does not
retry failed files by default, because some indexing failures
can be quite costly (for example failing to uncompress a big
file because of insufficient disk space).
Retrying will only occur if an explicit option
(<option>-k</option>) is set on
the <command>recollindex</command> command line, or if a script
executed when <command>recollindex</command> starts up says
so. The script is defined by a configuration variable
(<literal>checkneedretryindexscript</literal>), and makes a
rather lame attempt at deciding if a helper command may have been
installed, by checking if any of the
common <filename>bin</filename> directories have changed.</para>
</sect2>
<sect2>
<title>Recovery</title>
<para>In the rare case where the index becomes corrupted (which can
signal itself by weird search results or crashes), the index files
need to be erased before restarting a clean indexing pass. Just delete
the <filename>xapiandb</filename> directory (see
<link linkend="RCL.INDEXING.STORAGE">next section</link>), or,
alternatively, start the next <command>recollindex</command> with the
<option>-z</option> option, which will reset the database before
indexing. The difference between the two methods is that the
second will not change the current index format, which may be
undesirable if a newer format is supported by the &XAP;
version.</para>
</sect2>
</sect1>
<sect1 id="RCL.INDEXING.STORAGE">
<title>Index storage</title>
<para>The default location for the index data is the
<filename>xapiandb</filename> subdirectory of the &RCL;
configuration directory, typically
<filename>$HOME/.recoll/xapiandb/</filename>. This can be
changed via two different methods (with different purposes):
<orderedlist>
<listitem><para>For a given configuration directory, you can
specify a non-default storage location for the index by setting
the <varname>dbdir</varname> parameter in the configuration file
(see the
<link linkend="RCL.INSTALL.CONFIG.RECOLLCONF">configuration section</link>).
This method would mainly be of use if you wanted
to keep the configuration directory in its default location, but
desired another location for the index, typically out of disk
occupation or performance concerns.</para>
</listitem>
<listitem><para>You can specify a different configuration
directory by setting the <envar>RECOLL_CONFDIR</envar>
environment variable, or using the <option>-c</option>
option to the &RCL; commands. This method would typically be
used to index different areas of the file system to
different indexes. For example, if you were to issue the
following command:
<programlisting>recoll -c ~/.indexes-email</programlisting> Then
&RCL; would use configuration files
stored in <filename>~/.indexes-email/</filename> and,
(unless specified otherwise in
<filename>recoll.conf</filename>) would look for
the index in
<filename>~/.indexes-email/xapiandb/</filename>.</para>
<para>Using multiple configuration directories and
<link linkend="RCL.INSTALL.CONFIG.RECOLLCONF">configuration options</link>
allows you to tailor multiple configurations and
indexes to handle whatever subset of the available data you wish
to make searchable.</para>
</listitem>
</orderedlist>
</para>
<para>The size of the index is determined by the size of the set
of documents, but the ratio can vary a lot. For a typical
mixed set of documents, the index size will often be close to
the data set size. In specific cases (a set of compressed mbox
files for example), the index can become much bigger than the
documents. It may also be much smaller if the documents
contain a lot of images or other non-indexed data (an extreme
example being a set of mp3 files where only the tags would be
indexed).</para>
<para>Of course, images, sound and video do not increase the index
size, which means that in most cases, the space used by the index
will be negligible compared to the total amount of data on the
computer.</para>
<para>The index data directory (<filename>xapiandb</filename>)
only contains data that can be completely rebuilt by an index run
(as long as the original documents exist), and it can always be
destroyed safely.</para>
<sect2 id="RCL.INDEXING.STORAGE.FORMAT">
<title>&XAP; index formats</title>
<para>&XAP; versions usually support several formats for index
storage. A given major &XAP; version will have a current format,
used to create new indexes, and will also support the format from
the previous major version.</para>
<para>&XAP; will not convert automatically an existing index from
the older format to the newer one. If you want to upgrade to the
new format, or if a very old index needs to be converted because
its format is not supported any more, you will have to explicitly
delete the old index (typically
<filename>~/.recoll/xapiandb</filename>), then run a normal
indexing command. Using <command>recollindex</command> option
<option>-z</option> would not work in this situation.</para>
</sect2>
<sect2 id="RCL.INDEXING.STORAGE.SECURITY">
<title>Security aspects</title>
<para>The &RCL; index does not hold complete copies of the indexed
documents (it almost does after version 1.24). But it does
hold enough data to allow for an almost complete reconstruction. If
confidential data is indexed, access to the database directory
should be restricted. </para>
<para>&RCL; will create the configuration directory with a mode of
0700 (access by owner only). As the index data directory is by
default a sub-directory of the configuration directory, this should
result in appropriate protection.</para>
<para>If you use another setup, you should think of the kind
of protection you need for your index, set the directory
and files access modes appropriately, and also maybe adjust
the <literal>umask</literal> used during index updates.</para>
</sect2>
<sect2 id="RCL.INDEXING.STORAGE.BIG">
<title>Special considerations for big indexes</title>
<para>This only needs concern you if your index is going to be
bigger than around 5 GBytes. Beyond 10 GBytes, it becomes a serious
issue. Most people have much smaller indexes. For reference, 5
GBytes would be around 2000 bibles, a lot of text. If you have a
huge text dataset (remember: images don't count, the text content
of PDFs is typically less than 5% of the file size), read on.</para>
<para>The amount of writing performed by Xapian during index
creation is not linear with the index size (it is somewhere between
linear and quadratic). For big indexes this becomes a performance
issue, and may even be an SSD disk wear issue.</para>
<para>The problem can be mitigated by observing the following
rules:</para>
<itemizedlist>
<listitem><para>Partition the data set and create several indexes
of reasonable size rather than a huge one. These indexes can then
be queried in parallel (using the &RCL; external indexes
facility), or merged using
<command>xapian-compact</command>.</para></listitem>
<listitem><para>Have a lot of RAM available and set the
<literal>idxflushmb</literal> &RCL; configuration parameter as
high as you can without swapping (experimentation will be
needed). 200 would be a minimum in this
context.</para></listitem>
<listitem><para>Use Xapian 1.4.10 or newer, as this version
brought a significant improvement in the amount of writes.</para>
</listitem>
</itemizedlist>
</sect2>
</sect1>
<sect1 id="RCL.INDEXING.CONFIG">
<title>Index configuration</title>
<para>Variables stored inside the
<link linkend="RCL.INSTALL.CONFIG">&RCL; configuration files</link>
control which areas of the file system are indexed, and how files
are processed. The values can be set by editing the text
files. Most of the more commonly used ones can also be adjusted by
using the <link linkend="RCL.INDEXING.CONFIG.GUI">
dialogs in the <command>recoll</command> GUI</link>.</para>
<para>The first time you start <command>recoll</command>, you will be
asked whether or not you would like it to build the index. If you
want to adjust the configuration before indexing, just click
<guilabel>Cancel</guilabel> at this point, which will get you into
the configuration interface. If you exit at this point,
<filename>recoll</filename> will have created a default configuration
directory with empty configuration files, which you can then
edit.</para>
<para>The configuration is documented inside the
<link linkend="RCL.INSTALL.CONFIG">installation chapter</link>
of this document, or in the
<ulink url="https://www.lesbonscomptes.com/recoll/manpages/recoll.conf.5.html"><citerefentry><refentrytitle>recoll.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry></ulink>
manual page. Both documents are automatically generated from
the comments inside the configuration file.</para>
<para>The most immediately useful variable
is probably
<link linkend="RCL.INSTALL.CONFIG.RECOLLCONF.TOPDIRS"><varname>topdirs</varname></link>,
which lists the subtrees and files to be indexed.</para>
<para>The applications needed to index file types other than
text, HTML or email (ie: pdf, postscript, ms-word...) are
described in the <link linkend="RCL.INSTALL.EXTERNAL">external packages section</link>.
</para>
<para>There are two incompatible types of Recoll
indexes, depending on the treatment of character case and
diacritics. A <link linkend="RCL.INDEXING.CONFIG.SENS">further
section</link> describes the two types in more detail. The default
type is appropriate in most cases.</para>
<sect2 id="RCL.INDEXING.CONFIG.MULTIPLE">
<title>Multiple indexes</title>
<para>Multiple &RCL; indexes can be created by using several
configuration directories which are typically set to index
different areas of the file system.</para>
<para>A specific index can be selected by setting the
<envar>RECOLL_CONFDIR</envar> environment variable or giving the
<option>-c</option> option to <command>recoll</command> and
<command>recollindex</command>.</para>
<para>The <command>recollindex</command> program, used for creating
or updating indexes, always works on a single index. The different
configurations are entirely independent (no parameters are ever
shared between configurations when indexing). </para>
<para>All the search interfaces (<command>recoll</command>,
<command>recollq</command>, the Python API, etc.) operate with a
main configuration, from which both configuration and index data
are used, and can also query data from multiple additional
indexes. Only the index data from the latter is used, their
configuration parameters are ignored. This implies that some
parameters should be consistent among index configurations which
are to be used together.</para>
<para>When searching, the current main index (defined by
<envar>RECOLL_CONFDIR</envar> or <option>-c</option>) is always
active. If this is undesirable, you can set up your base
configuration to index an empty directory.</para>
<para>Index configuration parameters can be set either by using a
text editor on the files, or, for most parameters, by using the
<link linkend="RCL.INDEXING.CONFIG.GUI"><command>recoll</command> index configuration GUI</link>.
In the latter case, the configuration directory for which
parameters are modified is the one which was selected by
<envar>RECOLL_CONFDIR</envar> or the <option>-c</option> parameter,
and there is no way to switch configurations within the GUI.</para>
<para>See the <link linkend="RCL.INSTALL.CONFIG.RECOLLCONF">configuration section</link>
for a detailed description of the parameters</para>
<para>Some configuration parameters must be consistent among a set
of multiple indexes used together for searches. Most importantly,
all indexes to be queried concurrently must have the same option
concerning character case and diacritics stripping, but there are
other constraints. Most of the relevant parameters affect the
<link linkend="RCL.INSTALL.CONFIG.RECOLLCONF.TERMS">term generation</link>.
</para>
<para>Using multiple configurations implies a small
level of command line or file manager usage. The user must
explicitly create additional configuration directories, the GUI
will not do it. This is to avoid mistakenly creating additional
directories when an argument is mistyped. Also, the GUI or the
indexer must be launched with a specific option or environment to
work on the right configuration.</para>
<simplesect>
<title>In practise: creating and using an additional index</title>
<para>Initially creating the configuration and index:<programlisting>
mkdir <replaceable>/path/to/my/new/config</replaceable></programlisting></para>
<para>Configuring the new index can be done from the
<command>recoll</command> GUI, launched from the
command line to pass the <literal>-c</literal> option
(you could create a desktop file to do it for you), and then using the
<link linkend="RCL.INDEXING.CONFIG.GUI">GUI index configuration tool</link>
to set up the index.
<programlisting>
recoll -c <replaceable>/path/to/my/new/config</replaceable></programlisting>
</para>
<para>Alternatively, you can just start a text editor on the main
configuration file:
<programlisting>
<replaceable>someEditor</replaceable> <replaceable>/path/to/my/new/config</replaceable>/<link linkend="RCL.INSTALL.CONFIG.RECOLLCONF"><filename>recoll.conf</filename></link>
</programlisting>
</para>
<para>Creating and updating the index can be done from the command line:
<programlisting>recollindex -c <replaceable>/path/to/my/new/config</replaceable>
</programlisting>
or from the File menu of a GUI launched with the same option
(<command>recoll</command>, see above).</para>
<para>The same GUI would also let you set up batch indexing for
the new index. Real time indexing can only be set up from the GUI
for the default index (the menu entry will be inactive if the GUI
was started with a non-default <literal>-c</literal>
option).</para>
<para>The new index can be queried alone with<programlisting>
recoll -c <replaceable>/path/to/my/new/config</replaceable></programlisting>
Or, in parallel with the default index, by starting
<command>recoll</command> without a <literal>-c</literal> option,
and using the
<menuchoice>
<guimenu>Preferences</guimenu>
<guimenuitem>External Index Dialog</guimenuitem>
</menuchoice> menu.</para>
</simplesect>
</sect2>
<sect2 id="RCL.INDEXING.CONFIG.SENS">
<title>Index case and diacritics sensitivity</title>
<para>As of &RCL; version 1.18 you have a choice of building an
index with terms stripped of character case and diacritics, or
one with raw terms. For a source term of
<literal>Résumé</literal>, the former will store
<literal>resume</literal>, the latter
<literal>Résumé</literal>.</para>
<para>Each type of index allows performing searches insensitive to
case and diacritics: with a raw index, the user entry will be
expanded to match all case and diacritics variations present in
the index. With a stripped index, the search term will be stripped
before searching.</para>
<para>A raw index allows using case and diacritics to discriminate
between terms, e.g., returning different results when searching for
<literal>US</literal> and <literal>us</literal> or
<literal>resume</literal> and <literal>résumé</literal>.
Read the
<link linkend="RCL.SEARCH.CASEDIAC">section about search case and diacritics sensitivity</link>
for more details.</para>
<para>The type of index to be created is controlled by the
<literal>indexStripChars</literal> configuration
variable which can only be changed by editing the
configuration file. Any change implies an index reset (not
automated by &RCL;), and all indexes in a search must be set
in the same way (again, not checked by &RCL;). </para>
<para>&RCL; creates a stripped index by default if
<literal>indexStripChars</literal> is not set.</para>
<para>As a cost for added capability, a raw index will be slightly
bigger than a stripped one (around 10%). Also, searches will be
more complex, so probably slightly slower, and the feature is
relatively little used, so that a certain amount of weirdness
cannot be excluded.</para>
<para>One of the most adverse consequence of using a raw index
is that some phrase and proximity searches may become
impossible: because each term needs to be expanded, and all
combinations searched for, the multiplicative expansion may
become unmanageable.</para>
</sect2>
<sect2 id="RCL.INDEXING.CONFIG.THREADS">
<title>Indexing threads configuration (&LIN;)</title>
<para>The &RCL; indexing process
<command>recollindex</command> can use multiple threads to
speed up indexing on multiprocessor systems. The work done
to index files is divided in several stages and some of the
stages can be executed by multiple threads. The stages are:
<orderedlist>
<listitem><para>File system walking: this is always performed by
the main thread.</para></listitem>
<listitem><para>File conversion and data
extraction.</para></listitem>
<listitem><para>Text processing (splitting, stemming,
etc.).</para></listitem>
<listitem><para>&XAP; index update.</para></listitem>
</orderedlist>
</para>
<para>You can also read a
<ulink url="http://www.recoll.org/pages/idxthreads/threadingRecoll.html">
longer document</ulink> about the transformation of
&RCL; indexing to multithreading.</para>
<para>The threads configuration is controlled by two
configuration file parameters.</para>
<variablelist>
<varlistentry><term><varname>thrQSizes</varname></term>
<listitem><para>This variable defines the job input queues
configuration. There are three possible queues for stages
2, 3 and 4, and this parameter should give the queue depth
for each stage (three integer values). If a value of -1 is
used for a given stage, no queue is used, and the thread
will go on performing the next stage. In practise, deep
queues have not been shown to increase performance. A value
of 0 for the first queue tells &RCL; to perform
autoconfiguration (no need for anything else in this case,
thrTCounts is not used) - this is the default
configuration.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>thrTCounts</varname></term>
<listitem><para>This defines the number of threads used
for each stage. If a value of -1 is used for one of
the queue depths, the corresponding thread count is
ignored. It makes no sense to use a value other than 1
for the last stage because updating the &XAP; index is
necessarily single-threaded (and protected by a
mutex).</para>
</listitem>
</varlistentry>
</variablelist>
<note><para>If the first value in <varname>thrQSizes</varname> is
0, <varname>thrTCounts</varname> is ignored.</para></note>
<para>The following example would use three queues (of depth 2),
and 4 threads for converting source documents, 2 for
processing their text, and one to update the index. This was
tested to be the best configuration on the test system
(quadri-processor with multiple disks).
<programlisting>
thrQSizes = 2 2 2
thrTCounts = 4 2 1
</programlisting>
</para>
<para>The following example would use a single queue, and the
complete processing for each document would be performed by
a single thread (several documents will still be processed
in parallel in most cases). The threads will use mutual
exclusion when entering the index update stage. In practise
the performance would be close to the precedent case in
general, but worse in certain cases (e.g. a Zip archive
would be performed purely sequentially), so the previous
approach is preferred. YMMV... The 2 last values for
thrTCounts are ignored.
<programlisting>
thrQSizes = 2 -1 -1
thrTCounts = 6 1 1
</programlisting>
</para>
<para>The following example would disable
multithreading. Indexing will be performed by a single
thread.
<programlisting>
thrQSizes = -1 -1 -1
</programlisting>
</para>
</sect2>
<sect2 id="RCL.INDEXING.CONFIG.GUI">
<title>The index configuration GUI</title>
<para>Most parameters for a given index configuration can
be set from a <command>recoll</command> GUI running on this
configuration (either as default, or by setting
<envar>RECOLL_CONFDIR</envar> or the <option>-c</option>
option.)</para>
<para>The interface is started from the
<menuchoice>
<guimenu>Preferences</guimenu>
<guimenuitem>Index Configuration</guimenuitem>
</menuchoice>
menu entry. It is divided in four tabs,
<guilabel>Global parameters</guilabel>, <guilabel>Local
parameters</guilabel>, <guilabel>Web history</guilabel>
(which is explained in the next section) and <guilabel>Search
parameters</guilabel>.</para>
<para>The <guilabel>Global parameters</guilabel> tab allows setting
global variables, like the lists of top directories, skipped paths,
or stemming languages.</para>
<para>The <guilabel>Local parameters</guilabel> tab allows setting
variables that can be redefined for subdirectories. This second tab
has an initially empty list of customisation directories, to which
you can add. The variables are then set for the currently selected
directory (or at the top level if the empty line is
selected).</para>
<para>The <guilabel>Search parameters</guilabel> section defines
parameters which are used at query time, but are global to an
index and affect all search tools, not only the GUI.</para>
<para>The meaning for most entries in the interface is
self-evident and documented by a <literal>ToolTip</literal>
popup on the text label. For more detail, you will need to
refer to the
<link linkend="RCL.INSTALL.CONFIG">configuration section</link>
of this guide.</para>
<para>The configuration tool normally respects the comments
and most of the formatting inside the configuration file, so
that it is quite possible to use it on hand-edited files,
which you might nevertheless want to backup first...</para>
</sect2>
</sect1>
<sect1 id="RCL.INDEXING.REMOVABLE">
<title>Removable volumes</title>
<para>&RCL; used to have no support for indexing removable volumes
(portable disks, USB keys, etc.). Recent versions have improved the
situation and support indexing removable volumes in two different
ways:</para>
<itemizedlist>
<listitem><para>By indexing the volume in the main, fixed, index, and
ensuring that the volume data is not purged if the indexing runs
while the volume is mounted. (since &RCL; 1.25.2).</para></listitem>
<listitem><para>By storing a volume index on the volume
itself (since &RCL; 1.24).</para></listitem>
</itemizedlist>
<simplesect id="RCL.INDEXING.REMOVABLE.MAIN">
<title>Indexing removable volumes in the main index</title>
<para>As of version 1.25.2, &RCL; provides a simple way to ensure
that the index data for an absent volume will not be purged. Two
conditions must be met:
<itemizedlist>
<listitem><para>The volume mount
point must be a member of the <literal>topdirs</literal>
list.</para></listitem>
<listitem><para>The mount directory must be empty (when the volume
is not mounted).</para></listitem>
</itemizedlist>
</para>
<para>If <command>recollindex</command> finds that one of the
<literal>topdirs</literal> is empty when starting up, any existing
data for the tree will be preserved by the indexing
pass (no purge for this area).</para>
</simplesect>
<simplesect id="RCL.INDEXING.REMOVABLE.SELF">
<title>Self contained volumes</title>
<para>As of &RCL; 1.24, it has become possible to build
self-contained datasets including a &RCL; configuration directory and
index together with the indexed documents, and to move such a dataset
around (for example copying it to an USB drive), without having to
adjust the configuration for querying the index.</para>
<note><para>This is a query-time feature only. The index must only be
updated in its original location. If an update is necessary in a
different location, the index must be reset.</para></note>
<para>The principle of operation is that the configuration stores the
location of the original configuration directory, which must reside
on the movable volume. If the volume is later mounted elsewhere,
&RCL; adjusts the paths stored inside the index by the difference
between the original and current locations of the configuration
directory.</para>
<para>To make a long story short, here follows a script to create a
&RCL; configuration and index under a given directory (given as single
parameter). The resulting data set (files + recoll directory) can later
to be moved to a CDROM or thumb drive. Longer explanations come after
the script.</para>
<programlisting>#!/bin/sh
fatal()
{
echo $*;exit 1
}
usage()
{
fatal "Usage: init-recoll-volume.sh &lt;top-directory>"
}
test $# = 1 || usage
topdir=$1
test -d "$topdir" || fatal $topdir should be a directory
confdir="$topdir/recoll-config"
test ! -d "$confdir" || fatal $confdir should not exist
mkdir "$confdir"
cd "$topdir"
topdir=`pwd`
cd "$confdir"
confdir=`pwd`
(echo topdirs = '"'$topdir'"'; \
echo orgidxconfdir = $topdir/recoll-config) > "$confdir/recoll.conf"
recollindex -c "$confdir"
</programlisting>
<para>The examples below will assume that you have a dataset under
<filename>/home/me/mydata/</filename>, with the index configuration and
data stored inside
<filename>/home/me/mydata/recoll-confdir</filename>.</para>
<para>In order to be able to run queries after the dataset has been
moved, you must ensure the following:
<itemizedlist>
<listitem><para>The main configuration file must define the
<link linkend="RCL.INSTALL.CONFIG.RECOLLCONF.ORGIDXCONFDIR">orgidxconfdir</link>
variable to be the original location of the configuration directory
(<filename>orgidxconfdir=/home/me/mydata/recoll-confdir</filename>
must be set inside
<filename>/home/me/mydata/recoll-confdir/recoll.conf</filename> in
the example above).</para></listitem>
<listitem><para>The configuration directory must exist with the
documents, somewhere under the directory which will be
moved. E.g. if you are moving <filename>/home/me/mydata</filename>
around, the configuration directory must exist somewhere below this
point, for example
<filename>/home/me/mydata/recoll-confdir</filename>, or
<filename>/home/me/mydata/sub/recoll-confdir</filename>.</para></listitem>
<listitem><para>You should keep the default locations for the index
elements which are relative to the configuration directory by
default (principally <literal>dbdir</literal>). Only the paths
referring to the documents themselves
(e.g. <literal>topdirs</literal> values) should be absolute (in
general, they are only used when indexing anyway).</para></listitem>
</itemizedlist>
</para>
<para>Only the first point needs an explicit user action, the &RCL;
defaults are compatible with the third one, and the second is
natural.</para>
<para>If, after the move, the configuration directory needs to be
copied out of the dataset (for example because the thumb drive is too
slow), you can set the
<link linkend="RCL.INSTALL.CONFIG.RECOLLCONF.CURIDXCONFDIR">curidxconfdir</link>,
variable inside the copied configuration to
define the location of the moved one. For example if
<filename>/home/me/mydata</filename> is now mounted onto
<filename>/media/me/somelabel</filename>, but the configuration
directory and index has been copied to
<filename>/tmp/tempconfig</filename>, you would set
<literal>curidxconfdir</literal> to
<filename>/media/me/somelabel/recoll-confdir</filename> inside
<filename>/tmp/tempconfig/recoll.conf</filename>.
<literal>orgidxconfdir</literal> would still be
<filename>/home/me/mydata/recoll-confdir</filename> in the original and
the copy.</para>
<para>If you are regularly copying the configuration out of the
dataset, it will be useful to write a script to automate the
procedure. This can't really be done inside &RCL; because there are
probably many possible variants. One example would be to copy the
configuration to make it writable, but keep the index data on the
medium because it is too big - in this case, the script would also need
to set <literal>dbdir</literal> in the copied configuration.</para>
<para>The same set of modifications (&RCL; 1.24) has also made it
possible to run queries from a readonly configuration directory (with
slightly reduced function of course, such as not recording the query
history).</para>
</simplesect>
</sect1>
<sect1 id="RCL.INDEXING.WebQUEUE">
<title>&LIN;: indexing visited Web pages</title>
<para>With the help of a <application>Firefox</application>
extension, &RCL; can index the Internet pages that you visit. The
extension has a long history: it was initially designed for
the <application>Beagle</application> indexer, then adapted to
&RCL; and
the <application>Firefox</application> <application>XUL</application>
API. The current version of the extension is located in
the <ulink url="https://addons.mozilla.org/en-US/firefox/addon/recoll-we/">Mozilla
add-ons repository</ulink> uses
the <application>WebExtensions</application> API, and works with
current <application>Firefox</application> versions.</para>
<para>The extension works by copying visited Web pages to an indexing
queue directory, which &RCL; then processes, storing the data into a
local cache, then indexing it, then removing the file from the
queue.</para>
<note><title>The local cache is not an archive</title><para>As
mentioned above, a copy of the indexed Web pages is retained by
Recoll in a local cache (from which data is fetched for previews,
or when resetting the index). The cache is not changed by an
index reset, just read for indexing. The cache has a maximum
size, which can be adjusted from the <guilabel>Index
configuration</guilabel> / <guilabel>Web history</guilabel> panel
(<literal>webcachemaxmbs</literal> parameter
in <filename>recoll.conf</filename>). Once the maximum size is
reached, old pages are erased to make room for new ones. The
pages which you want to keep indefinitely need to be explicitly
archived elsewhere. Using a very high value for the cache size
can avoid data erasure, but see the above 'Howto' page for more
details and gotchas.</para></note>
<para>The visited Web pages indexing feature can be enabled on the
&RCL; side from the GUI <guilabel>Index configuration</guilabel>
panel, or by editing the configuration file (set
<varname>processwebqueue</varname> to 1).</para>
<para>The &RCL; GUI has a tool to list and edit the contents of the
Web cache. (<menuchoice><guimenu>Tools</guimenu><guimenuitem>Webcache
editor</guimenuitem></menuchoice>)</para>
<para>The <command>recollindex</command> command has two options to
help manage the Web cache:</para>
<itemizedlist>
<listitem><option>--webcache-compact</option> will recover
the space from erased entries. It may need to use twice the disk space
currently needed for the Web cache.</listitem>
<listitem><option>--webcache-burst <replaceable>destdir</replaceable></option>
will extract all current entries into pairs of metadata and data
files created
inside <replaceable>destdir</replaceable></listitem>
</itemizedlist>
<para>You can find more details on Web indexing, its usage and configuration
in a <ulink url="&FAQS;IndexWebHistory">Recoll 'Howto'
entry</ulink>.</para>
</sect1>
<sect1 id="RCL.INDEXING.EXTATTR">
<title>&LIN;: using extended attributes</title>
<para>User extended attributes are named pieces of information
that most modern file systems can attach to any file.</para>
<para>&RCL; processes extended attributes as document fields by
default.</para>
<para>A
<ulink url="http://www.freedesktop.org/wiki/CommonExtendedAttributes">
freedesktop standard</ulink> defines a few special
attributes, which are handled as such by &RCL;:
<variablelist>
<varlistentry>
<term>mime_type</term>
<listitem><para>If set, this overrides any other
determination of the file MIME type.</para></listitem>
</varlistentry>
<varlistentry>
<term>charset</term>
<listitem><para>If set, this defines the file character set
(mostly useful for plain text files).</para></listitem>
</varlistentry>
</variablelist>
</para>
<para>By default, other attributes are handled as &RCL; fields of the
same name.</para>
<para>On Linux, the <literal>user</literal> prefix is removed from
the name.</para>
<para>The name translation can be configured more precisely inside the
<link linkend="RCL.INSTALL.CONFIG.FIELDS"><filename>fields</filename> configuration file</link>.
</para>
</sect1>
<sect1 id="RCL.INDEXING.EXTTAGS">
<title>&LIN;: importing external tags</title>
<para>During indexing, it is possible to import metadata for each
file by executing commands. This allows, for example, extracting tag
data from an external application and storing it in a field for
indexing.</para>
<para>See the
<link linkend="RCL.INSTALL.CONFIG.RECOLLCONF.METADATACMDS">section about the <literal>metadatacmds</literal> field</link>
in the main configuration chapter for a description of the
configuration syntax.</para>
<para>For example, if you would want &RCL; to use tags managed by
<application>tmsu</application> in a field named
<replaceable>tags</replaceable>, you would add the following to the
configuration file:</para>
<programlisting>[/some/area/of/the/fs]
metadatacmds = ; <replaceable>tags</replaceable> = tmsu tags %f
</programlisting>
<note><para>Depending on the <application>tmsu</application> version,
you may need/want to add options like
<literal>--database=/some/db</literal>.</para></note>
<para>You may want to restrict this processing to a subset of
the directory tree, because it may slow down indexing a bit
(<literal>[some/area/of/the/fs]</literal>).</para>
<para>Note the initial semi-colon after the equal sign.</para>
<para>In the example above, the output of <command>tmsu</command> is
used to set a field named <replaceable>tags</replaceable>. The field
name is arbitrary and could be <replaceable>tmsu</replaceable> or
<replaceable>myfield</replaceable> just the same, but
<replaceable>tags</replaceable> is an alias for the standard &RCL;
<literal>keywords</literal> field, and the <command>tmsu</command>
output will just augment its contents. This will avoid the need to
extend the <link linkend="RCL.PROGRAM.FIELDS">field
configuration</link>.</para>
<para>Once re-indexing is performed (you will need to force the file
reindexing, &RCL; will not detect the need by itself), you will be
able to search from the query language, through any of its aliases:
<replaceable>tags:some/alternate/values</replaceable> or
<replaceable>tags:all,these,values</replaceable> (the compact field search
syntax is supported for recoll 1.20 and later. For older versions,
you would need to repeat the <replaceable>tags:</replaceable>
specifier for each term, e.g. <replaceable>tags:some</replaceable>
<literal>OR</literal>
<replaceable>tags:alternate</replaceable>).</para>
<para>Tags changes will not be detected by
the indexer if the file itself did not change. One possible
workaround would be to update the file <literal>ctime</literal> when
you modify the tags, which
would be consistent with how extended attributes function. A pair of
<command>chmod</command> commands could accomplish this, or a
<literal>touch -a</literal> . Alternatively, just
couple the tag update with a
<literal>recollindex -e -i</literal> <replaceable>/path/to/the/file</replaceable>.</para>
</sect1>
<sect1 id="RCL.INDEXING.PDF">
<title>The PDF input handler</title>
<para>The PDF format is very important for scientific and technical
documentation, and document archival. It has extensive
facilities for storing metadata along with the document, and these
facilities are actually used in the real world.</para>
<para>In consequence, the <command>rclpdf.py</command> PDF input
handler has more complex capabilities than most others, and it is
also more configurable. Specifically, <command>rclpdf.py</command>
has the following features:
<itemizedlist>
<listitem><para>It can be configured to extract
specific metadata tags from an XMP packet.</para></listitem>
<listitem><para>It can extract PDF
attachments.</para></listitem>
<listitem><para>It can automatically perform
OCR if the document text is empty. This is done by
executing an external program and is now described in a
<link linkend="RCL.INDEXING.OCR">separate
section</link>, because the OCR framework can also be used
with non-PDF image files.</para></listitem>
</itemizedlist>
</para>
<sect2 id="RCL.INDEXING.PDF.XMP">
<title>XMP fields extraction</title>
<para>The <filename>rclpdf.py</filename> script in &RCL; version
1.23.2 and later can extract XMP metadata fields by executing the
<command>pdfinfo</command> command (usually found with
<application>poppler-utils</application>). This is controlled by
the
<link linkend="RCL.INSTALL.CONFIG.RECOLLCONF.PDFEXTRAMETA">pdfextrameta</link>
configuration variable, which specifies which tags to extract and,
possibly, how to rename them.</para>
<para>The
<link linkend="RCL.INSTALL.CONFIG.RECOLLCONF.PDFEXTRAMETAFIX">pdfextrametafix</link>
variable can be used to designate a file with Python code to edit
the metadata fields (available for &RCL; 1.23.3 and later. 1.23.2
has equivalent code inside the handler script). Example:</para>
<programlisting>import sys
import re
class MetaFixer(object):
def __init__(self):
pass
def metafix(self, nm, txt):
if nm == 'bibtex:pages':
txt = re.sub(r'--', '-', txt)
elif nm == 'someothername':
# do something else
pass
elif nm == 'stillanother':
# etc.
pass
return txt
def wrapup(self, metaheaders):
pass
</programlisting>
<para>If the 'metafix()' method is defined, it is called for each
metadata field. A new MetaFixer object is created for each PDF
document (so the object can keep state for, for example,
eliminating duplicate values). If the 'wrapup()' method is defined, it
is called at the end of XMP fields processing with the whole
metadata as parameter, as an array of '(nm, val)' pairs, allowing
an alternate approach for editing or adding/deleting fields.</para>
<!-- <para> There is a <ulink url="&FAQS;PDFXMP.wiki">complete example of XMP
tags setup</ulink>, including a nice result list paragraph format in the
&RCL; Wiki </para> -->
</sect2>
<sect2 id="RCL.INDEXING.PDF.ATTACH">
<title>PDF attachment indexing</title>
<para>If <application>pdftk</application> is installed, and if the
the
<link linkend="RCL.INSTALL.CONFIG.RECOLLCONF.PDFATTACH">pdfattach</link>
configuration variable is set, the PDF input handler will try to
extract PDF attachments for indexing as sub-documents of the PDF
file. This is disabled by default, because it slows down PDF
indexing a bit even if not one attachment is ever found (PDF
attachments are uncommon in my experience).</para>
</sect2>
</sect1>
<sect1 id="RCL.INDEXING.OCR">
<title>Recoll and OCR</title>
<para>This is new in &RCL; 1.26.5. Older versions had a more limited,
non-caching capability to execute an external OCR program in the PDF
handler. The new function has the following features:
<itemizedlist>
<listitem><para>The OCR output is cached, stored as separate
files. The caching is ultimately based on a hash value of the
original file contents, so that it is immune to file renames. A
first path-based layer ensures fast operation for unchanged
(unmoved files), and the data hash (which is still orders of
magnitude faster than OCR) is only re-computed if the file has
moved. OCR is only performed if the file was not previously
processed or if it changed.</para></listitem>
<listitem><para>The support for a specific program is implemented
in a simple Python module. It should be straightforward to add
support for any OCR engine with a capability to run from the
command line.</para></listitem>
<listitem><para>Modules initially exist for
<application>tesseract</application> (Linux and Windows), and
<application>ABBYY FineReader</application> (Linux, tested with
version 11). ABBYY FineReader is a commercial closed source
program, but it sometimes perform better than
tesseract.</para></listitem>
<listitem><para>The OCR is currently only called from the PDF
handler, but there should be no problem using it for other image
types.</para></listitem>
</itemizedlist>
</para>
<para>To enable this feature, you need to install one of
the supported OCR applications
(<application>tesseract</application>
or <application>ABBYY</application>), enable OCR in the PDF
handler, and tell &RCL; where the appropriate command resides. The
last parts are done by setting configuration variables. See the
<link linkend="RCL.INSTALL.CONFIG.RECOLLCONF.OCR">
relevant section</link>. All parameters can be localized in
subdirectories through the usual main configuration mechanism (path
sections).</para>
</sect1>
<sect1 id="RCL.INDEXING.PERIODIC">
<title>Periodic indexing</title>
<simplesect id="RCL.INDEXING.PERIODIC.EXEC">
<title>Running the indexer</title>
<para>The <command>recollindex</command> program performs index
updates. You can start it either from the command line or from the
<guimenu>File</guimenu> menu in the <command>recoll</command> GUI
program. When started from the GUI, the indexing will run on the
same configuration <command>recoll</command> was started on. When
started from the command line, <command>recollindex</command> will
use the <envar>RECOLL_CONFDIR</envar> variable or accept a
<option>-c</option> <replaceable>confdir</replaceable> option to
specify a non-default configuration directory.</para>
<para>If the <command>recoll</command> program finds no index
when it starts, it will automatically start indexing (except
if canceled).</para>
<para>The GUI <menuchoice><guimenu>File</guimenu> </menuchoice>
menu has entries to start or stop the current indexing
operation. When indexing is not currently running, you have a
choice between <guimenuitem>Update
Index</guimenuitem> or <guimenuitem>Rebuild Index</guimenuitem>.
The first choice only processes changed files, the second one
erases the index before starting so that all files are
processed.</para>
<para>On Linux and Windows, the GUI can be used to manage the indexing
operation. Stopping the indexer can be done
from the <command>recoll</command> GUI
<menuchoice>
<guimenu>File</guimenu>
<guimenuitem>Stop Indexing</guimenuitem>
</menuchoice>
menu entry.
</para>
<para>On Linux, the <command>recollindex</command> indexing process
can be interrupted by sending an interrupt
(<keysym>Ctrl-C</keysym>, SIGINT) or terminate (SIGTERM)
signal.
</para>
<para>When stopped, some time may elapse before
<command>recollindex</command> exits, because it needs to properly
flush and close the index.</para>
<para>After an interruption, the index will be somewhat
inconsistent because some operations which are normally
performed at the end of the indexing pass will have been
skipped (for example, the stemming and spelling databases
will be inexistent or out of date). You just need to restart
indexing at a later time to restore consistency. The
indexing will restart at the interruption point (the full
file tree will be traversed, but files that were indexed up
to the interruption and for which the index is still up to
date will not need to be reindexed).</para>
</simplesect>
<simplesect id="RCL.INDEXING.PERIODIC.CMDLINE">
<title>recollindex command line</title>
<para><command>recollindex</command> has many options
which are listed in its
<ulink url="https://www.lesbonscomptes.com/recoll/manpages/recollindex.1.html">manual page</ulink>.
Only a few will be described here.</para>
<para>Option <option>-z</option> will reset the index when
starting. This is almost the same as destroying the index
files (the nuance is that the &XAP; format version will not
be changed).</para>
<para>Option <option>-Z</option> will force the update of all
documents without resetting the index first. This will not
have the "clean start" aspect of <option>-z</option>, but
the advantage is that the index will remain available for
querying while it is rebuilt, which can be a significant
advantage if it is very big (some installations need days
for a full index rebuild).</para>
<para>Option <option>-k</option> will force retrying files
which previously failed to be indexed, for example because
of a missing helper program.</para>
<para>Of special interest also, maybe, are
the <option>-i</option> and <option>-f</option>
options. <option>-i</option> allows indexing an explicit
list of files (given as command line parameters or read on
<literal>stdin</literal>). <option>-f</option> tells
<command>recollindex</command> to ignore file selection
parameters from the configuration. Together, these options
allow building a custom file selection process for some area
of the file system, by adding the top directory to the
<varname>skippedPaths</varname> list and using an
appropriate file selection method to build the file list to
be fed to <command>recollindex</command>
<option>-if</option>. Trivial example:</para>
<programlisting>
find . -name indexable.txt -print | recollindex -if
</programlisting>
<para><command>recollindex</command> <option>-i</option> will
not descend into subdirectories specified as parameters,
but just add them as index entries. It is
up to the external file selection method to build the complete
file list.</para>
</simplesect>
<simplesect id="RCL.INDEXING.PERIODIC.AUTOMAT">
<title>Linux: using <command>cron</command> to automate indexing</title>
<para>The most common way to set up indexing is to have a cron
task execute it every night. For example the following
<filename>crontab</filename> entry would do it every day at
3:30AM (supposing <command>recollindex</command> is in your
PATH):
<screen><![CDATA[
30 3 * * * recollindex > /some/tmp/dir/recolltrace 2>&1
]]></screen>
Or, using <command>anacron</command>:
<screen><![CDATA[
1 15 su mylogin -c "recollindex recollindex > /tmp/rcltraceme 2>&1"
]]></screen>
</para>
<para>The &RCL; GUI has dialogs to manage
<filename>crontab</filename> entries for
<command>recollindex</command>. You can reach them from the
<menuchoice>
<guimenu>Preferences</guimenu>
<guimenuitem>Indexing Schedule</guimenuitem>
</menuchoice>
menu. They only
work with the good old <command>cron</command>, and do not give
access to all features of <command>cron</command>
scheduling. Entries created via the tool are marked with
a <literal>RCLCRON_RCLINDEX=</literal> marker so that the tool
knows which entries belong to it. As a side effect, this sets an
environment variable for the process, but it's not actually used,
this is just a marker.</para>
<para>The usual command to edit your
<filename>crontab</filename> is <command>crontab</command>
<option>-e</option> (which will usually start the
<command>vi</command> editor to edit the file). You may have
more sophisticated tools available on your system.</para>
<para>Please be aware that there may be differences between your
usual interactive command line environment and the one seen by
crontab commands. Especially the PATH variable may be of
concern. Please check the crontab manual pages about possible
issues.</para>
</simplesect>
</sect1>
<sect1 id="RCL.INDEXING.MONITOR">
<title>&LIN;: real time indexing</title>
<para>Real time monitoring/indexing is performed by starting the
<command>recollindex</command> <option>-m</option> command.
With this option, <command>recollindex</command> will detach
from the terminal and become a daemon, permanently monitoring
file changes and updating the index.</para>
<para>In this situation, the <command>recoll</command>
GUI <menuchoice><guimenu>File</guimenu></menuchoice> menu makes two
operations available: <guimenuitem>Stop</guimenuitem>
and <guimenuitem>Trigger incremental pass</guimenuitem>.
</para>
<para><guimenuitem>Trigger incremental pass</guimenuitem> has the
same effect as restarting the indexer, and will cause a complete
walk of the indexed area, processing the changed files, then switch
to monitoring. This is only marginally useful, maybe in cases where
the indexer is configured to delay updates, or to force an
immediate rebuild of the stemming and phonetic data, which are only
processed at intervals by the real time indexer.</para>
<para>While it is convenient that data is indexed in real time,
repeated indexing can generate a significant load on the
system when files such as email folders change. Also,
monitoring large file trees by itself significantly taxes
system resources. You probably do not want to enable it if
your system is short on resources. Periodic indexing is
adequate in most cases.</para>
<para>As of &RCL; 1.24, you can set the
<link linkend="RCL.INSTALL.CONFIG.RECOLLCONF.MONITORDIRS">monitordirs</link>
configuration variable to specify that only a subset of your indexed
files will be monitored for instant indexing. In this situation, an
incremental pass on the full tree can be triggered by either
restarting the indexer, or just running
<command>recollindex</command>, which will notify the running
process. The <command>recoll</command> GUI also has a menu entry for
this.</para>
<simplesect id="RCL.INDEXING.MONITOR.START.SYSTEMD">
<title>Automatic daemon start with systemd</title>
<para>The installation contains two example files
(in <filename>share/recoll/examples</filename>) for starting the indexing daemon with
<application>systemd</application>.</para>
<para><filename>recollindex-user.service</filename> would be used for
starting <command>recollindex</command> as a user service, and can be installed with the
following commands:
<programlisting>systemctl --user link /usr/share/recoll/examples/recollindex-user.service
systemctl --user enable --now recollindex-user.service</programlisting>
The indexer will start when the user logs in and run while there is a session open for
them.</para>
<para><filename>recollindex-system.service</filename> would be used for starting the indexer
at boot time, running as a specific user. It can be useful when running the text search as a
shared service (e.g. when users access it through the WEB UI). You will need to edit it to
replace the @SOMEUSER@ value with something which makes sense in your case, then install it
as a regular <application>systemd</application> system service. Of course, if you want to
run several such units, you will also need to rename the installed file.</para>
</simplesect>
<simplesect id="RCL.INDEXING.MONITOR.START">
<title>Automatic daemon start from the desktop session</title>
<para>Under <application>KDE</application>,
<application>Gnome</application> and some other desktop
environments, the daemon can automatically started when you log
in, by creating a desktop file inside the
<filename>~/.config/autostart</filename> directory. This can be
done for you by the &RCL; GUI. Use the
<guimenu>Preferences->Indexing Schedule</guimenu> menu.</para>
<para>With older <application>X11</application> setups, starting
the daemon is normally performed as part of the user session
script.</para>
<para>The <filename>rclmon.sh</filename> script can be used to
easily start and stop the daemon. It can be found in the
<filename>examples</filename> directory (typically
<filename>/usr/local/[share/]recoll/examples</filename>).</para>
<para>For example, a good old <application>xdm</application>-based
session could have a <filename>.xsession</filename> script with the
following lines at the end:</para>
<programlisting>recollconf=$HOME/.recoll-home
recolldata=/usr/local/share/recoll
RECOLL_CONFDIR=$recollconf $recolldata/examples/rclmon.sh start
fvwm
</programlisting>
<para>The indexing daemon gets started, then the window manager,
for which the session waits.</para> <para>By default the
indexing daemon will monitor the state of the X11 session, and
exit when it finishes, it is not necessary to kill it
explicitly. (The <application>X11</application> server
monitoring can be disabled with option <option>-x</option> to
<command>recollindex</command>).</para>
<para>If you use the daemon completely out of an
<application>X11</application> session, you need to add option
<option>-x</option> to disable <application>X11</application>
session monitoring (else the daemon will not start).</para>
</simplesect>
<simplesect id="RCL.INDEXING.MONITOR.DETAILS">
<title>Miscellaneous details</title>
<para>By default, the messages from the indexing daemon will be
sent to the same file as those from the interactive commands
(<literal>logfilename</literal>). You may want to change this
by setting the <varname>daemlogfilename</varname> and
<varname>daemloglevel</varname> configuration parameters. Also
the log file will only be truncated when the daemon starts. If
the daemon runs permanently, the log file may grow quite big,
depending on the log level.</para>
<formalpara><title>Increasing resources for inotify</title>
<para>On Linux systems, monitoring a big tree may need
increasing the resources available to inotify, which are
normally defined in <filename>/etc/sysctl.conf</filename>.
<programlisting>
### inotify
#
# cat /proc/sys/fs/inotify/max_queued_events - 16384
# cat /proc/sys/fs/inotify/max_user_instances - 128
# cat /proc/sys/fs/inotify/max_user_watches - 16384
#
# -- Change to:
#
fs.inotify.max_queued_events=32768
fs.inotify.max_user_instances=256
fs.inotify.max_user_watches=32768
</programlisting>
Especially, you will need to trim your tree or adjust
the <literal>max_user_watches</literal> value if indexing exits with
a message about errno <literal>ENOSPC</literal> (28) from
<function>inotify_add_watch</function>.
</para>
</formalpara>
<formalpara><title>Slowing down the reindexing rate for fast changing
files</title>
<para>When using the real time monitor, it may happen that some
files need to be indexed, but change so often that they impose an
excessive load for the system.
&RCL; provides a configuration option to specify the minimum
time before which a file, specified by a wildcard pattern, cannot be
reindexed. See the <varname>mondelaypatterns</varname> parameter in
the <link linkend="RCL.INSTALL.CONFIG.RECOLLCONF.MISC">configuration section</link>.
</para>
</formalpara>
</simplesect>
</sect1>
</chapter>
<chapter id="RCL.SEARCH">
<title>Searching</title>
<sect1 id="RCL.SEARCH.INTRODUCTION">
<title>Introduction</title>
<para>Getting answers to specific queries is of course the whole
point of &RCL;. The multiple provided interfaces always understand
simple queries made of one or several words, and return appropriate
results in most cases.</para>
<para>In order to make the most of &RCL; though, it may be worthwhile
to understand how it processes your input. Five different modes
exist:
<itemizedlist>
<listitem><para>In <literal>All Terms</literal> mode, &RCL; looks
for documents containing all your input terms.</para></listitem>
<listitem><para><literal>Query Language</literal> mode behaves like
<literal>All Terms</literal> in the absence of special input, but
it can also do much more. This is the best mode for getting the
most of &RCL;.</para></listitem>
<listitem><para>In <literal>Any Term</literal> mode, &RCL; looks
for documents containing any your input terms, preferring those
which contain more.</para></listitem>
<listitem><para>In <literal>File Name</literal> mode, &RCL; will
only match file names, not content. Using a small subset of the
index allows things like left-hand wildcards without performance
issues, and may sometimes be useful.</para></listitem>
<listitem><para>The GUI <literal>Advanced Search</literal> mode is
actually not more powerful than the query language, but it helps
you build complex queries without having to remember the language,
and avoids any interpretation ambiguity, as it bypasses the user
input parser.</para></listitem>
</itemizedlist>
</para>
<para>These five input modes are supported by the different user
interfaces which are described in the following sections.</para>
</sect1>
<sect1 id="RCL.SEARCH.GUI">
<title>Searching with the Qt graphical user interface</title>
<para>The <command>recoll</command> program provides the main user
interface for searching. It is based on the
<application>Qt</application> library.</para>
<para><command>recoll</command> has two search interfaces:</para>
<itemizedlist>
<listitem><para>Simple search (the default, on the main screen) has
a single entry field where you can enter multiple words.</para>
</listitem>
<listitem><para>Advanced search (a panel accessed through the
<guilabel>Tools</guilabel> menu or the toolbox bar icon) has
multiple entry fields, which you may use to build a logical
condition, with additional filtering on file type, location
in the file system, modification date, and size.</para>
</listitem>
</itemizedlist>
<para>In most cases, you can enter the terms as you think them, even
if they contain embedded punctuation or other non-textual characters
(e.g. &RCL; can handle things like email addresses).</para>
<para>The main case where you should enter text differently from
how it is printed is for east-asian languages (Chinese,
Japanese, Korean). Words composed of single or multiple
characters should be entered separated by white space in this
case (they would typically be printed without white
space).</para>
<para>Some searches can be quite complex, and you may want to re-use
them later, perhaps with some tweaking. &RCL; can save and restore
searches. See <link linkend="RCL.SEARCH.SAVING">Saving and restoring
queries</link>.
</para>
<sect2 id="RCL.SEARCH.GUI.SIMPLE">
<title>Simple search</title>
<procedure>
<step><para>Start the <command>recoll</command> program.</para>
</step>
<step><para>Possibly choose a search mode: <guilabel>Any
term</guilabel>, <guilabel>All terms</guilabel>,
<guilabel>File name</guilabel> or
<guilabel>Query language</guilabel>.</para>
</step>
<step><para>Enter search term(s) in the text field at the top of the
window.</para>
</step>
<step><para>Click the <guilabel>Search</guilabel> button or
hit the <keycap>Enter</keycap> key to start the search.</para>
</step>
</procedure>
<para>The initial default search mode is <guilabel>Query
language</guilabel>. Without special directives, this will look for
documents containing all of the search terms (the ones with more
terms will get better scores), just like the <guilabel>All
terms</guilabel> mode. <guilabel>Any term</guilabel> will search
for documents where at least one of the terms
appear. <guilabel>File name</guilabel> will exclusively look for
file names, not contents</para>
<para>All search modes allow terms to be expanded with wildcards
characters (<literal>*</literal>, <literal>?</literal>,
<literal>[]</literal>). See the
<link linkend="RCL.SEARCH.WILDCARDS">section about wildcards</link> for
more details.</para>
<para>In all modes except <guilabel>File name</guilabel>, you can
search for exact phrases (adjacent words in a given order) by
enclosing the input inside double quotes. Ex:
<literal>"virtual reality"</literal>.</para>
<para>The <guilabel>Query Language</guilabel> features are
described in
<link linkend="RCL.SEARCH.LANG">a separate section</link>.
</para>
<para>When using a stripped index (the default), character case has
no influence on search, except that you can disable stem expansion
for any term by capitalizing it. Ie: a search for
<literal>floor</literal> will also normally look for
<literal>flooring</literal>, <literal>floored</literal>, etc., but
a search for <literal>Floor</literal> will only look for
<literal>floor</literal>, in any character case. Stemming can also
be disabled globally in the preferences. When using a raw index,
<link linkend="RCL.SEARCH.CASEDIAC">the rules are a bit more complicated</link>.</para>
<para>&RCL; remembers the last few searches that you performed. You
can directly access the search history by clicking the clock button
on the right of the search entry, while the latter is
empty. Otherwise, the history is used for entry completion (see
next). Only the search texts are remembered, not the mode
(all/any/file name).</para>
<para>While text is entered in the search area,
<command>recoll</command> will display possible completions,
filtered from the history and the index search terms. This can be
disabled with a GUI Preferences option.</para>
<para>Double-clicking on a word in the result list or a preview
window will insert it into the simple search entry field.</para>
<para>You can cut and paste any text into an <guilabel>All
terms</guilabel> or <guilabel>Any term</guilabel> search field,
punctuation, newlines and all - except for wildcard characters
(single <literal>?</literal> characters are ok). &RCL; will process
it and produce a meaningful search. This is what most differentiates
this mode from the <guilabel>Query Language</guilabel> mode, where
you have to care about the syntax.</para>
<para>You can use the <link linkend="RCL.SEARCH.GUI.COMPLEX"><menuchoice><guimenu>Tools</guimenu><guimenuitem>Advanced search</guimenuitem></menuchoice></link>
dialog for more complex searches.</para>
<para>The <guilabel>File name</guilabel> search mode will
specifically look for file names. The point of having a separate
file name search is that wild card expansion can be performed more
efficiently on a small subset of the index (allowing wild cards on
the left of terms without excessive cost). Things to know:
<itemizedlist>
<listitem><para>White space in the entry should match white
space in the file name, and is not treated specially.</para>
</listitem>
<listitem><para>The search is insensitive to character case and
accents, independently of the type of index.</para>
</listitem>
<listitem><para>An entry without any wild card
character and not capitalized will be prepended and appended
with '*' (ie: <replaceable>etc</replaceable> ->
<replaceable>*etc*</replaceable>, but
<replaceable>Etc</replaceable> ->
<replaceable>etc</replaceable>).</para>
</listitem>
<listitem><para>If you have a big index (many files),
excessively generic fragments may result in inefficient
searches.</para>
</listitem>
</itemizedlist>
</para>
</sect2>
<sect2 id="RCL.SEARCH.GUI.RESLIST">
<title>The result list</title>
<para>After starting a search, a list of results will instantly
be displayed in the main window.</para>
<para>By default, the document list is presented in order of
relevance (how well the system estimates that the document
matches the query). You can sort the result by ascending or
descending date by using the vertical arrows in the toolbar.</para>
<para>Clicking the <literal>Preview</literal> link for an entry
will open an internal preview window for the document. Further
<literal>Preview</literal> clicks for the same search will open
tabs in the existing preview window. You can use
<keycap>Shift</keycap>+Click to force the creation of another
preview window, which may be useful to view the documents side
by side. (You can also browse successive results in a single
preview window by typing
<keycap>Shift</keycap>+<keycap>ArrowUp/Down</keycap> in the
window).</para>
<para>Clicking the <literal>Open</literal> link will
start an external viewer for the document. By default, &RCL; lets
the desktop choose the appropriate application for most document
types. See
<link linkend="RCL.SEARCH.GUI.RESLIST.APPLICATIONS">further</link>
for customizing the applications.</para>
<para>You can click on the <literal>Query details</literal> link
at the top of the results page to see the query actually
performed, after stem expansion and other processing.</para>
<para>Double-clicking on any word inside the result list or a
preview window will insert it into the simple search text.</para>
<para>The result list is divided into pages (the size of which
you can change in the preferences). Use the arrow buttons in the
toolbar or the links at the bottom of the page to browse the
results.</para>
<para>The <literal>Preview</literal> and <literal>Open</literal>
edit links may not be present for all entries, meaning that
&RCL; has no configured way to preview a given file type (which
was indexed by name only), or no configured external editor for
the file type. This can sometimes be adjusted simply by tweaking
the <link linkend="RCL.INSTALL.CONFIG.MIMEMAP">
<filename>mimemap</filename></link>
and <link linkend="RCL.INSTALL.CONFIG.MIMEVIEW">
<filename>mimeview</filename></link>
configuration files (the latter can be modified with the user
preferences dialog).</para>
<para>The format of the result list entries is entirely
configurable by using the preference dialog to
<link linkend="RCL.SEARCH.GUI.CUSTOM.RESLIST">
edit an HTML fragment</link>.</para>
<simplesect id="RCL.SEARCH.GUI.RESLIST.APPLICATIONS">
<title>Customising the applications</title>
<para>By default &RCL; lets the desktop choose what
application should be used to open a given document, with
exceptions.</para>
<para>The details of this behaviour can be customized with the
<menuchoice>
<guimenu>Preferences</guimenu>
<guimenuitem>GUI configuration</guimenuitem>
<guimenuitem>User interface</guimenuitem>
<guimenuitem>Choose editor applications</guimenuitem>
</menuchoice> dialog or by editing
the <link linkend="RCL.INSTALL.CONFIG.MIMEVIEW">
<filename>mimeview</filename> configuration file.</link></para>
<para>When <guilabel>Use desktop preferences</guilabel>, at the
top of the dialog, is checked, the desktop default is generally
used, but there is a small default list of exceptions, for MIME
types where the &RCL; choice should override the desktop
one. These are applications which are well integrated with
&RCL;, for example, on Linux, <application>evince</application>
for viewing PDF and Postscript files because of its support for
opening the document at a specific page and passing a search
string as an argument. You can add or remove document types to
the exceptions by using the dialog.</para>
<para>If you prefer to completely customize the choice of
applications, you can uncheck <guilabel>Use desktop
preferences</guilabel>, in which case the &RCL; predefined
applications will be used, and can be changed for each document
type. This is probably not the most convenient approach in most
cases.</para>
<para>In all cases, the applications choice dialog accepts
multiple selections of MIME types in the top section, and lets
you define how they are processed in the bottom one. In most
cases, you will be using <literal>%f</literal> as a place
holder to be replaced by the file name in the application
command line.</para>
<para>You may also change the choice of applications by editing
the
<link linkend="RCL.INSTALL.CONFIG.MIMEVIEW">
<filename>mimeview</filename></link>
configuration file if you find this more convenient.</para>
<para>Under &LIN;, each result list entry also has a right-click
menu with an
<guilabel>Open With</guilabel> entry. This lets you choose an
application from the list of those which registered with the desktop
for the document MIME type, on a case by case basis.</para>
</simplesect>
<sect3 id="RCL.SEARCH.GUI.RESLIST.SUGGS">
<title>No results: the spelling suggestions</title>
<para>When a search yields no result, and if the
<application>aspell</application> dictionary is configured, &RCL;
will try to check for misspellings among the query terms, and
will propose lists of replacements. Clicking on one of the
suggestions will replace the word and restart the search. You can
hold any of the modifier keys (Ctrl, Shift, etc.) while clicking
if you would rather stay on the suggestion screen because several
terms need replacement.</para>
</sect3>
<sect3 id="RCL.SEARCH.GUI.RESULTLIST.MENU">
<title>The result list right-click menu</title>
<para>Apart from the preview and edit links, you can display a
pop-up menu by right-clicking over a paragraph in the result
list. This menu has the following entries:</para>
<itemizedlist>
<listitem><para><guilabel>Preview</guilabel></para></listitem>
<listitem><para><guilabel>Open</guilabel></para></listitem>
<listitem><para><guilabel>Open With</guilabel></para></listitem>
<listitem><para><guilabel>Run Script</guilabel></para></listitem>
<listitem><para><guilabel>Copy File Name</guilabel></para></listitem>
<listitem><para><guilabel>Copy Url</guilabel></para></listitem>
<listitem><para><guilabel>Save to File</guilabel></para></listitem>
<listitem><para><guilabel>Find similar</guilabel></para></listitem>
<listitem><para><guilabel>Preview Parent
document</guilabel></para></listitem>
<listitem><para><guilabel>Open Parent
document</guilabel></para></listitem>
<listitem><para><guilabel>Open Snippets
Window</guilabel></para></listitem>
</itemizedlist>
<para>The <guilabel>Preview</guilabel> and
<guilabel>Open</guilabel> entries do the same thing as the
corresponding links.</para>
<para><guilabel>Open With</guilabel> (&LIN;) lets you open the
document with one of the applications claiming to be able to
handle its MIME type (the information comes from
the <literal>.desktop</literal> files
in <filename>/usr/share/applications</filename>).</para>
<para><guilabel>Run Script</guilabel> (&LIN;) allows starting an
arbitrary command on the result file. It will only appear for
results which are top-level
files. See <link linkend="RCL.SEARCH.GUI.RUNSCRIPT">further</link>
for a more detailed description.</para>
<para>The <guilabel>Copy File Name</guilabel> and
<guilabel>Copy Url</guilabel> copy the relevant data to the
clipboard, for later pasting.</para>
<para><guilabel>Save to File</guilabel> allows saving the
contents of a result document to a chosen file. This entry
will only appear if the document does not correspond to an
existing file, but is a subdocument inside such a file (ie: an
email attachment). It is especially useful to extract attachments
with no associated editor.</para>
<para>The <guilabel>Open/Preview Parent document</guilabel> entries
allow working with the higher level document (e.g. the email
message an attachment comes from). &RCL; is sometimes not totally
accurate as to what it can or can't do in this area. For example
the <guilabel>Parent</guilabel> entry will also appear for an
email which is part of an mbox folder file, but you can't actually
visualize the mbox (there will be an error dialog if you
try).</para>
<para>If the document is a top-level file, <guilabel>Open
Parent</guilabel> will start the default file manager on the
enclosing filesystem directory.</para>
<para>The <guilabel>Find similar</guilabel> entry will select
a number of relevant term from the current document and enter
them into the simple search field. You can then start a simple
search, with a good chance of finding documents related to the
current result. I can't remember a single instance where this
function was actually useful to me...</para>
<para id="RCL.SEARCH.GUI.RESULTLIST.MENU.SNIPPETS">The
<guilabel>Open Snippets Window</guilabel> entry will only
appear for documents which support page breaks (typically
PDF, Postscript, DVI). The snippets window lists extracts from
the document, taken around search terms occurrences, along with the
corresponding page number, as links which can be used to start
the native viewer on the appropriate page. If the viewer supports
it, its search function will also be primed with one of the
search terms.</para>
</sect3>
</sect2>
<sect2 id="RCL.SEARCH.GUI.RESTABLE">
<title>The result table</title>
<para>As an alternative to the result list, the results can also be
displayed in spreadsheet-like fashion. You can switch to this
presentation by clicking the table-like icon in the toolbar (this
is a toggle, click again to restore the list).</para>
<para>Clicking on the column headers will allow sorting by the
values in the column. You can click again to invert the order, and
use the header right-click menu to reset sorting to the default
relevance order (you can also use the sort-by-date arrows to do
this).</para>
<para>Both the list and the table display the same underlying
results. The sort order set from the table is still active if you
switch back to the list mode. You can click twice on a date sort
arrow to reset it from there.</para>
<para>The header right-click menu allows adding or deleting
columns. The columns can be resized, and their order can be changed
(by dragging). All the changes are recorded when you quit
<command>recoll</command></para>
<para>Hovering over a table row will update the detail area at the
bottom of the window with the corresponding values. You can click
the row to freeze the display. The bottom area is equivalent to a
result list paragraph, with links for starting a preview or a
native application, and an equivalent right-click menu. Typing
<keycap>Esc</keycap> (the Escape key) will unfreeze the
display.</para>
</sect2>
<sect2 id="RCL.SEARCH.GUI.RUNSCRIPT">
<title>&LIN;: running arbitrary commands on result files</title>
<para>Apart from the <guilabel>Open</guilabel> and <guilabel>Open
With</guilabel> operations, which allow starting an application on a
result document (or a temporary copy), based on its MIME type, it is
also possible to run arbitrary commands on results which are
top-level files, using the <guilabel>Run Script</guilabel> entry in
the results pop-up menu.</para>
<para>The commands which will appear in the <guilabel>Run
Script</guilabel> submenu must be defined by
<literal>.desktop</literal> files inside the
<filename>scripts</filename> subdirectory of the current
configuration directory.</para>
<para>Here follows an example of a <literal>.desktop</literal> file,
which could be named for example,
<filename>~/.recoll/scripts/myscript.desktop</filename> (the exact
file name inside the directory is irrelevant):
<programlisting>
[Desktop Entry]
Type=Application
Name=MyFirstScript
Exec=/home/me/bin/tryscript %F
MimeType=*/*
</programlisting>
The <literal>Name</literal> attribute defines the label which will
appear inside the <guilabel>Run Script</guilabel> menu. The
<literal>Exec</literal> attribute defines the program to be run,
which does not need to actually be a script, of course. The
<literal>MimeType</literal> attribute is not used, but needs to exist.
</para>
<para>The commands defined this way can also be used from links
inside the
<link linkend="RCL.SEARCH.GUI.CUSTOM.RESLIST.PARA">result paragraph</link>.
</para>
<para>As an example, it might make sense to write a script which
would move the document to the trash and purge it from the &RCL;
index.</para>
</sect2>
<sect2 id="RCL.SEARCH.GUI.THUMBNAILS">
<title>&LIN;: displaying thumbnails</title>
<para>The default format for the result list entries and the
detail area of the result table display an icon for each result
document. The icon is either a generic one determined from the
MIME type, or a thumbnail of the document appearance. Thumbnails
are only displayed if found in the standard
<application>freedesktop</application> location, where they would
typically have been created by a file manager.</para>
<para>Recoll has no capability to create thumbnails. A relatively
simple trick is to use the <guilabel>Open parent
document/folder</guilabel> entry in the result list popup
menu. This should open a file manager window on the containing
directory, which should in turn create the thumbnails (depending on
your settings). Restarting the search should then display the
thumbnails.</para>
<para>There are also <ulink url="&FAQS;ResultsThumbnails.html">some
pointers about thumbnail generation</ulink> in the &RCL;
FAQ.</para>
</sect2>
<sect2 id="RCL.SEARCH.GUI.PREVIEW">
<title>The preview window</title>
<para>The preview window opens when you first click a
<literal>Preview</literal> link inside the result list.</para>
<para>Subsequent preview requests for a given search open new
tabs in the existing window (except if you hold the
<keycap>Shift</keycap> key while clicking which will open a new
window for side by side viewing).</para>
<para>Starting another search and requesting a preview will
create a new preview window. The old one stays open until you
close it.</para>
<para>You can close a preview tab by typing <keycap>Ctrl-W</keycap>
(<keycap>Ctrl</keycap> + <keycap>W</keycap>) in the window. Closing
the last tab, or using the window manager button in the top of the
frame will also close the window.</para>
<para>You can display successive or previous documents from the
result list inside a preview tab by typing
<keycap>Shift</keycap>+<keycap>Down</keycap> or
<keycap>Shift</keycap>+<keycap>Up</keycap> (<keycap>Down</keycap>
and <keycap>Up</keycap> are the arrow keys).</para>
<para>A right-click menu in the text area allows switching
between displaying the main text or the contents of fields
associated to the document (ie: author, abtract, etc.). This is
especially useful in cases where the term match did not occur in
the main text but in one of the fields. In the case of
images, you can switch between three displays: the image
itself, the image metadata as extracted
by <command>exiftool</command> and the fields, which is the
metadata stored in the index.</para>
<para>You can print the current preview window contents by typing
<keycap>Ctrl-P</keycap> (<keycap>Ctrl</keycap> +
<keycap>P</keycap>) in the window text.</para>
<sect3 id="RCL.SEARCH.GUI.PREVIEW.SEARCH">
<title>Searching inside the preview</title>
<para>The preview window has an internal search capability,
mostly controlled by the panel at the bottom of the window,
which works in two modes: as a classical editor incremental
search, where we look for the text entered in the entry
zone, or as a way to walk the matches between the document
and the &RCL; query that found it.</para>
<variablelist>
<varlistentry>
<term>Incremental text search</term>
<listitem><para>The preview tabs have an internal incremental search
function. You initiate the search either by typing a
<keycap>/</keycap> (slash) or <keycap>CTL-F</keycap>
inside the text area or by clicking into
the <guilabel>Search for:</guilabel> text field and
entering the search string. You can then use the
<guilabel>Next</guilabel>
and <guilabel>Previous</guilabel> buttons
to find the next/previous occurrence. You can also type
<keycap>F3</keycap> inside the text area to get to the next
occurrence.</para>
<para>If you have a search string entered and you use
Ctrl-Up/Ctrl-Down to browse the results, the search is
initiated for each successive document. If the string is
found, the cursor will be positioned at the first
occurrence of the search string.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Walking the match lists</term>
<listitem><para>If the entry area is empty when you click
the <guilabel>Next</guilabel>
or <guilabel>Previous</guilabel> buttons, the editor will
be scrolled to show the next match to any search term
(the next highlighted zone). If you select a search group
from the dropdown list and click <guilabel>Next</guilabel>
or <guilabel>Previous</guilabel>, the match list for this
group will be walked. This is not the same as a text
search, because the occurrences will include non-exact
matches (as caused by stemming or wildcards). The search
will revert to the text mode as soon as you edit the
entry area.</para></listitem>
</varlistentry>
</variablelist>
</sect3>
</sect2>
<sect2 id="RCL.SEARCH.GUI.FRAGBUTS">
<title>The Query Fragments window</title>
<para>Selecting the <menuchoice><guimenu>Tools</guimenu>
<guimenuitem>Query Fragments</guimenuitem></menuchoice> menu
entry will open a window with radio- and check-buttons which
can be used to activate query language fragments for
filtering the current query. This can be useful if you have
frequent reusable selectors, for example, filtering on
alternate directories, or searching just one category of
files, not covered by the standard category
selectors.</para>
<para>The contents of the window are entirely customizable, and
defined by the contents of the <filename>fragbuts.xml</filename>
file inside the configuration directory. The sample file
distributed with &RCL; (which you should be able to find under
<filename>/usr/share/recoll/examples/fragbuts.xml</filename>),
contains an example which filters the results from the Web
history.</para>
<para>Here follows an example:
<programlisting><![CDATA[
<?xml version="1.0" encoding="UTF-8"?>
<fragbuts version="1.0">
<radiobuttons>
<!-- Actually useful: toggle Web queue results inclusion -->
<fragbut>
<label>Include Web Results</label>
<frag></frag>
</fragbut>
<fragbut>
<label>Exclude Web Results</label>
<frag>-rclbes:BGL</frag>
</fragbut>
<fragbut>
<label>Only Web Results</label>
<frag>rclbes:BGL</frag>
</fragbut>
</radiobuttons>
<buttons>
<fragbut>
<label>Example: Year 2010</label>
<frag>date:2010-01-01/2010-12-31</frag>
</fragbut>
<fragbut>
<label>Example: c++ files</label>
<frag>ext:cpp OR ext:cxx</frag>
</fragbut>
<fragbut>
<label>Example: My Great Directory</label>
<frag>dir:/my/great/directory</frag>
</fragbut>
</buttons>
</fragbuts>
]]></programlisting>
</para>
<para>Each <literal>radiobuttons</literal> or
<literal>buttons</literal> section defines a line of
checkbuttons or radiobuttons inside the window. Any number of
buttons can be selected, but the radiobuttons in a line are
exclusive.</para>
<para>Each <literal>fragbut</literal> section defines the label
for a button, and the Query Language fragment which will be
added (as an AND filter) before performing the query if the
button is active.</para>
</sect2>
<sect2 id="RCL.SEARCH.GUI.COMPLEX">
<title>Complex/advanced search</title>
<para>The advanced search dialog helps you build more complex queries
without memorizing the search language constructs. It can be opened
through the <guilabel>Tools</guilabel> menu or through the main
toolbar.</para>
<para>&RCL; keeps a history of searches. See
<link linkend="RCL.SEARCH.GUI.COMPLEX.HISTORY">Advanced search history</link>.
</para>
<para>The dialog has two tabs:</para>
<orderedlist>
<listitem><para>The first tab lets you specify terms to search
for, and permits specifying multiple clauses which are combined
to build the search.</para>
</listitem>
<listitem><para>The second tab lets filter the results according
to file size, date of modification, MIME type, or
location.</para>
</listitem>
</orderedlist>
<para>Click on the <guilabel>Start Search</guilabel> button in
the advanced search dialog, or type <keycap>Enter</keycap> in
any text field to start the search. The button in
the main window always performs a simple search.</para>
<para>Click on the <literal>Show query details</literal> link at
the top of the result page to see the query expansion.</para>
<sect3 id="RCL.SEARCH.GUI.COMPLEX.TERMS">
<title>Advanced search: the "find" tab</title>
<para>This part of the dialog lets you constructc a query by
combining multiple clauses of different types. Each entry
field is configurable for the following modes:</para>
<itemizedlist>
<listitem><para>All terms.</para>
</listitem>
<listitem><para>Any term.</para>
</listitem>
<listitem><para>None of the terms.</para>
</listitem>
<listitem><para>Phrase (exact terms in order within an
adjustable window).</para>
</listitem>
<listitem><para>Proximity (terms in any order within an
adjustable window).</para>
</listitem>
<listitem><para>Filename search.</para>
</listitem>
</itemizedlist>
<para>Additional entry fields can be created by clicking the
<guilabel>Add clause</guilabel> button.</para>
<para>When searching, the non-empty clauses will be
combined either with an AND or an OR conjunction, depending on
the choice made on the left (<guilabel>All clauses</guilabel> or
<guilabel>Any clause</guilabel>).</para>
<para>Entries of all types except "Phrase" and "Near" accept
a mix of single words and phrases enclosed in double quotes.
Stemming and wildcard expansion will be performed as for simple
search. </para>
<formalpara><title>Phrases and Proximity searches</title>
<para>These two clauses work in similar ways, with the difference
that proximity searches do not impose an order on the words. In
both cases, an adjustable number (slack) of non-matched words may
be accepted between the searched ones (use the counter on the
left to adjust this count). For phrases, the default count is
zero (exact match). For proximity it is ten (meaning that two
search terms, would be matched if found within a window of twelve
words). Examples: a phrase search for
<literal>quick fox</literal> with a slack of 0 will match
<literal>quick fox</literal> but not
<literal>quick brown fox</literal>. With
a slack of 1 it will match the latter, but not
<literal>fox quick</literal>. A proximity search for
<literal>quick fox</literal> with the default slack will
match the latter, and also
<literal>a fox is a cunning and quick animal</literal>.</para>
</formalpara>
</sect3>
<sect3 id="RCL.SEARCH.GUI.COMPLEX.FILTER">
<title>Advanced search: the "filter" tab</title>
<para>This part of the dialog has several sections which allow
filtering the results of a search according to a number of
criteria</para>
<itemizedlist>
<listitem>
<para>The first section allows filtering by dates of last
modification. You can specify both a minimum and a maximum
date. The initial values are set according to the oldest and
newest documents found in the index.</para>
</listitem>
<listitem>
<para>The next section allows filtering the results by
file size. There are two entries for minimum and maximum
size. Enter decimal numbers. You can use suffix multipliers:
<literal>k/K</literal>, <literal>m/M</literal>,
<literal>g/G</literal>, <literal>t/T</literal> for 1E3, 1E6,
1E9, 1E12 respectively.</para>
</listitem>
<listitem>
<para>The next section allows filtering the results by their MIME
types, or MIME categories (ie: media/text/message/etc.).</para>
<para>You can transfer the types between two boxes, to define
which will be included or excluded by the search.</para>
<para>The state of the file type selection can be saved as
the default (the file type filter will not be activated at
program start-up, but the lists will be in the restored
state).</para>
</listitem>
<listitem>
<para>The bottom section allows restricting the search results to a
sub-tree of the indexed area. You can use the
<guilabel>Invert</guilabel> checkbox to search for files not in
the sub-tree instead. If you use directory filtering often and on
big subsets of the file system, you may think of setting up
multiple indexes instead, as the performance may be
better.</para>
<para>You can use relative/partial paths for filtering. Ie,
entering <literal>dirA/dirB</literal> would match either
<filename>/dir1/dirA/dirB/myfile1</filename> or
<filename>/dir2/dirA/dirB/someother/myfile2</filename>.</para>
</listitem>
</itemizedlist>
</sect3>
<sect3 id="RCL.SEARCH.GUI.COMPLEX.HISTORY">
<title>Advanced search history</title>
<para>The advanced search tool memorizes the last 100 searches
performed. You can walk the saved searches by using the up and
down arrow keys while the keyboard focus belongs to the advanced
search dialog.</para>
<para>The complex search history can be erased, along with the
one for simple search, by selecting the <menuchoice>
<guimenu>File</guimenu>
<guimenuitem>Erase Search History</guimenuitem>
</menuchoice> menu entry.</para>
</sect3>
</sect2>
<sect2 id="RCL.SEARCH.GUI.TERMEXPLORER">
<title>The term explorer tool</title>
<para>&RCL; automatically manages the expansion of search terms
to their derivatives (ie: plural/singular, verb
inflections). But there are other cases where the exact search
term is not known. For example, you may not remember the exact
spelling, or only know the beginning of the name.</para>
<para>The search will only propose replacement terms with
spelling variations when no matching document were found. In some
cases, both proper spellings and mispellings are present in the
index, and it may be interesting to look for them explicitly.</para>
<para>The term explorer tool (started from the toolbar icon or
from the <guilabel>Term explorer</guilabel> entry of the
<guilabel>Tools</guilabel> menu) can be used to search the full index
terms list. It has three modes of operations:</para>
<variablelist>
<varlistentry>
<term>Wildcard</term>
<listitem><para>In this mode of operation, you can enter a
search string with shell-like wildcards (*, ?, []). ie:
<replaceable>xapi*</replaceable> would display all index terms
beginning with <replaceable>xapi</replaceable>. (More
about wildcards
<link linkend="RCL.SEARCH.WILDCARDS">here</link>
).</para></listitem>
</varlistentry>
<varlistentry>
<term>Regular expression</term>
<listitem><para>This mode will accept a regular expression
as input. Example:
<replaceable>word[0-9]+</replaceable>. The expression is
implicitly anchored at the beginning. Ie:
<replaceable>press</replaceable> will match
<replaceable>pression</replaceable> but not
<replaceable>expression</replaceable>. You can use
<replaceable>.*press</replaceable> to match the latter,
but be aware that this will cause a full index term list
scan, which can be quite long.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Stem expansion</term>
<listitem><para>This mode will perform the usual stem expansion
normally done as part user input processing. As such it is
probably mostly useful to demonstrate the process.
</para></listitem>
</varlistentry>
<varlistentry>
<term>Spelling/Phonetic</term> <listitem><para>In this
mode, you enter the term as you think it is spelled, and
&RCL; will do its best to find index terms that sound like
your entry. This mode uses the
<application>Aspell</application> spelling application,
which must be installed on your system for things to work
(if your documents contain non-ascii characters, &RCL;
needs an aspell version newer than 0.60 for UTF-8
support). The language which is used to build the
dictionary out of the index terms (which is done at the
end of an indexing pass) is the one defined by your NLS
environment. Weird things will probably happen if
languages are mixed up.</para></listitem>
</varlistentry>
<varlistentry>
<term>Show index statistics</term> <listitem><para>This will
print a long list of boring numbers about the index</para>
</listitem></varlistentry>
<varlistentry>
<term>List files which could not be indexed</term>
<listitem><para>This will show the files which caused errors,
usually because <command>recollindex</command> could not
translate their format into text.</para>
</listitem></varlistentry>
</variablelist>
<para>Note that in cases where &RCL; does not know the beginning
of the string to search for (ie a wildcard expression like
<replaceable>*coll</replaceable>), the expansion can take quite
a long time because the full index term list will have to be
processed. The expansion is currently limited at 10000 results for
wildcards and regular expressions. It is possible to change the
limit in the configuration file.</para>
<para>Double-clicking on a term in the result list will insert
it into the simple search entry field. You can also cut/paste
between the result list and any entry field (the end of lines
will be taken care of).</para>
</sect2>
<sect2 id="RCL.SEARCH.GUI.MULTIDB">
<title>Multiple indexes</title>
<para>See the section describing
<link linkend="RCL.INDEXING.CONFIG.MULTIPLE">the use of multiple indexes</link> for
generalities. Only the aspects concerning the
<command>recoll</command> GUI are described here.</para>
<para>A <command>recoll</command> program instance is always
associated with a specific index, which is the one to be updated
when requested from the <guimenu>File</guimenu> menu, but it can
use any number of &RCL; indexes for searching. The external
indexes can be selected through the <guilabel>external
indexes</guilabel> tab in the preferences dialog.</para>
<para>Index selection is performed in two phases. A set of all usable
indexes must first be defined, and then the subset of indexes to be
used for searching. These parameters are retained across program
executions (there are kept separately for each &RCL;
configuration). The set of all indexes is usually quite stable, while
the active ones might typically be adjusted quite frequently.</para>
<para>The main index (defined by
<envar>RECOLL_CONFDIR</envar>) is always active. If this is
undesirable, you can set up your base configuration to index
an empty directory.</para>
<para>When adding a new index to the set, you can select either
a &RCL; configuration directory, or directly a &XAP; index
directory. In the first case, the &XAP; index directory will
be obtained from the selected configuration.</para>
<para>As building the set of all indexes can be a little tedious
when done through the user interface, you can use the
<envar>RECOLL_EXTRA_DBS</envar> environment
variable to provide an initial set. This might typically be
set up by a system administrator so that every user does not
have to do it. The variable should define a colon-separated list
of index directories, ie:
</para>
<screen>export RECOLL_EXTRA_DBS=/some/place/xapiandb:/some/other/db</screen>
<para>Another environment
variable, <envar>RECOLL_ACTIVE_EXTRA_DBS</envar> allows adding to
the active list of indexes. This variable was suggested and
implemented by a &RCL; user. It is mostly useful if you use scripts
to mount external volumes with &RCL; indexes. By
using <envar>RECOLL_EXTRA_DBS</envar>
and <envar>RECOLL_ACTIVE_EXTRA_DBS</envar>, you can add and
activate the index for the mounted volume when
starting <command>recoll</command>. Unreachable indexes will
automatically be deactivated when starting up.</para>
</sect2>
<sect2 id="RCL.SEARCH.GUI.HISTORY">
<title>Document history</title>
<para>Documents that you actually view (with the internal preview
or an external tool) are entered into the document history,
which is remembered.</para>
<para>You can display the history list by using
the <guilabel>Tools/</guilabel><guilabel>Doc History</guilabel> menu
entry.</para>
<para>You can erase the document history by using the
<guilabel>Erase document history</guilabel> entry in the
<guimenu>File</guimenu> menu.</para>
</sect2>
<sect2 id="RCL.SEARCH.GUI.SORT">
<title>Sorting search results and collapsing duplicates</title>
<para>The documents in a result list are normally sorted in
order of relevance. It is possible to specify a different sort
order, either by using the vertical arrows in the GUI toolbox to
sort by date, or switching to the result table display and clicking
on any header. The sort order chosen inside the result table
remains active if you switch back to the result list, until you
click one of the vertical arrows, until both are unchecked (you are
back to sort by relevance).</para>
<para>Sort parameters are remembered between program
invocations, but result sorting is normally always inactive
when the program starts. It is possible to keep the sorting
activation state between program invocations by checking the
<guilabel>Remember sort activation state</guilabel> option in
the preferences.</para>
<para>It is also possible to hide duplicate entries inside
the result list (documents with the exact same contents as the
displayed one). The test of identity is based on an MD5 hash
of the document container, not only of the text contents (so
that ie, a text document with an image added will not be a
duplicate of the text only). Duplicates hiding is controlled
by an entry in the <guilabel>GUI configuration</guilabel>
dialog, and is off by default.</para>
<para>When a result document does have undisplayed duplicates,
a <literal>Dups</literal> link will be shown with the result list
entry. Clicking the link will display the paths (URLs + ipaths)
for the duplicate entries.</para>
</sect2>
<sect2 id="RCL.SEARCH.GUI.SHORTCUTS">
<title>Keyboard shortcuts</title>
<para>A number of common actions within the graphical interface can
be triggered through keyboard shortcuts. As of &RCL; 1.29, many
of the shortcut values can be customised from a screen in the GUI
preferences. Most shortcuts are specific to a given context
(e.g. within a preview window, within the result table).</para>
<table frame='all'>
<title>Keyboard shortcuts</title>
<tgroup cols='2' align='left' colsep='1' rowsep='1'>
<colspec colname='c1'/>
<colspec colname='c2'/>
<thead>
<row><entry>Description</entry><entry>Default value</entry></row>
</thead>
<tbody>
<row><entry namest="c1" nameend="c2">
<command>Context: almost everywhere</command></entry></row>
<row>
<entry>Program exit</entry>
<entry>Ctrl+Q</entry>
</row>
<row><entry namest="c1" nameend="c2">
<command>Context: advanced search</command></entry></row>
<row>
<entry>Load the next entry from the search history</entry>
<entry>Up</entry>
</row>
<row>
<entry>Load the previous entry from the search history</entry>
<entry>Down</entry>
</row>
<row><entry namest="c1" nameend="c2">
<command>Context: main window</command></entry>
</row>
<row>
<entry>Clear search. This will move the keyboard cursor to
the simple search entry and erase the current text</entry>
<entry>Ctrl+S</entry>
</row>
<row>
<entry>Move the keyboard cursor to the search entry area
without erasing the current text</entry>
<entry>Ctrl+L</entry>
</row>
<row>
<entry>Move the keyboard cursor to the search entry area
without erasing the current text</entry>
<entry>Ctrl+Shift+S</entry>
</row>
<row>
<entry>Toggle displaying the current results as a table or
as a list</entry>
<entry>Ctrl+T</entry>
</row>
<row><entry namest="c1" nameend="c2">
<command>Context: main window, when showing the results
as a table</command></entry>
</row>
<row>
<entry>Move the keyboard cursor to currently the selected row
in the table, or to the first one if none is selected</entry>
<entry>Ctrl+R</entry>
</row>
<row>
<entry>Jump to row 0-9 or a-z in the table</entry>
<entry>Ctrl+[0-9] or Ctrl+Shift+[a-z]</entry>
</row>
<row>
<entry>Cancel the current selection</entry><entry>Esc</entry>
</row>
<row><entry namest="c1" nameend="c2">
<command>Context: preview window</command></entry>
</row>
<row>
<entry>Close the preview window</entry>
<entry>Esc</entry>
</row>
<row>
<entry>Close the current tab</entry>
<entry>Ctrl+W</entry>
</row>
<row>
<entry>Open a print dialog for the current tab contents</entry>
<entry>Ctrl+P</entry>
</row>
<row>
<entry>Load the next result from the list to the current tab</entry>
<entry>Shift+Down</entry>
</row>
<row>
<entry>Load the previous result from the list to the current tab</entry>
<entry>Shift+Up</entry>
</row>
<row><entry namest="c1" nameend="c2">
<command>Context: result table</command></entry></row>
<row>
<entry>Copy the text contained in the selected
document to the clipboard</entry> <entry>Ctrl+G</entry>
</row>
<row>
<entry>Open the current document and exit Recoll</entry>
<entry>Ctrl+Shift+O</entry>
</row>
<row>
<entry>Open the current document</entry>
<entry>Ctrl+O</entry>
</row>
<row>
<entry>Show a full preview for the current document</entry>
<entry>Ctrl+D</entry>
</row>
<row>
<entry>Toggle showing the column names</entry>
<entry>Ctrl+H</entry>
</row>
<row>
<entry>Show a snippets (keyword in context) list for the current document</entry>
<entry>Ctrl+E</entry>
</row>
<row>
<entry>Toggle showing the row letters/numbers</entry>
<entry>Ctrl+V</entry>
</row>
<row><entry namest="c1" nameend="c2">
<command>Context: snippets window</command></entry></row>
<row>
<entry>Close the snippets window</entry>
<entry>Esc</entry>
</row>
<row>
<entry>Find in the snippets list (method #1)</entry>
<entry>Ctrl+F</entry>
</row>
<row>
<entry>Find in the snippets list (method #2)</entry>
<entry>/</entry>
</row>
<row>
<entry>Find the next instance of the search term</entry>
<entry>F3</entry>
</row>
<row>
<entry>Find the previous instance of the search term</entry>
<entry>Shift+F3</entry>
</row>
</tbody>
</tgroup>
</table>
</sect2>
<sect2 id="RCL.SEARCH.GUI.TIPS">
<title>Search tips</title>
<sect3 id="RCL.SEARCH.GUI.TIPS.TERMS">
<title>Terms and search expansion</title>
<formalpara><title>Term completion</title>
<para>While typing into the
simple search entry, a popup menu will appear and show
completions for the current string. Values preceded by a clock
icon come from the history, those preceded by a magnifier icon
come from the index terms. This can be disabled in the
preferences.</para>
</formalpara>
<formalpara><title>Picking up new terms from result or preview
text</title>
<para>Double-clicking on a word in the result list or in a
preview window will copy it to the simple search entry field.</para>
</formalpara>
<formalpara><title>Wildcards</title>
<para>Wildcards can be used inside search terms in all forms
of searches. <link linkend="RCL.SEARCH.WILDCARDS">More about wildcards</link>.
</para>
</formalpara>
<formalpara><title>Automatic suffixes</title>
<para>Words like <literal>odt</literal> or <literal>ods</literal>
can be automatically turned into query language
<literal>ext:xxx</literal> clauses. This can be enabled in the
<guilabel>Search preferences</guilabel> panel in the GUI.
</para>
</formalpara>
<formalpara><title>Disabling stem expansion</title>
<para>Entering a capitalized word in any search field will prevent
stem expansion (no search for
<literal>gardening</literal> if you enter
<literal>Garden</literal> instead of
<literal>garden</literal>). This is the only case where
character case should make a difference for a &RCL;
search. You can also disable stem expansion or change the
stemming language in the preferences.</para>
</formalpara>
<formalpara><title>Finding related documents</title>
<para>Selecting the <guilabel>Find similar documents</guilabel> entry
in the result list paragraph right-click menu will select a
set of "interesting" terms from the current result, and insert
them into the simple search entry field. You can then possibly
edit the list and start a search to find documents which may
be apparented to the current result.</para>
</formalpara>
<formalpara><title>File names</title>
<para>File names are added as terms during indexing, and you can
specify them as ordinary terms in normal search fields (&RCL; used
to index all directories in the file path as terms. This has been
abandoned as it did not seem really useful). Alternatively, you
can use the specific file name search which will
<emphasis>only</emphasis> look for file names, and may be
faster than the generic search especially when using wildcards.</para>
</formalpara>
</sect3>
<sect3 id="RCL.SEARCH.GUI.TIPS.PHRASES">
<title>Working with phrases and proximity</title>
<formalpara><title>Phrases searches</title>
<para>A phrase can be
looked for by enclosing a number of terms in double
quotes. Example: <literal>"user manual"</literal> will look only
for occurrences of <literal>user</literal> immediately followed
by <literal>manual</literal>. You can use
the <guilabel>"Phrase"</guilabel> field of the advanced search
dialog to the same effect. Phrases can be entered along simple
terms in all simple or advanced search entry fields,
except <guilabel>"Phrase"</guilabel>. </para></formalpara>
<formalpara><title>Proximity searches</title>
<para>A proximity search differs from a phrase search in that
it does not impose an order on the terms. Proximity searches
can be entered by specifying
the <guilabel>"Proximity"</guilabel> type in the advanced
search, or by postfixing a phrase search with a 'p'. Example:
"user manual"p would also match "manual user". Also
see <link linkend="RCL.SEARCH.LANG.MODIFIERS">the modifier
section</link> from the query language
documentation.</para></formalpara>
<formalpara><title>AutoPhrases</title>
<para>This option can be set in the preferences dialog. If it is
set, a phrase will be automatically built and added to simple
searches when looking for <literal>Any terms</literal>. This
will not change radically the results, but will give a relevance
boost to the results where the search terms appear as a
phrase. Ie: searching for <literal>virtual reality</literal>
will still find all documents where either
<literal>virtual</literal> or <literal>reality</literal> or
both appear, but those which contain
<literal>virtual reality</literal> should appear sooner in the
list.</para></formalpara>
<para>Phrase searches can slow down a query if most of the
terms in the phrase are common. If
the <varname>autophrase</varname> option is on, very common
terms will be removed from the automatically constructed
phrase. The removal threshold can be adjusted from the search
preferences.</para>
<formalpara><title>Phrases and abbreviations</title>
<para>Dotted abbreviations like
<literal>I.B.M.</literal> are also automatically indexed as a
word without the dots: <literal>IBM</literal>. Searching for
the word inside a phrase (ie: <literal>"the IBM
company"</literal>) will only match the dotted abrreviation
if you increase the phrase slack (using the advanced search
panel control, or the <literal>o</literal> query language
modifier). Literal occurrences of the word will be matched
normally.</para>
</formalpara>
</sect3>
<sect3 id="RCL.SEARCH.GUI.TIPS.MISC">
<title>Others</title>
<formalpara><title>Using fields</title>
<para>You can use the <link linkend="RCL.SEARCH.LANG">query
language </link> and field specifications
to only search certain parts of documents. This can be
especially helpful with email, for example only searching
emails from a specific originator:
<literal>search tips from:helpfulgui</literal>
</para></formalpara>
<formalpara><title>Adjusting the result table columns</title>
<para>When displaying results in table mode, you can use a
right click on the table headers to activate a pop-up menu
which will let you adjust what columns are displayed. You can
drag the column headers to adjust their order. You can click
them to sort by the field displayed in the column. You can
also save the result list in CSV format.</para>
</formalpara>
<formalpara><title>Changing the GUI geometry</title>
<para>It is possible to configure the GUI in wide form
factor by dragging the toolbars to one of the sides (their
location is remembered between sessions), and moving the
category filters to a menu (can be set in the
<menuchoice>
<guimenu>Preferences</guimenu>
<guimenuitem>GUI configuration</guimenuitem>
<guimenuitem>User interface</guimenuitem>
</menuchoice> panel).</para>
</formalpara>
<formalpara><title>Query explanation</title>
<para>You can get an exact description of what the query
looked for, including stem expansion, and Boolean operators
used, by clicking on the result list header.</para>
</formalpara>
<formalpara><title>Advanced search history</title> <para>You can
display any of the last 100 complex searches performed by
using the up and down arrow keys while the advanced search
panel is active.</para>
</formalpara>
<formalpara><title>Forced opening of a preview window</title>
<para>You can use <keycap>Shift</keycap>+Click on a result list
<literal>Preview</literal> link to force the creation of a
preview window instead of a new tab in the existing one.</para>
</formalpara>
</sect3>
</sect2>
<sect2 id="RCL.SEARCH.SAVING">
<title>Saving and restoring queries (1.21 and later)</title>
<para>Both simple and advanced query dialogs save recent
history, but the amount is limited: old queries will eventually
be forgotten. Also, important queries may be difficult to find
among others. This is why both types of queries can also be
explicitly saved to files, from the GUI menus:
<menuchoice>
<guimenu>File</guimenu>
<guimenuitem>Save last query / Load last query</guimenuitem>
</menuchoice>
</para>
<para>The default location for saved queries is a subdirectory
of the current configuration directory, but saved queries are
ordinary files and can be written or moved anywhere.</para>
<para>Some of the saved query parameters are part of the
preferences (e.g. <literal>autophrase</literal> or the active
external indexes), and may differ when the query is
loaded from the time it was saved. In this case, &RCL; will warn
of the differences, but will not change the user
preferences.</para>
</sect2>
<sect2 id="RCL.SEARCH.GUI.CUSTOM">
<title>Customizing the search interface</title>
<para>You can customize some aspects of the search interface by using
the <guimenu>GUI configuration</guimenu> entry in the
<guimenu>Preferences</guimenu> menu.</para>
<para>There are several tabs in the dialog, dealing with the
interface itself, the parameters used for searching and
returning results, and what indexes are searched.</para>
<formalpara id="RCL.SEARCH.GUI.CUSTOM.UI">
<title>User interface parameters:</title>
<para>
<itemizedlist>
<listitem><para><guilabel>Highlight color for query
terms</guilabel>: Terms from the user query are highlighted in
the result list samples and the preview window. The color can
be chosen here. Any Qt color string should work (ie
<literal>red</literal>, <literal>#ff0000</literal>). The
default is <literal>blue</literal>.</para>
</listitem>
<listitem><para><guilabel>Style sheet</guilabel>:
The name of a <application>Qt</application> style sheet
text file which is applied to the whole Recoll application
on startup. The default value is empty, but there is a
skeleton style sheet (<filename>recoll.qss</filename>)
inside the <filename>/usr/share/recoll/examples</filename>
directory. Using a style sheet, you can change most
<command>recoll</command> graphical parameters:
colors, fonts, etc. See the sample file for a few
simple examples.</para>
<para>You should be aware that parameters (e.g.: the
background color) set inside the &RCL; GUI style sheet
will override global system preferences, with possible
strange side effects: for example if you set the
foreground to a light color and the background to a
dark one in the desktop preferences, but only the
background is set inside the &RCL; style sheet, and it
is light too, then text will appear light-on-light
inside the &RCL; GUI.</para>
</listitem>
<listitem><para><guilabel>Maximum text size highlighted for
preview</guilabel> Inserting highlights on search term inside
the text before inserting it in the preview window involves
quite a lot of processing, and can be disabled over the given
text size to speed up loading.</para>
</listitem>
<listitem><para><guilabel>Prefer HTML to plain text for
preview</guilabel> if set, Recoll will display HTML as such
inside the preview window. If this causes problems with the Qt
HTML display, you can uncheck it to display the plain text
version instead. </para>
</listitem>
<listitem><para><guilabel>Activate links in
preview</guilabel> if set, Recoll will turn HTTP links found
inside plain text into proper HTML anchors, and clicking a
link inside a preview window will start the default browser
on the link target.</para> </listitem>
<listitem><para><guilabel>Plain text to HTML line
style</guilabel>: when displaying plain text inside the
preview window, &RCL; tries to preserve some of the original
text line breaks and indentation. It can either use PRE HTML
tags, which will well preserve the indentation but will force
horizontal scrolling for long lines, or use BR tags to break
at the original line breaks, which will let the editor
introduce other line breaks according to the window width,
but will lose some of the original indentation. The third
option has been available in recent releases and is probably
now the best one: use PRE tags with line wrapping.</para>
</listitem>
<listitem><para><guilabel>Choose editor
application</guilabel>: this opens a dialog which allows you
to select the application to be used to open each MIME
type. The default is to use the <command>xdg-open</command>
utility, but you can use this dialog to override it, setting
exceptions for MIME types that will still be opened according
to &RCL; preferences. This is useful for passing parameters
like page numbers or search strings to applications that
support them (e.g. <application>evince</application>). This
cannot be done with <command>xdg-open</command> which only
supports passing one parameter.</para>
</listitem>
<listitem><para><guilabel>Disable Qt autocompletion in search
entry</guilabel>: this will disable the completion popup. Il
will only appear, and display the full history, either if you
enter only white space in the search area, or if you click
the clock button on the right of the area.</para>
</listitem>
<listitem><para><guilabel>Document filter choice
style</guilabel>: this will let you choose if the document
categories are displayed as a list or a set of buttons, or a
menu.</para>
</listitem>
<listitem><para><guilabel>Start with simple search
mode</guilabel>: this lets you choose the value of the simple
search type on program startup. Either a fixed value
(e.g. <literal>Query Language</literal>, or the value in use
when the program last exited.</para></listitem>
<listitem><para><guilabel>Start with advanced search dialog open
</guilabel>: If you use this dialog frequently, checking
the entries will get it to open when recoll starts.</para>
</listitem>
<listitem><para><guilabel>Remember sort activation
state</guilabel> if set, Recoll will remember the sort tool
stat between invocations. It normally starts with sorting
disabled.</para>
</listitem>
</itemizedlist>
</para>
</formalpara>
<formalpara id="RCL.SEARCH.GUI.CUSTOM.RL">
<title>Result list parameters:</title>
<para>
<itemizedlist>
<listitem><para><guilabel>Number of results in a result
page</guilabel></para>
</listitem>
<listitem><para><guilabel>Result list font</guilabel>: There is
quite a lot of information shown in the result list, and you
may want to customize the font and/or font size. The rest of
the fonts used by &RCL; are determined by your generic Qt
config (try the <command>qtconfig</command> command).</para>
</listitem>
<listitem id="RCL.SEARCH.GUI.CUSTOM.RESULTPARA">
<para><guilabel>Edit result list paragraph format string</guilabel>:
allows you to change the presentation of each result list
entry. See the
<link linkend="RCL.SEARCH.GUI.CUSTOM.RESLIST">result list customisation section</link>.
</para>
</listitem>
<listitem id="RCL.SEARCH.GUI.CUSTOM.RESULTHEAD">
<para><guilabel>Edit result page HTML header insert</guilabel>:
allows you to define text inserted at the end of the result
page HTML header.
More detail in the
<link linkend="RCL.SEARCH.GUI.CUSTOM.RESLIST">result list customisation section</link>.
</para>
</listitem>
<listitem>
<para><guilabel>Date format</guilabel>: allows specifying the
format used for displaying dates inside the result list. This
should be specified as an strftime() string (man strftime).</para>
</listitem>
<listitem id="RCL.SEARCH.GUI.CUSTOM.ABSSEP">
<para><guilabel>Abstract snippet separator</guilabel>:
for synthetic abstracts built from index data, which are
usually made of several snippets from different parts of the
document, this defines the snippet separator, an ellipsis by
default. </para>
</listitem>
</itemizedlist></para>
</formalpara>
<formalpara id="RCL.SEARCH.GUI.CUSTOM.SEARCH">
<title>Search parameters:</title>
<para>
<itemizedlist>
<listitem><para><guilabel>Hide duplicate results</guilabel>:
decides if result list entries are shown for identical
documents found in different places.</para>
</listitem>
<listitem><para><guilabel>Stemming language</guilabel>:
stemming obviously depends on the document's language. This
listbox will let you chose among the stemming databases which
were built during indexing (this is set in the
<link linkend="RCL.INSTALL.CONFIG.RECOLLCONF">main configuration file</link>),
or later added with
<command>recollindex -s</command> (See the recollindex
manual). Stemming languages
which are dynamically added will be deleted at the next
indexing pass unless they are also added in the configuration
file.</para>
</listitem>
<listitem><para>
<guilabel>Automatically add phrase to simple searches</guilabel>:
a phrase will be automatically built and
added to simple searches when looking for
<literal>Any terms</literal>. This will give a relevance
boost to the results where the search terms appear as a
phrase (consecutive and in order).</para>
</listitem>
<listitem><para><guilabel>Autophrase term frequency threshold
percentage</guilabel>: very frequent terms should not be included
in automatic phrase searches for performance reasons. The
parameter defines the cutoff percentage (percentage of the
documents where the term appears).</para>
</listitem>
<listitem><para><guilabel>Replace abstracts from
documents</guilabel>: this decides if we should synthesize and
display an abstract in place of an explicit abstract found
within the document itself.</para>
</listitem>
<listitem><para><guilabel>Dynamically build
abstracts</guilabel>: this decides if &RCL; tries to build
document abstracts (lists of <emphasis>snippets</emphasis>)
when displaying the result list. Abstracts are constructed by
taking context from the document information, around the search
terms.</para>
</listitem>
<listitem><para><guilabel>Synthetic abstract size</guilabel>:
adjust to taste...</para>
</listitem>
<listitem><para><guilabel>Synthetic abstract context
words</guilabel>: how many words should be displayed around
each term occurrence.</para>
</listitem>
<listitem><para><guilabel>Query language magic file name
suffixes</guilabel>: a list of words which automatically get
turned into <literal>ext:xxx</literal> file name suffix clauses
when starting a query language query (e.g.:
<literal>doc xls xlsx...</literal>).
This will save some typing for people who
use file types a lot when querying.</para>
</listitem>
</itemizedlist>
</para>
</formalpara>
<formalpara id="RCL.SEARCH.GUI.CUSTOM.EXTRADB">
<title>External indexes:</title>
<para>This panel will let you browse for additional indexes
that you may want to search. External indexes are designated by
their database directory (ie:
<filename>/home/someothergui/.recoll/xapiandb</filename>,
<filename>/usr/local/recollglobal/xapiandb</filename>).</para>
</formalpara>
<para>Once entered, the indexes will appear in the
<guilabel>External indexes</guilabel> list, and you can
chose which ones you want to use at any moment by checking or
unchecking their entries.</para>
<para>Your main database (the one the current configuration
indexes to), is always implicitly active. If this is not
desirable, you can set up your configuration so that it indexes,
for example, an empty directory. An alternative indexer may also
need to implement a way of purging the index from stale data,
</para>
<sect3 id="RCL.SEARCH.GUI.CUSTOM.RESLIST">
<title>The result list format</title>
<para>Recoll normally uses a full function HTML processor to
display the result list and the
<link linkend="RCL.SEARCH.GUI.RESULTLIST.MENU.SNIPPETS">
snippets window</link>. Depending on the version, this may be
based on either Qt WebKit or Qt WebEngine.
It is then possible to completely customise the result list with full
support for CSS and Javascript.</para>
<para>It is also possible to build &RCL; to use a simpler Qt
QTextBrowser widget to display the HTML, which may be necessary
if the ones above are not ported on the system, or to reduce
the application size and dependencies. There are limits to what
you can do in this case, but it is still possible to decide
what data each result will contain, and how it will be
displayed.</para>
<para>The result list presentation can be customized
by adjusting two elements:
<itemizedlist>
<listitem><para>The paragraph format</para></listitem>
<listitem><para>HTML code inside the header section. For
versions 1.21 and later, this is also used for the
<link linkend="RCL.SEARCH.GUI.RESULTLIST.MENU.SNIPPETS">snippets window</link>.
</para></listitem>
</itemizedlist>
The paragraph format and the header fragment can be edited
from the <guilabel>Result list</guilabel> tab of the
<guilabel>GUI configuration</guilabel>.
</para>
<para>The header fragment is used both for the result list and
the snippets window. The snippets list is a table and has a
<literal>snippets</literal> class attribute. Each paragraph in
the result list is a table, with class
<literal>respar</literal>, but this can be changed by editing
the paragraph format.</para>
<para>There are a few examples on the
<ulink url="http://www.recoll.org/pages/custom.html">page about
customising the result list</ulink> on the &RCL; web site.</para>
<sect4 id="RCL.SEARCH.GUI.CUSTOM.RESLIST.PARA">
<title>The paragraph format</title>
<para>This is an arbitrary HTML string where the following printf-like
<literal>%</literal> substitutions will be performed:
<itemizedlist>
<listitem>
<formalpara><title>%A</title><para>Abstract</para></formalpara>
</listitem>
<listitem><formalpara><title>%D</title><para>Date</para></formalpara>
</listitem>
<listitem><formalpara><title>%I</title><para>Icon image
name. This is normally determined from the MIME type. The
associations are defined inside the
<link linkend="RCL.INSTALL.CONFIG.MIMECONF"><filename>mimeconf</filename> configuration file</link>.
If a thumbnail for the file is found at
the standard Freedesktop location, this will be displayed
instead.</para></formalpara>
</listitem>
<listitem><formalpara><title>%K</title><para>Keywords (if
any)</para></formalpara>
</listitem>
<listitem><formalpara><title>%L</title><para>Precooked Preview,
Edit, and possibly Snippets links</para></formalpara>
</listitem>
<listitem><formalpara><title>%M</title><para>MIME
type</para></formalpara>
</listitem>
<listitem><formalpara><title>%N</title><para>result Number inside
the result page</para></formalpara>
</listitem>
<listitem><formalpara><title>%P</title><para>Parent folder
Url. In the case of an embedded document, this is the parent folder
for the top level container file.</para></formalpara>
</listitem>
<listitem><formalpara><title>%R</title><para>Relevance
percentage</para></formalpara>
</listitem>
<listitem><formalpara><title>%S</title><para>Size
information</para></formalpara>
</listitem>
<listitem><formalpara><title>%T</title><para>Title or Filename if
not set.</para></formalpara>
</listitem>
<listitem><formalpara><title>%t</title><para>Title or empty.
</para></formalpara>
</listitem>
<listitem><formalpara><title>%(filename)</title><para>File name.
</para></formalpara>
</listitem>
<listitem><formalpara><title>%U</title><para>Url</para></formalpara>
</listitem>
</itemizedlist>
The format of the Preview, Edit, and Snippets links is
<literal>&lt;a href="P%N"&gt;</literal>,
<literal>&lt;a href="E%N"&gt;</literal>
and
<literal>&lt;a href="A%N"&gt;</literal>
where <replaceable>docnum</replaceable> (%N) expands to the document
number inside the result page).</para>
<para>A link target defined as <literal>"F%N"</literal> will open
the document corresponding to the <literal>%P</literal> parent
folder expansion, usually creating a file manager window on the
folder where the container file resides. E.g.:
<programlisting>&lt;a href="F%N"&gt;%P&lt;/a&gt;</programlisting>
</para>
<para>A link target defined as
<literal>R%N|<replaceable>scriptname</replaceable></literal> will
run the corresponding script on the result file (if the document is
embedded, the script will be started on the top-level parent).
See the <link linkend="RCL.SEARCH.GUI.RUNSCRIPT">section about defining scripts</link>.</para>
<para>In addition to the predefined values above, all strings
like <literal>%(fieldname)</literal> will be replaced by the
value of the field named <literal>fieldname</literal> for this
document. Only stored fields can be accessed in this way, the
value of indexed but not stored fields is not known at this
point in the search process
(see <link linkend="RCL.PROGRAM.FIELDS">field configuration</link>). There are currently very few fields
stored by default, apart from the values above
(only <literal>author</literal>
and <literal>filename</literal>), so this feature will need
some custom local configuration to be useful. An example
candidate would be the <literal>recipient</literal> field
which is generated by the message input handlers.</para>
<para>The default value for the paragraph format string is:
<screen><![CDATA[
"<table class=\"respar\">\n"
"<tr>\n"
"<td><a href='%U'><img src='%I' width='64'></a></td>\n"
"<td>%L &nbsp;<i>%S</i> &nbsp;&nbsp;<b>%T</b><br>\n"
"<span style='white-space:nowrap'><i>%M</i>&nbsp;%D</span>&nbsp;&nbsp;&nbsp; <i>%U</i>&nbsp;%i<br>\n"
"%A %K</td>\n"
"</tr></table>\n"
]]></screen>
You may, for example, try the following for a more web-like
experience:
<screen><![CDATA[
<u><b><a href="P%N">%T</a></b></u><br>
%A<font color=#008000>%U - %S</font> - %L
]]></screen>
Note that the P%N link in the above paragraph makes the title a
preview link. Or the clean looking:
<screen><![CDATA[
<img src="%I" align="left">%L <font color="#900000">%R</font>
&nbsp;&nbsp;<b>%T&</b><br>%S&nbsp;
<font color="#808080"><i>%U</i></font>
<table bgcolor="#e0e0e0">
<tr><td><div>%A</div></td></tr>
</table>%K
]]></screen>
</para>
<para>These samples, and some others are
<ulink url="http://www.recoll.org/pages/custom.html">on the web
site, with pictures to show how they look.</ulink></para>
<para>It is also possible to
<link linkend="RCL.SEARCH.GUI.CUSTOM.ABSSEP">define the value of the snippet separator inside the abstract section</link>.</para>
</sect4>
</sect3>
</sect2>
</sect1> <!-- search GUI -->
<sect1 id="RCL.SEARCH.KIO">
<title>Searching with the KDE KIO slave</title>
<sect2 id="RCL.SEARCH.KIO.INTRO">
<title>What's this</title>
<para>The &RCL; KIO slave allows performing a &RCL; search
by entering an appropriate URL in a KDE open dialog, or with an
HTML-based interface displayed in
<command>Konqueror</command>.</para>
<para>The HTML-based interface is similar to the Qt-based
interface, but slightly less powerful for now. Its advantage is
that you can perform your search while staying fully within the
KDE framework: drag and drop from the result list works normally
and you have your normal choice of applications for opening
files.</para>
<para>The alternative interface uses a directory view of search
results. Due to limitations in the current KIO slave interface,
it is currently not obviously useful (to me).</para>
<para>The interface is described in more detail inside a help
file which you can access by entering
<filename>recoll:/</filename> inside the
<command>konqueror</command> URL line (this works only if the
recoll KIO slave has been previously installed).</para>
<para>The instructions for building this module are located in the
source tree. See:
<filename>kde/kio/recoll/00README.txt</filename>. Some Linux
distributions do package the kio-recoll module, so check before
diving into the build process, maybe it's already out there ready for
one-click installation.</para>
</sect2>
<sect2 id="RCL.SEARCH.KIO.SEARCHABLEDOCS">
<title>Searchable documents</title>
<para>As a sample application, the &RCL; KIO slave could allow
preparing a set of HTML documents (for example a manual) so that
they become their own search interface inside
<command>konqueror</command>.</para>
<para>This can be done by either explicitly inserting
<literal><![CDATA[<a href="recoll://...">]]></literal> links
around some document areas, or automatically by adding a
very small <application>javascript</application> program to the
documents, like the following example, which would initiate a search by
double-clicking any term:</para>
<programlisting>&lt;script language="JavaScript">
function recollsearch() {
var t = document.getSelection();
window.location.href = 'recoll://search/query?qtp=a&amp;p=0&amp;q=' +
encodeURIComponent(t);
}
&lt;/script>
....
&lt;body ondblclick="recollsearch()">
</programlisting>
</sect2>
</sect1>
<sect1 id="RCL.SEARCH.COMMANDLINE">
<title>Searching on the command line</title>
<para>There are several ways to obtain search results as a text
stream, without a graphical interface:</para>
<itemizedlist>
<listitem><para>By passing option <option>-t</option> to the
<command>recoll</command> program, or by calling it as
<command>recollq</command> (through a link).</para>
</listitem>
<listitem><para>By using the <command>recollq</command> program.</para>
</listitem>
<listitem><para>By writing a custom
<application>Python</application> program, using the
<link linkend="RCL.PROGRAM.PYTHONAPI">Recoll Python API</link>.</para>
</listitem>
</itemizedlist>
<para>The first two methods work in the same way and accept/need the same
arguments (except for the additional <option>-t</option> to
<command>recoll</command>). The query to be executed is specified
as command line arguments.</para>
<para><command>recollq</command> is not always built by default. You
can use the <filename>Makefile</filename> in the
<filename>query</filename> directory to build it. This is a very
simple program, and if you can program a little c++, you may find it
useful to taylor its output format to your needs. Apart from being
easily customised, <command>recollq</command> is only really useful
on systems where the Qt libraries are not available, else it is
redundant with <literal>recoll -t</literal>.</para>
<para><command>recollq</command> has a
<ulink url="https://www.lesbonscomptes.com/recoll/manpages/recollq.1.html">man page</ulink>.
The Usage string follows:</para>
<programlisting><![CDATA[
recollq: usage:
-P: Show the date span for all the documents present in the index
[-o|-a|-f] [-q] <query string>
Runs a recoll query and displays result lines.
Default: will interpret the argument(s) as a xesam query string
Query elements:
* Implicit AND, exclusion, field spec: t1 -t2 title:t3
* OR has priority: t1 OR t2 t3 OR t4 means (t1 OR t2) AND (t3 OR t4)
* Phrase: "t1 t2" (needs additional quoting on cmd line)
-o Emulate the GUI simple search in ANY TERM mode
-a Emulate the GUI simple search in ALL TERMS mode
-f Emulate the GUI simple search in filename mode
-q is just ignored (compatibility with the recoll GUI command line)
Common options:
-c <configdir> : specify config directory, overriding $RECOLL_CONFDIR
-d also dump file contents
-n [first-]<cnt> define the result slice. The default value for [first]
is 0. Without the option, the default max count is 2000.
Use n=0 for no limit
-b : basic. Just output urls, no mime types or titles
-Q : no result lines, just the processed query and result count
-m : dump the whole document meta[] array for each result
-A : output the document abstracts
-S fld : sort by field <fld>
-D : sort descending
-s stemlang : set stemming language to use (must exist in index...)
Use -s "" to turn off stem expansion
-T <synonyms file>: use the parameter (Thesaurus) for word expansion
-i <dbdir> : additional index, several can be given
-e use url encoding (%xx) for urls
-F <field name list> : output exactly these fields for each result.
The field values are encoded in base64, output in one line and
separated by one space character. This is the recommended format
for use by other programs. Use a normal query with option -m to
see the field names. Use -F '' to output all fields, but you probably
also want option -N in this case
-N : with -F, print the (plain text) field names before the field values
]]></programlisting>
<para>Sample execution:</para>
<programlisting>
recollq 'ilur -nautique mime:text/html'
Recoll query: ((((ilur:(wqf=11) OR ilurs) AND_NOT (nautique:(wqf=11) OR nautiques OR nautiqu OR nautiquement)) FILTER Ttext/html))
4 results
text/html [file:///Users/uncrypted-dockes/projets/bateaux/ilur/comptes.html] [comptes.html] 18593 bytes
text/html [file:///Users/uncrypted-dockes/projets/nautique/webnautique/articles/ilur1/index.html] [Constructio...
text/html [file:///Users/uncrypted-dockes/projets/pagepers/index.html] [psxtcl/writemime/recoll]...
text/html [file:///Users/uncrypted-dockes/projets/bateaux/ilur/factEtCie/recu-chasse-maree....
</programlisting>
</sect1>
<sect1 id="RCL.SEARCH.LANG">
<title>The query language</title>
<para>The query language processor is activated in the GUI
simple search entry when the search mode selector is set to
<guilabel>Query Language</guilabel>. It can also be used with the KIO
slave or the command line search. It broadly has the same
capabilities as the complex search interface in the
GUI.</para>
<para>The language was based on the now defunct
<ulink url="http://www.xesam.org/main/XesamUserSearchLanguage95">
Xesam</ulink> user search language specification.</para>
<para>If the results of a query language search puzzle you and you
doubt what has been actually searched for, you can use the GUI
<literal>Show Query</literal> link at the top of the result list to
check the exact query which was finally executed by Xapian.</para>
<para>Here follows a sample request that we are going to
explain:</para>
<programlisting>
author:"john doe" Beatles OR Lennon Live OR Unplugged -potatoes
</programlisting>
<para>This would search for all documents with
<replaceable>John Doe</replaceable>
appearing as a phrase in the author field (exactly what this is
would depend on the document type, ie: the
<literal>From:</literal> header, for an email message),
and containing either <replaceable>beatles</replaceable> or
<replaceable>lennon</replaceable> and either
<replaceable>live</replaceable> or
<replaceable>unplugged</replaceable> but not
<replaceable>potatoes</replaceable> (in any part of the document).</para>
<para>An element is composed of an optional field specification,
and a value, separated by a colon (the field separator is the last
colon in the element). Examples:
<replaceable>Eugenie</replaceable>,
<replaceable>author:balzac</replaceable>,
<replaceable>dc:title:grandet</replaceable>
<replaceable>dc:title:"eugenie grandet"</replaceable>
</para>
<para>The colon, if present, means "contains". Xesam defines other
relations, which are mostly unsupported for now (except in special
cases, described further down).</para>
<para>All elements in the search entry are normally combined
with an implicit AND. It is possible to specify that elements be
OR'ed instead, as in <replaceable>Beatles</replaceable>
<literal>OR</literal> <replaceable>Lennon</replaceable>. The
<literal>OR</literal> must be entered literally (capitals), and
it has priority over the AND associations:
<replaceable>word1</replaceable>
<replaceable>word2</replaceable> <literal>OR</literal>
<replaceable>word3</replaceable>
means
<replaceable>word1</replaceable> AND
(<replaceable>word2</replaceable> <literal>OR</literal>
<replaceable>word3</replaceable>)
not
(<replaceable>word1</replaceable> AND
<replaceable>word2</replaceable>) <literal>OR</literal>
<replaceable>word3</replaceable>. </para>
<para>&RCL; versions 1.21 and later, allow using parentheses to
group elements, which will sometimes make things clearer, and may
allow expressing combinations which would have been difficult
otherwise.</para>
<para>An element preceded by a <literal>-</literal> specifies a
term that should <emphasis>not</emphasis> appear.</para>
<para>As usual, words inside quotes define a phrase
(the order of words is significant), so that
<replaceable>title:"prejudice pride"</replaceable> is not the same as
<replaceable>title:prejudice title:pride</replaceable>, and is
unlikely to find a result.</para>
<para>Words inside phrases and capitalized words are not
stem-expanded. Wildcards may be used anywhere inside a term.
Specifying a wild-card on the left of a term can produce a very
slow search (or even an incorrect one if the expansion is
truncated because of excessive size). Also see
<link linkend="RCL.SEARCH.WILDCARDS">More about wildcards</link>.
</para>
<para>To save you some typing, recent &RCL; versions (1.20 and later)
interpret a comma-separated list of terms for a field as an AND list
inside the field. Use slash characters ('/') for an OR list. No white
space is allowed. So
<programlisting>author:john,lennon</programlisting> will search for
documents with <literal>john</literal> and <literal>lennon</literal>
inside the <literal>author</literal> field (in any order), and
<programlisting>author:john/ringo</programlisting> would search for
<literal>john</literal> or <literal>ringo</literal>. This behaviour
only happens for field queries (input without a field, comma- or
slash- separated input will produce a phrase search). You can use a
<literal>text</literal> field name to search the main text this
way.</para>
<para>Modifiers can be set on a double-quote value, for example to specify
a proximity search (unordered). See
<link linkend="RCL.SEARCH.LANG.MODIFIERS">the modifier section</link>.
No space must separate the final double-quote and the modifiers
value, e.g. <replaceable>"two one"po10</replaceable></para>
<para>&RCL; currently manages the following default fields:</para>
<itemizedlist>
<listitem><para><literal>title</literal>,
<literal>subject</literal> or <literal>caption</literal> are
synonyms which specify data to be searched for in the
document title or subject.</para>
</listitem>
<listitem><para><literal>author</literal> or
<literal>from</literal> for searching the documents
originators.</para>
</listitem>
<listitem><para><literal>recipient</literal> or
<literal>to</literal> for searching the documents
recipients.</para>
</listitem>
<listitem><para><literal>keyword</literal> for searching the
document-specified keywords (few documents actually have
any).</para>
</listitem>
<listitem><para><literal>filename</literal> for the document's
file name. This is not necessarily set for all documents:
internal documents contained inside a compound one (for example
an EPUB section) do not inherit the container file name any more,
this was replaced by an explicit field (see next). Sub-documents
can still have a specific <literal>filename</literal>, if it is
implied by the document format, for example the attachment file
name for an email attachment.</para></listitem>
<listitem><para><literal>containerfilename</literal>. This is
set for all documents, both top-level and contained
sub-documents, and is always the name of the filesystem directory
entry which contains the data. The terms from this field can
only be matched by an explicit field specification (as opposed
to terms from <literal>filename</literal> which are also indexed
as general document content). This avoids getting matches for
all the sub-documents when searching for the container file
name.</para></listitem>
<listitem><para><literal>ext</literal> specifies the file
name extension
(Ex: <literal>ext:html</literal>).</para></listitem>
<listitem><para><literal>rclmd5</literal> the MD5 checksum for the
document. This is used for displaying the duplicates of a
search result (when querying with the option to collapse
duplicate results). Incidentally, this could be used to find
the duplicates of any given file by computing its MD5 checksum
and executing a query with just the <literal>rclmd5</literal>
value.</para>
</listitem>
</itemizedlist>
<para>&RCL; 1.20 and later have a way to specify aliases for the
field names, which will save typing, for example by aliasing
<literal>filename</literal> to <replaceable>fn</replaceable> or
<literal>containerfilename</literal> to
<replaceable>cfn</replaceable>. See the
<link linkend="RCL.INSTALL.CONFIG.FIELDS">section about the <filename>fields</filename> file</link>.
</para>
<para>The document input handlers used while indexing have the
possibility to create other fields with arbitrary names, and
aliases may be defined in the configuration, so that the exact
field search possibilities may be different for you if someone
took care of the customisation.</para>
<para>The field syntax also supports a few field-like, but
special, criteria:</para>
<itemizedlist>
<listitem><para><literal>dir</literal> for filtering the
results on file location
(Ex: <literal>dir:/home/me/somedir</literal>).
<literal>-dir</literal>
also works to find results not in the specified directory
(release >= 1.15.8). Tilde expansion will be performed as
usual (except for a bug in versions 1.19 to
1.19.11p1). Wildcards will be expanded, but
please
<link linkend="RCL.SEARCH.WILDCARDS.PATH"> have a look</link>
at an important limitation of wildcards in path filters.</para>
<para>Relative paths also make sense, for example,
<literal>dir:share/doc</literal> would match either
<filename>/usr/share/doc</filename> or
<filename>/usr/local/share/doc</filename> </para>
<para>Several <literal>dir</literal> clauses can be specified,
both positive and negative. For example the following makes sense:
<programlisting>
dir:recoll dir:src -dir:utils -dir:common
</programlisting> This would select results which have both
<filename>recoll</filename> and <filename>src</filename> in the
path (in any order), and which have not either
<filename>utils</filename> or
<filename>common</filename>.</para>
<para>You can also use <literal>OR</literal> conjunctions
with <literal>dir:</literal> clauses.</para>
<para>A special aspect of <literal>dir</literal> clauses is
that the values in the index are not transcoded to UTF-8, and
never lower-cased or unaccented, but stored as binary. This means
that you need to enter the values in the exact lower or upper
case, and that searches for names with diacritics may sometimes
be impossible because of character set conversion
issues. Non-ASCII UNIX file paths are an unending source of
trouble and are best avoided.</para>
<para>You need to use double-quotes around the path value if it
contains space characters.</para>
</listitem>
<listitem><para><literal>size</literal> for filtering the
results on file size. Example:
<literal>size&lt;10000</literal>. You can use
<literal>&lt;</literal>, <literal>&gt;</literal> or
<literal>=</literal> as operators. You can specify a range like the
following: <literal>size>100 size&lt;1000</literal>. The usual
<literal>k/K, m/M, g/G, t/T</literal> can be used as (decimal)
multipliers. Ex: <literal>size&gt;1k</literal> to search for files
bigger than 1000 bytes.</para>
</listitem>
<listitem><para><literal>date</literal> for searching or filtering
on dates. The syntax for the argument is based on the ISO8601
standard for dates and time intervals. Only dates are supported, no
times. The general syntax is 2 elements separated by a
<literal>/</literal> character. Each element can be a date or a
period of time. Periods are specified as
<literal>P</literal><replaceable>n</replaceable><literal>Y</literal><replaceable>n</replaceable><literal>M</literal><replaceable>n</replaceable><literal>D</literal>.
The <replaceable>n</replaceable> numbers are the respective numbers
of years, months or days, any of which may be missing. Dates are
specified as
<replaceable>YYYY</replaceable>-<replaceable>MM</replaceable>-<replaceable>DD</replaceable>.
The days and months parts may be missing. If the
<literal>/</literal> is present but an element is missing, the
missing element is interpreted as the lowest or highest date in the
index. Examples:</para>
<itemizedlist>
<listitem><para><literal>2001-03-01/2002-05-01</literal> the
basic syntax for an interval of dates.</para>
</listitem>
<listitem><para><literal>2001-03-01/P1Y2M</literal> the
same specified with a period.</para>
</listitem>
<listitem><para><literal>2001/</literal> from the beginning of
2001 to the latest date in the index.</para>
</listitem>
<listitem><para><literal>2001</literal> the whole year of
2001</para></listitem>
<listitem><para><literal>P2D/</literal> means 2 days ago up to
now if there are no documents with dates in the future.</para>
</listitem>
<listitem><para><literal>/2003</literal> all documents from
2003 or older.</para>
</listitem>
</itemizedlist>
<para>Periods can also be specified with small letters (ie:
p2y).</para>
</listitem>
<listitem><para><literal>mime</literal> or
<literal>format</literal> for specifying the
MIME type. These clauses are processed besides the normal
Boolean logic of the search. Multiple values will be OR'ed
(instead of the normal AND). You can specify types to be
excluded, with the usual <literal>-</literal>, and use
wildcards. Example: <replaceable>mime:text/*
-mime:text/plain</replaceable>
Specifying an explicit boolean
operator before a <literal>mime</literal> specification is not
supported and will produce strange results. </para>
</listitem>
<listitem><para><literal>type</literal> or
<literal>rclcat</literal> for specifying the category (as in
text/media/presentation/etc.). The classification of MIME
types in categories is defined in the &RCL; configuration
(<filename>mimeconf</filename>), and can be modified or
extended. The default category names are those which permit
filtering results in the main GUI screen. Categories are OR'ed
like MIME types above, and can be negated with
<literal>-</literal>.</para>
</listitem>
<listitem><para><literal>issub</literal>
for specifying that only standalone (<literal>issub:0</literal>) or
only embedded (<literal>issub:1</literal>) documents should be
returned as results.</para>
</listitem>
</itemizedlist>
<note><para>
<literal>mime</literal>, <literal>rclcat</literal>, <literal>size</literal>,
<literal>issub</literal> and <literal>date</literal> criteria always
affect the whole query (they are applied as a final filter), even if set
with other terms inside a parenthese.</para>
</note>
<note><para>
<literal>mime</literal> (or the equivalent
<literal>rclcat</literal>) is the <emphasis>only</emphasis>
field with an <literal>OR</literal> default. You do need to use
<literal>OR</literal> with <literal>ext</literal> terms for
example.</para> </note>
<sect2 id="RCL.SEARCH.LANG.RANGES">
<title>Range clauses</title>
<para>&RCL; 1.24 and later support range clauses on fields which
have been configured to support it. No default field uses them
currently, so this paragraph is only interesting if you modified
the fields configuration and possibly use a custom input
handler.</para>
<para>A range clause looks like one of the following:</para>
<programlisting><replaceable>myfield</replaceable>:<replaceable>small</replaceable>..<replaceable>big</replaceable>
<replaceable>myfield</replaceable>:<replaceable>small</replaceable>..
<replaceable>myfield</replaceable>:..<replaceable>big</replaceable>
</programlisting>
<para>The nature of the clause is indicated by the two dots
<literal>..</literal>, and the effect is to filter the results for
which the <replaceable>myfield</replaceable> value is in the
possibly open-ended interval.</para>
<para>See the section about the
<link linkend="RCL.INSTALL.CONFIG.FIELDS"><filename>fields</filename> configuration file</link>
for the details of configuring a field for range searches (list
them in the [values] section).</para>
</sect2>
<sect2 id="RCL.SEARCH.LANG.MODIFIERS">
<title>Modifiers</title>
<para>Some characters are recognized as search modifiers when found
immediately after the closing double quote of a phrase, as in
<literal>"some term"modifierchars</literal>. The actual "phrase"
can be a single term of course. Supported modifiers:
<itemizedlist>
<listitem><para><literal>l</literal> can be used to turn off
stemming (mostly makes sense with <literal>p</literal> because
stemming is off by default for phrases).</para>
</listitem>
<listitem><para><literal>s</literal> can be used to turn off
synonym expansion, if a synonyms file is in place (only for
&RCL; 1.22 and later).</para>
</listitem>
<listitem><para><literal>o</literal> can be used to specify a
"slack" for phrase and proximity searches: the number of
additional terms that may be found between the specified
ones. If <literal>o</literal> is followed by an integer number,
this is the slack, else the default is 10.</para>
</listitem>
<listitem><para><literal>p</literal> can be used to turn the
default phrase search into a proximity one
(unordered). Example: <literal>"order any in"p</literal></para>
</listitem>
<listitem><para><literal>C</literal> will turn on case
sensitivity (if the index supports it).</para></listitem>
<listitem><para><literal>D</literal> will turn on diacritics
sensitivity (if the index supports it).</para></listitem>
<listitem><para>A weight can be specified for a query element
by specifying a decimal value at the start of the
modifiers. Example: <literal>"Important"2.5</literal>.</para>
</listitem>
</itemizedlist>
</para>
</sect2> <!-- search modifiers -->
</sect1> <!-- rcl.search.lang -->
<sect1 id="RCL.SEARCH.ANCHORWILD">
<title>Anchored searches and wildcards</title>
<para>Some special characters are interpreted by &RCL; in search
strings to expand or specialize the search. Wildcards expand a root
term in controlled ways. Anchor characters can restrict a search to
succeed only if the match is found at or near the beginning of the
document or one of its fields.</para>
<sect2 id="RCL.SEARCH.WILDCARDS">
<title>More about wildcards</title>
<para>All words entered in &RCL; search fields will be processed
for wildcard expansion before the request is finally
executed.</para>
<para>The wildcard characters are:</para>
<itemizedlist>
<listitem><para><literal>*</literal> which matches 0 or more
characters.</para>
</listitem>
<listitem><para><literal>?</literal> which matches
a single character.</para>
</listitem>
<listitem><para><literal>[]</literal> which allow
defining sets of characters to be matched (ex:
<literal>[</literal><userinput>abc</userinput><literal>]</literal>
matches a single character which may be 'a' or 'b' or 'c',
<literal>[</literal><userinput>0-9</userinput><literal>]</literal>
matches any number.</para>
</listitem>
</itemizedlist>
<para>You should be aware of a few things when using
wildcards.</para>
<itemizedlist>
<listitem><para>Using a wildcard character at the beginning of
a word can make for a slow search because &RCL; will have to
scan the whole index term list to find the
matches. However, this is much less a problem for field
searches, and queries
like <replaceable>author:*@domain.com</replaceable> can
sometimes be very useful.</para></listitem>
<listitem><para>For &RCL; version 18 only, when working with a
raw index (preserving character case and diacritics), the
literal part of a wildcard expression will be matched
exactly for case and diacritics. This is not true any
more for versions 19 and later.</para></listitem>
<listitem><para>Using a <literal>*</literal> at the end of a
word can produce more matches than you would think, and
strange search results. You can use the
<link linkend="RCL.SEARCH.GUI.TERMEXPLORER">term explorer</link>
tool to check what completions exist for
a given term. You can also see exactly what search was
performed by clicking on the link at the top of the result
list. In general, for natural language terms, stem
expansion will produce better results than an
ending <literal>*</literal> (stem expansion is turned off
when any wildcard character appears in the
term).</para></listitem>
</itemizedlist>
<sect3 id="RCL.SEARCH.WILDCARDS.PATH">
<title>Wildcards and path filtering</title>
<para>Due to the way that &RCL; processes wildcards
inside <literal>dir</literal> path filtering clauses, they
will have a multiplicative effect on the query size. A clause
containing wildcards in several paths elements, like, for
example,
<literal>dir:</literal><replaceable>/home/me/*/*/docdir</replaceable>,
will almost certainly fail if your indexed tree is of any realistic
size.</para>
<para>Depending on the case, you may be able to work around
the issue by specifying the paths elements more narrowly, with
a constant prefix, or by using 2
separate <literal>dir:</literal> clauses instead of multiple
wildcards, as
in <literal>dir:</literal><replaceable>/home/me</replaceable> <literal>dir:</literal><replaceable>docdir</replaceable>. The
latter query is not equivalent to the initial one because it
does not specify a number of directory levels, but that's
the best we can do (and it may be actually more useful in
some cases).</para>
</sect3>
</sect2> <!-- wildchars -->
<sect2 id="RCL.SEARCH.ANCHOR">
<title>Anchored searches</title>
<para>Two characters are used to specify that a search hit should
occur at the beginning or at the end of the
text. <literal>^</literal> at the beginning of a term or phrase
constrains the search to happen at the start, <literal>$</literal>
at the end force it to happen at the end.</para>
<para>As this function is implemented as a phrase search it is
possible to specify a maximum distance at which the hit should
occur, either through the controls of the advanced search panel, or
using the query language, for example, as in:
<programlisting>"^someterm"o10</programlisting> which would force
<literal>someterm</literal> to be found within 10 terms of the
start of the text. This can be combined with a field search as in
<literal>somefield:"^someterm"o10</literal> or
<literal>somefield:someterm$</literal>.</para>
<para>This feature can also be used with an actual phrase search,
but in this case, the distance applies to the whole phrase and
anchor, so that, for example,
<literal>bla bla my unexpected term</literal> at the
beginning of the text would be a match for
<literal>"^my term"o5</literal>.</para>
<para>Anchored searches can be very useful for searches inside
somewhat structured documents like scientific articles, in case
explicit metadata has not been supplied (a most frequent case), for
example for looking for matches inside the abstract or the list of
authors (which occur at the top of the document).</para>
</sect2>
</sect1> <!-- wildchars and anchors -->
<sect1 id="RCL.SEARCH.SYNONYMS">
<title>Using Synonyms (1.22)</title>
<formalpara><title>Term synonyms and text search:</title> <para>in
general, there are two main ways to use term synonyms for
searching text:
<itemizedlist>
<listitem><para>At index creation time, they can be used to alter the
indexed terms, either increasing or decreasing their number, by
expanding the original terms to all synonyms, or by
reducing all synonym terms to a canonical one.</para></listitem>
<listitem><para>At query time, they can be used to match texts
containing terms which are synonyms of the ones specified by the user,
either by expanding the query for all synonyms, or by reducing the user
entry to canonical terms (the latter only works if the corresponding
processing has been performed while creating the
index).</para></listitem>
</itemizedlist>
</para>
</formalpara>
<para>&RCL; only uses synonyms at query time. A user query term which
part of a synonym group will be optionally expanded into an
<literal>OR</literal> query for all terms in the group.</para>
<para>Synonym groups are defined inside ordinary text files. Each line
in the file defines a group.</para>
<para>Example:
<programlisting>
hi hello "good morning"
# not sure about "au revoir" though. Is this english ?
bye goodbye "see you" \
"au revoir"
</programlisting>
</para>
<para>As usual, lines beginning with a <literal>#</literal> are comments,
empty lines are ignored, and lines can be continued by ending them with
a backslash.
</para>
<para>Multi-word synonyms are supported, but be aware that these will
generate phrase queries, which may degrade performance and will disable
stemming expansion for the phrase terms.</para>
<para>The contents of the synonyms file must be casefolded (not only
lowercased), because this is what expected at the point in the query
processing where it is used. There are a few cases where this makes a
difference, for example, German sharp s should be expressed as
<literal>ss</literal>, Greek final sigma as sigma. For reference,
Python3 has an easy way to casefold words (str.casefold()).</para>
<para>The synonyms file can be specified in the <guilabel>Search
parameters</guilabel> tab of the <guilabel>GUI configuration</guilabel>
<guilabel>Preferences</guilabel> menu entry, or as an option for
command-line searches.</para>
<para>Once the file is defined, the use of synonyms can be enabled or
disabled directly from the <guilabel>Preferences</guilabel>
menu.</para>
<para>The synonyms are searched for matches with user terms after the
latter are stem-expanded, but the contents of the synonyms file itself
is not subjected to stem expansion. This means that a match will not be
found if the form present in the synonyms file is not present anywhere
in the document set (same with accents when using a raw index).</para>
<para>The synonyms function is probably not going to help you find your
letters to Mr. Smith. It is best used for domain-specific searches. For
example, it was initially suggested by a user performing searches among
historical documents: the synonyms file would contains nicknames and
aliases for each of the persons of interest.</para>
</sect1>
<sect1 id="RCL.SEARCH.PTRANS">
<title>Path translations</title>
<para>In some cases, the document paths stored inside the index do
not match the actual ones, so that document
previews and accesses will fail. This can occur in a number of
circumstances:</para>
<itemizedlist>
<listitem><para>When using multiple indexes it is a relatively common
occurrence that some will actually reside on a remote volume, for
example mounted via NFS. In this case, the paths used to access
the documents on the local machine are not necessarily the same
than the ones used while indexing on the remote machine. For
example, <filename>/home/me</filename> may have been used as
a <literal>topdirs</literal> elements while indexing, but the
directory might be mounted
as <filename>/net/server/home/me</filename> on the local
machine.</para></listitem>
<listitem><para>The case may also occur with removable
disks. It is perfectly possible to configure an index to
live with the documents on the removable disk, but it may
happen that the disk is not mounted at the same place so
that the documents paths from the index are
invalid.</para></listitem>
<listitem><para>As a last example, one could imagine that a big
directory has been moved, but that it is currently
inconvenient to run the indexer.</para></listitem>
</itemizedlist>
<para>&RCL; has a facility for rewriting access paths when
extracting the data from the index. The translations can be
defined for the main index and for any additional query
index.</para>
<para>The path translation facility will be useful
whenever the documents paths seen by the indexer are not the same
as the ones which should be used at query time.</para>
<para>In the above NFS example, &RCL; could be instructed to
rewrite any <filename>file:///home/me</filename> URL from the
index to <filename>file:///net/server/home/me</filename>,
allowing accesses from the client.</para>
<para>The translations are defined in the
<link linkend="RCL.INSTALL.CONFIG.PTRANS"><filename>ptrans</filename></link>
configuration file, which
can be edited by hand or from the GUI external indexes
configuration dialog: <menuchoice>
<guimenu>Preferences</guimenu>
<guimenuitem>External index dialog</guimenuitem>
</menuchoice>, then click the <guilabel>Paths
translations</guilabel> button on the right below the index
list.</para>
<note><para>Due to a current bug, the GUI must be restarted
after changing the <filename>ptrans</filename> values (even when they
were changed from the GUI).</para></note>
</sect1>
<sect1 id="RCL.SEARCH.CASEDIAC">
<title>Search case and diacritics sensitivity</title>
<para>For &RCL; versions 1.18 and later, and <emphasis>when working
with a raw index</emphasis> (not the default), searches can be
sensitive to character case and diacritics. How this happens
is controlled by configuration variables and what search data is
entered.</para>
<para>The general default is that searches entered without upper-case
or accented characters are insensitive to case and diacritics. An
entry of <literal>resume</literal> will match any of
<literal>Resume</literal>, <literal>RESUME</literal>,
<literal>résumé</literal>, <literal>Résumé</literal> etc.</para>
<para>Two configuration variables can automate switching on
sensitivity (they were documented but actually did nothing until
&RCL; 1.22):</para>
<variablelist>
<varlistentry>
<term>autodiacsens</term><listitem><para>If this is set, search
sensitivity to diacritics will be turned on as soon as an
accented character exists in a search term. When the variable
is set to true, <literal>resume</literal> will start a
diacritics-unsensitive search, but <literal>résumé</literal>
will be matched exactly. The default value is
<emphasis>false</emphasis>.</para></listitem>
</varlistentry>
<varlistentry>
<term>autocasesens</term><listitem><para>If this is set, search
sensitivity to character case will be turned on as soon as an
upper-case character exists in a search term <emphasis>except
for the first one</emphasis>. When the variable is set to
true, <literal>us</literal> or <literal>Us</literal> will
start a diacritics-unsensitive search, but
<literal>US</literal> will be matched exactly. The default
value is <emphasis>true</emphasis> (contrary to
<literal>autodiacsens</literal>).</para></listitem>
</varlistentry>
</variablelist>
<para>As in the past, capitalizing the first letter of a word will
turn off its stem expansion and have no effect on
case-sensitivity.</para>
<para>You can also explicitly activate case and diacritics
sensitivity by using modifiers with the query
language. <literal>C</literal> will make the term case-sensitive, and
<literal>D</literal> will make it
diacritics-sensitive. Examples:</para>
<programlisting>
"us"C
</programlisting>
<para>will search for the term <literal>us</literal> exactly
(<literal>Us</literal> will not be a match).</para>
<programlisting>
"resume"D
</programlisting>
<para>will search for the term <literal>resume</literal> exactly
(<literal>résumé</literal> will not be a match).</para>
<para>When either case or diacritics sensitivity is activated, stem
expansion is turned off. Having both does not make much sense.</para>
</sect1>
<sect1 id="RCL.SEARCH.DESKTOP">
<title>Desktop integration</title>
<para>Being independent of the desktop type has its drawbacks: &RCL;
desktop integration is minimal. However there are a few tools
available:
<itemizedlist>
<listitem>
<para>Users of recent Ubuntu-derived distributions, or
any other Gnome desktop systems (e.g. Fedora) can install the
<ulink
url="https://www.lesbonscomptes.com/recoll/pages/download.html#gssp">
Recoll GSSP</ulink> (Gnome Shell Search Provider).</para>
</listitem>
<listitem>
<para>The <application>KDE</application> KIO Slave was described
in a <link linkend="RCL.SEARCH.KIO">previous
section</link>. It can provide search results
inside <command>Dolphin</command>. </para>
</listitem>
<listitem>
<para>If you use an oldish version of Ubuntu Linux, you may
find the <ulink url="&FAQS;UnityLens">Ubuntu Unity
Lens</ulink> module useful.</para>
</listitem>
<listitem>
<para>There is also an independently developed
<ulink
url="http://kde-apps.org/content/show.php/recollrunner?content=128203">
Krunner plugin</ulink>.</para>
</listitem>
</itemizedlist>
</para>
<para>Here follow a few other things that may help.</para>
<sect2 id="RCL.SEARCH.SHORTCUT">
<title>Hotkeying recoll</title>
<para>It is surprisingly convenient to be able to show or hide the
&RCL; GUI with a single keystroke. Recoll comes with a small
Python script, based on the <application>libwnck</application> window
manager interface library, which will allow you to do just
this. The detailed instructions are on
<ulink url="&FAQS;HotRecoll">this wiki page</ulink>.</para>
</sect2>
<sect2 id="RCL.KICKER-APPLET">
<title>The KDE Kicker Recoll applet</title>
<para>This is probably obsolete now. Anyway:</para>
<para>The &RCL; source tree contains the source code to the
<application>recoll_applet</application>, a small application derived
from the <application>find_applet</application>. This can be used to
add a small &RCL; launcher to the KDE panel.</para>
<para>The applet is not automatically built with the main &RCL;
programs, nor is it included with the main source distribution
(because the KDE build boilerplate makes it relatively big). You can
download its source from the recoll.org download page. Use the
omnipotent <userinput>configure;make;make install</userinput>
incantation to build and install.</para>
<para>You can then add the applet to the panel by right-clicking the
panel and choosing the <guilabel>Add applet</guilabel> entry.</para>
<para>The <application>recoll_applet</application> has a small text
window where you can type a &RCL; query (in query language form),
and an icon which can be used to restrict the search to certain
types of files. It is quite primitive, and launches a new recoll
GUI instance every time (even if it is already running). You may
find it useful anyway.</para>
</sect2>
</sect1> <!-- rcl.search.desktop -->
</chapter> <!-- Search -->
<chapter id="RCL.PROGRAM">
<title>Programming interface</title>
<para>&RCL; has an Application Programming Interface, usable both
for indexing and searching, currently accessible from the
<application>Python</application> language.</para>
<para>Another less radical way to extend the application is to
write input handlers for new types of documents.</para>
<para>The processing of metadata attributes for documents
(<literal>fields</literal>) is highly configurable.</para>
<sect1 id="RCL.PROGRAM.FILTERS">
<title>Writing a document input handler</title>
<note><title>Terminology</title><para>The small programs or pieces
of code which handle the processing of the different document
types for &RCL; used to be called <literal>filters</literal>,
which is still reflected in the name of the directory which
holds them and many configuration variables. They were named
this way because one of their primary functions is to filter
out the formatting directives and keep the text
content. However these modules may have other behaviours, and
the term <literal>input handler</literal> is now progressively
substituted in the documentation. <literal>filter</literal> is
still used in many places though.</para></note>
<para>&RCL; input handlers cooperate to translate from the multitude
of input document formats, simple ones as
<application>opendocument</application>,
<application>acrobat</application>, or compound ones such as
<application>Zip</application> or <application>Email</application>,
into the final &RCL; indexing input format, which is plain text (in
many cases the processing pipeline has an intermediary HTML step,
which may be used for better previewing presentation). Most input
handlers are executable programs or scripts. A few handlers are coded
in C++ and live inside <command>recollindex</command>. This latter
kind will not be described here.</para>
<para>There are two kinds of external executable input handlers:
<itemizedlist>
<listitem><para>Simple <literal>exec</literal> handlers
run once and exit. They can be bare programs like
<command>antiword</command>, or scripts using other
programs. They are very simple to write, because they just
need to print the converted document to the standard
output. Their output can be plain text or HTML. HTML is
usually preferred because it can store metadata fields and
it allows preserving some of the formatting for the GUI
preview. However, these handlers have limitations:
<itemizedlist>
<listitem><para>They can only process one document
per file.</para></listitem>
<listitem><para>The output MIME type must be known and
fixed.</para></listitem>
<listitem><para>The character encoding, if relevant, must be
known and fixed (or possibly just depending on
location).</para></listitem>
</itemizedlist>
</para>
</listitem>
<listitem><para>Multiple <literal>execm</literal> handlers can
process multiple files (sparing the process startup time which can
be very significant), or multiple documents per file (e.g.: for
archives or multi-chapter publications). They communicate with the
indexer through a simple protocol, but are nevertheless a bit more
complicated than the older kind. Most of the new handlers are
written in <application>Python</application> (exception:
<command>rclimg</command> which is written in Perl because
<literal>exiftool</literal> has no real Python equivalent). The
Python handlers use common modules to factor out the boilerplate,
which can make them very simple in favorable cases. The
subdocuments output by these handlers can be directly indexable
(text or HTML), or they can be other simple or compound documents
that will need to be processed by another handler.</para>
</listitem>
</itemizedlist>
</para>
<para>In both cases, handlers deal with regular file system
files, and can process either a single document, or a
linear list of documents in each file. &RCL; is responsible
for performing up to date checks, deal with more complex
embedding and other upper level issues.</para>
<para>A simple handler returning a
document in <literal>text/plain</literal> format, can transfer
no metadata to the indexer. Generic metadata, like document
size or modification date, will be gathered and stored by
the indexer.</para>
<para>Handlers that produce <literal>text/html</literal>
format can return an arbitrary amount of metadata inside HTML
<literal>meta</literal> tags. These will be processed
according to the directives found in
the <link linkend="RCL.PROGRAM.FIELDS"><filename>fields</filename> configuration file</link>.
</para>
<para>The handlers that can handle multiple documents per file
return a single piece of data to identify each document inside
the file. This piece of data, called
an <literal>ipath</literal> will be sent back by
&RCL; to extract the document at query time, for previewing,
or for creating a temporary file to be opened by a
viewer. These handlers can also return metadata either as HTML
<literal>meta</literal> tags, or as named data through the
communication protocol.</para>
<para>The following section describes the simple
handlers, and the next one gives a few explanations about
the <literal>execm</literal> ones. You could conceivably
write a simple handler with only the elements in the
manual. This will not be the case for the other ones, for
which you will have to look at the code.</para>
<sect2 id="RCL.PROGRAM.FILTERS.SIMPLE">
<title>Simple input handlers</title>
<para>&RCL; simple handlers are usually shell-scripts, but this is in
no way necessary. Extracting the text from the native format is the
difficult part. Outputting the format expected by &RCL; is
trivial. Happily enough, most document formats have translators or
text extractors which can be called from the handler. In some cases
the output of the translating program is completely appropriate,
and no intermediate shell-script is needed.</para>
<para>Input handlers are called with a single argument which is the
source file name. They should output the result to stdout.</para>
<para>When writing a handler, you should decide if it will output
plain text or HTML. Plain text is simpler, but you will not be able
to add metadata or vary the output character encoding (this will be
defined in a configuration file). Additionally, some formatting may
be easier to preserve when previewing HTML. Actually the deciding factor
is metadata: &RCL; has a way to
<link linkend="RCL.PROGRAM.FILTERS.HTML">extract metadata from the HTML header and use it for field searches.</link>.
</para>
<para>The <envar>RECOLL_FILTER_FORPREVIEW</envar> environment
variable (values <literal>yes</literal>, <literal>no</literal>)
tells the handler if the operation is for indexing or
previewing. Some handlers use this to output a slightly different
format, for example stripping uninteresting repeated keywords (ie:
<literal>Subject:</literal> for email) when indexing. This is not
essential.</para>
<para>You should look at one of the simple handlers, for example
<command>rclps</command> for a starting point.</para>
<para>Don't forget to make your handler executable before
testing !</para>
</sect2>
<sect2 id="RCL.PROGRAM.FILTERS.MULTIPLE">
<title>"Multiple" handlers</title>
<para>If you can program and want to write
an <literal>execm</literal> handler, it should not be too
difficult to make sense of one of the existing handlers.</para>
<para>The existing handlers differ in the amount of helper code
which they are using:
<itemizedlist>
<listitem><para><literal>rclimg</literal> is written in Perl and
handles the execm protocol all by itself (showing how trivial it
is).</para></listitem> <listitem><para>All the Python handlers
share at least the <filename>rclexecm.py</filename> module, which
handles the communication. Have a look at, for
example, <filename>rclzip</filename> for a handler which
uses <filename>rclexecm.py</filename>
directly.</para></listitem> <listitem><para>Most Python handlers
which process single-document files by executing another command
are further abstracted by using
the <filename>rclexec1.py</filename> module. See for
example <filename>rclrtf.py</filename> for a simple one,
or <filename>rcldoc.py</filename> for a slightly more complicated
one (possibly executing several
commands).</para></listitem> <listitem><para>Handlers which
extract text from an XML document by using an XSLT style sheet
are now executed inside <command>recollindex</command>, with only
the style sheet stored in the <filename>filters/</filename>
directory. These can use a single style sheet
(e.g. <filename>abiword.xsl</filename>), or two sheets for the
data and metadata (e.g. <filename>opendoc-body.xsl</filename>
and <filename>opendoc-meta.xsl</filename>). The <filename>mimeconf</filename>
configuration file defines how the sheets are used, have a
look. Before the C++ import, the xsl-based handlers used a common
module <filename>rclgenxslt.py</filename>, it is still around but
unused at the moment. The handler for OpenXML presentations is
still the Python version because the format did not fit with what
the C++ code does. It would be a good base for another similar
issue.</para></listitem>
</itemizedlist>
</para>
<para>There is a sample trivial handler based on
<filename>rclexecm.py</filename>, with many comments, not actually
used by &RCL;. It would index a text file as one document per
line. Look for <filename>rcltxtlines.py</filename> in the
<filename>src/filters</filename> directory in the online &RCL;
<ulink url="https://framagit.org/medoc92/recoll">Git
repository</ulink> (the sample not in the distributed release at
the moment).</para>
<para>You can also have a look at the slightly more complex
<command>rclzip</command> which uses Zip
file paths as identifiers (<literal>ipath</literal>).</para>
<para><literal>execm</literal> handlers sometimes need to make
a choice for the nature of the <literal>ipath</literal>
elements that they use in communication with the
indexer. Here are a few guidelines:
<itemizedlist>
<listitem><para>Use ASCII or UTF-8 (if the identifier is an
integer print it, for example, like printf %d would
do).</para></listitem>
<listitem><para>If at all possible, the data should make some
kind of sense when printed to a log file to help with
debugging.</para></listitem>
<listitem><para>&RCL; uses a colon (<literal>:</literal>) as a
separator to store a complex path internally (for
deeper embedding). Colons inside
the <literal>ipath</literal> elements output by a
handler will be escaped, but would be a bad choice as a
handler-specific separator (mostly, again, for
debugging issues).</para></listitem>
</itemizedlist>
In any case, the main goal is that it should
be easy for the handler to extract the target document, given
the file name and the <literal>ipath</literal>
element.</para>
<para><literal>execm</literal> handlers will also produce
a document with a null <literal>ipath</literal>
element. Depending on the type of document, this may have
some associated data (e.g. the body of an email message), or
none (typical for an archive file). If it is empty, this
document will be useful anyway for some operations, as the
parent of the actual data documents.</para>
</sect2>
<sect2 id="RCL.PROGRAM.FILTERS.ASSOCIATION">
<title>Telling &RCL; about the handler</title>
<para>There are two elements that link a file to the handler which
should process it: the association of file to MIME type and the
association of a MIME type with a handler.</para>
<para>The association of files to MIME types is mostly based on
name suffixes. The types are defined inside the
<link linkend="RCL.INSTALL.CONFIG.MIMEMAP"><filename>mimemap</filename> file</link>.
Example:
<programlisting>
.doc = application/msword
</programlisting>
If no suffix association is found for the file name, &RCL; will try
to execute a system command (typically <command>file -i</command> or
<command>xdg-mime</command>) to determine a MIME type.</para>
<para>The second element is the association of MIME types to handlers
in the <link linkend="RCL.INSTALL.CONFIG.MIMECONF"><filename>mimeconf</filename> file</link>.
A sample will probably be better than a long explanation:</para>
<programlisting>
[index]
application/msword = exec antiword -t -i 1 -m UTF-8;\
mimetype = text/plain ; charset=utf-8
application/ogg = exec rclogg
text/rtf = exec unrtf --nopict --html; charset=iso-8859-1; mimetype=text/html
application/x-chm = execm rclchm
</programlisting>
<para>The fragment specifies that:
<itemizedlist>
<listitem><para><literal>application/msword</literal> files
are processed by executing the <command>antiword</command>
program, which outputs
<literal>text/plain</literal> encoded in
<literal>utf-8</literal>.</para>
</listitem>
<listitem><para><literal>application/ogg</literal> files are
processed by the <command>rclogg</command> script, with
default output type (<literal>text/html</literal>, with
encoding specified in the header, or <literal>utf-8</literal>
by default).</para>
</listitem>
<listitem><para><literal>text/rtf</literal> is processed by
<command>unrtf</command>, which outputs
<literal>text/html</literal>. The
<literal>iso-8859-1</literal> encoding is specified because it
is not the <literal>utf-8</literal> default, and not output by
<command>unrtf</command> in the HTML header section.</para>
</listitem>
<listitem><para><literal>application/x-chm</literal> is processed
by a persistent handler. This is determined by the
<literal>execm</literal> keyword.</para>
</listitem>
</itemizedlist>
</para>
</sect2>
<sect2 id="RCL.PROGRAM.FILTERS.HTML">
<title>Input handler output</title>
<para>Both the simple and persistent input handlers can return any
MIME type to Recoll, which will further process the data according
to the MIME configuration.</para>
<para>Most input filters filters produce either
<literal>text/plain</literal> or <literal>text/html</literal>
data. There are exceptions, for example, filters which process
archive file (<literal>zip</literal>, <literal>tar</literal>, etc.)
will usually return the documents as they are found, without
processing them further.</para>
<para>There is nothing to say about <literal>text/plain</literal>
output, except that its character encoding should be consistent
with what is specified in the <filename>mimeconf</filename>
file.</para>
<para>For filters producing HTML, the output could be very minimal
like the following example:
<programlisting><![CDATA[
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=UTF-8"/>
</head>
<body>
Some text content
</body>
</html>
]]></programlisting>
</para>
<para>You should take care to escape some
characters inside the text by transforming them into
appropriate entities. At the very minimum,
"<literal>&amp;</literal>" should be transformed into
"<literal>&amp;amp;</literal>", "<literal>&lt;</literal>"
should be transformed into
"<literal>&amp;lt;</literal>". This is not always properly
done by external helper programs which output HTML, and of
course never by those which output plain text. </para>
<para>When encapsulating plain text in an HTML body,
the display of a preview may be improved by enclosing the
text inside <literal>&lt;pre></literal> tags.</para>
<para>The character set needs to be specified in the
header. It does not need to be UTF-8 (&RCL; will take care
of translating it), but it must be accurate for good
results.</para>
<para>&RCL; will process <literal>meta</literal> tags inside
the header as possible document fields candidates. Documents
fields can be processed by the indexer in different ways,
for searching or displaying inside query results. This is
described in a <link linkend="RCL.PROGRAM.FIELDS">following section.</link>
</para>
<para>By default, the indexer will process the standard header
fields if they are present: <literal>title</literal>,
<literal>meta/description</literal>,
and <literal>meta/keywords</literal> are both indexed and stored
for query-time display.</para>
<para>A predefined non-standard <literal>meta</literal> tag
will also be processed by &RCL; without further
configuration: if a <literal>date</literal> tag is present
and has the right format, it will be used as the document
date (for display and sorting), in preference to the file
modification date. The date format should be as follows:
<programlisting>
&lt;meta name="date" content="YYYY-mm-dd HH:MM:SS">
or
&lt;meta name="date" content="YYYY-mm-ddTHH:MM:SS">
</programlisting>
Example:
<programlisting>
&lt;meta name="date" content="2013-02-24 17:50:00">
</programlisting>
</para>
<para>Input handlers also have the possibility to "invent" field
names. This should also be output as meta tags:</para>
<programlisting>
&lt;meta name="somefield" content="Some textual data" /&gt;
</programlisting>
<para>You can embed HTML markup inside the content of custom
fields, for improving the display inside result lists. In this
case, add a (wildly non-standard) <literal>markup</literal>
attribute to tell &RCL; that the value is HTML and should not
be escaped for display.</para>
<programlisting>
&lt;meta name="somefield" markup="html" content="Some &lt;i>textual&lt;/i> data" /&gt;
</programlisting>
<para>As written above, the processing of fields is described
in a <link linkend="RCL.PROGRAM.FIELDS">further section</link>.</para>
<para>Persistent filters can use another, probably simpler,
method to produce metadata, by calling the
<literal>setfield()</literal> helper method. This avoids the
necessity to produce HTML, and any issue with HTML quoting. See,
for example, <filename>rclaudio</filename> in &RCL; 1.23 and
later for an example of handler which outputs
<literal>text/plain</literal> and uses
<literal>setfield()</literal> to produce metadata.</para>
</sect2>
<sect2 id="RCL.PROGRAM.FILTERS.PAGES">
<title>Page numbers</title>
<para>The indexer will interpret <literal>^L</literal> characters
in the handler output as indicating page breaks, and will record
them. At query time, this allows starting a viewer on the right
page for a hit or a snippet. Currently, only the PDF, Postscript
and DVI handlers generate page breaks.</para>
</sect2>
</sect1>
<sect1 id="RCL.PROGRAM.FIELDS">
<title>Field data processing</title>
<para><literal>Fields</literal> are named pieces of information
in or about documents, like <literal>title</literal>,
<literal>author</literal>, <literal>abstract</literal>.</para>
<para>The field values for documents can appear in several ways
during indexing: either output by input handlers
as <literal>meta</literal> fields in the HTML header section, or
extracted from file extended attributes, or added as attributes
of the <literal>Doc</literal> object when using the API, or
again synthetized internally by &RCL;.</para>
<para>The &RCL; query language allows searching for text in a
specific field.</para>
<para>&RCL; defines a number of default fields. Additional
ones can be output by handlers, and described in the
<filename>fields</filename> configuration file.</para>
<para>Fields can be:</para>
<itemizedlist>
<listitem><para><literal>indexed</literal>, meaning that their
terms are separately stored in inverted lists (with a specific
prefix), and that a field-specific search is possible.</para>
</listitem>
<listitem><para><literal>stored</literal>, meaning that their
value is recorded in the index data record for the document,
and can be returned and displayed with search results.</para>
</listitem>
</itemizedlist>
<para>A field can be either or both indexed and stored. This and
other aspects of fields handling is defined inside the
<filename>fields</filename> configuration file.</para>
<para>Some fields may also designated as supporting range queries,
meaning that the results may be selected for an interval of its
values. See the <link linkend="RCL.INSTALL.CONFIG.FIELDS">configuration section</link> for more details.</para>
<para>The sequence of events for field processing is as follows:
<itemizedlist>
<listitem><para>During indexing,
<command>recollindex</command> scans all <literal>meta</literal>
fields in HTML documents (most document types are transformed
into HTML at some point). It compares the name for each element
to the configuration defining what should be done with fields
(the <filename>fields</filename> file)</para>
</listitem>
<listitem><para>If the name for the <literal>meta</literal>
element matches one for a field that should be indexed, the
contents are processed and the terms are entered into the index
with the prefix defined in the <filename>fields</filename>
file.</para>
</listitem>
<listitem><para>If the name for the <literal>meta</literal> element
matches one for a field that should be stored, the content of the
element is stored with the document data record, from which it
can be extracted and displayed at query time.</para>
</listitem>
<listitem><para>At query time, if a field search is performed, the
index prefix is computed and the match is only performed against
appropriately prefixed terms in the index.</para>
</listitem>
<listitem><para>At query time, the field can be displayed inside
the result list by using the appropriate directive in the
definition of the
<link linkend="RCL.SEARCH.GUI.CUSTOM.RESLIST">result list paragraph format</link>.
All fields are displayed on the fields screen of
the preview window (which you can reach through the right-click
menu). This is independent of the fact that the search which
produced the results used the field or not.</para>
</listitem>
</itemizedlist>
</para>
<para>You can find more information in the
<link linkend="RCL.INSTALL.CONFIG.FIELDS">section about the <filename>fields</filename> file</link>,
or in comments inside the file.</para>
<para>You can also have a look at the
<ulink url="&FAQS;HandleCustomField">example in the FAQs area</ulink>,
detailing how one could add a <emphasis>page count</emphasis> field
to pdf documents for displaying inside result lists.</para>
</sect1>
<sect1 id="RCL.PROGRAM.PYTHONAPI">
<title>Python API</title>
<sect2 id="RCL.PROGRAM.PYTHONAPI.INTRO">
<title>Introduction</title>
<para>The &RCL; Python programming interface can be used both for
searching and for creating/updating an index. Bindings exist for
Python2 and Python3 (Jan 2021: python2 support will be dropped
soon).</para>
<para>The search interface is used in a number of active projects:
the <ulink
url="https://www.lesbonscomptes.com/recoll/pages/download.html#gssp">
&RCL; <application>Gnome Shell Search Provider</application>
</ulink>,
the <ulink url="https://framagit.org/medoc92/recollwebui">
&RCL; Web UI</ulink>, and the
<ulink
url="https://www.lesbonscomptes.com/upmpdcli/upmpdcli-manual.html#UPRCL">
upmpdcli UPnP Media Server</ulink>, in addition
to many small scripts.</para>
<para>The index update section of the API may be used to create and
update &RCL; indexes on specific configurations (separate from the
ones created by <command>recollindex</command>). The resulting
databases can be queried alone, or in conjunction with regular
ones, through the GUI or any of the query interfaces.</para>
<para>The search API is modeled along the Python database API
version 2.0 specification (early versions used the version 1.0 spec).</para>
<para>The <literal>recoll</literal> package contains two modules:</para>
<itemizedlist>
<listitem><para>The <literal>recoll</literal> module contains
functions and classes used to query (or update) the
index.</para></listitem>
<listitem><para>The <literal>rclextract</literal> module contains
functions and classes used at query time to access document
data. The <literal>recoll</literal> module must be imported
before <literal>rclextract</literal></para>
</listitem>
</itemizedlist>
<para>There is a good chance that your system repository has
packages for the Recoll Python API, sometimes in a package separate
from the main one (maybe named something like python-recoll). Else
refer to the <link linkend="RCL.INSTALL.BUILDING">Building from source chapter</link>.</para>
<para>As an introduction, the following small sample will run a
query and list the title and url for each of the results. The
<filename>python/samples</filename> source directory contains
several examples of Python programming with &RCL;, exercising the
extension more completely, and especially its data extraction
features.</para>
<programlisting><![CDATA[
#!/usr/bin/python3
from recoll import recoll
db = recoll.connect()
query = db.query()
nres = query.execute("some query")
results = query.fetchmany(20)
for doc in results:
print("%s %s" % (doc.url, doc.title))
]]></programlisting>
<para>You can also take a look at the source for the
<ulink
url="https://framagit.org/medoc92/recollwebui/-/blob/master/webui.py">
Recoll WebUI</ulink>, the
<ulink url="https://framagit.org/medoc92/upmpdcli/-/blob/master/src/mediaserver/cdplugins/uprcl/uprclfolders.py">
upmpdcli local media server</ulink>, or the
<ulink
url="https://framagit.org/medoc92/recoll-gssp/-/blob/master/gssp-recoll.py">
Gnome Shell Search Provider</ulink>.</para>
</sect2>
<sect2 id="RCL.PROGRAM.PYTHONAPI.ELEMENTS">
<title>Interface elements</title>
<para>A few elements in the interface are specific and and need
an explanation.</para>
<variablelist>
<varlistentry id="RCL.PROGRAM.PYTHONAPI.ELEMENTS.IPATH">
<term>ipath</term>
<listitem><para>This data value (set as a field in the Doc
object) is stored, along with the URL, but not indexed by
&RCL;. Its contents are not interpreted by the index layer, and
its use is up to the application. For example, the &RCL; file
system indexer uses the <literal>ipath</literal> to store the
part of the document access path internal to (possibly
imbricated) container documents. <literal>ipath</literal> in
this case is a vector of access elements (e.g, the first part
could be a path inside a zip file to an archive member which
happens to be an mbox file, the second element would be the
message sequential number inside the mbox
etc.). <literal>url</literal> and <literal>ipath</literal> are
returned in every search result and define the access to the
original document. <literal>ipath</literal> is empty for
top-level document/files (e.g. a PDF document which is a
filesystem file). The &RCL; GUI knows about the structure of the
<literal>ipath</literal> values used by the filesystem indexer,
and uses it for such functions as opening the parent of a given
document.</para>
</listitem>
</varlistentry>
<varlistentry id="RCL.PROGRAM.PYTHONAPI.ELEMENTS.UDI">
<term>udi</term>
<listitem><para>An <literal>udi</literal> (unique document
identifier) identifies a document. Because of limitations inside
the index engine, it is restricted in length (to 200 bytes),
which is why a regular URI cannot be used. The structure and
contents of the <literal>udi</literal> is defined by the
application and opaque to the index engine. For example, the
internal file system indexer uses the complete document path
(file path + internal path), truncated to length, the suppressed
part being replaced by a hash value. The <literal>udi</literal>
is not explicit in the query interface (it is used "under the
hood" by the <filename>rclextract</filename> module), but it is
an explicit element of the update interface.</para> </listitem>
</varlistentry>
<varlistentry id="RCL.PROGRAM.PYTHONAPI.ELEMENTS.PARENTUDI">
<term>parent_udi</term>
<listitem><para>If this attribute is set on a document when
entering it in the index, it designates its physical container
document. In a multilevel hierarchy, this may not be the
immediate parent. <literal>parent_udi</literal> is optional, but
its use by an indexer may simplify index maintenance, as &RCL;
will automatically delete all children defined by
<literal>parent_udi == udi</literal> when the document designated
by <literal>udi</literal> is destroyed. e.g. if a
<literal>Zip</literal> archive contains entries which are
themselves containers, like <literal>mbox</literal> files, all
the subdocuments inside the <literal>Zip</literal> file (mbox,
messages, message attachments, etc.) would have the same
<literal>parent_udi</literal>, matching the
<literal>udi</literal> for the <literal>Zip</literal> file, and
all would be destroyed when the <literal>Zip</literal> file
(identified by its <literal>udi</literal>) is removed from the
index. The standard filesystem indexer uses
<literal>parent_udi</literal>.</para></listitem>
</varlistentry>
<varlistentry>
<term>Stored and indexed fields</term>
<listitem><para>The
<link linkend="RCL.INSTALL.CONFIG.FIELDS"><filename>fields</filename> file</link>
inside the &RCL; configuration defines which
document fields are either <literal>indexed</literal>
(searchable), <literal>stored</literal> (retrievable with
search results), or both. Apart from a few standard/internal
fields, only the <literal>stored</literal> fields are
retrievable through the Python search interface.</para>
</listitem>
</varlistentry>
</variablelist>
</sect2>
<sect2 id="RCL.PROGRAM.PYTHONAPI.LOG">
<title>Log messages for Python scripts</title>
<para>Two specific configuration variables:
<literal>pyloglevel</literal> and <literal>pylogfilename</literal>
allow overriding the generic values for Python programs. Set
<literal>pyloglevel</literal> to 2 to suppress default startup messages
(printed at level 3).</para>
</sect2>
<sect2 id="RCL.PROGRAM.PYTHONAPI.SEARCH">
<title>Python search interface</title>
<sect3 id="RCL.PROGRAM.PYTHONAPI.RECOLL">
<title>The recoll module</title>
<simplesect id="RCL.PROGRAM.PYTHONAPI.RECOLL.CONNECT">
<title>connect(confdir=None, extra_dbs=None, writable = False)</title>
<para>The <literal>connect()</literal> function connects to
one or several &RCL; index(es) and returns
a <literal>Db</literal> object.</para>
<para>This call initializes the recoll module, and it should
always be performed before any other call or object
creation.</para>
<itemizedlist>
<listitem><para><literal>confdir</literal> may specify
a configuration directory. The usual defaults
apply.</para></listitem>
<listitem><para><literal>extra_dbs</literal> is a list of
additional indexes (Xapian directories).</para></listitem>
<listitem><para><literal>writable</literal> decides if
we can index new data through this
connection.</para></listitem>
</itemizedlist>
</simplesect>
<simplesect id="RCL.PROGRAM.PYTHONAPI.RECOLL.DB">
<title>The Db class</title>
<para>A Db object is created by a <literal>connect()</literal>
call and holds a connection to a Recoll index.</para>
<variablelist>
<varlistentry>
<term>Db.close()</term>
<listitem><para>Closes the connection. You can't do anything
with the <literal>Db</literal> object after
this.</para></listitem>
</varlistentry>
<varlistentry>
<term>Db.query(), Db.cursor()</term> <listitem><para>These
aliases return a blank <literal>Query</literal> object
for this index.</para></listitem>
</varlistentry>
<varlistentry>
<term>Db.setAbstractParams(maxchars,
contextwords)</term> <listitem><para>Set the parameters used
to build snippets (sets of keywords in context text
fragments). <literal>maxchars</literal> defines the
maximum total size of the abstract.
<literal>contextwords</literal> defines how many
terms are shown around the keyword.</para></listitem>
</varlistentry>
<varlistentry>
<term>Db.termMatch(match_type, expr, field='', maxlen=-1, casesens=False, diacsens=False, lang='english')</term>
<listitem><para>Expand an expression against the
index term list. Performs the basic function from the
GUI term explorer tool. <literal>match_type</literal>
can be either
of <literal>wildcard</literal>, <literal>regexp</literal>
or <literal>stem</literal>. Returns a list of terms
expanded from the input expression.
</para></listitem>
</varlistentry>
</variablelist>
</simplesect>
<simplesect id="RCL.PROGRAM.PYTHONAPI.RECOLL.CLASSES.QUERY">
<title>The Query class</title>
<para>A <literal>Query</literal> object (equivalent to a
cursor in the Python DB API) is created by
a <literal>Db.query()</literal> call. It is used to
execute index searches.</para>
<variablelist>
<varlistentry>
<term>Query.sortby(fieldname, ascending=True)</term>
<listitem><para>Sort results
by <replaceable>fieldname</replaceable>, in ascending
or descending order. Must be called before executing
the search.</para></listitem>
</varlistentry>
<varlistentry>
<term>Query.execute(query_string, stemming=1, stemlang="english", fetchtext=False, collapseduplicates=False)</term>
<listitem><para>Starts a search
for <replaceable>query_string</replaceable>, a &RCL;
search language string. If the index stores the document
texts and <literal>fetchtext</literal> is True, store the
document extracted text in
<literal>doc.text</literal>.</para></listitem>
</varlistentry>
<varlistentry>
<term>Query.executesd(SearchData, fetchtext=False, collapseduplicates=False)</term>
<listitem><para>Starts a search for the query defined by
the SearchData object. If the index stores the document
texts and <literal>fetchtext</literal> is True, store the
document extracted text in
<literal>doc.text</literal>.</para></listitem>
</varlistentry>
<varlistentry>
<term>Query.fetchmany(size=query.arraysize)</term>
<listitem><para>Fetches
the next <literal>Doc</literal> objects in the current
search results, and returns them as an array of the
required size, which is by default the value of
the <literal>arraysize</literal> data member.</para></listitem>
</varlistentry>
<varlistentry>
<term>Query.fetchone()</term> <listitem><para>Fetches the
next <literal>Doc</literal> object from the current
search results. Generates a StopIteration exception if
there are no results left.</para></listitem>
</varlistentry>
<varlistentry>
<term>Query.close()</term>
<listitem><para>Closes the query. The object is unusable
after the call.</para></listitem>
</varlistentry>
<varlistentry>
<term>Query.scroll(value, mode='relative')</term>
<listitem><para>Adjusts the position in the current result
set. <literal>mode</literal> can
be <literal>relative</literal>
or <literal>absolute</literal>. </para></listitem>
</varlistentry>
<varlistentry>
<term>Query.getgroups()</term>
<listitem><para>Retrieves the expanded query terms as a list
of pairs. Meaningful only after executexx In each
pair, the first entry is a list of user terms (of size
one for simple terms, or more for group and phrase
clauses), the second a list of query terms as derived
from the user terms and used in the Xapian
Query.</para></listitem>
</varlistentry>
<varlistentry>
<term>Query.getxquery()</term>
<listitem><para>Return the Xapian query description as a
Unicode string.
Meaningful only after executexx.</para></listitem>
</varlistentry>
<varlistentry>
<term>Query.highlight(text, ishtml = 0, methods = object)</term>
<listitem><para>Will insert &lt;span "class=rclmatch">,
&lt;/span> tags around the match areas in the input text
and return the modified text. <literal>ishtml</literal>
can be set to indicate that the input text is HTML and
that HTML special characters should not be escaped.
<literal>methods</literal> if set should be an object
with methods startMatch(i) and endMatch() which will be
called for each match and should return a begin and end
tag</para></listitem>
</varlistentry>
<varlistentry>
<term>Query.makedocabstract(doc, methods = object))</term>
<listitem><para>Create a snippets abstract
for <literal>doc</literal> (a <literal>Doc</literal>
object) by selecting text around the match terms.
If methods is set, will also perform highlighting. See
the highlight method.
</para></listitem>
</varlistentry>
<varlistentry>
<term>Query.getsnippets(doc, maxoccs = -1, ctxwords = -1,
sortbypage=False, methods = object)</term>
<listitem><para>Will return a list of extracts from the result
document by selecting text around the match terms. Each
entry in the result list is a triple: page number, term,
text. By default, the most relevants snippets appear first
in the list. Set <literal>sortbypage</literal> to sort by
page number instead. If <literal>methods</literal> is set,
the fragments will be highlighted (see the highlight
method). If <literal>maxoccs</literal> is set, it defines
the maximum result list
length. <literal>ctxwords</literal> allows adjusting the
individual snippet context size. </para></listitem>
</varlistentry>
<varlistentry>
<term>Query.__iter__() and Query.next()</term>
<listitem><para>So that things like
<literal>for doc in query:</literal>
will work.</para></listitem>
</varlistentry>
</variablelist>
<variablelist>
<varlistentry>
<term>Query.arraysize</term>
<listitem><para>Default number of records processed by
fetchmany (r/w).</para></listitem>
</varlistentry>
<varlistentry>
<term>Query.rowcount</term>
<listitem><para>Number of records returned by the last
execute.</para></listitem>
</varlistentry>
<varlistentry>
<term>Query.rownumber</term>
<listitem><para>Next index to be fetched from
results. Normally increments after each fetchone() call, but
can be set/reset before the call to effect seeking
(equivalent to using <literal>scroll()</literal>). Starts at
0.</para></listitem>
</varlistentry>
</variablelist>
</simplesect>
<simplesect id="RCL.PROGRAM.PYTHONAPI.RECOLL.CLASSES.DOC">
<title>The Doc class</title>
<para>A <literal>Doc</literal> object contains index data
for a given document. The data is extracted from the
index when searching, or set by the indexer program when
updating. The Doc object has many attributes to be read or
set by its user. It mostly matches the Rcl::Doc C++
object. Some of the attributes are predefined, but,
especially when indexing, others can be set, the name of
which will be processed as field names by the indexing
configuration. Inputs can be specified as Unicode or
strings. Outputs are Unicode objects. All dates are
specified as Unix timestamps, printed as strings. Please
refer to the <filename>rcldb/rcldoc.cpp</filename> C++ file
for a full description of the predefined attributes. Here
follows a short list.</para>
<para><itemizedlist>
<listitem><para><literal>url</literal> the document URL but
see also <literal>getbinurl()</literal></para></listitem>
<listitem><para><literal>ipath</literal> the document
<literal>ipath</literal> for embedded
documents.</para></listitem>
<listitem><para><literal>fbytes, dbytes</literal> the document
file and text sizes.</para></listitem>
<listitem><para><literal>fmtime, dmtime</literal> the document
file and document times.</para></listitem>
<listitem><para><literal>xdocid</literal> the document
Xapian document ID. This is useful if you want to access
the document through a direct Xapian
operation.</para></listitem>
<listitem><para><literal>mtype</literal> the document
MIME type.</para></listitem>
<listitem><para>Fields stored by default:
<literal>author</literal>, <literal>filename</literal>,
<literal>keywords</literal>,
<literal>recipient</literal></para></listitem>
</itemizedlist>
</para>
<para>At query time, only the fields that are defined as
<literal>stored</literal> either by default or in the
<filename>fields</filename> configuration file will be meaningful
in the <literal>Doc</literal> object. The document processed text
may be present or not, depending if the index stores the text at
all, and if it does, on the <literal>fetchtext</literal> query
execute option. See also the <literal>rclextract</literal> module
for accessing document contents.</para>
<variablelist>
<varlistentry>
<term>get(key), [] operator</term>
<listitem><para>Retrieve the named document
attribute. You can also use
<literal>getattr(doc, key)</literal> or
<literal>doc.key</literal>.</para></listitem>
</varlistentry>
<varlistentry>
<term>doc.key = value</term>
<listitem><para>Set the the named document attribute. You
can also use
<literal>setattr(doc, key, value)</literal>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>getbinurl()</term>
<listitem><para>Retrieve the URL in byte array format (no
transcoding), for use as parameter to a system
call.</para></listitem>
</varlistentry>
<varlistentry>
<term>setbinurl(url)</term>
<listitem><para>Set the URL in byte array format (no
transcoding).</para></listitem>
</varlistentry>
<varlistentry>
<term>items()</term>
<listitem><para>Return a dictionary of doc object
keys/values</para></listitem>
</varlistentry>
<varlistentry>
<term>keys()</term>
<listitem><para>list of doc object keys (attribute
names).</para></listitem>
</varlistentry>
</variablelist>
</simplesect> <!-- Doc -->
<simplesect id="RCL.PROGRAM.PYTHONAPI.RECOLL.CLASSES.SEARCHDATA">
<title>The SearchData class</title>
<para>A <literal>SearchData</literal> object allows building
a query by combining clauses, for execution
by <literal>Query.executesd()</literal>. It can be used
in replacement of the query language approach. The
interface is going to change a little, so no detailed doc
for now...</para>
<variablelist>
<varlistentry>
<term>addclause(type='and'|'or'|'excl'|'phrase'|'near'|'sub',
qstring=string, slack=0, field='', stemming=1,
subSearch=SearchData)</term>
<listitem><para></para></listitem>
</varlistentry>
</variablelist>
</simplesect> <!-- SearchData -->
</sect3> <!-- Recoll module -->
<sect3 id="RCL.PROGRAM.PYTHONAPI.RCLEXTRACT">
<title>The rclextract module</title>
<para>Prior to &RCL; 1.25, index queries could not provide document
content because it was never stored. &RCL; 1.25 and later usually
store the document text, which can be optionally retrieved when
running a query (see <literal>query.execute()</literal>
above - the result is always plain text).</para>
<para>The <literal>rclextract</literal> module can give access to
the original document and to the document text content (if not
stored by the index, or to access an HTML version of the text).
Accessing the original document is particularly useful if it is
embedded (e.g. an email attachment).</para>
<para>You need to import the <literal>recoll</literal> module
before the <literal>rclextract</literal> module.</para>
<simplesect id="RCL.PROGRAM.PYTHONAPI.RCLEXTRACT.CLASSES.EXTRACTOR">
<title>The Extractor class</title>
<variablelist>
<varlistentry>
<term>Extractor(doc)</term>
<listitem><para>An <literal>Extractor</literal> object is
built from a <literal>Doc</literal> object, output
from a query.</para></listitem>
</varlistentry>
<varlistentry>
<term>Extractor.textextract(ipath)</term>
<listitem><para>Extract document defined by
<replaceable>ipath</replaceable> and return a
<literal>Doc</literal> object. The
<literal>doc.text</literal> field has the document text
converted to either text/plain or text/html according to
<literal>doc.mimetype</literal>. The typical use would be
as follows:</para>
<programlisting>
from recoll import recoll, rclextract
qdoc = query.fetchone()
extractor = recoll.Extractor(qdoc)
doc = extractor.textextract(qdoc.ipath)
# use doc.text, e.g. for previewing</programlisting>
<para>Passing <literal>qdoc.ipath</literal> to
<literal>textextract()</literal> is redundant, but
reflects the fact that the <literal>Extractor</literal>
object actually has the capability to access the other
entries in a compound document.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Extractor.idoctofile(ipath, targetmtype, outfile='')</term>
<listitem><para>Extracts document into an output file,
which can be given explicitly or will be created as a
temporary file to be deleted by the caller. Typical
use:</para>
<programlisting>
from recoll import recoll, rclextract
qdoc = query.fetchone()
extractor = recoll.Extractor(qdoc)
filename = extractor.idoctofile(qdoc.ipath, qdoc.mimetype)</programlisting>
<para>In all cases the output is a copy, even if the
requested document is a regular system file, which may be
wasteful in some cases. If you want to avoid this, you
can test for a simple file document as follows:
<programlisting>
not doc.ipath and (not "rclbes" in doc.keys() or doc["rclbes"] == "FS")
</programlisting>
</para></listitem>
</varlistentry>
</variablelist>
</simplesect>
</sect3> <!-- rclextract module -->
<sect3 id="RCL.PROGRAM.PYTHONAPI.SEARCH.EXAMPLE">
<title>Search API usage example</title>
<para>The following sample would query the index with a user
language string. See the <filename>python/samples</filename>
directory inside the &RCL; source for other
examples. The <filename>recollgui</filename> subdirectory
has a very embryonic GUI which demonstrates the
highlighting and data extraction functions.</para>
<programlisting><![CDATA[
#!/usr/bin/python3
from recoll import recoll
db = recoll.connect()
db.setAbstractParams(maxchars=80, contextwords=4)
query = db.query()
nres = query.execute("some user question")
print("Result count: %d" % nres)
if nres > 5:
nres = 5
for i in range(nres):
doc = query.fetchone()
print("Result #%d" % (query.rownumber))
for k in ("title", "size"):
print("%s : %s" % (k, getattr(doc, k)))
print("%s\n" % db.makeDocAbstract(doc, query))
]]></programlisting>
</sect3>
</sect2>
<sect2 id="RCL.PROGRAM.PYTHONAPI.UPDATE">
<title>Creating Python external indexers</title>
<para>The update API can be used to create an index from data which
is not accessible to the regular &RCL; indexer, or structured to
present difficulties to the &RCL; input handlers.</para>
<para>An indexer created using this API will be have equivalent work
to do as the the Recoll file system indexer: look for modified
documents, extract their text, call the API for indexing it, take
care of purging the index out of data from documents which do not
exist in the document store any more.</para>
<para>The data for such an external indexer should be stored in an
index separate from any used by the &RCL; internal file system
indexer. The reason is that the main document indexer purge pass
(removal of deleted documents) would also remove all the documents
belonging to the external indexer, as they were not seen during the
filesystem walk. The main indexer documents would also probably be a
problem for the external indexer own purge operation.</para>
<para>While there would be ways to enable multiple foreign indexers
to cooperate on a single index, it is just simpler to use separate
ones, and use the multiple index access capabilities of the query
interface, if needed.</para>
<para>There are two parts in the update interface:</para>
<itemizedlist>
<listitem><para>Methods inside the <filename>recoll</filename>
module allow inserting data into the index, to make it accessible by
the normal query interface.</para></listitem>
<listitem><para>An interface based on scripts execution is defined
to allow either the GUI or the <filename>rclextract</filename>
module to access original document data for previewing or
editing.</para></listitem>
</itemizedlist>
<sect3 id="RCL.PROGRAM.PYTHONAPI.UPDATE.UPDATE">
<title>Python update interface</title>
<para>The update methods are part of the
<filename>recoll</filename> module described above. The connect()
method is used with a <literal>writable=true</literal> parameter to
obtain a writable <literal>Db</literal> object. The following
<literal>Db</literal> object methods are then available.</para>
<variablelist>
<varlistentry>
<term>addOrUpdate(udi, doc, parent_udi=None)</term>
<listitem><para>Add or update index data for a given document
The
<literal><link linkend="RCL.PROGRAM.PYTHONAPI.ELEMENTS.UDI">udi</link></literal>
string must define a unique id for
the document. It is an opaque interface element and not
interpreted inside Recoll. <literal>doc</literal> is a
<literal><link linkend="RCL.PROGRAM.PYTHONAPI.RECOLL.CLASSES.DOC">Doc</link></literal>
object, created from the data to be
indexed (the main text should be in
<literal>doc.text</literal>). If
<literal><link linkend="RCL.PROGRAM.PYTHONAPI.ELEMENTS.PARENTUDI">parent_udi</link></literal>
is set, this is a unique identifier for the top-level
container (e.g. for the filesystem indexer, this would
be the one which is an actual file).</para>
</listitem>
</varlistentry>
<varlistentry>
<term>delete(udi)</term>
<listitem><para>Purge index from all data for
<literal>udi</literal>, and all documents (if any) which have a
matrching <literal>parent_udi</literal>. </para> </listitem>
</varlistentry>
<varlistentry>
<term>needUpdate(udi, sig)</term>
<listitem><para>Test if the index needs to be updated for the
document identified by <literal>udi</literal>. If this call is
to be used, the <literal>doc.sig</literal> field should contain
a signature value when calling
<literal>addOrUpdate()</literal>. The
<literal>needUpdate()</literal> call then compares its
parameter value with the stored <literal>sig</literal> for
<literal>udi</literal>. <literal>sig</literal> is an opaque
value, compared as a string.</para>
<para>The filesystem indexer uses a
concatenation of the decimal string values for file size and
update time, but a hash of the contents could also be
used.</para>
<para>As a side effect, if the return value is false (the index
is up to date), the call will set the existence flag for the
document (and any subdocument defined by its
<literal>parent_udi</literal>), so that a later
<literal>purge()</literal> call will preserve them).</para>
<para>The use of <literal>needUpdate()</literal> and
<literal>purge()</literal> is optional, and the indexer may use
another method for checking the need to reindex or to delete
stale entries.</para></listitem>
</varlistentry>
<varlistentry>
<term>purge()</term>
<listitem><para>Delete all documents that were not touched
during the just finished indexing pass (since
open-for-write). These are the documents for the needUpdate()
call was not performed, indicating that they no longer exist in
the primary storage system.</para></listitem>
</varlistentry>
</variablelist>
</sect3>
<sect3 id="RCL.PROGRAM.PYTHONAPI.UPDATE.ACCESS">
<title>Query data access for external indexers (1.23)</title>
<para>&RCL; has internal methods to access document data for its
internal (filesystem) indexer. An external indexer needs to provide
data access methods if it needs integration with the GUI
(e.g. preview function), or support for the
<filename>rclextract</filename> module.</para>
<para>The index data and the access method are linked by the
<literal>rclbes</literal> (recoll backend storage)
<literal>Doc</literal> field. You should set this to a short string
value identifying your indexer (e.g. the filesystem indexer uses either
"FS" or an empty value, the Web history indexer uses "BGL").</para>
<para>The link is actually performed inside a
<filename>backends</filename> configuration file (stored in the
configuration directory). This defines commands to execute to
access data from the specified indexer. Example, for the mbox
indexing sample found in the Recoll source (which sets
<literal>rclbes="MBOX"</literal>):</para>
<programlisting>[MBOX]
fetch = /path/to/recoll/src/python/samples/rclmbox.py fetch
makesig = path/to/recoll/src/python/samples/rclmbox.py makesig
</programlisting>
<para><literal>fetch</literal> and <literal>makesig</literal>
define two commands to execute to respectively retrieve the
document text and compute the document signature (the example
implementation uses the same script with different first parameters
to perform both operations).</para>
<para>The scripts are called with three additional arguments:
<literal>udi</literal>, <literal>url</literal>,
<literal>ipath</literal>, stored with the document when it was
indexed, and may use any or all to perform the requested
operation. The caller expects the result data on
<literal>stdout</literal>.</para>
</sect3>
<sect3 id="RCL.PROGRAM.PYTHONAPI.UPDATE.SAMPLES">
<title>External indexer samples</title>
<para>The Recoll source tree has two samples of external indexers
in the <filename>src/python/samples</filename> directory. The more
interesting one is <filename>rclmbox.py</filename> which indexes a
directory containing <literal>mbox</literal> folder files. It
exercises most features in the update interface, and has a data
access interface.</para>
<para>See the comments inside the file for more information.</para>
</sect3>
</sect2>
<sect2 id="RCL.PROGRAM.PYTHONAPI.COMPAT">
<title>Package compatibility with the previous version</title>
<para>The following code fragments can be used to ensure that
code can run with both the old and the new API (as long as it
does not use the new abilities of the new API of
course).</para>
<para>Adapting to the new package structure:</para>
<programlisting><![CDATA[
try:
from recoll import recoll
from recoll import rclextract
hasextract = True
except:
import recoll
hasextract = False
]]></programlisting>
<para>Adapting to the change of nature of
the <literal>next</literal> <literal>Query</literal>
member. The same test can be used to choose to use
the <literal>scroll()</literal> method (new) or set
the <literal>next</literal> value (old).</para>
<programlisting><![CDATA[rownum = query.next if type(query.next) == int else query.rownumber]]></programlisting>
</sect2> <!-- compat with previous version -->
</sect1>
</chapter>
<chapter id="RCL.INSTALL">
<title>Installation and configuration</title>
<sect1 id="RCL.INSTALL.BINARY">
<title>Installing a binary copy</title>
<para>&RCL; binary copies are always distributed as regular
packages for your system. They can be obtained either through
the system's normal software distribution framework (e.g.
<application>Debian/Ubuntu apt</application>,
<application>FreeBSD</application> ports, etc.), or from some type
of "backports" repository providing versions newer than the standard
ones, or found on the &RCL; Web site in some
cases. The most up-to-date information about Recoll packages can
usually be found on the
<ulink url="http://www.recoll.org/pages/download.html">
<application>Recoll</application> Web site downloads
page</ulink></para>
<para>The &WIN; version of Recoll comes in a self-contained setup
file, there is nothing else to install.</para>
<para>On &LIN;, the package management tools will automatically
install hard dependencies for packages obtained from a proper package
repository. You will have to deal with them by hand for downloaded
packages (for example, when <command>dpkg</command> complains about
missing dependencies).</para>
<para>In all cases, you will have to check or install
<link linkend="RCL.INSTALL.EXTERNAL">supporting applications</link>
for the file types that you want to index beyond those that are
natively processed by &RCL; (text, HTML, email files, and a few
others).</para>
<para>You should also maybe have a look at the
<link linkend="RCL.INSTALL.CONFIG">configuration section</link>
(but this may not be necessary for a quick test with default
parameters). Most parameters can be more conveniently set from the
GUI interface.</para>
</sect1>
<sect1 id="RCL.INSTALL.EXTERNAL">
<title>Supporting packages</title>
<note><para>The &WIN; installation of &RCL; is self-contained.
&WIN; users can skip this section.</para></note>
<para>&RCL; uses external applications to index some file
types. You need to install them for the file types that you wish to
have indexed (these are run-time optional dependencies. None is
needed for building or running &RCL; except for indexing their
specific file type).</para>
<para>After an indexing pass, the commands that were found
missing can be displayed from the <command>recoll</command>
<guilabel>File</guilabel> menu. The list is stored in the
<filename>missing</filename> text file inside the configuration
directory.</para>
<para>The past has proven that I was unable to maintain an up to date
application list in this manual. Please check &RCLAPPS; for a
complete list along with links to the home pages or best
source/patches pages, and misc tips. What follows is only a
very short extract of the stable essentials.</para>
<itemizedlist>
<listitem><para>PDF files need <command>pdftotext</command>
which is part of <application>Poppler</application> (usually
comes with the <literal>poppler-utils</literal>
package). Avoid the original one from
<application>Xpdf</application>.</para></listitem>
<listitem><para>MS Word documents need
<command>antiword</command>. It is also useful to have
<command>wvWare</command> installed as it may be
be used as a fallback for some files which
<command>antiword</command> does not handle.</para></listitem>
<listitem><para>RTF files need <command>unrtf</command>,
which, in its older versions, has much trouble with
non-western character sets. Many Linux distributions carry
outdated <command>unrtf</command> versions. Check
&RCLAPPS; for details.</para></listitem>
<listitem><para>Pictures: &RCL; uses the
<application>Exiftool</application>
<application>Perl</application> package to extract tag
information. Most image file formats are
supported.</para></listitem>
<listitem><para>Up to &RCL; 1.24, many XML-based formats need the
<command>xsltproc</command> command, which usually comes with
<application>libxslt</application>. These are: abiword, fb2
ebooks, kword, openoffice, opendocument svg. &RCL; 1.25 and later
process them internally (using libxslt).</para>
</listitem>
</itemizedlist>
</sect1>
<sect1 id="RCL.INSTALL.BUILDING">
<title>Building from source</title>
<sect2 id="RCL.INSTALL.BUILDING.PREREQS">
<title>Prerequisites</title>
<para>The following prerequisites are described in broad terms and
not as specific package names (which will depend on the exact
platform). The dependencies should be available as packages on most
common Unix derivatives, and it should be quite uncommon that you
would have to build one of them.</para>
<para>If you do not need the GUI, you can avoid all GUI
dependencies by disabling its build. (See the configure section
further).</para>
<para>The shopping list:</para>
<itemizedlist>
<listitem><para>If you start from git code, you will need the
<command>autoconf</command>, <command>automake</command> and
<command>libtool</command> triad. They are not needed for
building from tar distributions.</para></listitem>
<listitem><para>C++ compiler. Recent versions require C++11
compatibility (1.23 and later).</para></listitem>
<listitem><para><command>bison</command> command (for &RCL; 1.21
and later).</para></listitem>
<listitem><para>For building the documentation: the
<command>xsltproc</command> command, and the Docbook XML and
style sheet files. You can avoid this dependency by disabling
documentation building with the
<literal>--disable-userdoc</literal> <command>configure</command>
option.</para></listitem>
<listitem><para>Development files
for <ulink url="http://www.xapian.org"> <application>Xapian
core</application></ulink>.</para>
<important>
<para>If you are
building Xapian for an older CPU (before Pentium 4 or Athlon
64), you need to add the <option>--disable-sse</option> flag
to the configure command. Else all Xapian application will
crash with an <literal>illegal instruction</literal>
error.</para>
</important>
</listitem>
<listitem> <para>Development files for
<ulink url="http://qt-project.org/downloads"><application>Qt 5</application> </ulink>.
and its own dependencies (X11 etc.)</para> </listitem>
<listitem><para>Development files for libxslt</para></listitem>
<listitem><para>Development files for
<application>zlib</application>.</para> </listitem>
<listitem><para>Development files for
<application>Python</application> (or use
<literal>--disable-python-module</literal>).</para></listitem>
<listitem><para>Development files for libchm</para></listitem>
<listitem><para>You may also need
<ulink url="http://www.gnu.org/software/libiconv/">libiconv</ulink>.
On <application>Linux</application> systems, the iconv
interface is part of libc and you should not need to do
anything special.</para></listitem>
</itemizedlist>
<para>Check the <ulink url="http://www.recoll.org/pages/download.html">
&RCL; download page</ulink> for up to date version
information.</para>
</sect2>
<sect2 id="RCL.INSTALL.BUILDING.BUILDING">
<title>Building</title>
<para>&RCL; has been built on Linux, FreeBSD, Mac OS X, and Solaris,
most versions after 2005 should be ok, maybe some older ones too
(Solaris 8 used to be ok). If you build on another system, and
need to modify things,
<ulink url="mailto:jfd@recoll.org">I would
very much welcome patches</ulink>.</para>
<formalpara>
<title>Configure options:</title>
<para>
<itemizedlist>
<listitem><para><option>--without-aspell</option>
will disable the code for phonetic matching of search
terms. </para></listitem>
<listitem><para><option>--with-fam</option> or
<option>--with-inotify</option> will enable the code for real
time indexing. Inotify support is enabled by default on Linux
systems.</para></listitem>
<listitem><para><option>--with-qzeitgeist</option> will
enable sending <application>Zeitgeist</application>
events about the visited search results, and needs
the <application>qzeitgeist</application>
package.</para></listitem>
<listitem><para><option>--disable-webkit</option> is available
from version 1.17 to implement the result list with a
<application>Qt</application> QTextBrowser instead of a
WebKit widget if you do not or can't depend on the
latter.</para></listitem>
<listitem><para><option>--disable-qtgui</option> Disable the Qt
interface. Will allow building the indexer and the command line
search program in absence of a Qt environment.</para>
</listitem>
<listitem><para><option>--enable-webengine</option> Enable the
use of Qt Webengine (only meaningful if the Qt GUI
is enabled), in place or Qt Webkit.</para></listitem>
<listitem><para><option>--disable-idxthreads</option> is available
from version 1.19 to suppress multithreading inside the
indexing process. You can also use the run-time
configuration to restrict <command>recollindex</command>
to using a single thread, but the compile-time option
may disable a few more unused locks. This only applies
to the use of multithreading for the core index
processing (data input). The &RCL; monitor mode always
uses at least two threads of execution.</para></listitem>
<listitem><para><option>--disable-python-module</option> will
avoid building the <application>Python</application>
module.</para></listitem>
<listitem><para><option>--disable-python-chm</option> will
avoid building the Python libchm interface used to index CHM
files.</para></listitem>
<listitem><para><option>--enable-camelcase</option> will enable
splitting <replaceable>camelCase</replaceable> words. This
is not enabled by default as it has the unfortunate
side-effect of making some phrase searches quite
confusing: ie, <literal>"MySQL manual"</literal> would be
matched by <literal>"MySQL manual"</literal> and
<literal>"my sql manual"</literal> but not
<literal>"mysql manual"</literal> (only inside phrase
searches).</para>
</listitem>
<listitem><para><option>--with-file-command</option> Specify
the version of the 'file' command to use (ie:
--with-file-command=/usr/local/bin/file). Can be useful to
enable the gnu version on systems where the native one is
bad.</para> </listitem>
<listitem><para><option>--disable-x11mon</option> Disable
<application>X11</application> connection monitoring
inside recollindex. Together with --disable-qtgui, this
allows building recoll without
<application>Qt</application> and
<application>X11</application>.</para> </listitem>
<listitem><para><option>--disable-userdoc</option>
will avoid building the user manual. This avoids having to
install the Docbook XML/XSL files and the TeX toolchain used for
translating the manual to PDF.</para></listitem>
<listitem><para><option>--enable-recollq</option> Enable
building the <command>recollq</command> command line query
tool (recoll -t without need for Qt). This is done by
default if --disable-qtgui is set but this option
enables forcing it.</para></listitem>
<listitem><para><option>--disable-pic</option> (&RCL; versions up
to 1.21 only) will compile
&RCL; with position-dependant code. This is incompatible with
building the KIO or the <application>Python</application>
or <application>PHP</application> extensions, but might
yield very marginally faster code.</para></listitem>
<listitem><para>Of course the usual
<application>autoconf</application> <command>configure</command>
options, like <option>--prefix</option> apply.</para>
</listitem>
</itemizedlist>
</para>
</formalpara>
<para>Normal procedure (for source extracted from a tar
distribution):</para>
<screen>
<userinput>cd recoll-xxx</userinput>
<userinput>./configure</userinput>
<userinput>make</userinput>
<userinput>(practices usual hardship-repelling invocations)</userinput>
</screen>
<para>When building from source cloned from the git repository,
you also need to install <application>autoconf</application>,
<application>automake</application>, and
<application>libtool</application> and you must execute
<literal>sh autogen.sh</literal> in the top source directory
before running <literal>configure</literal>.</para>
</sect2>
<sect2 id="RCL.INSTALL.BUILDING.INSTALL">
<title>Installing</title>
<para>Use <userinput>make install</userinput>
in the root
of the source tree. This will copy the commands to
<filename><replaceable>prefix</replaceable>/bin</filename>
and the sample configuration files, scripts and other shared
data to
<filename><replaceable>prefix</replaceable>/share/recoll</filename>.
</para>
</sect2>
<sect2 id="RCL.INSTALL.BUILDING.PYTHON">
<title>Python API package</title>
<para>The Python interface can be found in the source tree,
under the <filename>python/recoll</filename> directory.</para>
<para>As of &RCL; 1.19, the module can be compiled for
Python3.</para>
<para>The normal &RCL; build procedure (see above) installs the API
package for the default system version (python) along with the main
code. The package for other Python versions (e.g. python3 if the
system default is python2) must be explicitly built and
installed.</para>
<para>The <filename>python/recoll/</filename> directory contains
the usual <filename>setup.py</filename>. After configuring and
building the main &RCL; code, you can use the script to build and
install the Python module:
<screen>
<userinput>cd recoll-xxx/python/recoll</userinput>
<userinput>pythonX setup.py build</userinput>
<userinput>sudo pythonX setup.py install</userinput>
</screen>
</para>
</sect2>
<sect2 id="RCL.INSTALL.BUILDING.SOLARIS">
<title>Building on Solaris</title>
<para>We did not test building the GUI on Solaris for recent
versions. You will need at least Qt 4.4. There are some hints
on <ulink url="http://www.recoll.org/download-1.14.html">an old
web site page</ulink>, they may still be valid.</para>
<para>Someone did test the 1.19 indexer and Python module build,
they do work, with a few minor glitches. Be sure to use
GNU <command>make</command> and <command>install</command>.</para>
</sect2>
</sect1>
<sect1 id="RCL.INSTALL.CONFIG">
<title>Configuration overview</title>
<para>Most of the parameters specific to the
<command>recoll</command> GUI are set through the
<guilabel>Preferences</guilabel> menu and stored in the standard Qt
place (<filename>$HOME/.config/Recoll.org/recoll.conf</filename>).
You probably do not want to edit this by hand.</para>
<para>&RCL; indexing options are set inside text configuration
files located in a configuration directory. There can be
several such directories, each of which defines the parameters
for one index.</para>
<para>The configuration files can be edited by hand or through
the <guilabel>Index configuration</guilabel> dialog
(<guilabel>Preferences</guilabel> menu). The GUI tool will try
to respect your formatting and comments as much as possible,
so it is quite possible to use both approaches on the same
configuration.</para>
<para>The most accurate documentation for the
configuration parameters is given by comments inside the default
files, and we will just give a general overview here.</para>
<para>For each index, there are at least two sets of
configuration files. System-wide configuration files are kept
in a directory named
like <filename>/usr/share/recoll/examples</filename>,
and define default values, shared by all indexes. For each
index, a parallel set of files defines the customized
parameters.</para>
<para>The default location of the customized configuration is the
<filename>.recoll</filename>
directory in your home. Most people will only use this
directory.</para>
<para>This location can be changed, or others can be added with the
<envar>RECOLL_CONFDIR</envar> environment variable or the
<option>-c</option> option parameter to <command>recoll</command> and
<command>recollindex</command>.</para>
<para>In addition (as of &RCL; version 1.19.7), it is possible
to specify two additional configuration directories which will
be stacked before and after the user configuration
directory. These are defined by
the <envar>RECOLL_CONFTOP</envar>
and <envar>RECOLL_CONFMID</envar> environment
variables. Values from configuration files inside the top
directory will override user ones, values from configuration
files inside the middle directory will override system ones
and be overridden by user ones. These two variables may be of
use to applications which augment &RCL; functionality, and
need to add configuration data without disturbing the user's
files. Please note that the two, currently single, values will
probably be interpreted as colon-separated lists in the
future: do not use colon characters inside the directory
paths.</para>
<para>If the <filename>.recoll</filename> directory does not
exist when <command>recoll</command> or
<command>recollindex</command> are started, it will be created
with a set of empty configuration files.
<command>recoll</command> will give you a chance to edit the
configuration file before starting
indexing. <command>recollindex</command> will proceed
immediately. To avoid mistakes, the automatic directory
creation will only occur for the
default location, not if <option>-c</option> or
<envar>RECOLL_CONFDIR</envar> were used (in the latter
cases, you will have to create the directory).</para>
<para>All configuration files share the same format. For
example, a short extract of the main configuration file might
look as follows:</para>
<programlisting>
# Space-separated list of files and directories to index.
topdirs = ~/docs /usr/share/doc
[~/somedirectory-with-utf8-txt-files]
defaultcharset = utf-8
</programlisting>
<para>There are three kinds of lines: </para>
<itemizedlist>
<listitem><para>Comment (starts with
<emphasis>#</emphasis>) or empty.</para>
</listitem>
<listitem><para>Parameter affectation (<emphasis>name =
value</emphasis>).</para>
</listitem>
<listitem><para>Section definition
([<emphasis>somedirname</emphasis>]).</para>
</listitem>
</itemizedlist>
<para>Long lines can be broken by ending each incomplete part with
a backslash (<literal>\</literal>).</para>
<para>Depending on the type of configuration file, section
definitions either separate groups of parameters or allow
redefining some parameters for a directory sub-tree. They stay
in effect until another section definition, or the end of
file, is encountered. Some of the parameters used for indexing
are looked up hierarchically from the current directory
location upwards. Not all parameters can be meaningfully
redefined, this is specified for each in the next
section. </para>
<important>
<para>Global parameters <emphasis>must not</emphasis> be defined in
a directory subsection, else they will not be found at all by the
&RCL; code, which looks for them at the top level
(e.g. <literal>skippedPaths</literal>).</para>
</important>
<para>When found at the beginning of a file path, the tilde
character (~) is expanded to the name of the user's home
directory, as a shell would do.</para>
<para>Some parameters are lists of strings. White space is used for
separation. List elements with embedded spaces can be quoted using
double-quotes. Double quotes inside these elements can be escaped
with a backslash.</para>
<para>No value inside a configuration file can contain a newline
character. Long lines can be continued by escaping the
physical newline with backslash, even inside quoted strings.</para>
<programlisting>
astringlist = "some string \
with spaces"
thesame = "some string with spaces"
</programlisting>
<para>Parameters which are not part of string lists can't be
quoted, and leading and trailing space characters are
stripped before the value is used.</para>
<formalpara>
<title>Encoding issues</title>
<para>Most of the configuration parameters are plain ASCII. Two
particular sets of values may cause encoding issues:</para>
</formalpara>
<para>
<itemizedlist>
<listitem><para>File path parameters may contain non-ascii
characters and should use the exact same byte values as found in
the file system directory. Usually, this means that the
configuration file should use the system default locale
encoding.</para>
</listitem>
<listitem><para>The <envar>unac_except_trans</envar> parameter
should be encoded in UTF-8. If your system locale is not UTF-8, and
you need to also specify non-ascii file paths, this poses a
difficulty because common text editors cannot handle multiple
encodings in a single file. In this relatively unlikely case, you
can edit the configuration file as two separate text files with
appropriate encodings, and concatenate them to create the complete
configuration.</para>
</listitem>
</itemizedlist>
</para>
<sect2 id="RCL.INSTALL.CONFIG.ENVIR">
<title>Environment variables</title>
<variablelist>
<varlistentry>
<term><varname>RECOLL_CONFDIR</varname></term>
<listitem><para>Defines the main configuration
directory.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>RECOLL_TMPDIR, TMPDIR</varname></term>
<listitem><para>Locations for temporary files, in this order
of priority. The default if none of these is set is to use
<filename>/tmp</filename>. Big temporary files may be created
during indexing, mostly for decompressing, and also for
processing, e.g. email attachments.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>RECOLL_CONFTOP, RECOLL_CONFMID</varname></term>
<listitem><para>Allow adding configuration directories with
priorities below and above the user directory (see above the
Configuration overview section for details).</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>RECOLL_EXTRA_DBS, RECOLL_ACTIVE_EXTRA_DBS</varname></term>
<listitem><para>
Help for setting up external indexes. See
<link linkend="RCL.SEARCH.GUI.MULTIDB">this paragraph</link> for
explanations.
</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>RECOLL_DATADIR</varname></term>
<listitem><para>Defines replacement for the default location
of Recoll data files, normally found in, e.g.,
<filename>/usr/share/recoll</filename>).</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>RECOLL_FILTERSDIR</varname></term>
<listitem><para>Defines replacement for the default location
of Recoll filters, normally found in, e.g.,
<filename>/usr/share/recoll/filters</filename>).</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>ASPELL_PROG</varname></term>
<listitem><para><command>aspell</command> program to use for
creating the spelling dictionary. The result has to be
compatible with the <filename>libaspell</filename> which &RCL;
is using.</para></listitem>
</varlistentry>
</variablelist>
</sect2>
<!-- <sect2 id="RCL.INSTALL.CONFIG.RECOLLCONF"> -->
&RCLCONF;
<sect2 id="RCL.INSTALL.CONFIG.FIELDS">
<title>The fields file</title>
<para>This file contains information about dynamic fields handling
in &RCL;. Some very basic fields have hard-wired behaviour,
and, mostly, you should not change the original data inside the
<filename>fields</filename> file. But you can create custom fields
fitting your data and handle them just like they were native
ones.</para>
<para>The <filename>fields</filename> file has several sections,
which each define an aspect of fields processing. Quite often,
you'll have to modify several sections to obtain the desired
behaviour.</para>
<para>We will only give a short description here, you should refer
to the comments inside the default file for more detailed
information.</para>
<para>Field names should be lowercase alphabetic ASCII.</para>
<variablelist>
<varlistentry>
<term>[prefixes]</term>
<listitem><para>A field becomes indexed (searchable) by having
a prefix defined in this section. There is a more complete
explanation of what prefixes are in used by a standard recoll
installation. In a nutshell: extension prefixes should be all
caps, begin with XY, and short. E.g. XYMFLD.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>[values]</term>
<listitem><para>Fields listed in this section will be stored as
&XAP; <literal>values</literal> inside the index. This makes
them available for range queries, allowing to filter results
according to the field value. This feature currently supports
string and integer data. See the comments in the file for more
detail</para>
</listitem>
</varlistentry>
<varlistentry>
<term>[stored]</term>
<listitem><para>A field becomes stored (displayable inside
results) by having its name listed in this section (typically
with an empty value).</para>
</listitem>
</varlistentry>
<varlistentry>
<term>[aliases]</term>
<listitem><para>This section defines lists of synonyms for the
canonical names used inside the <literal>[prefixes]</literal>
and <literal>[stored]</literal> sections</para>
</listitem>
</varlistentry>
<varlistentry>
<term>[queryaliases]</term>
<listitem><para>This section also defines aliases for the
canonic field names, with the difference that the substitution
will only be used at query time, avoiding any possibility that
the value would pick-up random metadata from documents.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>handler-specific sections</term>
<listitem><para>Some input handlers may need specific
configuration for handling fields. Only the email message handler
currently has such a section (named
<literal>[mail]</literal>). It allows indexing arbitrary email
headers in addition to the ones indexed by default. Other such
sections may appear in the future.</para>
</listitem>
</varlistentry>
</variablelist>
<para>Here follows a small example of a personal
<filename>fields</filename>
file. This would extract a specific email header and
use it as a searchable field, with data displayable inside result
lists. (Side note: as the email handler does no decoding on the values,
only plain ascii headers can be indexed, and only the
first occurrence will be used for headers that occur several times).
<programlisting>[prefixes]
# Index mailmytag contents (with the given prefix)
mailmytag = XMTAG
[stored]
# Store mailmytag inside the document data record (so that it can be
# displayed - as %(mailmytag) - in result lists).
mailmytag =
[queryaliases]
filename = fn
containerfilename = cfn
[mail]
# Extract the X-My-Tag mail header, and use it internally with the
# mailmytag field name
x-my-tag = mailmytag
</programlisting>
</para>
<sect3 id="RCL.INSTALL.CONFIG.FIELDS.XATTR">
<title>Extended attributes in the fields file</title>
<para>&RCL; versions 1.19 and later process user extended
file attributes as documents fields by default.</para>
<para>Attributes are processed as fields of the same name,
after removing the <literal>user</literal> prefix on
Linux.</para>
<para>The <literal>[xattrtofields]</literal>
section of the <filename>fields</filename> file allows
specifying translations from extended attributes names to
&RCL; field names. An empty translation disables use of the
corresponding attribute data.</para>
</sect3>
</sect2>
<sect2 id="RCL.INSTALL.CONFIG.MIMEMAP">
<title>The mimemap file</title>
<para><filename>mimemap</filename> specifies the
file name extension to MIME type mappings.</para>
<para>For file names without an extension, or with an unknown one,
a system command (<command>file</command> <option>-i</option>, or
<command>xdg-mime</command>) will be executed to determine the MIME
type (this can be switched off, or the command changed inside the
main configuration file).</para>
<para>All extension values in <filename>mimemap</filename> must be
entered in lower case. File names extensions are lower-cased for
comparison during indexing, meaning that an upper case
<filename>mimemap</filename> entry will never be matched.</para>
<para>The mappings can be specified on a per-subtree basis,
which may be useful in some cases. Example:
<application>okular</application> notes have a
<filename>.xml</filename> extension but
should be handled specially, which is possible because they
are usually all located in one place. Example:
<programlisting>[~/.kde/share/apps/okular/docdata]
.xml = application/x-okular-notes</programlisting></para>
<para>The <varname>recoll_noindex</varname>
<filename>mimemap</filename> variable has been moved to
<filename>recoll.conf</filename> and renamed to
<varname>noContentSuffixes</varname>, while keeping the same
function, as of &RCL; version 1.21. For older &RCL; versions,
see the documentation for <varname>noContentSuffixes</varname>
but use <varname>recoll_noindex</varname> in
<filename>mimemap</filename>.</para>
</sect2>
<sect2 id="RCL.INSTALL.CONFIG.MIMECONF">
<title>The mimeconf file</title>
<para>The main purpose of the <filename>mimeconf</filename> file is
to specify how the different MIME types are handled for
indexing. This is done in the <literal>[index]</literal>
section, which should not be modified casually. See the comments in
the file.</para>
<para>The file also contains other definitions which affect the
query language and the GUI, and which, in retrospect, should have
been stored elsewhere.</para>
<para>The <literal>[icons]</literal> section allows you to change
the icons which are displayed by the <command>recoll</command> GUI
in the result lists (the values are the basenames of the
<literal>png</literal> images inside the
<filename>iconsdir</filename> directory (which is itself defined
in <filename>recoll.conf</filename>).</para>
<para>The <literal>[categories]</literal> section defines the
groupings of MIME types into <literal>categories</literal> as used
when adding an <literal>rclcat</literal> clause to a
<link linkend="RCL.SEARCH.LANG">query language</link>
query. <literal>rclcat</literal> clauses are also used by the
default <literal>guifilters</literal> buttons in the GUI (see
next).</para>
<para>The filter controls appear at the top of the
<command>recoll</command> GUI, either as checkboxes just above the
result list, or as a dropbox in the tool area.</para>
<para>By default, they are labeled: <literal>media</literal>,
<literal>message</literal>, <literal>other</literal>,
<literal>presentation</literal>, <literal>spreadsheet</literal> and
<literal>text</literal>, and each maps to a document category. This
is determined in the <literal>[guifilters]</literal> section, where
each control is defined by a variable naming a query language
fragment.</para>
<para>A simple example will hopefully make things clearer.</para>
<programlisting>[guifilters]
Big Books = dir:"~/My Books" size&gt;10K
My Docs = dir:"~/My Documents"
Small Books = dir:"~/My Books" size&lt;10K
System Docs = dir:/usr/share/doc
</programlisting>
<para>The above definition would create four filter checkboxes,
labelled <literal>Big Books</literal>, <literal>My Docs</literal>,
etc.</para>
<para>The text after the equal sign must be a valid query language
fragment, and, when the button is checked, it will be combined with
the rest of the query with an AND conjunction.</para>
<para>Any name text before a colon character will be erased in the
display, but used for sorting. You can use this to display the
checkboxes in any order you like. For example, the following would
do exactly the same as above, but ordering the checkboxes in the
reverse order.</para>
<programlisting>[guifilters]
d:Big Books = dir:"~/My Books" size&gt;10K
c:My Docs = dir:"~/My Documents"
b:Small Books = dir:"~/My Books" size&lt;10K
a:System Docs = dir:/usr/share/doc
</programlisting>
<para>As you may have guessed, The default
<literal>[guifilters]</literal> section looks like:</para>
<programlisting>[guifilters]
text = rclcat:text
spreadsheet = rclcat:spreadsheet
presentation = rclcat:presentation
media = rclcat:media
message = rclcat:message
other = rclcat:other
</programlisting>
</sect2>
<sect2 id="RCL.INSTALL.CONFIG.MIMEVIEW">
<title>The mimeview file</title>
<para><filename>mimeview</filename> specifies which programs
are started when you click on an <guilabel>Open</guilabel> link
in a result list. Ie: HTML is normally displayed using
<application>firefox</application>, but you may prefer
<application>Konqueror</application>, your
<application>openoffice.org</application>
program might be named <command>oofice</command> instead of
<command>openoffice</command> etc.</para>
<para>Changes to this file can be done by direct editing, or
through the <command>recoll</command> GUI preferences dialog.</para>
<para>If <guilabel>Use desktop preferences to choose document
editor</guilabel> is checked in the &RCL; GUI preferences, all
<filename>mimeview</filename> entries will be ignored except the
one labelled <literal>application/x-all</literal> (which is set to
use <command>xdg-open</command> by default).</para>
<para>In this case, the <literal>xallexcepts</literal> top level
variable defines a list of MIME type exceptions which
will be processed according to the local entries instead of being
passed to the desktop. This is so that specific &RCL; options
such as a page number or a search string can be passed to
applications that support them, such as the
<application>evince</application> viewer.</para>
<para>As for the other configuration files, the normal usage
is to have a <filename>mimeview</filename> inside your own
configuration directory, with just the non-default entries,
which will override those from the central configuration
file.</para>
<para>All viewer definition entries must be placed under a
<literal>[view]</literal> section.</para>
<para>The keys in the file are normally MIME types. You can add an
application tag to specialize the choice for an area of the
filesystem (using a <varname>localfields</varname> specification
in <filename>mimeconf</filename>). The syntax for the key is
<replaceable>mimetype</replaceable><literal>|</literal><replaceable>tag</replaceable></para>
<para>The <varname>nouncompforviewmts</varname> entry, (placed at
the top level, outside of the <literal>[view]</literal> section),
holds a list of MIME types that should not be uncompressed before
starting the viewer (if they are found compressed, ie:
<replaceable>mydoc.doc.gz</replaceable>).</para>
<para>The right side of each assignment holds a command to be
executed for opening the file. The following substitutions are
performed:</para>
<itemizedlist>
<listitem>
<formalpara><title>%D</title>
<para>Document date</para></formalpara>
</listitem>
<listitem><formalpara><title>%f</title>
<para>File name. This may be the name of a temporary file if
it was necessary to create one (ie: to extract a subdocument
from a container).</para></formalpara>
</listitem>
<listitem><formalpara><title>%i</title>
<para>Internal path, for subdocuments of containers. The
format depends on the container type. If this appears in the
command line, &RCL; will not create a temporary file to
extract the subdocument, expecting the called application
(possibly a script) to be able to handle it.</para></formalpara>
</listitem>
<listitem><formalpara><title>%M</title>
<para>MIME type</para></formalpara>
</listitem>
<listitem><formalpara><title>%p</title>
<para>Page index. Only significant for a subset of document
types, currently only PDF, Postscript and DVI files. Can be
used to start the editor at the right page for a match or
snippet.</para></formalpara>
</listitem>
<listitem><formalpara><title>%s</title>
<para>Search term. The value will only be set for documents
with indexed page numbers (ie: PDF). The value will be one of
the matched search terms. It would allow pre-setting the
value in the "Find" entry inside Evince for example, for easy
highlighting of the term.</para></formalpara>
</listitem>
<listitem><formalpara><title>%u</title>
<para>Url.</para></formalpara>
</listitem>
</itemizedlist>
<para>In addition to the predefined values above, all strings like
<literal>%(fieldname)</literal> will be replaced by the value of
the field named <literal>fieldname</literal> for the
document. This could be used in combination with field
customisation to help with opening the document.</para>
</sect2>
<sect2 id="RCL.INSTALL.CONFIG.PTRANS">
<title>The <filename>ptrans</filename> file</title>
<para><filename>ptrans</filename> specifies query-time path
translations. These can be useful
in <link linkend="RCL.SEARCH.PTRANS">multiple cases</link>.
</para>
<para>The file has a section for any index which needs
translations, either the main one or additional query
indexes. The sections are named with the &XAP; index
directory names. No slash character should exist at the end
of the paths (all comparisons are textual). An example
should make things sufficiently clear</para>
<programlisting>
[/home/me/.recoll/xapiandb]
/this/directory/moved = /to/this/place
[/path/to/additional/xapiandb]
/server/volume1/docdir = /net/server/volume1/docdir
/server/volume2/docdir = /net/server/volume2/docdir
</programlisting>
</sect2>
<sect2 id="RCL.INSTALL.CONFIG.EXAMPLES">
<title>Examples of configuration adjustments</title>
<sect3 id="RCL.INSTALL.CONFIG.EXAMPLES.ADDVIEW">
<title>Adding an external viewer for an non-indexed type</title>
<para>Imagine that you have some kind of file which does not
have indexable content, but for which you would like to have a
functional <guilabel>Open</guilabel> link in the result list
(when found by file name). The file names end in
<replaceable>.blob</replaceable> and can be displayed by
application <replaceable>blobviewer</replaceable>.</para>
<para>You need two entries in the configuration files for this
to work:</para>
<itemizedlist>
<listitem><para>In <filename>$RECOLL_CONFDIR/mimemap</filename>
(typically <filename>~/.recoll/mimemap</filename>), add the
following line:<programlisting>
.blob = application/x-blobapp
</programlisting>
Note that the MIME type is made up here, and you could
call it <replaceable>diesel/oil</replaceable> just the
same.</para>
</listitem>
<listitem><para>In <filename>$RECOLL_CONFDIR/mimeview</filename>
under the <literal>[view]</literal> section, add:</para>
<programlisting>
application/x-blobapp = blobviewer %f
</programlisting>
<para>We are supposing
that <replaceable>blobviewer</replaceable> wants a file
name parameter here, you would use <literal>%u</literal> if
it liked URLs better.</para>
</listitem>
</itemizedlist>
<para>If you just wanted to change the application used by
&RCL; to display a MIME type which it already knows, you
would just need to edit <filename>mimeview</filename>. The
entries you add in your personal file override those in the
central configuration, which you do not need to
alter. <filename>mimeview</filename> can also be modified
from the Gui.</para>
</sect3>
<sect3 id="RCL.INSTALL.CONFIG.EXAMPLES.ADDINDEX">
<title>Adding indexing support for a new file type</title>
<para>Let us now imagine that the above
<replaceable>.blob</replaceable> files actually contain
indexable text and that you know how to extract it with a
command line program. Getting &RCL; to index the files is
easy. You need to perform the above alteration, and also to
add data to the <filename>mimeconf</filename> file
(typically in <filename>~/.recoll/mimeconf</filename>):</para>
<itemizedlist>
<listitem><para>Under the <literal>[index]</literal>
section, add the following line (more about the
<replaceable>rclblob</replaceable> indexing script
later):<programlisting>
application/x-blobapp = exec rclblob</programlisting>
Or if the files are mostly text and you don't need to process them
for indexing:<programlisting>
application/x-blobapp = internal text/plain</programlisting>
</para>
</listitem>
<listitem><para>Under the <literal>[icons]</literal>
section, you should choose an icon to be displayed for the
files inside the result lists. Icons are normally 64x64
pixels PNG files which live in
<filename>/usr/share/recoll/images</filename>.</para>
</listitem>
<listitem><para>Under the <literal>[categories]</literal>
section, you should add the MIME type where it makes sense
(you can also create a category). Categories may be used
for filtering in advanced search.</para>
</listitem>
</itemizedlist>
<para>The <replaceable>rclblob</replaceable> handler should
be an executable program or script which exists inside
<filename>/usr/share/recoll/filters</filename>. It
will be given a file name as argument and should output the
text or html contents on the standard output.</para>
<para>The <link linkend="RCL.PROGRAM.FILTERS">filter programming</link>
section describes in more detail how to write an input handler.</para>
</sect3>
</sect2>
</sect1>
</chapter>
</book>
Reference in New Issue View Git Blame Copy Permalink