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<!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/features.html#doctypes'>http://www.recoll.org/features.html</ulink>">
<!ENTITY RCLVERSION "1.22">
<!ENTITY XAP "<application>Xapian</application>">
<!ENTITY WIN "<application>Windows</application>">
<!ENTITY WIKI "http://bitbucket.org/medoc/recoll/wiki/">
]>
<book lang="en">
<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>2005-2015</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. This version describes &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;. Some described features are also not available on
&WIN;. The manual will be progressively updated. Until this happens,
most references to shared files can be translated by looking under
the Recoll installation directory (esp. 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 by default, 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 (for the very impatient with a completed package install, from the <command>recoll</command> GUI: <menuchoice>
<guimenu>Preferences</guimenu>
<guimenuitem>Indexing configuration</guimenuitem>
</menuchoice>, then adjust the <guilabel>Top
directories</guilabel> section).</para>
<para>Also be aware that, on Unix/Linux, 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).</para>
<para>The &RCL; installation for &WIN; is self-contained and includes
most useful auxiliary programs. You will just need to install Python
2.7.</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.</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 may
propose, depending on index contents, <replaceable>alliteration
alteration alterations altercation</replaceable> as possible
replacement terms. </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. (Actually, there is a
way to reconstruct a document from the information in the
index, but the result is not nice, as all formatting,
punctuation and capitalization are lost).</para>
<para>&RCL; stores all internal data in <application>Unicode
UTF-8</application> format, and it can index files of many types
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; versions 1.18 and newer 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 <link linkend="RCL.INDEXING.CONFIG.SENS">section about index
case and diacritics sensitivity</link>.</para>
<para>&RCL; has many parameters which 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, found
by default in the <filename>.recoll</filename> sub-directory
of your home directory. The default configuration will index
your home directory with default parameters and should be
sufficient for giving &RCL; a try, but you may want to adjust
it later, which can be done either by editing the text files
or by using configuration menus in the
<command>recoll</command> GUI. Some other parameters affecting only
the <command>recoll</command> GUI are stored in the standard
location defined by <application>Qt</application>.</para>
<para>The <link linkend="RCL.INDEXING.PERIODIC.EXEC">indexing
process</link> is started automatically 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 among 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 perform &RCL; searches: mostly a <link
linkend="RCL.SEARCH.COMMANDLINE">
command line interface</link>, a
<link linkend="RCL.PROGRAM.PYTHONAPI">
<application>Python</application>
programming interface</link>, a <link linkend="RCL.SEARCH.KIO">
<application>KDE</application> KIO slave module</link>, and
Ubuntu Unity <ulink url="https://bitbucket.org/medoc/unity-lens-recoll">
Lens</ulink> (for older versions) or
<ulink url="https://bitbucket.org/medoc/unity-scope-recoll">
Scope</ulink> (for current versions) modules.
</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 a new behaviour in version 1.21 (failed files
were always retried by previous versions). The command line
option <option>-k</option> can be set to retry failed files, for
example after updating a filter.</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 different modes:
<itemizedlist>
<listitem>
<formalpara>
<title><link linkend="RCL.INDEXING.PERIODIC">
Periodic (or batch) indexing:</link></title>
<para>indexing takes place at discrete
times, by executing the <command>recollindex</command>
command. The typical usage is to have a nightly indexing run
<link linkend="RCL.INDEXING.PERIODIC.AUTOMAT">
programmed</link> into
your <command>cron</command> file.</para>
</formalpara>
</listitem>
<listitem>
<formalpara><title><link linkend="RCL.INDEXING.MONITOR">Real
time indexing:</link></title>
<para>indexing takes place as soon as a file is created or
changed. <command>recollindex</command> runs as a daemon
and uses a file system alteration monitor such as
<application>inotify</application>,
<application>Fam</application> or
<application>Gamin</application>
to detect file changes.</para>
</formalpara>
</listitem>
</itemizedlist>
</para>
<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). Monitoring a big file system tree can consume
significant system resources.</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>
</para>
<para>The <menuchoice><guimenu>File</guimenu>
</menuchoice> menu also has entries to start or stop
the current indexing operation. Stopping indexing is performed by
killing the <command>recollindex</command> process, which will
checkpoint its state and exit. A later restart of indexing will
mostly resume from where things stopped (the file tree walk has to
be restarted from the beginning).</para>
<para>When the real time indexer is running, only a stop operation
is available from the menu. When no indexing is running, you have
a choice of updating the index or rebuilding it (the first choice
only processes changed files, the second one zeroes the index
before starting so that all files are processed).</para>
</sect2>
<sect2 id="RCL.INDEXING.INTRODUCTION.CONFIG">
<title>Configurations, multiple indexes</title>
<para>The parameters describing what is to be indexed and
local preferences are defined in text files contained in a
<link linkend="RCL.INDEXING.CONFIG">configuration
directory</link>.</para>
<para>All parameters have defaults, defined in system-wide
files.</para>
<para>Without further configuration, &RCL; will index all
appropriate files from your home directory, with a reasonable
set of defaults.</para>
<para>A default personal configuration directory
(<filename>$HOME/.recoll/</filename>) is created
when a &RCL; program is first executed. It is possible to
create other configuration directories, and use them by
setting the <envar>RECOLL_CONFDIR</envar> environment
variable, or giving the <option>-c</option> option to any of
the &RCL; commands.</para>
<para>In some cases, it may be interesting to index different
areas of the file system to separate databases. You can do this
by using multiple configuration directories, each indexing a
file system area to a specific database. Typically, this
would be done to separate personal and shared
indexes, or to take advantage of the organization of your data
to improve search precision.</para>
<para>The generated indexes can
be queried concurrently in a transparent manner.</para>
<para>For index generation, multiple configurations are
totally independant from each other. When multiple indexes need
to be used for a single search,
<link linkend="RCL.INDEXING.CONFIG.MULTIPLE">some parameters
should be consistent among the configurations</link>.</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>&RCL; indexing 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>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 to define a positive list of types to be
indexed. In the latter case, any type not in the list will
be ignored.</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>
<para>Excluding types 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. For
versions 1.20 and later, you can alternatively set the
<link linkend="RCL.INSTALL.CONFIG.RECOLLCONF.EXCLUDEDMIMETYPES">
excludedmimetypes</link> list in the configuration file. 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 settting
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">
main configuration file
(<filename>recoll.conf</filename>)</link>, or from the GUI
index configuration tool.</para>
</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>&RCL; versions prior to 1.21 always retried to index
files which had previously caused an error. This guaranteed
that anything that may have become indexable (for example
because a helper had been installed) would be indexed. However
this was bad for performance because some indexing failures
may be quite costly (for example failing to uncompress a big
file because of insufficient disk space).</para>
<para>The indexer in &RCL; versions 1.21 and later does not
retry failed file by default. 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.</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):
<itemizedlist>
<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>
<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 concerns.</para>
</listitem>
</itemizedlist>
</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 nowadays (2012), typically, even a big
index will be negligible against 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, then run a normal indexing
process.</para>
<para>Using the <option>-z</option> option to
<command>recollindex</command> is not sufficient to change the
format, you will have to delete all files inside the index
directory (typically <filename>~/.recoll/xapiandb</filename>)
before starting the indexing.</para>
</sect2>
<sect2 id="RCL.INDEXING.STORAGE.SECURITY">
<title>Security aspects</title>
<para>The &RCL; index does not hold copies of the indexed
documents. 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>
</sect1>
<sect1 id="RCL.INDEXING.CONFIG">
<title>Index configuration</title>
<para>Variables set 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. These variables can be set either by
editing the text files or 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 <filename>~/.recoll</filename> directory containing
empty configuration files, which you can edit by hand.</para>
<para>The configuration is documented inside the
<link linkend="RCL.INSTALL.CONFIG">installation chapter</link>
of this document, or in the
<citerefentry>
<refentrytitle>recoll.conf</refentrytitle>
<manvolnum>5</manvolnum>
</citerefentry>
man page, but the most
current information will most likely be the comments inside the
sample file. The most immediately useful variable you may
interested in is probably
<link linkend="RCL.INSTALL.CONFIG.RECOLLCONF.TOPDIRS">
<varname>topdirs</varname></link>,
which determines what subtrees get 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>As of Recoll 1.18 there are two incompatible types of Recoll
indexes, depending on the treatment of character case and
diacritics. The next section describes the two types in more
detail.</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 usually set to
index different areas of the file system. A specific index can
be selected for updating or searching, using the
<envar>RECOLL_CONFDIR</envar> environment variable or the
<option>-c</option> option to <command>recoll</command> and
<command>recollindex</command>.</para>
<para>When working with the <command>recoll</command> index
configuration GUI, 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>Additional configuration directory (beyond
<filename>~/.recoll</filename>) must be created by hand
(<command>mkdir</command> or such), the GUI will not do it. This is
to avoid mistakenly creating additional directories when an
argument is mistyped.</para>
<para>A typical 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. 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 will have much better performance and may be
worth the trouble.</para>
<para>A <command>recollindex</command> program instance can only
update one specific index.</para>
<para>The 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>The different search interfaces (GUI, command line, ...)
have different methods to define the set of indexes to be
used, see the appropriate section.</para>
<para>If a set of multiple indexes are to be used together for
searches, some configuration parameters must be consistent
among the set. These are parameters which need to be the same
when indexing and searching. As the parameters come from the
main configuration when searching, they need to be compatible
with what was set when creating the other indexes (which came
from their respective configuration directories).</para>
<para>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 are described in the
<link linkend="RCL.INSTALL.CONFIG.RECOLLCONF.TERMS">linked
section</link>.</para>
</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 for another possibility which a stripped
index cannot offer: using case and diacritics to discriminate
between terms, 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>If the <literal>indexStripChars</literal> is not set, &RCL;
1.18 creates a stripped index by default, for
compatibility with previous versions.</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
still young, 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</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>File system walking: this is always performed by
the main thread.</listitem>
<listitem>File conversion and data extraction.</listitem>
<listitem>Text processing (splitting, stemming,
etc.)</listitem>
<listitem>&XAP; index update.</listitem>
</orderedlist>
</para>
<para>You can also read a
<ulink url="http://www.recoll.org/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.WEBQUEUE">
<title>Indexing WEB pages you wisit</title>
<para>With the help of a <application>Firefox</application>
extension, &RCL; can index the Internet pages that you visit. The
extension was initially designed for the
<application>Beagle</application> indexer, but it has recently be
renamed and better adapted to &RCL;.</para>
<para>The extension works by copying visited WEB pages to an indexing
queue directory, which &RCL; then processes, indexing the data,
storing it into a local cache, then removing the file from the
queue.</para>
<para>This feature can be enabled in the GUI
<guilabel>Index configuration</guilabel>
panel, or by editing the configuration file (set
<varname>processwebqueue</varname> to 1).</para>
<para>A current pointer to the extension can be found, along with
up-to-date instructions, on the
<ulink url="&WIKI;IndexWebHistory">Recoll wiki</ulink>.</para>
<para>A copy of the indexed WEB pages is retained by Recoll in a
local cache (from which previews can be fetched). The cache size can
be adjusted from the <guilabel>Index configuration</guilabel> /
<guilabel>Web history</guilabel> panel. Once the maximum size
is reached, old pages are purged - both from the cache and the index
- to make room for new ones, so you need to explicitly archive in
some other place the pages that you want to keep
indefinitely.</para>
</sect1>
<sect1 id="RCL.INDEXING.EXTATTR">
<title>Extended attributes data</title>
<para>User extended attributes are named pieces of information
that most modern file systems can attach to any file.</para>
<para>&RCL; versions 1.19 and later process extended attributes
as document fields by default. For older versions, this has to
be activated at build time.</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>If set, this defines the file character set
(mostly useful for plain text files).</listitem>
</varlistentry>
</variablelist>
</para>
<para>By default, other attributes are handled as &RCL; fields.
On Linux, the <literal>user</literal> prefix is removed from
the name. This 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>Importing external tags</title>
<para>During indexing, it is possible to import metadata for
each file by executing commands. For example, this could
extract user tag data for the file and store 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>As an example, if you would want &RCL; to use tags managed by
<application>tmsu</application>, you would add the following to the
configuration file:</para>
<programlisting>[/some/area/of/the/fs]
metadatacmds = ; tags = 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 <literal>tags</literal>. The field name is
arbitrary and could be <literal>tmsu</literal> or
<literal>myfield</literal> just the same, but <literal>tags</literal>
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'll 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: <literal>tags:some/alternate/values</literal> or
<literal>tags:all,these,values</literal> (the compact field search
syntax is supported for recoll 1.20 and later. For
older versions, you would need to repeat the <literal>tags:</literal>
specifier for each term, e.g. <literal>tags:some OR
tags:alternate</literal>).</para>
<para>You should be aware that 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
filename.</literal></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 <filename>rclpdf.py</filename> PDF input
handler has more complex capabilities than most others, and it is
also more configurable. Specifically, <filename>rclpdf.py</filename>
can automatically use <application>tesseract</application> to perform
OCR if the document text is empty, it can be configured to extract
specific metadata tags from an XMP packet, and to extract PDF
attachments.</para>
<sect2 id="RCL.INDEXING.PDF.OCR">
<title>OCR with Tesseract</title>
<para>If both <application>tesseract</application> and
<command>pdftoppm</command> (generally from the
<application>poppler-utils</application> package) are installed,
the PDF handler may attempt OCR on PDF files with no text
content. This is controlled by the <link
linkend="RCL.INSTALL.CONFIG.RECOLLCONF.PDFOCR">pdfocr</link>
configuration variable, which is false by default because
OCR is very slow.</para>
<para>The choice of language is very important for successfull
OCR. Recoll has currently no way to determine this from the
document itself. You can set the language to use through the
contents of a <filename>.ocrpdflang</filename> text file in the
same directory as the PDF document, or through the
<envar>RECOLL_TESSERACT_LANG</envar> environment variable, or
through the contents of an <filename>ocrpdf</filename> text file
inside the configuration directory. If none of the above are used,
&RCL; will try to guess the language from the NLS
environment.</para>
</sect2>
<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
</programlisting>
<!-- <para> There is a <ulink url="&WIKI;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 attachements 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.PERIODIC">
<title>Periodic indexing</title>
<sect2 id="RCL.INDEXING.PERIODIC.EXEC">
<title>Running indexing</title>
<para>Indexing is always performed by the
<command>recollindex</command> program, which can be started
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 <command>recollindex</command> indexing process can be
interrupted by sending an interrupt (<keysym>Ctrl-C</keysym>,
SIGINT) or terminate
(SIGTERM) signal. Some time may elapse before the process exits,
because it needs to properly flush and close the index. This can
also be done from the <command>recoll</command> GUI
<menuchoice>
<guimenu>File</guimenu>
<guimenuitem>Stop Indexing</guimenuitem>
</menuchoice>
menu entry.</para>
<para>After such 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 inexistant 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>
<para><command>recollindex</command> has a number of other options
which are described in its man page. 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>
</sect2>
<sect2 id="RCL.INDEXING.PERIODIC.AUTOMAT">
<title>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>As of version 1.17 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.</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>
</sect2>
</sect1>
<sect1 id="RCL.INDEXING.MONITOR">
<title>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>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, my out of fashion
<application>xdm</application>-based session has 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>
<para>By default, the messages from the indexing daemon will be
setn 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>
<para>When building &RCL;, the real time indexing support can be
customised during package <link
linkend="RCL.INSTALL.BUILDING.BUILD">configuration</link> with
the <option>--with[out]-fam</option> or
<option>--with[out]-inotify</option> options. The default is
currently to include <application>inotify</application>
monitoring on systems that support it, and, as of &RCL; 1.17,
<application>gamin</application> support on
<application>FreeBSD</application>.</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>
<note><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>
</para>
<para>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>
</note>
<sect2 id="RCL.INDEXING.MONITOR.FASTFILES">
<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.</para>
<para>&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>
</sect2>
</sect1>
</chapter>
<chapter id="RCL.SEARCH">
<title>Searching</title>
<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 modes:</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. For
example, &RCL; can handle things like email addresses, or
arbitrary cut and paste from another text window, punctation
and all.</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; versions
1.21 and later can save and restore searches, using XML files. 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 which will ignore such
directives. <guilabel>Any term</guilabel> will search for documents
where at least one of the terms appear. </para>
<para>The <guilabel>Query Language</guilabel> features are
described in <link linkend="RCL.SEARCH.LANG">a separate
section</link>.</para>
<para>All search modes allow wildcards inside terms
(<literal>*</literal>, <literal>?</literal>,
<literal>[]</literal>). You may want to have a look at the
<link linkend="RCL.SEARCH.WILDCARDS">section about wildcards</link>
for more information about this.</para>
<para><guilabel>File name</guilabel> 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 penality).
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, independantly 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>
<para>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>When using a stripped index, 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 use the simple search text entry widget (a
combobox) to recall them (click on the thing at the right of the
text field). Please note, however, that only the search texts
are remembered, not the mode (all/any/file name).</para>
<para>Typing <keycap>Esc</keycap> <keycap>Space</keycap> while
entering a word in the simple search entry will open a window
with possible completions for the word. The completions are
extracted from the database.</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>
</sect2>
<sect2 id="RCL.SEARCH.GUI.RESLIST">
<title>The default result list</title>
<para>After starting a search, a list of results will instantly
be displayed in the main list 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 on 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 (there is a short list of exceptions, see further). If you
prefer to completely customize the choice of applications, you can
uncheck the <guilabel>Use desktop preferences</guilabel> option in
the GUI preferences dialog, and click the <guilabel>Choose editor
applications</guilabel> button to adjust the predefined &RCL;
choices. The tool accepts multiple selections of MIME types (e.g. to
set up the editor for the dozens of office file types).</para>
<para>Even when <guilabel>Use desktop preferences</guilabel> is
checked, there is a small list of exceptions, for MIME types where
the &RCL; choice should override the desktop one. These are
applications which are well integrated with &RCL;, especially
<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. Of course, you can
edit the list (in the GUI preferences) if you would prefer to lose
the functionality and use the standard desktop tool.</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>Each result 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.</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>
<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>
<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> 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> 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>In &RCL; 1.15 and newer, the results can 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>Running arbitrary commands on result files (1.20 and later)</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>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="&WIKI;ResultsThumbnails.wiki">some
pointers about thumbnail generation</ulink> on the &RCL; wiki.
</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 for a window will also close the
window.</para>
<para>Of course you can also close a preview window by using the
window manager button in the top of the frame.</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 occurences 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>
&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?&gt;
&lt;fragbuts version=&quot;1.0&quot;&gt;
&lt;radiobuttons&gt;
&lt;fragbut&gt;
&lt;label&gt;Include Web Results&lt;/label&gt;
&lt;frag&gt;&lt;/frag&gt;
&lt;/fragbut&gt;
&lt;fragbut&gt;
&lt;label&gt;Exclude Web Results&lt;/label&gt;
&lt;frag&gt;-rclbes:BGL&lt;/frag&gt;
&lt;/fragbut&gt;
&lt;fragbut&gt;
&lt;label&gt;Only Web Results&lt;/label&gt;
&lt;frag&gt;rclbes:BGL&lt;/frag&gt;
&lt;/fragbut&gt;
&lt;/radiobuttons&gt;
&lt;buttons&gt;
&lt;fragbut&gt;
&lt;label&gt;Year 2010&lt;/label&gt;
&lt;frag&gt;date:2010-01-01/2010-12-31&lt;/frag&gt;
&lt;/fragbut&gt;
&lt;fragbut&gt;
&lt;label&gt;My Great Directory Only&lt;/label&gt;
&lt;frag&gt;dir:/my/great/directory&lt;/frag&gt;
&lt;/fragbut&gt;
&lt;/buttons&gt;
&lt;/fragbuts&gt;
</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>
<para>This feature is new in &RCL; 1.20, and will probably be
refined depending on user feedback.</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>Avanced 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>Avanced 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>Avanced 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 explicitely.</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
implicitely 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>
</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 <link linkend="RCL.INDEXING.CONFIG.MULTIPLE">section
describing 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>.
</para>
<para><envar>RECOLL_ACTIVE_EXTRA_DBS</envar> is available for
&RCL; versions 1.17.2 and later. A change was made in the same
update so that <command>recoll</command> will
automatically deactivate unreachable indexes 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>As of release 1.19, 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.TIPS">
<title>Search tips, shortcuts</title>
<sect3 id="RCL.SEARCH.GUI.TIPS.TERMS">
<title>Terms and search expansion</title>
<formalpara><title>Term completion</title>
<para>Typing <keycap>Esc</keycap> <keycap>Space</keycap> in
the simple search entry field while entering a word will
either complete the current word if its beginning matches a
unique term in the index, or open a window to propose a list
of completions.</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 and Proximity searches</title>
<para>A phrase can be looked for by enclosing it 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>This 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>This exact phrase</guilabel>).</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 strongly slow down a query if most of the
terms in the phrase are common. This is why the
<varname>autophrase</varname> option is off by default for &RCL;
versions before 1.17. As of version 1.17,
<varname>autophrase</varname> is on by default, but very common
terms will be removed from the constructed phrase. The removal
threshold can be adjusted from the search preferences.</para>
<formalpara><title>Phrases and abbreviations</title> <para>As of
&RCL; version 1.17, 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 occurences 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>Ajusting 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>As of &RCL; 1.18, 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>Browsing the result list inside a preview
window</title>
<para>Entering <keycap>Shift-Down</keycap> or <keycap>Shift-Up</keycap>
(<keycap>Shift</keycap> + an arrow key) in a preview window will
display the next or the previous document from the result
list. Any secondary search currently active will be executed on
the new document.</para>
</formalpara>
<formalpara><title>Scrolling the result list from the keyboard</title>
<para>You can use <keycap>PageUp</keycap> and <keycap>PageDown</keycap>
to scroll the result list, <keycap>Shift+Home</keycap> to go back
to the first page. These work even while the focus is in the
search entry.</para>
</formalpara>
<formalpara><title>Result table: moving the focus to the table</title>
<para>You can use <keycap>Ctrl-r</keycap> to move the focus
from the search entry to the table, and then use the arrow keys
to change the current row. <keycap>Ctrl-Shift-s</keycap> returns to
the search.</para>
</formalpara>
<formalpara><title>Result table: open / preview</title>
<para>With the focus in the result table, you can use
<keycap>Ctrl-o</keycap> to open the document from the current
row, <keycap>Ctrl-Shift-o</keycap> to open the document and close
<command>recoll</command>, <keycap>Ctrl-d</keycap> to preview
the document.</para>
</formalpara>
<formalpara><title>Editing a new search while the focus is not
in the search entry</title>
<para>You can use the <keycap>Ctrl-Shift-S</keycap> shortcut to
return the cursor to the search entry (and select the current
search text), while the focus is anywhere in the main
window.</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>
<formalpara><title>Closing previews</title>
<para>Entering <keycap>Ctrl-W</keycap> in a tab will
close it (and, for the last tab, close the preview
window). Entering <keycap>Esc</keycap> will close the preview
window and all its tabs.</para>
</formalpara>
<formalpara><title>Printing previews</title>
<para>Entering <keycap>Ctrl-P</keycap> in a preview window will print
the currently displayed text.</para>
</formalpara>
<formalpara><title>Quitting</title>
<para>Entering <keycap>Ctrl-Q</keycap> almost anywhere will
close the application.</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
explicitely 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>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
applicationsr</guilabel>: this opens a dialog which allows you
to select the application to be used to open each MIME
type. The default is nornally to use the
<command>xdg-open</command> utility, but you can override it.</para>
</listitem>
<listitem><para><guilabel>Exceptions</guilabel>: even wen
<command>xdg-open</command> is used by default for opening
documents, you can set 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>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>Auto-start simple search on white
space entry</guilabel>: if this is checked, a search will be
executed each time you enter a space in the simple search input
field. This lets you look at the result list as you enter new
terms. This is off by default, you may like it or not...</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 (ie: <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>Newer versions of Recoll (from 1.17) normally use WebKit HTML
widgets for the result list and the
<link linkend="RCL.SEARCH.GUI.RESULTLIST.MENU.SNIPPETS">
snippets window</link> (this may be disabled at build time).
Total customisation is possible with full support for CSS and
Javascript. Conversely, there are limits to what you can do with
the older Qt QTextBrowser, but still, it is possible to decide
what data each result will contain, and how it will be
displayed.</para>
<para>The result list presentation can be exhaustively 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/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 Filename if
not set.</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/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 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. Not that recollq is
only really useful on systems where the Qt libraries (or even the X11
ones) are not available. Otherwise, just use <literal>recoll
-t</literal>, which takes the exact same parameters and options which
are described for <command>recollq</command></para>
<para><command>recollq</command> has a man page (not installed by
default, look in the <filename>doc/man</filename> directory). The
Usage string is as follows:</para>
<programlisting>
recollq: usage:
-P: Show the date span for all the documents present in the index
[-o|-a|-f] [-q] &lt;query string&gt;
Runs a recoll query and displays result lines.
Default: will interpret the argument(s) as a xesam query string
query may be like:
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 &lt;configdir&gt; : specify config directory, overriding $RECOLL_CONFDIR
-d also dump file contents
-n [first-]&lt;cnt&gt; 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 &lt;fld&gt;
-s stemlang : set stemming language to use (must exist in index...)
Use -s "" to turn off stem expansion
-D : sort descending
-i &lt;dbdir&gt; : additional index, several can be given
-e use url encoding (%xx) for urls
-F &lt;field name list&gt; : 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.
</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.SYNONYMS">
<title>Using Synonyms (1.22)</title>
<formalpara><title>Term synonyms:</title>
<para>there are a number of 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 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.</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
exemple 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 exemple, 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.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 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>.</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>
</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>
</itemizedlist>
<note><para>
<literal>mime</literal>, <literal>rclcat</literal>,
<literal>size</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.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.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 explicitely 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.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
containg 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.DESKTOP">
<title>Desktop integration</title>
<para>Being independant of the desktop type has its drawbacks: &RCL;
desktop integration is minimal. However there are a few tools
available:
<itemizedlist>
<listitem>
<para>The <application>KDE</application> KIO Slave was
described in a <link linkend="RCL.SEARCH.KIO">previous
section</link>.</para>
</listitem>
<listitem>
<para>If you use a recent version of Ubuntu Linux, you may
find the <ulink url="&WIKI;UnityLens">Ubuntu Unity
Lens</ulink> module useful.</para>
</listitem>
<listitem>
<para>There is also an independantly 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="&WIKI;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.
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 currently (since version 1.13) 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.</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 <application>zip</application> or
<application>chm</application> files). They communicate
with the indexer through a simple protocol, but are
nevertheless a bit more complicated than the older
kind. Most of new handlers are written in
<application>Python</application>, using a common module
to handle the protocol. There is an exception,
<command>rclimg</command> which is written in Perl. 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 element</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.</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 modules. There is
a sample one with many comments, not actually used by &RCL;,
which 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 &RCL; <ulink
url="https://bitbucket.org/medoc/recoll/src">BitBucket
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 persistant 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>
&lt;html>
&lt;head>
&lt;meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
&lt;/head>
&lt;body>
Some text content
&lt;/body>
&lt;/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>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 independant 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="&WIKI;HandleCustomField">example on the Wiki</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>&RCL; versions after 1.11 define a Python programming
interface, both for searching and creating/updating an
index.</para>
<para>The search interface is used in the &RCL; Ubuntu Unity Lens
and the &RCL; Web UI. It can run queries on any &RCL;
configuration.</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
specification. There were two major changes along &RCL; versions:
<itemizedlist>
<listitem><para>The basis for the &RCL; API changed from Python
database API version 1.0 (&RCL; versions up to 1.18.1),
to version 2.0 (&RCL; 1.18.2 and later).</para></listitem>
<listitem><para>The <literal>recoll</literal> module became a
package (with an internal <literal>recoll</literal>
module) as of &RCL; version 1.19, in order to add more
functions. For existing code, this only changes the way
the interface must be imported.</para></listitem>
</itemizedlist>
</para>
<para>We will describe the new API and package structure here. A
paragraph at the end of this section will explain a few differences
and ways to write code compatible with both versions.</para>
<para>The Python interface can be found in the source package,
under <filename>python/recoll</filename>.</para>
<para>The <filename>python/recoll/</filename> directory
contains the usual <filename>setup.py</filename>. After
configuring 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>python setup.py build</userinput>
<userinput>python setup.py install</userinput>
</screen>
</para>
<para>As of &RCL; 1.19, the module can be compiled for
Python3.</para>
<para>The normal &RCL; installer installs the Python2
API along with the main code. The Python3 version must be
explicitely built and installed.</para>
<para>When installing from a repository, and depending on the
distribution, the Python API can sometimes be found in a
separate package.</para>
<para>As an introduction, the following small sample will run a
query and list the title and url for each of the results. It would
work with &RCL; 1.19 and later. 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/env python
from recoll import recoll
db = recoll.connect()
query = db.query()
nres = query.execute("some query")
results = query.fetchmany(20)
for doc in results:
print(doc.url, doc.title)
]]></programlisting>
</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 <filename>fields</filename> file inside
the &RCL; configuration defines which document fields are
either "indexed" (searchable), "stored" (retrievable with
search results), or both.</para>
</listitem>
</varlistentry>
</variablelist>
</sect2>
<sect2 id="RCL.PROGRAM.PYTHONAPI.SEARCH">
<title>Python search interface</title>
<sect3 id="RCL.PROGRAM.PYTHONAPI.PACKAGE">
<title>Recoll package</title>
<para>The <literal>recoll</literal> package contains two
modules:
<itemizedlist>
<listitem><para>The <literal>recoll</literal> module contains
functions and classes used to query (or update) the
index. This section will only describe the query part, see
further for the update part.</para></listitem>
<listitem><para>The <literal>rclextract</literal> module contains
functions and classes used to access document
data.</para></listitem>
</itemizedlist>
</para>
</sect3>
<sect3 id="RCL.PROGRAM.PYTHONAPI.RECOLL">
<title>The recoll module</title>
<sect4 id="RCL.PROGRAM.PYTHONAPI.RECOLL.FUNCTIONS">
<title>Functions</title>
<variablelist>
<varlistentry>
<term>connect(confdir=None, extra_dbs=None,
writable = False)</term>
<listitem>
<para>The <literal>connect()</literal> function connects to
one or several &RCL; index(es) and returns
a <literal>Db</literal> object.</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>
<para>This call initializes the recoll module, and it should
always be performed before any other call or object
creation.</para>
</listitem>
</varlistentry>
</variablelist>
</sect4>
<sect4 id="RCL.PROGRAM.PYTHONAPI.RECOLL.CLASSES">
<title>Classes</title>
<sect5 id="RCL.PROGRAM.PYTHONAPI.RECOLL.CLASSES.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>
</sect5>
<sect5 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")</term>
<listitem><para>Starts a search
for <replaceable>query_string</replaceable>, a &RCL;
search language string.</para></listitem>
</varlistentry>
<varlistentry>
<term>Query.executesd(SearchData)</term>
<listitem><para>Starts a search for the query defined by the
SearchData object.</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.</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.__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>
</sect5>
<sect5 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 matches exactly 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.h</filename> C++ file
for a description of the predefined attributes.</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. Especially this will not be the case for the
document text. See the <literal>rclextract</literal>
module for accessing document contents.</para>
<variablelist>
<varlistentry>
<term>get(key), [] operator</term>
<listitem><para>Retrieve the named doc
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 doc
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>
</sect5> <!-- Doc -->
<sect5 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>
</sect5> <!-- SearchData -->
</sect4> <!-- recoll.classes -->
</sect3> <!-- Recoll module -->
<sect3 id="RCL.PROGRAM.PYTHONAPI.RCLEXTRACT">
<title>The rclextract module</title>
<para>Index queries do not provide document content (only a
partial and unprecise reconstruction is performed to show the
snippets text). In order to access the actual document data,
the data extraction part of the indexing process
must be performed (subdocument access and format
translation). This is not trivial in
general. The <literal>rclextract</literal> module currently
provides a single class which can be used to access the data
content for result documents.</para>
<sect4 id="RCL.PROGRAM.PYTHONAPI.RCLEXTRACT.CLASSES">
<title>Classes</title>
<sect5 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 doc.text field
has the document text converted to either text/plain or
text/html according to doc.mimetype. The typical use
would be as follows:
<programlisting>
qdoc = query.fetchone()
extractor = recoll.Extractor(qdoc)
doc = extractor.textextract(qdoc.ipath)
# use doc.text, e.g. for previewing
</programlisting>
</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:
<programlisting>
qdoc = query.fetchone()
extractor = recoll.Extractor(qdoc)
filename = extractor.idoctofile(qdoc.ipath, qdoc.mimetype)</programlisting>
</para></listitem>
</varlistentry>
</variablelist>
</sect5> <!-- Extractor class -->
</sect4> <!-- rclextract classes -->
</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>
#!/usr/bin/env python
<![CDATA[
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: ", 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 k, ":", getattr(doc, k).encode('utf-8')
abs = db.makeDocAbstract(doc, query).encode('utf-8')
print abs
print
]]>
</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/download.html">
<application>Recoll</application> WEB site downloads
page</ulink></para>
<para>There used to exist another form of binary install, as
pre-compiled source trees, but these are just less convenient than
the packages and don't exist any more.</para>
<para>The package management tools will usually automatically
deal with hard dependancies 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 dependancies).</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, and
only needs Python 2.7 to be externally installed. &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>A list of common file types which need external
commands follows. Many of the handlers need the
<command>iconv</command> command, which is not always listed as a
dependancy.</para>
<para>Please note that, due to the relatively dynamic nature of this
information, the most up to date version is now kept on &RCLAPPS;
along with links to the home pages or best source/patches pages,
and misc tips. The list below is not updated often and may be quite
stale.</para>
<para>For many Linux distributions, most of the commands listed can
be installed from the package repositories. However, the packages
are sometimes outdated, or not the best version for &RCL;, so you
should take a look at &RCLAPPS; if a file
type is important to you.</para>
<para>As of &RCL; release 1.14, a number of XML-based formats that
were handled by ad hoc handler code now use the
<command>xsltproc</command> command, which usually comes with
<application>libxslt</application>. These are: abiword, fb2
(ebooks), kword, openoffice, svg.</para>
<para>Now for the list:</para>
<itemizedlist>
<listitem><para>Openoffice files need <command>unzip</command> and
<command>xsltproc</command>.</para></listitem>
<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>Postscript files need <command>pstotext</command>.
The original version has an issue with shell
character in file names, which is corrected in recent
packages. See &RCLAPPS; for more detail.</para>
</listitem>
<listitem><para>MS Word needs
<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>MS Excel and PowerPoint are processed by
internal <command>Python</command> handlers.</para></listitem>
<listitem><para>MS Open XML (docx) needs <command>
xsltproc</command>.</para></listitem>
<listitem><para>Wordperfect files need <command>wpd2html</command>
from the <application>libwpd</application> (or
<application>libwpd-tools</application> on Ubuntu)
package.</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>TeX files need <command>untex</command> or
<command>detex</command>. Check &RCLAPPS; for sources if it's not
packaged for your distribution.</para></listitem>
<listitem><para>dvi files need <command>dvips</command>.</para>
</listitem>
<listitem><para>djvu files need <command>djvutxt</command> and
<command>djvused</command> from the
<application>DjVuLibre</application> package.</para></listitem>
<listitem><para>Audio files: &RCL; releases 1.14 and later use
a single <application>Python</application> handler based
on <application>mutagen</application> for all audio file
types.</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. Note that
there may not be much interest in indexing the technical tags
(image size, aperture, etc.). This is only of interest if you
store personal tags or textual descriptions inside the image
files.</para></listitem>
<listitem><para>chm: files in Microsoft help format need Python and
the <application>pychm</application> module (which needs
<application>chmlib</application>).</para></listitem>
<listitem><para>ICS: up to &RCL; 1.13, iCalendar files need
<application>Python</application>
and the <application>icalendar</application>
module. <application>icalendar</application> is not needed for newer
versions, which use internal code.</para></listitem>
<listitem><para>Zip archives need <application>Python</application>
(and the standard zipfile module). </para></listitem>
<listitem><para>Rar archives need
<application>Python</application>, the
<application>rarfile</application> Python module and the
<command>unrar</command> utility.</para></listitem>
<listitem><para>Midi karaoke files need
<application>Python</application> and the
<ulink url="http://pypi.python.org/pypi/midi/0.2.1">
<application>Midi module</application></ulink></para>
</listitem>
<listitem><para>Konqueror webarchive format with Python (uses the
Tarfile module).</para></listitem>
<listitem><para>Mimehtml web archive format (support based on
the email handler, which introduces some mild weirdness, but
still usable).</para></listitem>
</itemizedlist>
<para>Text, HTML, email folders, and Scribus files are
processed internally. <application>Lyx</application> is used to
index Lyx files. Many handlers need <command>iconv</command> and the
standard <command>sed</command> and <command>awk</command>.
</para>
</sect1>
<sect1 id="RCL.INSTALL.BUILDING">
<title>Building from source</title>
<sect2 id="RCL.INSTALL.BUILDING.PREREQS">
<title>Prerequisites</title>
<para>If you can install any or all of the following through
the package manager for your system, all the
better. Especially <application>Qt</application> is a very
big piece of software, but you will most probably be able to
find a binary package.</para>
<para>If you are building for an exotic or older system, it may
be useful to note that functional improvements in &RCL;
have been relatively marginal in recent versions,
and that you may make your life easier by using an older
release, without losing major function.</para>
<para>The shopping list:</para>
<itemizedlist>
<listitem><para>The <literal>autoconf</literal>,
<literal>automake</literal> and <literal>libtool</literal>
triad. Only <literal>autoconf</literal> is needed before &RCL;
and including 1.21.</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><command>xsltproc</command> command. For building
the documentation (for &RCL; 1.21
and later). This sometimes comes with the
<literal>libxslt</literal> package. And also the Docbook XML and
style sheet files.</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 4 or Qt 5</application> </ulink>. &RCL; 1.15.9
was the last version to support <application>Qt 3</application>.
If you do not want to install or build the
<application>Qt Webkit</application> module, &RCL;
has a configuration option to disable its use (see further).
</para>
</listitem>
<listitem>
<para>Development files for <application>X11</application> and
<application>zlib</application>.</para>
</listitem>
<listitem>
<para>Development files for <application>Python</application>
(or use <literal>--disable-python-module</literal>).</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/download.html">
&RCL; download page</ulink> for up to date version
information.</para>
</sect2>
<sect2 id="RCL.INSTALL.BUILDING.BUILD">
<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 is 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
recent 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-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-xattr</option> will prevent
fetching data from file extended attributes. Beyond a
few standard attributes, fetching extended attributes
data can only be useful is some application stores data
in there, and also needs some simple configuration (see
comments in the <filename>fields</filename> configuration
file).</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-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>--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>--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 BitBucket 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>
<sect3 id="RCL.INSTALL.BUILDING.BUILD.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>
</sect3>
</sect2>
<sect2 id="RCL.INSTALL.BUILDING.INSTALL">
<title>Installation</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>
</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 overriden 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 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>
<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>
<varlistentry>
<term><varname>VARNAME</varname></term>
<listitem><para>Blabla</para></listitem>
</varlistentry>
</variablelist>
</sect2>
<!-- <sect2 id="RCL.INSTALL.CONFIG.RECOLLCONF"> -->
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude"
href="recoll.conf.xml" />
<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.</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><filename>mimeconf</filename> specifies how the
different MIME types are handled for indexing, and which icons
are displayed in the <command>recoll</command> result lists.</para>
<para>Changing the parameters in the [index] section is
probably not a good idea except if you are a &RCL;
developer.</para>
<para>The [icons] section allows you to change the icons which
are displayed by <command>recoll</command> in the result
lists (the values are the basenames of the png images inside
the <filename>iconsdir</filename> directory (specified in
<filename>recoll.conf</filename>).</para>
</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 exemple
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></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>
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