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More documentation can be found in the doc/ directory or at http://www.recoll.org
Recoll user manual
Jean-Francois Dockes
<jfd@recoll.org>
Copyright (c) 2005 Jean-Francois Dockes
This document introduces full text search notions and describes the
installation and use of the Recoll application. It currently describes
Recoll 1.14.
[ Split HTML / Single HTML ]
----------------------------------------------------------------------
Table of Contents
1. Introduction
1.1. Giving it a try
1.2. Full text search
1.3. Recoll overview
2. Indexing
2.1. Introduction
2.2. Index storage
2.2.1. Xapian index formats
2.2.2. Security aspects
2.3. Indexing configuration
2.3.1. The indexing configuration GUI
2.4. Using Beagle WEB browser plugins
2.5. Periodic indexing
2.5.1. Starting indexing
2.5.2. Using cron to automate indexing
2.6. Real time indexing
3. Searching
3.1. Searching with the Qt graphical user interface
3.1.1. Simple search
3.1.2. The result list
3.1.3. The preview window
3.1.4. Complex/advanced search
3.1.5. The term explorer tool
3.1.6. Multiple databases
3.1.7. Document history
3.1.8. Sorting search results and collapsing
duplicates
3.1.9. Search tips, shortcuts
3.1.10. Customizing the search interface
3.2. Searching with the KDE KIO slave
3.2.1. What's this
3.2.2. Searchable documents
3.3. Searching on the command line
3.4. The query language
3.4.1. More about wildcards
3.5. Desktop integration
3.5.1. Hotkeying recoll
3.5.2. The KDE Kicker Recoll applet
4. Programming interface
4.1. Writing a document filter
4.1.1. Filter HTML output
4.2. Field data processing
4.3. API
4.3.1. Interface elements
4.3.2. Python interface
5. Installation and configuration
5.1. Installing a binary copy
5.1.1. Installing through a package system
5.1.2. Installing a prebuilt Recoll
5.2. Supporting packages
5.3. Building from source
5.3.1. Prerequisites
5.3.2. Building
5.3.3. Installation
5.4. Configuration overview
5.4.1. Main configuration file
5.4.2. The fields file
5.4.3. The mimemap file
5.4.4. The mimeconf file
5.4.5. The mimeview file
5.4.6. Examples of configuration adjustments
----------------------------------------------------------------------
Chapter 1. Introduction
1.1. Giving it a try
If you do not like reading manuals (who does?) and would like to give
Recoll a try, just perform installation and start the recoll user
interface, which will index your home directory by default, allowing you
to search immediately after indexing completes.
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 configuration to restrict the indexed
area.
Also be aware that you may need to install the appropriate supporting
applications for document types that need them (for example antiword for
ms-word files).
----------------------------------------------------------------------
1.2. Full text search
Recoll is a full text search application. Full text search applications
let you find your data by content rather than by external attributes (like
a file name). More specifically, they will let you specify words (terms)
that should or should not appear in the text you are looking for, and
return a list of matching documents, ordered so that the most relevant
documents will appear first.
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 those terms are prominent, in a
similar way to Internet search engines.
Recoll tries 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 by the
search tool is probably the most important element for a search
application.
In many cases, you are looking for all the forms of a word, not for a
specific form or spelling. These different forms may include plurals,
different tenses for a verb, or terms derived from the same root or stem
(example: floor, floors, floored, flooring...). Recoll will by default
expand queries to all such related terms (words that reduce to the same
stem). This expansion can be disabled at search time.
Stemming, by itself, does not accommodate for misspellings or phonetic
searches. Recoll supports these features through a specific tool (the term
explorer) which will let you explore the set of index terms along
different modes.
----------------------------------------------------------------------
1.3. Recoll overview
Recoll uses the Xapian information retrieval library as its storage and
retrieval engine. Xapian is a very mature package using a sophisticated
probabilistic ranking model. Recoll provides the interface to get data
into (indexing) and out (searching) of the system.
In practice, Xapian works by remembering where terms appear in your
document files. The acquisition process is called indexing.
The resulting index can be big (roughly the size of the original document
set), but it is not a document archive. Recoll 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).
Recoll stores all internal data in Unicode UTF-8 format, and it can index
files with different character sets, encodings, and languages into the
same index. It has input filters for many document types.
Stemming depends on the document language. Recoll stores the unstemmed
versions of terms and uses auxiliary databases for term expansion. It can
switch stemming languages, or add a language, without re-indexing. Storing
documents in different languages in the same index is possible, and useful
in practice, but does introduce possibilities of confusion. Recoll
currently makes no attempt at automatic language recognition.
Recoll has many parameters which define exactly what to index, and how to
classify and decode the source documents. These are kept in configuration
files. A default configuration is copied into a standard location (usually
something like /usr/[local/]share/recoll/examples) during installation.
The default parameters from this file may be overridden by values that you
set inside your personal configuration, found by default in the .recoll
sub-directory of your home directory. The default configuration will index
your home directory with default parameters and should be sufficient for
giving Recoll a try, but you may want to adjust it later.
Indexing is started automatically the first time you execute the recoll
search graphical user interface, or by executing the recollindex command.
Searches are performed inside the recoll program, which has many options
to help you find what you are looking for.
----------------------------------------------------------------------
Chapter 2. Indexing
2.1. Introduction
Indexing is the process by which the set of documents is analyzed and the
data entered into the database. Recoll indexing is normally incremental:
documents will only be processed if they have been modified. On the first
execution, of course, all documents will need processing. A full index
build can be forced later by specifying an option to the indexing command
(recollindex -z).
Recoll indexing can be performed with two different methods:
* Periodic indexing: indexing takes place at discrete times, by
executing the recollindex command. The typical usage is to have a
nightly indexing run programmed into your cron file.
* Real time indexing: indexing takes place as soon as a file is created
or changed. recollindex runs as a daemon and uses a file system
alteration monitor such as Fam, Gamin or inotify do detect file
changes. Monitoring a big directory tree can consume significant
system resources.
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, for dubious gains.
Recoll knows about quite a few different document types. The parameters
for document types recognition and processing are set in configuration
files Most file types, like HTML or word processing files, only hold one
document. Some file types, like mail folder files, can hold many
individually indexed documents.
Recoll indexing processes plain text, HTML, openoffice and e-mail files
internally (a few more actually).
Other file types (ie: postscript, pdf, ms-word, rtf ...) need external
applications for preprocessing. The list is in the installation section.
After every indexing operation, Recoll updates a list of commands that
would be needed for indexing existing files types. This list can be
displayed from the recoll File menu. It is stored in the missing text file
inside the configuration directory.
Without further configuration, Recoll will index all appropriate files
from your home directory, with a reasonable set of defaults.
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. See the section about using multiple databases for more
information on multiple configurations and indexes.
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 xapiandb
directory (see next section), or, alternatively, start the next
recollindex with the -z option, which will reset the database before
indexing.
----------------------------------------------------------------------
2.2. Index storage
The default location for the index data is the xapiandb subdirectory of
the Recoll configuration directory, typically $HOME/.recoll/xapiandb/.
This can be changed via two different methods (with different purposes):
* You can specify a different configuration directory by setting the
RECOLL_CONFDIR environment variable, or using the -c option to the
Recoll 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 commands:
export RECOLL_CONFDIR=~/.indexes-email
recoll
Then Recoll would use configuration files stored in ~/.indexes-email/
and, (unless specified otherwise in recoll.conf) would look for the
index in ~/.indexes-email/xapiandb/.
Using multiple configuration directories and configuration options
allows you to tailor multiple configurations and indexes to handle
whatever subset of the available data that you wish to make
searchable.
* You can also specify a different storage location for the index by
setting the dbdir parameter in the configuration file (see the
configuration section). 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.
The size of the index is determined by the document set size, 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).
Of course, images, sound and video do not increase the index size, which
means that it will be quite typical nowadays (2006), that even a big index
will be negligible against the total amount of data on the computer.
The index data directory (xapiandb) only contains data that can be
completely rebuilt by an index run, and it can always be destroyed safely.
----------------------------------------------------------------------
2.2.1. Xapian index formats
If your first installation of Recoll was 1.9.0 or more recent, you can
skip this section.
Xapian has had two possible index formats for quite some time. The "old"
one named Quartz, and the new one named Flint. Xapian 0.9 used Quartz by
default, but could use Flint if a specific environment variable
(XAPIAN_PREFER_FLINT) was set. Xapian 1.0 still supports Quartz but will
use Flint by default for new index creations.
The number of disk accesses performed during indexing has been much
optimized in the new Flint engine and you may see indexing times improved
by 50% in some cases (compared to Quartz), typically for big indexes where
disk accesses dominate the indexing time. There is also a more modest
improvement of index size.
Xapian will not convert automatically an existing index from the Quartz to
the Flint format. If you have an older index and want to take advantage of
the new format (which can be done without setting the environment variable
as of Recoll 1.8.2 and Xapian 1.0.0), you will have to explicitly delete
the old index, then run a normal indexing process.
Unfortunately, using the -z option to recollindex is not sufficient to
change the format, you have to delete all files inside the index directory
(typically ~/.recoll/xapiandb) before starting indexing.
----------------------------------------------------------------------
2.2.2. Security aspects
The Recoll 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.
As of version 1.4, Recoll 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.
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 umask used during index updates.
----------------------------------------------------------------------
2.3. Indexing configuration
Variables set inside the Recoll configuration files 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 using the dialogs in the
recoll GUI.
You can also use multiple indexes defined by separate configurations,
typically to separate personal and shared indexes, or to take advantage of
the organization of your data to improve search precision.
The first time you start recoll, 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 Cancel at this point, which will get you into
the configuration interface. If you exit, recoll will have created a
~/.recoll directory containing empty configuration files, which you can
edit by hand.
The configuration is documented inside the installation chapter of this
document, or in the recoll.conf(5) 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
topdirs, which determines what subtrees get indexed.
The applications needed to index file types other than text, HTML or email
(ie: pdf, postscript, ms-word...) are described in the external packages
section
----------------------------------------------------------------------
2.3.1. The indexing configuration GUI
Most parameters for a given indexing configuration can be set from a
recoll GUI running on this configuration (either as default, or by setting
RECOLL_CONFDIR or the -c option.)
The interface is started from the Preferences menu. It has two main
panels. The first panel allows setting global variables, like the list of
top directories or the list of skipped paths. The second panel allows
setting variables that can be redefined for subdirectories. This second
panel 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).
The meaning for most entries in the interface is self-evident and
documented by a ToolTip popup on the text label. For more detail, you will
need to refer to the configuration section of this guide.
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...
----------------------------------------------------------------------
2.4. Using Beagle WEB browser plugins
Beagle is a concurrent desktop indexer, built on Lucene and the Mono
project (C#), for which a number of add-on browser plugins were written.
These work by copying visited web pages to an indexing queue directory,
which the indexer then processes.
If, for any reason, you so happen to prefer Recoll to Beagle, you can
still use the browser plugins (they are written in Javascript and
completely independant of C#, Beagle, Lucene...). Recoll can process the
Beagle queue directory. Of course, this supposes that Beagle is not
running, else both programs will fight for the same files.
This feature can be enabled in the GUI indexing configuration panel, or by
editing the configuration file (set processbeaglequeue to 1).
----------------------------------------------------------------------
2.5. Periodic indexing
2.5.1. Starting indexing
Indexing is performed either by the recollindex program, or by the
indexing thread inside the recoll program (use the File menu). Both
programs will use the RECOLL_CONFDIR variable or accept a -c confdir
option to specify a non-default configuration directory.
If the recoll program finds no index when it starts, it will automatically
start indexing (except if canceled).
The indexing process can be interrupted by sending an interrupt (^C,
SIGINT) or terminate (SIGTERM) signal. Some time may elapse before the
process exits, because it needs to properly flush and close the index. The
indexing will restart at the interruption point the next time (the full
file tree will still be traversed, but files that were indexed up to the
interruption and are still up to date will not need to be reindexed).
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 exemple, 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.
----------------------------------------------------------------------
2.5.2. Using cron to automate indexing
The most common way to set up indexing is to have a cron task execute it
every night. For example the following crontab entry would do it every day
at 3:30AM (supposing recollindex is in your PATH):
30 3 * * * recollindex > /some/tmp/dir/recolltrace 2>&1
Or, using anacron:
1 15 su mylogin -c "recollindex recollindex > /tmp/rcltraceme 2>&1"
The usual command to edit your crontab is crontab -e (which will usually
start the vi editor to edit the file). You may have more sophisticated
tools available on your system.
----------------------------------------------------------------------
2.6. Real time indexing
Real time monitoring/indexing is performed by starting the recollindex -m
command. With this option, recollindex will detach from the terminal and
become a daemon, permanently monitoring file changes and updating the
index.
The real time indexing support can be customised during package
configuration with the --with[out]-fam or --with[out]-inotify options. The
default is currently to include inotify monitoring on systems that support
it.
The rclmon.sh script can be used to easily start and stop the daemon. It
can be found in the examples directory (typically
/usr/local/[share/]recoll/examples).
Starting the daemon is normally performed as part of the user session
script. For example, my out of fashion xdm-based session has a .xsession
script with the following lines at the end:
recollconf=$HOME/.recoll-home
recolldata=/usr/local/share/recoll
RECOLL_CONFDIR=$recollconf $recolldata/examples/rclmon.sh start
fvwm
The indexing daemon gets started, then the window manager, for which the
session waits.
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
X11 server monitoring can be disabled with option -x to recollindex).
Under KDE, you can place a small script to start recollindex -m under
$HOME/.kde/Autostart. This will be executed when the session begins.
There is a similar mechanism under Gnome (find the session control tool in
the menus and use the "Startup programs" tab).
By default, the messages from the indexing daemon will be discarded. You
may want to change this by setting the daemlogfilename and daemloglevel
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.
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.
----------------------------------------------------------------------
Chapter 3. Searching
3.1. Searching with the Qt graphical user interface
The recoll program provides the main user interface for searching. It is
based on the Qt library.
recoll has two search modes:
* Simple search (the default, on the main screen) has a single entry
field where you can enter multiple words.
* Advanced search (a panel accessed through the Tools menu or the
toolbox bar icon) shas multiple entry fields, which you may use to
build a logical condition, with additional filtering on file type and
location in the file system.
In most cases, you can enter the terms as you think them, even if they
contain embedded punctuation or other non-textual characters. For exemple,
Recoll can handle things like e-mail addresses, or arbitrary cut and paste
from another text window, punctation and all.
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).
----------------------------------------------------------------------
3.1.1. Simple search
1. Start the recoll program.
2. Possibly choose a search mode: Any term, All terms, File name or Query
language.
3. Enter search term(s) in the text field at the top of the window.
4. Click the Search button or hit the Enter key to start the search.
The initial default search mode is All terms. This will look for documents
containing all of the search terms (the ones with more terms will get
better scores). Any term will search for documents where at least one of
the terms appear.
File name will specifically look for file names. The entry will be split
at white space characters, and each pattern will be separately expanded.
If you want to search for a pattern including white space, use double
quotes. The point of having a separate file name search is that wild card
expansion can be performed more efficiently on a relatively small subset
of the index.
The fourth entry (Query Language) is described in its own section.
All search modes allow wildcards inside terms (*, ?, []). You may want to
have a look at the section about wildcards for more information about
this.
You can search for exact phrases (adjacent words in a given order) by
enclosing the input inside double quotes. Ex: "virtual reality".
Character case has no influence on search, except that you can disable
stem expansion for any term by capitalizing it. Ie: a search for floor
will also normally look for flooring, floored, etc., but a search for
Floor will only look for floor, in any character case. Stemming can also
be disabled globally in the preferences.
Recoll 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).
Typing Esc Space 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.
Double-clicking on a word in the result list or a preview window will
insert it into the simple search entry field.
You can cut and paste any text into an All terms or Any term search field,
punctuation, newlines and all - except for wildcard characters (single ?
characters are ok). Recoll will process it and produce a meaningful
search. This is what most differentiates this mode from the Query Language
mode, where you have to care about the syntax.
You can use the Tools / Advanced search dialog for more complex searches.
----------------------------------------------------------------------
3.1.2. The result list
After starting a search, a list of results will instantly be displayed in
the main list window.
By default, the document list is presented in order of relevance (how well
the system estimates that the document matches the query). You can specify
a different ordering by using the Tools / Sort parameters dialog.
Clicking on the Preview link for an entry will open an internal preview
window for the document. Further Preview clicks for the same search will
open tabs in the existing preview window. You can use Shift+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 Shift+ArrowUp/Down in the window).
Clicking the Open link will attempt to start an external viewer. The
viewer for each document type can be configured through the user
preferences dialog, or by editing the mimeview configuration file. You can
also check the Use desktop preferences option in the user preferences
dialog to use the desktop defaults for all documents. This is probably the
best option if you are using a well configured Gnome or KDE desktop.
The Preview and Open edit links may not be present for all entries,
meaning that Recoll 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 mimemap
and mimeview configuration files (the latter can be modified with the user
preferences dialog).
The format of the result list entries is entirely configurable by using
the preference dialog to edit an HTML fragment.
You can click on the Query details link at the top of the results page to
see the query actually performed, after stem expansion and other
processing.
Double-clicking on any word inside the result list or a preview window
will insert it into the simple search text.
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.
----------------------------------------------------------------------
3.1.2.1. The result list right-click menu
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:
* Preview
* Open
* Copy File Name
* Copy Url
* Save to File
* Find similar
* Preview Parent document
* Open Parent document
The Preview and Open entries do the same thing as the corresponding links.
The Copy File Name and Copy Url copy the relevant data to the clipboard,
for later pasting.
Save to File 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.
The Find similar 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.
The Parent document entries will appear for documents which are not
actually files but are part of, or attached to, a higher level document.
This entry is mainly useful for email attachments and permits viewing the
message to which the document is attached. Note that the entry will also
appear for an email which is part of an mbox folder file, but that you
can't actually visualize the folder (there will be an error dialog if you
try). Recoll is unfortunately not yet smart enough to disable the entry in
this case. In other cases, the Open option makes sense, for exemple to
start a chm viewer on the parent document for a help page.
----------------------------------------------------------------------
3.1.3. The preview window
The preview window opens when you first click a Preview link inside the
result list.
Subsequent preview requests for a given search open new tabs in the
existing window (except if you hold the Shift key while clicking which
will open a new window for side by side viewing).
Starting another search and requesting a preview will create a new preview
window. The old one stays open until you close it.
You can close a preview tab by typing ^W (Ctrl + W) in the window. Closing
the last tab for a window will also close the window.
Of course you can also close a preview window by using the window manager
button in the top of the frame.
You can display successive or previous documents from the result list
inside a preview tab by typing Shift+Down or Shift+Up (Down and Up are the
arrow keys).
The preview tabs have an internal incremental search function. You
initiate the search either by typing a / (slash) inside the text area or
by clicking into the Search for: text field and entering the search
string. You can then use the Next and Previous buttons to find the
next/previous occurrence. You can also type F3 inside the text area to get
to the next occurrence.
If you have a search string entered and you use ^Up/^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.
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.
You can print the current preview window contents by typing ^P (Ctrl + P)
in the window text.
----------------------------------------------------------------------
3.1.4. Complex/advanced search
The advanced search dialog helps you build more complex queries without
memorizing the search language constructs. It can be opened through the
Tools menu or through the main toolbar.
The dialog has three parts:
* The top part allows constructing a query by combining multiple clauses
of different types. Each entry field is configurable for the following
modes:
* All terms.
* Any term.
* None of the terms.
* Phrase (exact terms in order within an adjustable window).
* Proximity (terms in any order within an adjustable window).
* Filename search.
Additional entry fields can be created by clicking the Add clause
button.
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
(All clauses or Any clause).
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.
* The next part allows filtering the results by their mime types.
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).
* The bottom part allows restricting the search results to a sub-tree of
the indexed area. If you need to do this often, you may think of
setting up multiple indexes instead, as the performance will be much
better.
Phrases and Proximity searches. 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
quick fox with a slack of 0 will match quick fox but not quick brown fox.
With a slack of 1 it will match the latter, but not fox quick. A proximity
search for quick fox with the default slack will match the latter, and
also a fox is a cunning and quick animal.
Click on the Start Search button in the advanced search dialog, or type
Enter in any text field to start the search. The button in the main window
always performs a simple search.
Click on the Show query details link at the top of the result page to see
the query expansion.
----------------------------------------------------------------------
3.1.5. The term explorer tool
Recoll 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.
The term explorer tool (started from the toolbar icon or from the Term
explorer entry of the Tools menu) can be used to search the full index
terms list. It has three modes of operations:
Wildcard
In this mode of operation, you can enter a search string with
shell-like wildcards (*, ?, []). ie: xapi* would display all index
terms beginning with xapi. (More about wildcards here).
Regular expression
This mode will accept a regular expression as input. Example:
word[0-9]+. The expression is implicitely anchored at the
beginning. Ie: press will match pression but not expression. You
can use .*press to match the latter, but be aware that this will
cause a full index term list scan, which can be quite long.
Stem expansion
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.
Spelling/Phonetic
In this mode, you enter the term as you think it is spelled, and
Recoll will do its best to find index terms that sound like your
entry. This mode uses the Aspell spelling application, which must
be installed on your system for things to work (if your documents
contain non-ascii characters, Recoll 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.
Note that in cases where Recoll does not know the beginning of the string
to search for (ie a wildcard expression like *coll), 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 200 results for wildcards
and regular expressions.
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).
----------------------------------------------------------------------
3.1.6. Multiple databases
Multiple Recoll databases or 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 RECOLL_CONFDIR environment variable or the -c option
to recoll and recollindex.
A recollindex program instance can only update one specific index.
A recoll program instance is also associated with a specific index, which
is the one to be updated by its indexing thread, but it can use any number
of Recoll indexes for searching. The external indexes can be selected
through the external indexes tab in the preferences dialog.
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. Of course, these parameters are retained across program
executions (there are kept separately for each Recoll configuration). The
set of all indexes is usually quite stable, while the active ones might
typically be adjusted quite frequently.
The main index (defined by RECOLL_CONFDIR) is always active. If this is
undesirable, you can set up your base configuration to index an empty
directory.
As building the set of all indexes can be a little tedious when done
through the user interface, you can use the RECOLL_EXTRA_DBS 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:
export RECOLL_EXTRA_DBS=/some/place/xapiandb:/some/other/db
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.
----------------------------------------------------------------------
3.1.7. Document history
Documents that you actually view (with the internal preview or an external
tool) are entered into the document history, which is remembered.
You can display the history list by using the Tools/Doc History menu
entry.
You can erase the document history by using the Erase document history
entry in the File menu.
----------------------------------------------------------------------
3.1.8. Sorting search results and collapsing duplicates
The documents in a result list are normally sorted in order of relevance.
It is possible to specify different sort parameters by using the Sort
parameters dialog (located in the Tools menu).
The tool sorts a specified number of the most relevant documents in the
result list, according to specified criteria. The currently available
criteria are date and mime type.
The sort parameters stay in effect until they are explicitly reset, or the
program exits. An activated sort is indicated in the result list header.
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 Remember sort activation state option in the preferences.
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 Query configuration dialog, and is off by default.
----------------------------------------------------------------------
3.1.9. Search tips, shortcuts
3.1.9.1. Terms and search expansion
Term completion. Typing Esc Space 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.
Picking up new terms from result or preview text. Double-clicking on a
word in the result list or in a preview window will copy it to the simple
search entry field.
Wildcards. Wildcards can be used inside search terms in all forms of
searches. More about wildcards.
Automatic suffixes. Words like odt or ods can be automatically turned into
query language ext:xxx clauses. This can be enabled in the Search
preferences panel in the GUI.
Disabling stem expansion. Entering a capitalized word in any search field
will prevent stem expansion (no search for gardening if you enter Garden
instead of garden). This is the only case where character case should make
a difference for a Recoll search. You can also disable stem expansion or
change the stemming language in the preferences.
Finding related documents. Selecting the Find similar documents 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.
File names. File names are added as terms during indexing, and you can
specify them as ordinary terms in normal search fields (Recoll 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 only look for file names, and may be faster
than the generic search especially when using wildcards.
----------------------------------------------------------------------
3.1.9.2. Working with phrases and proximity
Phrases and Proximity searches. A phrase can be looked for by enclosing it
in double quotes. Example: "user manual" will look only for occurrences of
user immediately followed by manual. You can use the This phrase 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
This exact phrase).
AutoPhrases. 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 Any terms. 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 virtual reality will still find all
documents where either virtual or reality or both appear, but those which
contain virtual reality should appear sooner in the list.
----------------------------------------------------------------------
3.1.9.3. Others
Using fields. You can use the query language 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:
search tips from:helpfulgui
Query explanation. 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.
Browsing the result list inside a preview window. Entering Shift-Down or
Shift-Up (Shift + 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.
Scrolling the result list from the keyboard. You can use PageUp and
PageDown to scroll the result list, Shift+Home to go back to the first
page. These work even while the focus is in the search entry.
Forced opening of a preview window. You can use Shift+Click on a result
list Preview link to force the creation of a preview window instead of a
new tab in the existing one.
Closing previews. Entering ^W in a tab will close it (and, for the last
tab, close the preview window). Entering Esc will close the preview window
and all its tabs.
Printing previews. Entering ^P in a preview window will print the
currently displayed text.
Quitting. Entering ^Q almost anywhere will close the application.
----------------------------------------------------------------------
3.1.10. Customizing the search interface
You can customize some aspects of the search interface by using the Query
configuration entry in the Preferences menu.
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.
User interface parameters:
* Number of results in a result page:
* Hide duplicate results: decides if result list entries are shown for
identical documents found in different places.
* Highlight color for query terms: 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 red,
#ff0000). The default is blue.
* Result list font: 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 Recoll are determined by your generic Qt
config (try the qtconfig command).
* Result paragraph format string: allows you to change the presentation
of each result list entry. This is described in its own section.
* Maximum text size highlighted for preview 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.
* Use desktop preferences to choose document editor: if this is checked,
the xdg-open utility will be used to open files when you click the
Open link in the result list, instead of the application defined in
mimeview. xdg-open will in term use your desktop preferences to choose
an appropriate application.
* Choose editor applications this will let you choose the command
started by the Open links inside the result list, for specific
document types.
* Display category filter as toolbar... this will let you choose if the
document categories are displayed as a list or a set of buttons.
* Auto-start simple search on white space entry: 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...
* Start with advanced search dialog open and Start with sort dialog
open: If you use these dialogs all the time, checking these entries
will get them to open when recoll starts.
* Remember sort activation state if set, Recoll will remember the sort
tool stat between invocations. It normally starts with sorting
disabled.
* Prefer HTML to plain text for preview 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.
Search parameters:
* Stemming language: 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 main
configuration file), or later added with recollindex -s (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.
* Dynamically add phrase to simple searches: a phrase will be
automatically built and added to simple searches when looking for Any
terms. This will give a relevance boost to the results where the
search terms appear as a phrase (consecutive and in order).
* Replace abstracts from documents: this decides if we should synthesize
and display an abstract in place of an explicit abstract found within
the document itself.
* Dynamically build abstracts: this decides if Recoll tries to build
document abstracts when displaying the result list. Abstracts are
constructed by taking context from the document information, around
the search terms. This can slow down result list display significantly
for big documents, and you may want to turn it off.
* Synthetic abstract size: adjust to taste...
* Synthetic abstract context words: how many words should be displayed
around each term occurrence.
* Query language magic file name suffixes: a list of words which
automatically get turned into ext:xxx file name suffix clauses when
starting a query language query (ie: doc xls xlsx...). This will save
some typing for people who use file types a lot when querying.
External indexes: This panel will let you browse for additional indexes
that you may want to search. External indexes are designated by their
database directory (ie: /home/someothergui/.recoll/xapiandb,
/usr/local/recollglobal/xapiandb).
Once entered, the indexes will appear in the External indexes list, and
you can chose which ones you want to use at any moment by checking or
unchecking their entries.
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,
----------------------------------------------------------------------
3.1.10.1. The result list paragraph format
The presentation of each result inside the result list can be customized
by setting the result list paragraph format inside the User Interface tab
of the Query configuration.
This is a Qt HTML string where the following printf-like % substitutions
will be performed:
* %A. Abstract
* %D. Date
* %I. Icon image name
* %K. Keywords (if any)
* %L. Preview and Edit links
* %M. Mime type
* %N. result Number
* %R. Relevance percentage
* %S. Size information
* %T. Title
* %U. Url
The format of the Preview and Edit links is <a href="P%N"> and <a
href="E%N"> where docnum (%N expands to the document number inside the
result list).
In addition to the predefined values above, all strings like %(fieldname)
will be replaced by the value of the field named fieldname 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 field configuration). There are currently very few fields
stored by default, apart from the values above (only author), so this
feature will need some custom local configuration to be useful. For
example, you could look at the fields for the document types of interest
(use the right-click menu inside the preview window), and add what you
want to the list of stored fields. A candidate example would be the
recipient field which is generated by the message filters.
The default value for the paragraph format string is:
<img src="%I" align="left">%R %S %L &nbsp;&nbsp;<b>%T</b><br>
%M&nbsp;%D&nbsp;&nbsp;&nbsp;<i>%U</i>&nbsp;%i<br>
%A %K
You may, for example, try the following for a more web-like experience:
<u><b><a href="P%N">%T</a></b></u><br>
%A<font color=#008000>%U - %S</font> - %L
Or the clean looking:
<img src="%I" align="left">%L <font color="#900000">%R</font>
<b>%T</b><br>%S
<font color="#808080"><i>%U</i></font>
<table bgcolor="#e0e0e0">
<tr><td><div>%A</div></td></tr>
</table>%K
Note that the P%N link in the above paragraph makes the title a preview
link.
Due to the way the program handles right mouse clicks in the result list,
if the custom formatting results in multiple paragraphs per result, right
clicks will only work inside the first one.
----------------------------------------------------------------------
3.2. Searching with the KDE KIO slave
3.2.1. What's this
The Recoll KIO slave allows performing a Recoll search by entering an
appropriate URL in a KDE open dialog, or with an HTML-based interface
displayed in Konqueror.
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.
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).
The interface is described in more detail inside a help file which you can
access by entering recoll:/ inside the konqueror URL line (this works only
if the recoll KIO slave has been previously installed).
The instructions for building this module are located in the source tree.
See: kde/kio/recoll/00README.txt. 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.
----------------------------------------------------------------------
3.2.2. Searchable documents
As a sample application, the Recoll KIO slave could allow preparing a set
of HTML documents (for example a manual) so that they become their own
search interface inside konqueror.
This can be done by either explicitly inserting <a href="recoll:/...">
links around some document areas, or automatically by adding a very small
javascript program to the documents, like the following example, which
would initiate a search by double-clicking any term:
<script language="JavaScript">
function recollsearch() {
var t = document.getSelection();
window.location.href = 'recoll://search/query?qtp=a&p=0&q=' +
encodeURIComponent(t);
}
</script>
....
<body ondblclick="recollsearch()">
----------------------------------------------------------------------
3.3. Searching on the command line
There are several ways to obtain search results as a text stream, without
a graphical interface:
* By passing option -t to the recoll program.
* By using the recollq program.
* By writing a custom Python program, using the Recoll Python API.
The first two methods work in the same way and accept/need the same
arguments (except for the additional -t to recoll). The query to be
executed is specified as command line arguments.
recollq is not built by default. You can use the Makefile in the query
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.
recollq has a man page (not installed by default, look in the doc/man
directory). The Usage string is as follows:
recollq [-o|-a|-f] <query string>
Runs a recoll query and displays result lines.
Default: will interpret the argument(s) as a query language string
-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
Common options:
-c <configdir> : specify config directory, overriding $RECOLL_CONFDIR
-d also dump file contents
-n <cnt> limit the maximum number of results (0->no limit, default 2000)
-b : basic. Just output urls, no mime types or titles
-m : dump the whole document meta[] array
-S fld : sort by field name
-D : sort descending
Sample execution:
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....
----------------------------------------------------------------------
3.4. The query language
The query language processor is activated in the GUI simple search entry
when the search mode selector is set to Query Language. 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.
Additionally, the query language is for now the only way to access the
important Recoll field search capabilities.
The language is roughly based on the Xesam user search language
specification.
If the results of a query language search puzzle you and you doubt what
has been actually searched for, you can use the GUI show query link at the
top of the result list to check the exact query which was finally executed
by Xapian.
Here follows a sample request that we are going to explain:
author:"john doe" Beatles OR Lennon Live OR Unplugged -potatoes
This would search for all documents with John Doe appearing as a phrase in
the author field (exactly what this is would depend on the document type,
ie: the From: header, for an email message), and containing either beatles
or lennon and either live or unplugged but not potatoes (in any part of
the document).
An element is composed of an optional field specification, and a value,
separated by a colon. Exemple: Beatles, author:balzac, dc:title:grandet
The colon, if present, means "contains". Xesam defines other relations,
which are not supported for now.
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
Beatles OR Lennon. The OR must be entered literally (capitals), and it has
priority over the AND associations: word1 word2 OR word3 means word1 AND
(word2 OR word3) not (word1 AND word2) OR word3. Do not enter explicit
parenthesis, they are not supported for now.
An element preceded by a - specifies a term that should not appear. Pure
negative queries are forbidden.
As usual, words inside quotes define a phrase (the order of words is
significant), so that title:"prejudice pride" is not the same as
title:prejudice title:pride, and is unlikely to find a result.
Most Xesam phrase modifiers are unsupported, except for l (small ell) to
disable stemming, and p to turn a phrase into a NEAR (unordered proximity)
search. Exemple: "prejudice pride"p
Recoll currently manages the following default fields:
* title, subject or caption are synonyms which specify data to be
searched for in the document title or subject.
* author or from for searching the documents originators.
* recipient or to for searching the documents recipients.
* keyword for searching the document-specified keywords (few documents
actually have any).
* filename for the document's file name.
* ext specifies the file name extension (Ex: ext:html)
The field syntax also supports a few field-like, but special, criteria:
* dir for filtering the results on file location (Ex:
dir:/home/me/somedir). Please note that this is quite inefficient,
that it may produce very slow searches, and that it may be worth in
some cases to set up separate databases instead.
* date 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 / character. Each element can be a date or a period of
time. Periods are specified as PnYnMnD. The n numbers are the
respective numbers of years, months or days, any of which may be
missing. Dates are specified as YYYY-MM-DD. The days and months parts
may be missing. If the / is present but an element is missing, the
missing element is interpreted as the lowest or highest date in the
index. Exemples:
* 2001-03-01/2002-05-01 the basic syntax for an interval of dates.
* 2001-03-01/P1Y2M the same specified with a period.
* 2001/ from the beginning of 2001 to the latest date in the index.
* 2001 the whole year of 2001
* P2D/ means 2 days ago up to now if there are no documents with
dates in the future.
* /2003 all documents from 2003 or older.
Periods can also be specified with small letters (ie: p2y).
* mime or format for specifying the mime type. This one is quite special
because you can specify several values which will be OR'ed (the normal
default for the language is AND). Ex: mime:text/plain mime:text/html.
Specifying an explicit boolean operator or negation (-) before a mime
specification is not supported and will produce strange results. Note
that mime is the ONLY field with an OR default. You do need to use OR
with ext terms for example.
* type or rclcat for specifying the category (as in
text/media/presentation/etc.). The classification of mime types in
categories is defined in the Recoll configuration (mimeconf), 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.
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
More about wildcards.
The document filters 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.
----------------------------------------------------------------------
3.4.1. More about wildcards
All words entered in Recoll search fields will be processed for wildcard
expansion before the request is finally executed.
The wildcard characters are:
* * which matches 0 or more characters.
* ? which matches a single character.
* [] which allow defining sets of characters to be matched (ex: [abc]
matches a single character which may be 'a' or 'b' or 'c', [0-9]
matches any number.
You should be aware of a few things before using wildcards.
* Using a wildcard character at the beginning of a word can make for a
slow search because Recoll will have to scan the whole index term list
to find the matches.
* Using a * at the end of a word can produce more matches than you would
think, and strange search results. You can use the term explorer 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 * (stem expansion
is turned off when any wildcard character appears in the term).
----------------------------------------------------------------------
3.5. Desktop integration
Being independant of the desktop type has its drawbacks: Recoll desktop
integration is minimal. Here follow a few things that may help.
----------------------------------------------------------------------
3.5.1. Hotkeying recoll
It is surprisingly convenient to be able to show or hide the Recoll GUI
with a single keystroke. Recoll comes with a small python script, based on
the libwnck window manager interface library, which will allow you to do
just this. The detailed instructions are on this wiki page.
----------------------------------------------------------------------
3.5.2. The KDE Kicker Recoll applet
The Recoll source tree contains the source code to the recoll_applet, a
small application derived from the find_applet. This can be used to add a
small Recoll launcher to the KDE panel.
The applet is not automatically built with the main Recoll 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 configure;make;make install
incantation to build and install.
You can then add the applet to the panel by right-clicking the panel and
choosing the Add applet entry.
The recoll_applet has a small text window where you can type a Recoll
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.
----------------------------------------------------------------------
Chapter 4. Programming interface
Recoll has an Application programming Interface, usable both for indexing
and searching, currently accessible from the Python language.
Another less radical way to extend the application is to write filters for
new types of documents.
The processing of metadata attributes for documents (fields) is highly
configurable.
----------------------------------------------------------------------
4.1. Writing a document filter
Recoll filters are executable programs which translate from a specific
format (ie: openoffice, acrobat, etc.) to the Recoll indexing input
format, which may be text/plain or text/html.
As of Recoll 1.13, there are two kinds of filters:
* Simple filters (the old ones) run once and exit. They can be bare
programs like antiword, or shell-scripts using other programs. They
are very simple to write, just having to write the text to the
standard output.
* Multiple filters, new in 1.13, run as long as their master process
(ie: recollindex) is active. They can process multiple files (sparing
the process startup time which can be very significant), or multiple
documents per file (ie: for zip or chm files). They communicate with
the indexer through a simple protocol, but are nevertheless a bit more
complicated than the older kind. Most of these new filters are written
in Python, using a common module to handle the protocol.
The following will just describe the simple filters, if you are programmer
enough to write one of the other kind, it shouldn't be too difficult to
make sense of one of the existing modules (ie: rclzip).
Recoll simple filters are usually shell-scripts, but this is in no way
necessary. These programs are extremely simple and most of the difficulty
lies in extracting the text from the native format, not outputting what is
expected by Recoll. Happily enough, most document formats already have
translators or text extractors which handle the difficult part and can be
called from the filter. In some case the output of the translating program
is appropriate, and no intermediate shell-script is needed.
Filters are called with a single argument which is the source file name.
They should output the result to stdout.
The RECOLL_FILTER_FORPREVIEW environment variable (values yes, no) tells
the filter if the operation is for indexing or previewing. Some filters
use this to output a slightly different format. This is not essential.
The association of file types to filters is performed in the mimeconf
file. A sample:
[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
The fragment specifies that:
* application/msword files are processed by executing the antiword
program, which outputs text/plain encoded in utf-8.
* application/ogg files are processed by the rclogg script, with default
output type (text/html, with encoding specified in the header, or
utf-8 by default).
* text/rtf is processed by unrtf, which outputs text/html. The
iso-8859-1 encoding is specified because it is not the utf-8 default,
and not output by unrtf in the HTML header section.
* application/x-chm is processed by a persistant filter. This is
determined by the execm keyword.
The easiest way to write a new filter is probably to start from an
existing one.
Filters which output text/plain text are generally simpler, but they
cannot specify the character set and other metadata, so they are limited
to cases where these elements are not needed.
----------------------------------------------------------------------
4.1.1. Filter HTML output
The output HTML could be very minimal like the following example:
<html><head>
<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
</head>
<body>some text content</body></html>
You should take care to escape some characters inside the text by
transforming them into appropriate entities. "&" should be transformed
into "&amp;", "<" should be transformed into "&lt;". This is not always
properly done by translating programs which output HTML, and of course
nerver by those which output plain text.
The character set needs to be specified in the header. It does not need to
be UTF-8 (Recoll will take care of translating it), but it must be
accurate for good results.
Recoll will also make use of other header fields if they are present:
title, description, keywords.
Filters also have the possibility to "invent" field names. This should be
output as meta tags:
<meta name="somefield" content="Some textual data" />
See the following section for details about configuring how field data is
processed by the indexer.
----------------------------------------------------------------------
4.2. Field data processing
Fields are named pieces of information in or about documents, like title,
author, abstract.
The field values for documents can appear in several ways during indexing:
either output by filters as meta fields in the HTML header section, or
added as attributes of the Doc object when using the API, or again
synthetized internally by Recoll.
The Recoll query language allows searching for text in a specific field.
Recoll defines a number of default fields. Additional ones can be output
by filters, and described in the fields configuration file.
Fields can be:
* indexed, meaning that their terms are separately stored in inverted
lists (with a specific prefix), and that a field-specific search is
possible.
* stored, meaning that their value is recorded in the index data record
for the document, and can be returned and displayed with search
results.
A field can be either or both indexed and stored. This and other aspects
of fields handling is defined inside the fields configuration file.
You can find more information in the section about the fields file, or in
comments inside the file.
----------------------------------------------------------------------
4.3. API
4.3.1. Interface elements
A few elements in the interface are specific and and need an explanation.
udi
An udi (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 udi 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.
ipath
This data value (set as a field in the Doc object) is stored,
along with the URL, but not indexed by Recoll. Its contents are
not interpreted, and its use is up to the application. For
example, the Recoll internal file system indexer stores the part
of the document access path internal to the container file (ipath
in this case is a list of subdocument sequential numbers). url and
ipath are returned in every search result and permit access to the
original document.
Stored and indexed fields
The fields file inside the Recoll configuration defines which
document fields are either "indexed" (searchable), "stored"
(retrievable with search results), or both.
Data for an external indexer, should be stored in a separate index, not
the one for the Recoll internal file system indexer, except if the latter
is not used at all). The reason is that the main document indexer purge
pass would remove all the other indexer's documents, as they were not seen
during indexing. The main indexer documents would also probably be a
problem for the external indexer purge operation.
----------------------------------------------------------------------
4.3.2. Python interface
4.3.2.1. Introduction
Recoll versions after 1.11 define a Python programming interface, both for
searching and indexing.
The Python interface is not built by default and can be found in the
source package, under python/recoll.
In order to build the module, you should first build or re-build the
Recoll library using position-independant objects:
cd recoll-xxx/
configure --enable-pic
make
There is no significant disadvantage in using PIC objects for the main
Recoll executables, so you can use the --enable-pic option for the main
build too.
The python/recoll/ directory contains the usual setup.py script which you
can then use to build and install the module:
cd recoll-xxx/python/recoll
python setup.py build
python setup.py install
----------------------------------------------------------------------
4.3.2.2. Interface manual
NAME
recoll - This is an interface to the Recoll full text indexer.
FILE
/usr/local/lib/python2.5/site-packages/recoll.so
CLASSES
Db
Doc
Query
SearchData
class Db(__builtin__.object)
| Db([confdir=None], [extra_dbs=None], [writable = False])
|
| A Db object holds a connection to a Recoll index. Use the connect()
| function to create one.
| confdir specifies a Recoll configuration directory (default:
| $RECOLL_CONFDIR or ~/.recoll).
| extra_dbs is a list of external databases (xapian directories)
| writable decides if we can index new data through this connection
|
| Methods defined here:
|
|
| addOrUpdate(...)
| addOrUpdate(udi, doc, parent_udi=None) -> None
| Add or update index data for a given document
| The udi string must define a unique id for the document. It is not
| interpreted inside Recoll
| doc is a Doc object
| if parent_udi is set, this is a unique identifier for the
| top-level container (ie mbox file)
|
| delete(...)
| delete(udi) -> Bool.
| Purge index from all data for udi. If udi matches a container
| document, purge all subdocs (docs with a parent_udi matching udi).
|
| makeDocAbstract(...)
| makeDocAbstract(Doc, Query) -> string
| Build and return 'keyword-in-context' abstract for document
| and query.
|
| needUpdate(...)
| needUpdate(udi, sig) -> Bool.
| Check if the index is up to date for the document defined by udi,
| having the current signature sig.
|
| purge(...)
| purge() -> Bool.
| 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.
|
| query(...)
| query() -> Query. Return a new, blank query object for this index.
|
| setAbstractParams(...)
| setAbstractParams(maxchars, contextwords).
| Set the parameters used to build 'keyword-in-context' abstracts
|
| ----------------------------------------------------------------------
| Data and other attributes defined here:
|
class Doc(__builtin__.object)
| Doc()
|
| A Doc 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 no useful methods but
| 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
| Predefined attributes (index/query/both):
| text (index): document plain text
| url (both)
| fbytes (both) optional) file size in bytes
| filename (both)
| fmtime (both) optional file modification date. Unix time printed
| as string
| dbytes (both) document text bytes
| dmtime (both) document creation/modification date
| ipath (both) value private to the app.: internal access path
| inside file
| mtype (both) mime type for original document
| mtime (query) dmtime if set else fmtime
| origcharset (both) charset the text was converted from
| size (query) dbytes if set, else fbytes
| sig (both) app-defined file modification signature.
| For up to date checks
| relevancyrating (query)
| abstract (both)
| author (both)
| title (both)
| keywords (both)
|
| Methods defined here:
|
|
| ----------------------------------------------------------------------
| Data and other attributes defined here:
|
class Query(__builtin__.object)
| Recoll Query objects are used to execute index searches.
| They must be created by the Db.query() method.
|
| Methods defined here:
|
|
| execute(...)
| execute(query_string, stemming=1|0)
|
| Starts a search for query_string, a Recoll search language string
| (mostly Xesam-compatible).
| The query can be a simple list of terms (and'ed by default), or more
| complicated with field specs etc. See the Recoll manual.
|
| executesd(...)
| executesd(SearchData)
|
| Starts a search for the query defined by the SearchData object.
|
| fetchone(...)
| fetchone(None) -> Doc
|
| Fetches the next Doc object in the current search results.
|
| sortby(...)
| sortby(field=fieldname, ascending=true)
| Sort results by 'fieldname', in ascending or descending order.
| Only one field can be used, no subsorts for now.
| Must be called before executing the search
|
| ----------------------------------------------------------------------
| Data descriptors defined here:
|
| next
| Next index to be fetched from results. Normally increments after
| each fetchone() call, but can be set/reset before the call effect
| seeking. Starts at 0
|
| ----------------------------------------------------------------------
| Data and other attributes defined here:
|
class SearchData(__builtin__.object)
| SearchData()
|
| A SearchData object describes a query. It has a number of global
| parameters and a chain of search clauses.
|
| Methods defined here:
|
|
| addclause(...)
| addclause(type='and'|'or'|'excl'|'phrase'|'near'|'sub',
| qstring=string, slack=int, field=string, stemming=1|0,
| subSearch=SearchData)
| Adds a simple clause to the SearchData And/Or chain, or a subquery
| defined by another SearchData object
|
| ----------------------------------------------------------------------
| Data and other attributes defined here:
|
FUNCTIONS
connect(...)
connect([confdir=None], [extra_dbs=None], [writable = False])
-> Db.
Connects to a Recoll database and returns a Db object.
confdir specifies a Recoll configuration directory
(the default is built like for any Recoll program).
extra_dbs is a list of external databases (xapian directories)
writable decides if we can index new data through this connection
----------------------------------------------------------------------
4.3.2.3. Example code
The following sample would query the index with a user language string.
See the python/samples directory inside the Recoll source for other
examples.
#!/usr/bin/env python
import recoll
db = recoll.connect()
db.setAbstractParams(maxchars=80, contextwords=2)
query = db.query()
nres = query.execute("some user question")
print "Result count: ", nres
if nres > 5:
nres = 5
while query.next >= 0 and query.next < nres:
doc = query.fetchone()
print query.next
for k in ("title", "size"):
print k, ":", getattr(doc, k).encode('utf-8')
abs = db.makeDocAbstract(doc, query).encode('utf-8')
print abs
print
----------------------------------------------------------------------
Chapter 5. Installation and configuration
5.1. Installing a binary copy
There are three types of binary Recoll installations:
* Through your system normal software distribution framework (ie,
Debian/Ubuntu apt, FreeBSD ports, etc.).
* From a package downloaded from the Recoll web site.
* From a prebuilt tree downloaded from the Recoll web site.
In all cases, the strict software dependancies (ie on Xapian or iconv)
will be automatically satisfied, you should not have to worry about them.
You will only have to check or install supporting applications for the
file types that you want to index beyond those that are natively processed
by Recoll (text, HTML, mail files, and a few others).
You should also maybe have a look at the configuration section (but this
may not be necessary for a quick test with default parameters). Most
parameters can be more conveniently set from the GUI interface.
----------------------------------------------------------------------
5.1.1. Installing through a package system
If you use a BSD-type port system or a prebuilt package (DEB, RPM,
manually or through the system software configuration utility), just
follow the usual procedure for your system.
----------------------------------------------------------------------
5.1.2. Installing a prebuilt Recoll
The unpackaged binary versions on the Recoll web site are just compressed
tar files of a build tree, where only the useful parts were kept
(executables and sample configuration).
The executable binary files are built with a static link to libxapian and
libiconv, to make installation easier (no dependencies).
After extracting the tar file, you can proceed with installation as if you
had built the package from source (that is, just type make install). The
binary trees are built for installation to /usr/local.
----------------------------------------------------------------------
5.2. Supporting packages
Recoll 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
Recoll except for indexing their specific file type).
After an indexing pass, the commands that were found missing can be
displayed from the recoll File menu. The list is stored in the missing
text file inside the configuration directory.
A list of common file types which need external commands follows. Many of
the filters need the iconv command, which is not always listed as a
dependancy.
Please note that, due to the relatively dynamic nature of this
information, the most up to date version is now kept on the Recoll helper
applications page along with links to the home pages or best
source/patches download links. The list below is not updated often and may
be quite stale.
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 Recoll, so you should take a look at
the Recoll helper applications page if a file type is important to you.
As of Recoll release 1.14, a number of XML-based formats that were handled
by ad hoc filter code now use the xsltproc command, which usually comes
with libxslt. These are: abiword, fb2 (ebooks), kword, openoffice, svg.
Now for the list:
* Openoffice files need unzip and xsltproc.
* PDF files need pdftotext which is part of the Xpdf or Poppler
packages.
* Postscript files need pstotext. The original version has an issue with
shell character in file names, which is corrected in recent packages.
See the the Recoll helper applications page for more detail.
* MS Word needs antiword. It is also useful to have wvWare installed as
it may be be used as a fallback for some files which antiword does not
handle.
* MS Excel and PowerPoint need catdoc.
* MS Open XML (docx) needs xsltproc.
* Wordperfect files need wpd2html from the libwpd package.
* RTF files need unrtf, which, in its standard version, has much trouble
with non-western character sets. Check the Recoll helper applications
page.
* TeX files need untex or detex. Check the Recoll helper applications
page for sources if it's not packaged for your distribution.
* dvi files need dvips.
* djvu files need djvutxt and djvused from the DjVuLibre package.
* Audio files: Recoll releases before 1.13 used the id3info command from
the id3lib package to extract mp3 tag information, metaflac (standard
flac tools) for flac files, and ogginfo (vorbis tools) for ogg files.
Releases 1.14 and later use a single Python filter based on mutagen
for all audio file types.
* Pictures: Recoll uses the Exiftool Perl 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.
* chm: files in microsoft help format need Python and the pychm module
(which needs chmlib).
* ICS: up to Recoll 1.13, iCalendar files need Python and the icalendar
module. icalendar is not needed for newer versions, which use internal
code.
* Zip archives need Python (and the standard zipfile module).
Text, HTML, mail folders, and Scribus files are processed internally. Lyx
is used to index Lyx files. Many filters need iconv and the standard sed
and awk.
----------------------------------------------------------------------
5.3. Building from source
5.3.1. Prerequisites
C++ compiler. Up to Recoll version 1.13.04, its absence can manifest
itself by strange messages about a missing iconv_open.
Development files for Xapian core.
Important: If you are building Xapian for an older CPU (before Pentium 4
or Athlon 64), you need to add the --disable-sse flag to the configure
command. Else all Xapian application will crash with an illegal
instruction error.
Development files for Qt .
Development files for X11 and zlib.
Check the Recoll download page for up to date version information.
You will most probably be able to find a binary package for Qt for your
system. You may have to compile Xapian but this is not difficult (if you
are using FreeBSD, there is a port).
You may also need libiconv. Recoll currently uses version 1.9 (this should
not be critical). On Linux systems, the iconv interface is part of libc
and you should not need to do anything special.
----------------------------------------------------------------------
5.3.2. Building
Recoll 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, I would
very much welcome patches.
Depending on the Qt 3 configuration on your system, you may have to set
the QTDIR and QMAKESPECS variables in your environment:
* QTDIR should point to the directory above the one that holds the qt
include files (ie: if qt.h is /usr/local/qt/include/qt.h, QTDIR should
be /usr/local/qt).
* QMAKESPECS should be set to the name of one of the qt mkspecs
sub-directories (ie: linux-g++).
On many Linux systems, QTDIR is set by the login scripts, and QMAKESPECS
is not needed because there is a default link in mkspecs/.
Neither QTDIR nor QMAKESPECS should be needed with Qt 4, configuration
details are entirely determined by qmake (which is quite often installed
as qmake-qt4).
Configure options:
* --without-aspell will disable the code for phonetic matching of search
terms.
* --with-fam or --with-inotify will enable the code for real time
indexing. Inotify support is enabled by default on recent Linux
systems.
* --enable-xattr will enable code to fetch data from file extended
attributes. This is only useful is some application stores data in
there, and also needs some simple configuration (see comments in the
fields configuration file).
* --enable-camelcase will enable splitting camelCase words. This is not
enabled by default as it has the unfortunate side-effect of making
some phrase searches quite confusing: ie, "MySQL manual" would be
matched by "MySQL manual" and "my sql manual" but not "mysql manual"
(only inside phrase searches).
* --with-file-command 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.
* --without-gui Disable the Qt interface, and auxiliary uses of X11, and
compile the command line version.
* Of course the usual autoconf configure options, like --prefix apply.
Normal procedure:
cd recoll-xxx
configure
make
(practices usual hardship-repelling invocations)
There is little auto-configuration. The configure script will mainly link
one of the system-specific files in the mk directory to mk/sysconf. If
your system is not known yet, it will tell you as much, and you may want
to manually copy and modify one of the existing files (the new file name
should be the output of uname -s).
----------------------------------------------------------------------
5.3.3. Installation
Either type make install or execute recollinstall prefix, in the root of
the source tree. This will copy the commands to prefix/bin and the sample
configuration files, scripts and other shared data to prefix/share/recoll.
If the installation prefix given to recollinstall is different from either
the system default or the value which was specified when executing
configure (as in configure --prefix /some/path), you will have to set the
RECOLL_DATADIR environment variable to indicate where the shared data is
to be found (ie for (ba)sh: export
RECOLL_DATADIR=/some/path/share/recoll).
You can then proceed to configuration.
----------------------------------------------------------------------
5.4. Configuration overview
Most of the parameters specific to the recoll GUI are set through the
Preferences menu and stored in the standard Qt place ($HOME/.qt/recollrc).
You probably do not want to edit this by hand.
Recoll indexing options are set inside text configuration files located in
a configuration directory. There can be several such directories, each of
which define the parameters for one index.
The configuration files can be edited by hand or through the Indexing
configuration dialog (Preferences menu). The GUI tool will try to respect
your formatting and comments as much as possible, so it is quite possible
to use both ways.
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.
For each index, there are two sets of configuration files. System-wide
configuration files are kept in a directory named like
/usr/[local/]share/recoll/examples, and define default values, shared by
all indexes. For each index, a parallel set of files defines the
customized parameters.
The default location of the configuration is the .recoll directory in your
home. Most people will only use this directory.
This location can be changed, or others can be added with the
RECOLL_CONFDIR environment variable or the -c option parameter to recoll
and recollindex.
If the .recoll directory does not exist when recoll or recollindex are
started, it will be created with a set of empty configuration files.
recoll will give you a chance to edit the configuration file before
starting indexing. recollindex will proceed immediately. To avoid
mistakes, the automatic directory creation will only occur for the default
location, not if -c or RECOLL_CONFDIR were used (in the latter cases, you
will have to create the directory).
All configuration files share the same format. For example, a short
extract of the main configuration file might look as follows:
# Space-separated list of directories to index.
topdirs = ~/docs /usr/share/doc
[~/somedirectory-with-utf8-txt-files]
defaultcharset = utf-8
There are three kinds of lines:
* Comment (starts with #) or empty.
* Parameter affectation (name = value).
* Section definition ([somedirname]).
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.
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.
White space is used for separation inside lists. List elements with
embedded spaces can be quoted using double-quotes.
----------------------------------------------------------------------
5.4.1. Main configuration file
recoll.conf is the main configuration file. It defines things like what to
index (top directories and things to ignore), and the default character
set to use for document types which do not specify it internally.
The default configuration will index your home directory. If this is not
appropriate, start recoll to create a blank configuration, click Cancel,
and edit the configuration file before restarting the command. This will
start the initial indexing, which may take some time.
Most of the following parameters can be changed from the Index
Configuration menu in the recoll interface. Some can only be set by
editing the configuration file.
----------------------------------------------------------------------
5.4.1.1. Parameters affecting what documents we index:
topdirs
Specifies the list of directories or files to index (recursively
for directories). You can use symbolic links as elements of this
list. See the followLinks option about following symbolic links
found under the top elements (not followed by default).
skippedNames
A space-separated list of patterns for names of files or
directories that should be completely ignored. The list defined in
the default file is:
skippedNames = #* bin CVS Cache cache* caughtspam tmp .thumbnails .svn \
*~ .beagle .git .hg .bzr loop.ps .xsession-errors \
.recoll* xapiandb recollrc recoll.conf
The list can be redefined at any sub-directory in the indexed
area.
The top-level directories are not affected by this list (that is,
a directory in topdirs might match and would still be indexed).
The list in the default configuration does not exclude hidden
directories (names beginning with a dot), which means that it may
index quite a few things that you do not want. On the other hand,
mail user agents like thunderbird usually store messages in hidden
directories, and you probably want this indexed. One possible
solution is to have .* in skippedNames, and add things like
~/.thunderbird or ~/.evolution in topdirs.
Not even the file names are indexed for patterns in this list. See
the recoll_noindex variable in mimemap for an alternative approach
which indexes the file names.
skippedPaths and daemSkippedPaths
A space-separated list of patterns for paths of files or
directories that should be skipped. There is no default in the
sample configuration file, but the code always adds the
configuration and database directories in there.
skippedPaths is used both by batch and real time indexing.
daemSkippedPaths can be used to specify things that should be
indexed at startup, but not monitored.
Example of use for skipping text files only in a specific
directory:
skippedPaths = ~/somedir/*.txt
followLinks
Specifies if the indexer should follow symbolic links while
walking the file tree. The default is to ignore symbolic links to
avoid multiple indexing of linked files. No effort is made to
avoid duplication when this option is set to true. This option can
be set individually for each of the topdirs members by using
sections. It can not be changed below the topdirs level.
indexedmimetypes
Recoll normally indexes any file which it knows how to read. This
list lets you restrict the indexed mime types to what you specify.
If the variable is unspecified or the list empty (the default),
all supported types are processed.
compressedfilemaxkbs
Size limit for compressed (.gz or .bz2) files. These need to be
decompressed in a temporary directory for identification, which
can be very wasteful if 'uninteresting' big compressed files are
present. Negative means no limit, 0 means no processing of any
compressed file. Defaults to -1.
textfilemaxmbs
Maximum size for text files. Very big text files are often
uninteresting logs. Set to -1 to disable (default 20MB).
textfilepagekbs
If set to other than -1, text files will be indexed as multiple
documents of the given page size. This may be useful if you do
want to index very big text files as it will both reduce memory
usage at index time and help with loading data to the preview
window. A size of a few megabytes would seem reasonable (default:
1MB).
indexallfilenames
Recoll indexes file names in a special section of the database to
allow specific file names searches using wild cards. This
parameter decides if file name indexing is performed only for
files with mime types that would qualify them for full text
indexing, or for all files inside the selected subtrees,
independently of mime type.
usesystemfilecommand
Decide if we use the file -i system command as a final step for
determining the mime type for a file (the main procedure uses
suffix associations as defined in the mimemap file). This can be
useful for files with suffix-less names, but it will also cause
the indexing of many bogus "text" files.
processbeaglequeue
If this is set, process the directory where Beagle Web browser
plugins copy visited pages for indexing. Of course, Beagle MUST
NOT be running, else things will behave strangely.
beaglequeuedir
The path to the Beagle indexing queue. This is hard-coded in the
Beagle plugin as ~/.beagle/ToIndex so there should be no need to
change it.
----------------------------------------------------------------------
5.4.1.2. Parameters affecting how we generate terms:
Changing some of these parameters will imply a full reindex. Also, when
using multiple indexes, it may not make sense to search indexes that don't
share the values for these parameters, because they usually affect both
search and index operations.
nonumbers
If this set to true, no terms will be generated for numbers. For
example "123", "1.5e6", 192.168.1.4, would not be indexed
("value123" would still be). Numbers are often quite interesting
to search for, and this should probably not be set except for
special situations, ie, scientific documents with huge amounts of
numbers in them. This can only be set for a whole index, not for a
subtree.
nocjk
If this set to true, specific east asian (Chinese Korean Japanese)
characters/word splitting is turned off. This will save a small
amount of cpu if you have no CJK documents. If your document base
does include such text but you are not interested in searching it,
setting nocjk may be a significant time and space saver.
cjkngramlen
This lets you adjust the size of n-grams used for indexing CJK
text. The default value of 2 is probably appropriate in most
cases. A value of 3 would allow more precision and efficiency on
longer words, but the index will be approximately twice as large.
indexstemminglanguages
A list of languages for which the stem expansion databases will be
built. See recollindex(1) or use the recollindex -l command for
possible values. You can add a stem expansion database for a
different language by using recollindex -s, but it will be deleted
during the next indexing. Only languages listed in the
configuration file are permanent.
defaultcharset
The name of the character set used for files that do not contain a
character set definition (ie: plain text files). This can be
redefined for any sub-directory. If it is not set at all, the
character set used is the one defined by the nls environment
(LC_ALL, LC_CTYPE, LANG), or iso8859-1 if nothing is set.
maildefcharset
This can be used to define the default character set specifically
for mail messages which don't specify it. This is mainly useful
for readpst (libpst) dumps, which are utf-8 but do not say so.
localfields
This allows setting fields for all documents under a given
directory. Typical usage would be to set an "rclaptg" field, to be
used in mimeview to select a specific viewer. If several fields
are to be set, they should be separated with a colon (':')
character (which there is currently no way to escape). Ie:
localfields= rclaptg=gnus:other = val, then select specifier
viewer with mimetype|tag=... in mimeview.
----------------------------------------------------------------------
5.4.1.3. Parameters affecting where and how we store things:
dbdir
The name of the Xapian data directory. It will be created if
needed when the index is initialized. If this is not an absolute
path, it will be interpreted relative to the configuration
directory. The value can have embedded spaces but starting or
trailing spaces will be trimmed. You cannot use quotes here.
maxfsoccuppc
Maximum file system occupation before we stop indexing. The value
is a percentage, corresponding to what the "Capacity" df output
column shows. The default value is 0, meaning no checking.
mboxcachedir
The directory where mbox message offsets cache files are held.
This is normally $RECOLL_CONFDIR/mboxcache, but it may be useful
to share a directory between different configurations.
mboxcacheminmbs
The minimum mbox file size over which we cache the offsets. There
is really no sense in caching offsets for small files. The default
is 5 MB.
webcachedir
This is only used by the Beagle web browser plugin indexing code,
and defines where the cache for visited pages will live. Default:
$RECOLL_CONFDIR/webcache
webcachemaxmbs
This is only used by the Beagle web browser plugin indexing code,
and defines the maximum size for the web page cache. Default: 40
MB.
idxflushmb
Threshold (megabytes of new text data) where we flush from memory
to disk index. Setting this can help control memory usage. A value
of 0 means no explicit flushing, letting Xapian use its own
default, which is flushing every 10000 documents (memory usage
depends on average document size). The default value is 10.
----------------------------------------------------------------------
5.4.1.4. Miscellaneous parameters:
loglevel,daemloglevel
Verbosity level for recoll and recollindex. A value of 4 lists
quite a lot of debug/information messages. 2 only lists errors.
The daemversion is specific to the indexing monitor daemon.
logfilename, daemlogfilename
Where the messages should go. 'stderr' can be used as a special
value, and is the default. The daemversion is specific to the
indexing monitor daemon.
filtermaxseconds
Maximum filter execution time, after which it is aborted. Some
postscript programs just loop...
filtersdir
A directory to search for the external filter scripts used to
index some types of files. The value should not be changed, except
if you want to modify one of the default scripts. The value can be
redefined for any sub-directory.
iconsdir
The name of the directory where recoll result list icons are
stored. You can change this if you want different images.
idxabsmlen
Recoll stores an abstract for each indexed file inside the
database. The text can come from an actual 'abstract' section in
the document or will just be the beginning of the document. It is
stored in the index so that it can be displayed inside the result
lists without decoding the original file. The idxabsmlen parameter
defines the size of the stored abstract. The default value is 250
bytes. The search interface gives you the choice to display this
stored text or a synthetic abstract built by extracting text
around the search terms. If you always prefer the synthetic
abstract, you can reduce this value and save a little space.
aspellLanguage
Language definitions to use when creating the aspell dictionary.
The value must match a set of aspell language definition files.
You can type "aspell config" to see where these are installed
(look for data-dir). The default if the variable is not set is to
use your desktop national language environment to guess the value.
noaspell
If this is set, the aspell dictionary generation is turned off.
Useful for cases where you don't need the functionality or when it
is unusable because aspell crashes during dictionary generation.
guesscharset
Decide if we try to guess the character set of files if no
internal value is available (ie: for plain text files). This does
not work well in general, and should probably not be used.
----------------------------------------------------------------------
5.4.2. The fields file
This file contains information about dynamic fields handling in Recoll.
Some very basic fields have hard-wired behaviour, and, mostly, you should
not change the original data inside the fields file. But you can create
custom fields fitting your data and handle them just like they were native
ones.
The fields 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.
We will only give a short description here, you should refer to the
comments inside the file for more detailed information.
Field names should be lowercase alphabetic ASCII.
[prefixes]
A field becomes indexed (searchable) by having a prefix defined in
this section.
[stored]
A field becomes stored (displayable inside results) by having its
name listed in this section (typically with an empty value).
[aliases]
This section defines lists of synonyms for the canonical names
used inside the [prefixes] and [stored] sections
filter-specific sections
Some filters may need specific configuration for handling fields.
Only the mail message filter currently has such a section (named
[mail]). It allows indexing arbitrary mail headers in addition to
the ones indexed by default. Other such sections may appear in the
future.
Here follows a small example of a personal fields file. This would extract
a specific mail header and use it as a searchable field, with data
displayable inside result lists. (Side note: as the mail filter 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).
[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 =
[mail]
# Extract the X-My-Tag mail header, and use it internally with the
# mailmytag field name
x-my-tag = mailmytag
----------------------------------------------------------------------
5.4.3. The mimemap file
mimemap specifies the file name extension to mime type mappings.
For file names without an extension, or with an unknown one, the system's
file -i command will be executed to determine the mime type (this can be
switched off inside the main configuration file).
The mappings can be specified on a per-subtree basis, which may be useful
in some cases. Example: gaim logs have a .txt extension but should be
handled specially, which is possible because they are usually all located
in one place.
mimemap also has a recoll_noindex variable which is a list of suffixes.
Matching files will be skipped (which avoids unnecessary decompressions or
file executions). This is partially redundant with skippedNames in the
main configuration file, with a few differences: it will not affect
directories, it cannot be made dependant on the file-system location (it
is a configuration-wide parameter), and the file names will still be
indexed (not even the file names are indexed for patterns in skippedNames.
recoll_noindex is used mostly for things known to be unindexable by a
given Recoll version. Having it there avoids cluttering the more
user-oriented and locally customized skippedNames.
----------------------------------------------------------------------
5.4.4. The mimeconf file
mimeconf specifies how the different mime types are handled for indexing,
and which icons are displayed in the recoll result lists.
Changing the parameters in the [index] section is probably not a good idea
except if you are a Recoll developer.
The [icons] section allows you to change the icons which are displayed by
recoll in the result lists (the values are the basenames of the png images
inside the iconsdir directory (specified in recoll.conf).
----------------------------------------------------------------------
5.4.5. The mimeview file
mimeview specifies which programs are started when you click on an Open
link in a result list. Ie: HTML is normally displayed using firefox, but
you may prefer Konqueror, your openoffice.org program might be named
oofice instead of openoffice etc.
Changes to this file can be done by direct editing, or through the recoll
user preferences dialog.
If Use desktop preferences to choose document editor is checked in the
Recoll GUI user preferences, all mimeview entries will be ignored except
the one labelled application/x-all (which is set to use xdg-open by
default).
As for the other configuration files, the normal usage is to have a
mimeview inside your own configuration directory, with just the
non-default entries, which will override those from the central
configuration file.
Please note that these entries must be placed under a [view] section.
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
localfields specification in mimeconf). The syntax for the key is
mimetype|tag
The nouncompforviewmts entry, (placed at the top level, outside of the
[view] section), holds a list of mime types that should not be
uncompressed before starting the viewer (if they are found compressed, ie:
mydoc.doc.gz).
The right side of each assignment holds a command to be executed for
opening the file. The following substitutions are performed:
* %D. Document date
* %f. 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).
* %F. Original file name. Same as %f except if a temporary file is used.
* %i. Internal path, for subdocuments of containers. The format depends
on the container type. If this appears in the command line, Recoll
will not create a temporary file to extract the subdocument, expecting
the called application (possibly a script) to be able to handle it.
* %M. Mime type
* %U, %u. Url.
In addition to the predefined values above, all strings like %(fieldname)
will be replaced by the value of the field named fieldname for the
document. This could be used in combination with field customisation to
help with opening the document.
----------------------------------------------------------------------
5.4.6. Examples of configuration adjustments
5.4.6.1. Adding an external viewer for an non-indexed type
Imagine that you have some kind of file which does not have indexable
content, but for which you would like to have a functional Open link in
the result list (when found by file name). The file names end in .blob and
can be displayed by application blobviewer.
You need two entries in the configuration files for this to work:
* In $RECOLL_CONFDIR/mimemap (typically ~/.recoll/mimemap), add the
following line:
.blob = application/x-blobapp
Note that the mime type is made up here, and you could call it
diesel/oil just the same.
* In $RECOLL_CONFDIR/mimeview under the [view] section, add:
application/x-blobapp = blobviewer %f
We are supposing that blobviewer wants a file name parameter here, you
would use %u if it liked URLs better.
If you just wanted to change the application used by Recoll to display a
mime type which it already knows, you would just need to edit mimeview.
The entries you add in your personal file override those in the central
configuration, which you do not need to alter. mimeview can also be
modified from the Gui.
----------------------------------------------------------------------
5.4.6.2. Adding indexing support for a new file type
Let us now imagine that the above .blob files actually contain indexable
text and that you know how to extract it with a command line program.
Getting Recoll to index the files is easy. You need to perform the above
alteration, and also to add data to the mimeconf file (typically in
~/.recoll/mimeconf):
* Under the [index] section, add the following line (more about the
rclblob indexing script later):
application/x-blobapp = exec rclblob
* Under the [icons] 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 /usr/[local/]share/recoll/images.
* Under the [categories] 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.
The rclblob filter should be an executable program or script which exists
inside /usr/[local/]share/recoll/filters. It will be given a file name as
argument and should output the text or html contents on the standard
output.
The filter programming section describes in more detail how to write a
filter.
----------------------------------------------------------------------
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