usermanual.sgml
4648 lines (3923 with data), 209.2 kB
<!-- Use this header for the FreeBSD sgml toolchain -->
<!-- NOTE: the sgml version should be saved as ISO-8859-1. -->
<!DOCTYPE BOOK PUBLIC "-//FreeBSD//DTD DocBook V4.1-Based Extension//EN" [
<!-- Use this header for going XML -->
<!-- <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [ -->
<!ENTITY RCL "<application>Recoll</application>">
<!ENTITY RCLAPPS "<ulink url='http://www.recoll.org/features.html'>Recoll helper applications page</ulink>">
<!ENTITY RCLVERSION "1.17">
<!ENTITY XAP "<application>Xapian</application>">
]>
<book lang="en">
<bookinfo>
<title>Recoll user manual</title>
<author>
<firstname>Jean-Francois</firstname>
<surname>Dockes</surname>
<affiliation>
<address><email>jfd@recoll.org</email></address>
</affiliation>
</author>
<copyright>
<year>2005-2012</year>
<holder role="mailto:jfd@recoll.org">Jean-Francois Dockes</holder>
</copyright>
<abstract>
<para>This document introduces full text search notions
and describes the installation and use of the &RCL;
application. It currently describes &RCL; &RCLVERSION;.</para>
<!-- <para>[ <ulink url="index.html">Split HTML</ulink> /
<ulink url="usermanual-xml.html">Single HTML</ulink> ]</para>
-->
</abstract>
</bookinfo>
<chapter id="rcl.introduction">
<title>Introduction</title>
<sect1 id="rcl.introduction.tryit">
<title>Giving it a try</title>
<para>If you do not like reading manuals (who does?) and would like
to give &RCL; a try, just <link
linkend="rcl.install.binary">install</link> the application and
start the <command>recoll</command> graphical user interface (GUI),
which will ask to index your home directory by default, allowing
you to search immediately after indexing completes.</para>
<para>Do not do this if your home directory contains a huge
number of documents and you do not want to wait or are very
short on disk space. In this case, you may first want to customize
the <link linkend="rcl.indexing.config">configuration</link>
to restrict the indexed area.</para>
<para>Also be aware that you may need to install the
appropriate <link linkend="rcl.install.external"> supporting
applications</link> for document types that need them (for
example <application>antiword</application> for ms-word
files).</para>
</sect1>
<sect1 id="rcl.introduction.search">
<title>Full text search</title>
<para>&RCL; 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 <emphasis>relevant</emphasis> documents will appear
first.</para>
<para>You do not need to remember in what file or email message you
stored a given piece of information. You just ask for related
terms, and the tool will return a list of documents where
those terms are prominent, in a similar way to Internet search
engines.</para>
<para>A search application 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 is probably the most
important aspect when evaluating a search application.</para>
<para>In many cases, you are looking for all the forms of a
word, 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 <emphasis>stem</emphasis> (example: floor,
floors, floored, flooring...). Search applications usually expand
queries to all such related terms (words that reduce to the same
stem) and also provide a way to disable this expansion if you are
actually searching for a specific form.</para>
<para>Stemming, by itself, does not accommodate for misspellings or
phonetic searches. &RCL; supports these features through a specific
tool (the <literal>term explorer</literal>) which will let you
explore the set of index terms along different modes.</para>
</sect1>
<sect1 id="rcl.introduction.recoll">
<title>Recoll overview</title>
<para>&RCL; uses the
<ulink url="http://www.xapian.org">&XAP;</ulink> information retrieval
library as its storage and retrieval engine. &XAP; is a very
mature package using <ulink
url="http://www.xapian.org/docs/intro_ir.html">a sophisticated
probabilistic ranking model</ulink>. &RCL; provides the mechanisms
and interface to get data into and out of the system.</para>
<para>In practice, &XAP; works by remembering where terms appear
in your document files. The acquisition process is called
indexing. </para>
<para>The resulting index can be big (roughly the size of the
original document set), but it is not a document
archive. &RCL; can only display documents that still exist at
the place from which they were indexed. (Actually, there is a
way to reconstruct a document from the information in the
index, but the result is not nice, as all formatting,
punctuation and capitalization are lost).</para>
<para>&RCL; stores all internal data in <application>Unicode
UTF-8</application> format, and it can index files with
different character sets, encodings, and languages into the same
index. It has input filters for many document types.</para>
<para>Stemming is the process by which &RCL; reduces words to
their radicals so that searching does not depend, for example,
on a word being singular or plural (floor, floors), or on a verb
tense (flooring, floored). Because the mechanisms used for
stemming depend on the specific grammatical rules for each
language, there is a separate stemmer module for most common
languages where stemming makes sense. Storing documents written
in different languages in the same index is possible, and
commonly done. In this situation, you can specify several
stemming languages for the index. &RCL; stores the unstemmed
versions of terms in the main index and uses auxiliary databases
for term expansion (one for each stemming language), which means
that you can switch stemming languages between searches, or add
a language without needing a full reindex. &RCL; currently
makes no attempt at automatic language recognition, which means
that the stemmer will sometimes be applied to terms from other
languages with potentially strange results. In practise, even if
this introduces possibilities of confusion, this approach has
been proven quite useful, and, awaiting the addition of an
automatic language recognition module to &RCL;, it is much less
cumbersome than separating your documents according to what
language they are written in.</para>
<para>&RCL; has many parameters which define exactly what to
index, and how to classify and decode the source
documents. These are kept in <link
linkend="rcl.indexing.config">configuration files</link>. A
default configuration is copied into a standard location
(usually something like
<filename>/usr/[local/]share/recoll/examples</filename>)
during installation. The default values set by the
configuration files in this directory may be overridden by
values that you set inside your personal configuration, found
by default in the <filename>.recoll</filename> sub-directory
of your home directory. The default configuration will index
your home directory with default parameters and should be
sufficient for giving &RCL; a try, but you may want to adjust
it later, which can be done either by editing the text files
or by using configuration menus in the
<command>recoll</command> GUI</para>
<para>The <link linkend="rcl.indexing.periodic.exec">indexing
process</link> is started automatically the first time you
execute the <command>recoll</command> GUI. Indexing can also be
performed by executing the <command>recollindex</command>
command.</para>
<para><link linkend="rcl.search">Searches</link> are usually
performed inside the <command>recoll</command> GUI, which has many
options to help you find what you are looking for. However, there
are other ways to perform &RCL; searches: mostly a <link
linkend="rcl.search.commandline">
command line interface</link>, a
<link linkend="rcl.program.api.python">
<application>Python</application>
programming interface</link>, a <link linkend="rcl.search.kio">
<application>KDE</application> KIO slave module</link>, and
a <application>Ubuntu Unity Lens</application> module.
</para>
</sect1>
</chapter>
<chapter id="rcl.indexing">
<title>Indexing</title>
<sect1 id="rcl.indexing.introduction">
<title>Introduction</title>
<para>Indexing is the process by which the set of documents is
analyzed and the data entered into the database. &RCL;
indexing is normally incremental: documents will only be
processed if they have been modified. On the first execution,
all documents will need processing. A full index build can be
forced later by specifying an option to the indexing command
(<command>recollindex</command> <option>-z</option>
or <option>-Z</option>).</para>
<para>The following sections give an overview of different
aspects of the indexing processes and configuration, with links
to detailed sections.</para>
<sect2>
<title>Indexing modes</title>
<para>&RCL; indexing can be performed along two different modes:
<itemizedlist>
<listitem>
<formalpara>
<title><link linkend="rcl.indexing.periodic">
Periodic (or batch) indexing:</link></title>
<para>indexing takes place at discrete
times, by executing the <command>recollindex</command>
command. The typical usage is to have a nightly indexing run
<link linkend="rcl.indexing.periodic.automat">
programmed</link> into
your <command>cron</command> file.</para>
</formalpara>
</listitem>
<listitem>
<formalpara><title><link linkend="rcl.indexing.monitor">Real
time indexing:</link></title>
<para>indexing takes place as soon as a file is created or
changed. <command>recollindex</command> runs as a daemon
and uses a file system alteration monitor such as
<application>inotify</application>,
<application>Fam</application> or
<application>Gamin</application>
to detect file changes.</para>
</formalpara>
</listitem>
</itemizedlist>
</para>
<para>The choice between the two methods is mostly a matter of
preference, and they can be combined by setting up multiple
indexes (ie: use periodic indexing on a big documentation
directory, and real time indexing on a small home
directory). Monitoring a big file system tree can consume
significant system resources.</para>
</sect2>
<sect2>
<title>Configurations, multiple indexes</title>
<para>The parameters describing what is to be indexed and
local preferences are defined in text files contained in a
<link linkend="rcl.indexing.config">configuration
directory</link>.</para>
<para>All parameters have defaults, defined in system-wide
files.</para>
<para>Without further configuration, &RCL; will index all
appropriate files from your home directory, with a reasonable
set of defaults.</para>
<para>A default personal configuration directory
(<filename>$HOME/.recoll/</filename>) is created
when a &RCL; program is first executed. It is possible to
create other configuration directories, and use them by
setting the <envar>RECOLL_CONFDIR</envar> environment
variable, or giving the <option>-c</option> option to any of
the &RCL; commands.</para>
<para>In some cases, it may be interesting to index different
areas of the file system to separate databases. You can do this
by using multiple configuration directories, each indexing a
file system area to a specific database. Typically, this
would be done to separate personal and shared
indexes, or to take advantage of the organization of your data
to improve search precision.</para>
<para>The generated indexes can
be <link linkend="rcl.search.multidb">queried
concurrently</link> in a transparent manner.</para>
<para>For index generation, multiple configurations are
totally independant from each other. When multiple indexes
are used for searches,
<link linkend="rcl.search.multidb">some parameters
should be consistent among the configurations</link>.</para>
</sect2>
<sect2>
<title>Document types</title>
<para>&RCL; knows about quite a few different document
types. The parameters for document types recognition and
processing are set in
<link linkend="rcl.indexing.config">configuration files</link>.</para>
<para>Most file types, like HTML or word processing files, only hold
one document. Some file types, like email folders or zip
archives, can hold many individually indexed documents, which may
themselves be compound ones. Such hierarchies can go quite
deep, and &RCL; can process, for example, an
<application>ms-word</application>
document stored as an attachment to an email message inside an
email folder archived in a zip file...</para>
<para>&RCL; indexing processes plain text, HTML, OpenDocument
(Open/LibreOffice), email formats, and a few others internally.</para>
<para>Other file types (ie: postscript, pdf, ms-word, rtf ...)
need external applications for preprocessing. The list is in the
<link linkend="rcl.install.external"> installation</link>
section. After every indexing operation, &RCL; updates a list of
commands that would be needed for indexing existing files
types. This list can be displayed by selecting the menu option
<menuchoice>
<guimenu>File</guimenu>
<guimenuitem>Show Missing Helpers</guimenuitem>
</menuchoice>
in the <command>recoll</command> GUI. It is stored in the
<filename>missing</filename> text file inside the configuration
directory.</para>
</sect2>
<sect2>
<title>Recovery</title>
<para>In the rare case where the index becomes corrupted (which can
signal itself by weird search results or crashes), the index files
need to be erased before restarting a clean indexing pass. Just delete
the <filename>xapiandb</filename> directory (see
<link linkend="rcl.indexing.storage">next section</link>), or,
alternatively, start the next <command>recollindex</command> with the
<option>-z</option> option, which will reset the database before
indexing.</para>
</sect2>
</sect1>
<sect1 id="rcl.indexing.storage">
<title>Index storage</title>
<para>The default location for the index data is the
<filename>xapiandb</filename> subdirectory of the &RCL;
configuration directory, typically
<filename>$HOME/.recoll/xapiandb/</filename>. This can be
changed via two different methods (with different purposes):
<itemizedlist>
<listitem><para>You can specify a different configuration
directory by setting the <envar>RECOLL_CONFDIR</envar>
environment variable, or using the <option>-c</option>
option to the &RCL; commands. This method would typically be
used to index different areas of the file system to
different indexes. For example, if you were to issue the
following commands:
<programlisting>
export RECOLL_CONFDIR=~/.indexes-email
recoll
</programlisting> Then &RCL; would use configuration files
stored in <filename>~/.indexes-email/</filename> and,
(unless specified otherwise in
<filename>recoll.conf</filename>) would look for
the index in
<filename>~/.indexes-email/xapiandb/</filename>.</para>
<para>Using multiple configuration directories and
<link linkend="rcl.install.config.recollconf">configuration
options</link> allows you to tailor multiple configurations
and indexes to handle whatever subset of the available data
that you wish to make searchable.</para>
</listitem>
<listitem><para>You can also specify a different storage
location for the index by setting the <varname>dbdir</varname>
parameter in the configuration file
(see the <link linkend="rcl.install.config.recollconf">configuration
section</link>). This method would mainly be of use if you
wanted to keep the configuration directory in its default location,
but desired another location for the index, typically out of
disk occupation concerns.</para>
</listitem>
</itemizedlist>
</para>
<para>The size of the index is determined by the size of the set
of documents, but the ratio can vary a lot. For a typical
mixed set of documents, the index size will often be close to
the data set size. In specific cases (a set of compressed mbox
files for example), the index can become much bigger than the
documents. It may also be much smaller if the documents
contain a lot of images or other non-indexed data (an extreme
example being a set of mp3 files where only the tags would be
indexed).</para>
<para>Of course, images, sound and video do not increase the
index size, which means that nowadays (2012), typically, even a big
index will be negligible against the total amount of data on the
computer.</para>
<para>The index data directory (<filename>xapiandb</filename>)
only contains data that can be completely rebuilt by an index run
(as long as the original documents exist), and it can always be
destroyed safely.</para>
<sect2 id="rcl.indexing.storage.format">
<title>Xapian index formats</title>
<para>&XAP; versions usually support several formats for index
storage. A given major &XAP; version will have a current format,
used to create new indexes, and will also support the format from
the previous major version.</para>
<para>&XAP; will not convert automatically an existing index
from the older format to the newer one. If you want to upgrade to
the new format, or if a very old index needs to be converted
because its format is not supported any more, you will have to
explicitly delete the old index, then run a normal indexing
process.</para>
<para>Using the <option>-z</option> option to
<command>recollindex</command> is not sufficient to change the
format, you will have to delete all files inside the index
directory (typically <filename>~/.recoll/xapiandb</filename>)
before starting the indexing.</para>
</sect2>
<sect2 id="rcl.indexing.storage.security">
<title>Security aspects</title>
<para>The &RCL; index does not hold copies of the indexed
documents. But it does hold enough data to allow for an almost
complete reconstruction. If confidential data is indexed,
access to the database directory should be restricted. </para>
<para>&RCL; (since version 1.4) will create the configuration
directory with a mode of 0700 (access by owner only). As the
index data directory is by default a sub-directory of the
configuration directory, this should result in appropriate
protection.</para>
<para>If you use another setup, you should think of the kind
of protection you need for your index, set the directory
and files access modes appropriately, and also maybe adjust
the <literal>umask</literal> used during index updates.</para>
</sect2>
</sect1>
<sect1 id="rcl.indexing.config">
<title>Indexing configuration</title>
<para>Variables set inside the
<link linkend="rcl.install.config">&RCL; configuration files</link>
control which areas of the file system are indexed, and how
files are processed. These variables can be set either by
editing the text files or using the dialogs in the
<command>recoll</command> GUI.</para>
<para>The first time you start <command>recoll</command>, you
will be asked whether or not you would like it to build the
index. If you want to adjust the configuration before
indexing, just click <guilabel>Cancel</guilabel> at this
point, which will get you into the configuration interface. If
you exit at this point, <filename>recoll</filename> will have
created a <filename>~/.recoll</filename> directory containing
empty configuration files, which you can edit by hand.</para>
<para>The configuration is documented inside the
<link linkend="rcl.install.config">installation chapter</link>
of this document, or in the
<citerefentry>
<refentrytitle>recoll.conf</refentrytitle>
<manvolnum>5</manvolnum>
</citerefentry>
man page, but the most
current information will most likely be the comments inside the
sample file. The most immediately useful variable you may
interested in is probably
<link linkend="rcl.install.config.recollconf.topdirs">
<varname>topdirs</varname></link>,
which determines what subtrees get indexed.</para>
<para>The applications needed to index file types other than
text, HTML or email (ie: pdf, postscript, ms-word...) are
described in the <link linkend="rcl.install.external">external
packages section.</link></para>
<sect2 id="rcl.indexing.config.gui">
<title>The indexing configuration GUI</title>
<para>Most parameters for a given indexing configuration can
be set from a <command>recoll</command> GUI running on this
configuration (either as default, or by setting
<envar>RECOLL_CONFDIR</envar> or the <option>-c</option>
option.)</para>
<para>The interface is started from the
<menuchoice>
<guimenu>Preferences</guimenu>
<guimenuitem>Indexing Configuration</guimenuitem>
</menuchoice>
menu entry. It is divided in three tabs,
<guilabel>Global parameters</guilabel>, <guilabel>Local
parameters</guilabel>, and <guilabel>Beagle web history</guilabel>,
which is explained in the next section.</para>
<para>The first tab allows setting global variables, like the lists
of top directories, skipped paths, or stemming languages.</para>
<para>The second tab allows setting variables that can be redefined
for subdirectories. This second tab has an initially empty list of
customisation directories, to which you can add. The variables are
then set for the currently selected directory (or at the top level
if the empty line is selected).</para>
<para>The meaning for most entries in the interface is
self-evident and documented by a <literal>ToolTip</literal>
popup on the text label. For more detail, you will need to
refer to the <link linkend="rcl.install.config">configuration
section</link> of this guide.</para>
<para>The configuration tool normally respects the comments
and most of the formatting inside the configuration file, so
that it is quite possible to use it on hand-edited files,
which you might nevertheless want to backup first...</para>
</sect2>
</sect1>
<sect1 id="rcl.indexing.beaglequeue">
<title>Using Beagle WEB browser plugins</title>
<para><application>Beagle</application> is (was?) a concurrent desktop
indexer, built on <application>Lucene</application> and
the <application>Mono</application> project
(<application>C#</application>), 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. Especially, there is a
<application>Firefox</application> extension.</para>
<para>If, for any reason, you so happen to prefer &RCL; to
<application>Beagle</application>, you can still use the
<application>Firefox</application> plugin, which is written in
<application>Javascript</application> and completely independant of
<application>C#</application>, <application>Beagle</application>,
<application>Lucene</application>..., and
set &RCL; to process the <application>Beagle</application> queue
directory. This supposes that <application>Beagle</application> is
not running, else both programs will fight for the same
files.</para>
<para>This feature can be enabled in the GUI indexing configuration
panel, or by editing the configuration file (set
<varname>processbeaglequeue</varname> to 1).</para>
<para>There are more recent instructions about how to find and
install the <application>Firefox</application> extension on the
<ulink url="https://bitbucket.org/medoc/recoll/wiki/IndexBeagleWeb">
Recoll wiki</ulink>.</para>
<para>Unfortunately, it seems that the plugin does not work anymore
with recent <application>Firefox</application>
versions (tried with 10.0). This is not the
trival installation version check issue, explicit manual indexing
requests still work, but automatic indexing on page load does
not.</para>
</sect1>
<sect1 id="rcl.indexing.periodic">
<title>Periodic indexing</title>
<sect2 id="rcl.indexing.periodic.exec">
<title>Running indexing</title>
<para>Indexing is always performed by the
<command>recollindex</command> program, which can be started
either from the command line or from the <guimenu>File</guimenu>
menu in the <command>recoll</command> GUI program. When started
from the GUI, the indexing will run on the same configuration
<command>recoll</command> was started on. When started from the
command line, <command>recollindex</command> will use the
<envar>RECOLL_CONFDIR</envar> variable or accept a
<option>-c</option> <replaceable>confdir</replaceable> option
to specify a non-default configuration directory.</para>
<para>If the <command>recoll</command> program finds no index
when it starts, it will automatically start indexing (except
if canceled).</para>
<para>The <command>recollindex</command> indexing process can be
interrupted by sending an interrupt (<keysym>Ctrl-C</keysym>,
SIGINT) or terminate
(SIGTERM) signal. Some time may elapse before the process exits,
because it needs to properly flush and close the index. This can
also be done from the <command>recoll</command> GUI
<menuchoice>
<guimenu>File</guimenu>
<guimenuitem>Stop Indexing</guimenuitem>
</menuchoice>
menu entry.</para>
<para>After such an interruption, the index will be somewhat
inconsistent because some operations which are normally
performed at the end of the indexing pass will have been
skipped (for example, the stemming and spelling databases
will be inexistant or out of date). You just need to restart
indexing at a later time to restore consistency. The
indexing will restart at the interruption point (the full
file tree will be traversed, but files that were indexed up
to the interruption and for which the index is still up to
date will not need to be reindexed).</para>
<para><command>recollindex</command> has a number of other options
which are described in its man page. Only a few will be
described here.</para>
<para>Option <option>-z</option> will reset the index when
starting. This is almost the same as destroying the index
files (the nuance is that the Xapian format version will not
be changed).</para>
<para>Option <option>-Z</option> will force the update of all
documents without resetting the index first. This will not
have the "clean start" aspect of <option>-z</option>, but
the advantage is that the index will remain available for
querying while it is rebuilt, which can be a significant
advantage if it is very big (some installations need days
for a full index rebuild).</para>
<para>Of special interest also, maybe, are
the <option>-i</option> and
<option>-f</option> options. <option>-i</option> allows
indexing an explicit list of files (given as command line
parameters or read on <literal>stdin</literal>).
<option>-f</option> tells
<command>recollindex</command> to ignore file selection
parameters from the configuration. Together, these options allow
building a custom file selection process for some area of the
file system, by adding the top directory to the
<varname>skippedPaths</varname> list and using an appropriate
file selection method to build the file list to be fed to
<command>recollindex</command> <option>-if</option>.
Trivial example:</para>
<programlisting>
find . -name indexable.txt -print | recollindex -if
</programlisting>
<para><command>recollindex</command> <option>-i</option> will
not descend into subdirectories specified as parameters,
but just add them as index entries. It is
up to the external file selection method to build the complete
file list.</para>
</sect2>
<sect2 id="rcl.indexing.periodic.automat">
<title>Using <command>cron</command> to automate
indexing</title>
<para>The most common way to set up indexing is to have a cron
task execute it every night. For example the following
<filename>crontab</filename> entry would do it every day at
3:30AM (supposing <command>recollindex</command> is in your
PATH):
<screen><![CDATA[
30 3 * * * recollindex > /some/tmp/dir/recolltrace 2>&1
]]></screen>
Or, using <command>anacron</command>:
<screen><![CDATA[
1 15 su mylogin -c "recollindex recollindex > /tmp/rcltraceme 2>&1"
]]></screen>
</para>
<para>As of version 1.17 the &RCL; GUI has dialogs to manage
<filename>crontab</filename> entries for
<command>recollindex</command>. You can reach them from the
<menuchoice>
<guimenu>Preferences</guimenu>
<guimenuitem>Indexing Schedule</guimenuitem>
</menuchoice>
menu. They only
work with the good old <command>cron</command>, and do not give
access to all features of <command>cron</command> scheduling.</para>
<para>The usual command to edit your
<filename>crontab</filename> is <command>crontab</command>
<option>-e</option> (which will usually start the
<command>vi</command> editor to edit the file). You may have
more sophisticated tools available on your system.</para>
<para>Please be aware that there may be differences between your
usual interactive command line environment and the one seen by
crontab commands. Especially the PATH variable may be of
concern. Please check the crontab manual pages about possible
issues.</para>
</sect2>
</sect1>
<sect1 id="rcl.indexing.monitor">
<title>Real time indexing</title>
<para>Real time monitoring/indexing is performed by starting the
<command>recollindex</command> <option>-m</option> command.
With this option, <command>recollindex</command> will detach
from the terminal and become a daemon, permanently monitoring
file changes and updating the index.</para>
<para>Under <application>KDE</application>,
<application>Gnome</application> and some other desktop
environments, the daemon can automatically started when you log
in, by creating a desktop file inside the
<filename>~/.config/autostart</filename> directory. This can be
done for you by the &RCL; GUI. Use the
<guimenu>Preferences->Indexing Schedule</guimenu> menu.</para>
<para>With older <application>X11</application> setups, starting
the daemon is normally performed as part of the user session
script.</para>
<para>The <filename>rclmon.sh</filename> script can be used to
easily start and stop the daemon. It can be found in the
<filename>examples</filename> directory (typically
<filename>/usr/local/[share/]recoll/examples</filename>).</para>
<para>For example, my out of fashion
<application>xdm</application>-based session has a
<filename>.xsession</filename> script with the following lines
at the end:</para>
<programlisting>recollconf=$HOME/.recoll-home
recolldata=/usr/local/share/recoll
RECOLL_CONFDIR=$recollconf $recolldata/examples/rclmon.sh start
fvwm
</programlisting>
<para>The indexing daemon gets started, then the window manager,
for which the session waits.</para> <para>By default the
indexing daemon will monitor the state of the X11 session, and
exit when it finishes, it is not necessary to kill it
explicitly. (The <application>X11</application> server
monitoring can be disabled with option <option>-x</option> to
<command>recollindex</command>).</para>
<para>If you use the daemon completely out of an
<application>X11</application> session, you need to add option
<option>-x</option> to disable <application>X11</application> session monitoring (else
the daemon will not start).</para>
<para>By default, the messages from the indexing daemon will be
discarded. You may want to change this by setting the
<varname>daemlogfilename</varname> and
<varname>daemloglevel</varname> configuration parameters. Also the
log file will only be truncated when the daemon starts. If the
daemon runs permanently, the log file may grow quite big, depending
on the log level.</para>
<para>When building &RCL;, the real time indexing support can be
customised during package <link
linkend="rcl.install.building.build">configuration</link> with
the <option>--with[out]-fam</option> or
<option>--with[out]-inotify</option> options. The default is
currently to include <application>inotify</application>
monitoring on systems that support it, and, as of &RCL; 1.17,
<application>gamin</application> support on
<application>FreeBSD</application>.</para>
<para>While it is convenient that data is indexed in real time,
repeated indexing can generate a significant load on the
system when files such as email folders change. Also,
monitoring large file trees by itself significantly taxes
system resources. You probably do not want to enable it if
your system is short on resources. Periodic indexing is
adequate in most cases.</para>
<sect2 id="rcl.indexing.monitor.fastfiles">
<title>Slowing down the reindexing rate for fast changing
files</title>
<para>When using the real time monitor, it may happen that some
files need to be indexed, but change so often that they impose an
excessive load for the system.</para>
<para>&RCL; provides a configuration option to specify the minimum
time before which a file, specified by a wildcard pattern, cannot be
reindexed. See the <varname>mondelaypatterns</varname> parameter in
the <link linkend="rcl.install.config.recollconf.misc">
configuration section</link>.</para>
</sect2>
</sect1>
</chapter>
<chapter id="rcl.search">
<title>Searching</title>
<sect1 id="rcl.search.gui">
<title>Searching with the Qt graphical user interface</title>
<para>The <command>recoll</command> program provides the main user
interface for searching. It is based on the
<application>Qt</application> library.</para>
<para><command>recoll</command> has two search modes:</para>
<itemizedlist>
<listitem><para>Simple search (the default, on the main screen) has
a single entry field where you can enter multiple words.</para>
</listitem>
<listitem><para>Advanced search (a panel accessed through the
<guilabel>Tools</guilabel> menu or the toolbox bar icon) has
multiple entry fields, which you may use to build a logical
condition, with additional filtering on file type and location
in the file system.</para>
</listitem>
</itemizedlist>
<para>In most cases, you can enter the terms as you
think them, even if they contain embedded punctuation or other
non-textual characters. For
example, &RCL; can handle things like email addresses, or
arbitrary cut and paste from another text window, punctation
and all.</para>
<para>The main case where you should enter text differently from
how it is printed is for east-asian languages (Chinese,
Japanese, Korean). Words composed of single or multiple
characters should be entered separated by white space in this
case (they would typically be printed without white
space).</para>
<sect2 id="rcl.search.gui.simple">
<title>Simple search</title>
<procedure>
<step><para>Start the <command>recoll</command> program.</para>
</step>
<step><para>Possibly choose a search mode: <guilabel>Any
term</guilabel>, <guilabel>All terms</guilabel>,
<guilabel>File name</guilabel> or
<guilabel>Query language</guilabel>.</para>
</step>
<step><para>Enter search term(s) in the text field at the top of the
window.</para>
</step>
<step><para>Click the <guilabel>Search</guilabel> button or
hit the <keycap>Enter</keycap> key to start the search.</para>
</step>
</procedure>
<para>The initial default search mode is <guilabel>Query
language</guilabel>. Without special directives, this will look for
documents containing all of the search terms (the ones with more
terms will get better scores), just like the <guilabel>All
terms</guilabel> mode which will ignore such
directives. <guilabel>Any term</guilabel> will search for documents
where at least one of the terms appear. </para>
<para>The <guilabel>Query Language</guilabel> features are
described in <link linkend="rcl.search.lang">a separate
section</link>.</para>
<para><guilabel>File name</guilabel> will specifically look for file
names. The entry will be split at white space characters,
and each fragment will be separately expanded, then the search will
be for file names matching all fragments (this is new in 1.15,
older releases did an OR of the whole thing which did not make
sense). Things to know:
<itemizedlist>
<listitem><para>The search is case- and accent-insensitive.</para>
</listitem>
<listitem><para>Fragments without any wild card
character and not capitalized will be prepended and appended
with '*' (ie: <replaceable>etc</replaceable> ->
<replaceable>*etc*</replaceable>, but
<replaceable>Etc</replaceable> ->
<replaceable>etc</replaceable>). Of course it does not make
sense to have multiple fragments if one of them is capitalized
(as this one will require an exact match).</para>
</listitem>
<listitem><para>If you want to search for a pattern including
white space, use double quotes (ie: <replaceable>"admin
note*"</replaceable>).</para>
</listitem>
<listitem><para>If you have a big index (many files),
excessively generic fragments may result in inefficient
searches.</para>
</listitem>
<listitem><para>As an example, <replaceable>inst
recoll</replaceable> would match
<replaceable>recollinstall.in</replaceable> (and quite a few
others...).</para>
</listitem>
</itemizedlist>
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 (allowing
wild cards on the left of terms without excessive penality).</para>
<para>All search modes allow wildcards inside terms
(<literal>*</literal>, <literal>?</literal>,
<literal>[]</literal>). You may want to have a look at the
<link linkend="rcl.search.wildcards">section about wildcards</link>
for more information about this.</para>
<para>You can search for exact phrases (adjacent words in a
given order) by enclosing the input inside double quotes. Ex:
<literal>"virtual reality"</literal>.</para>
<para>Character case has no influence on search, except that you
can disable stem expansion for any term by capitalizing it. Ie:
a search for <literal>floor</literal> will also normally look for
<literal>flooring</literal>, <literal>floored</literal>, etc., but
a search for <literal>Floor</literal> will only look for
<literal>floor</literal>, in any character case. Stemming can
also be disabled globally in the preferences. </para>
<para>&RCL; remembers the last few searches that you
performed. You can use the simple search text entry widget (a
combobox) to recall them (click on the thing at the right of the
text field). Please note, however, that only the search texts
are remembered, not the mode (all/any/file name).</para>
<para>Typing <keycap>Esc</keycap> <keycap>Space</keycap> while
entering a word in the simple search entry will open a window
with possible completions for the word. The completions are
extracted from the database.</para>
<para>Double-clicking on a word in the result list or a preview
window will insert it into the simple search entry field.</para>
<para>You can cut and paste any text into an <guilabel>All
terms</guilabel> or <guilabel>Any term</guilabel> search field,
punctuation, newlines and all - except for wildcard characters
(single <literal>?</literal> characters are ok). &RCL; will process
it and produce a meaningful search. This is what most differentiates
this mode from the <guilabel>Query Language</guilabel> mode, where
you have to care about the syntax.</para>
<para>You can use the <link linkend="rcl.search.gui.complex">
<menuchoice>
<guimenu>Tools</guimenu>
<guimenuitem>Advanced search</guimenuitem>
</menuchoice>
</link> dialog for more complex searches.</para>
</sect2>
<sect2 id="rcl.search.gui.reslist">
<title>The default result list</title>
<para>After starting a search, a list of results will instantly
be displayed in the main list window.</para>
<para>By default, the document list is presented in order of
relevance (how well the system estimates that the document
matches the query). You can sort the result by ascending or
descending date by using the vertical arrows in the toolbar (the old
sort tool is gone after release 1.15, because the new <link
linkend="rcl.search.gui.restable">result table</link> has much better
capability).</para>
<para>Clicking on the
<literal>Preview</literal> link for an entry will open an
internal preview window for the document. Further
<literal>Preview</literal> clicks for the same search will open
tabs in the existing preview window. You can use
<keycap>Shift</keycap>+Click to force the creation of another
preview window, which may be useful to view the documents side
by side. (You can also browse successive results in a single
preview window by typing
<keycap>Shift</keycap>+<keycap>ArrowUp/Down</keycap> in the
window).</para>
<para>Clicking the <literal>Open</literal> link will attempt to
start an external viewer. The viewer for each document type can be
configured through the user preferences dialog, or by editing the
<filename>mimeview</filename> configuration file. You can also check
the <guilabel>Use desktop preferences</guilabel> 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 <application>Gnome</application> or
<application>KDE</application> desktop.</para>
<para>The <literal>Preview</literal> and <literal>Open</literal>
edit links may not be present for all entries, meaning that
&RCL; has no configured way to preview a given file type (which
was indexed by name only), or no configured external editor for
the file type. This can sometimes be adjusted simply by tweaking
the <link linkend="rcl.install.config.mimemap">
<filename>mimemap</filename></link> and
<link linkend="rcl.install.config.mimeview">
<filename>mimeview</filename></link> configuration files (the latter
can be modified with the user preferences dialog).</para>
<para>The format of the result list entries is entirely
configurable by using the preference dialog to
<link linkend="rcl.search.gui.custom.reslist">edit an HTML
fragment</link>.</para>
<para>You can click on the <literal>Query details</literal> link
at the top of the results page to see the query actually
performed, after stem expansion and other processing.</para>
<para>Double-clicking on any word inside the result list or a
preview window will insert it into the simple search text.</para>
<para>The result list is divided into pages (the size of which
you can change in the preferences). Use the arrow buttons in the
toolbar or the links at the bottom of the page to browse the
results.</para>
<sect3 id="rcl.search.gui.resultlist.menu">
<title>The result list right-click menu</title>
<para>Apart from the preview and edit links, you can display a
pop-up menu by right-clicking over a paragraph in the result
list. This menu has the following entries:</para>
<itemizedlist>
<listitem><para><guilabel>Preview</guilabel></para></listitem>
<listitem><para><guilabel>Open</guilabel></para></listitem>
<listitem><para><guilabel>Copy File Name</guilabel></para></listitem>
<listitem><para><guilabel>Copy Url</guilabel></para></listitem>
<listitem><para><guilabel>Save to File</guilabel></para></listitem>
<listitem><para><guilabel>Find similar</guilabel></para></listitem>
<listitem><para><guilabel>Preview Parent
document</guilabel></para></listitem>
<listitem><para><guilabel>Open Parent
document</guilabel></para></listitem>
</itemizedlist>
<para>The <guilabel>Preview</guilabel> and
<guilabel>Open</guilabel> entries do the same thing as the
corresponding links.</para>
<para>The <guilabel>Copy File Name</guilabel> and
<guilabel>Copy Url</guilabel> copy the relevant data to the
clipboard, for later pasting.</para>
<para><guilabel>Save to File</guilabel> allows saving the
contents of a result document to a chosen file. This entry
will only appear if the document does not correspond to an
existing file, but is a subdocument inside such a file (ie: an
email attachment). It is especially useful to extract attachments
with no associated editor.</para>
<para>The <guilabel>Find similar</guilabel> entry will select
a number of relevant term from the current document and enter
them into the simple search field. You can then start a simple
search, with a good chance of finding documents related to the
current result.</para>
<para>The <guilabel>Parent document</guilabel> 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). &RCL; is unfortunately not yet smart
enough to disable the entry in this case. In other cases, the
<guilabel>Open</guilabel> option makes sense, for example to
start a <application>chm</application> viewer on the parent
document for a help page.</para>
</sect3>
</sect2>
<sect2 id="rcl.search.gui.restable">
<title>The result table</title>
<para>In &RCL; 1.15 and newer, the results can be displayed in
spreadsheet-like fashion. You can switch to this presentation by
clicking the table-like icon in the toolbar (this is a toggle,
click again to restore the list).</para>
<para>Clicking on the column headers will allow sorting by the
values in the column. You can click again to invert the order, and
use the header right-click menu to reset sorting to the default
relevance order (you can also use the sort-by-date arrows to do
this).</para>
<para>Both the list and the table display the same underlying
results. The sort order set from the table is still active if you
switch back to the list mode. You can click twice on a date sort
arrow to reset it from there.</para>
<para>The header right-click menu allows adding or deleting
columns. The columns can be resized, and their order can be changed
(by dragging). All the changes are recorded when you quit
<command>recoll</command></para>
<para>Hovering over a table row will update the detail area at the
bottom of the window with the corresponding values. You can click
the row to freeze the display. The bottom area is equivalent to a
result list paragraph, with links for starting a preview or a
native application, and an equivalent right-click menu. Typing
<keycap>Esc</keycap> (the Escape key) will unfreeze the
display.</para>
</sect2>
<sect2 id="rcl.search.gui.preview">
<title>The preview window</title>
<para>The preview window opens when you first click a
<literal>Preview</literal> link inside the result list.</para>
<para>Subsequent preview requests for a given search open new
tabs in the existing window (except if you hold the
<keycap>Shift</keycap> key while clicking which will open a new
window for side by side viewing).</para>
<para>Starting another search and requesting a preview will
create a new preview window. The old one stays open until you
close it.</para>
<para>You can close a preview tab by typing <keycap>Ctrl-W</keycap>
(<keycap>Ctrl</keycap> + <keycap>W</keycap>) in the
window. Closing the last tab for a window will also close the
window.</para>
<para>Of course you can also close a preview window by using the
window manager button in the top of the frame.</para>
<para>You can display successive or previous documents from the
result list inside a preview tab by typing
<keycap>Shift</keycap>+<keycap>Down</keycap> or
<keycap>Shift</keycap>+<keycap>Up</keycap> (<keycap>Down</keycap>
and <keycap>Up</keycap> are the arrow keys).</para>
<para>A right-click menu in the text area allows switching
between displaying the main text or the contents of fields
associated to the document (ie: author, abtract, etc.). This is
especially useful in cases where the term match did not occur in
the main text but in one of the fields. In the case of
images, you can switch between three displays: the image
itself, the image metadata as extracted
by <command>exiftool</command> and the fields, which is the
metadata stored in the index.</para>
<para>You can print the current preview window contents by typing
<keycap>Ctrl-P</keycap> (<keycap>Ctrl</keycap> +
<keycap>P</keycap>) in the window text.</para>
<sect3 id="rcl.search.gui.preview.search">
<title>Searching inside the preview</title>
<para>The preview window has an internal search capability,
mostly controlled by the panel at the bottom of the window,
which works in two modes: as a classical editor incremental
search, where we look for the text entered in the entry
zone, or as a way to walk the matches between the document
and the &RCL; query that found it.</para>
<variablelist>
<varlistentry>
<term>Incremental text search</term>
<listitem><para>The preview tabs have an internal incremental search
function. You initiate the search either by typing a
<keycap>/</keycap> (slash) or <keycap>CTL-F</keycap>
inside the text area or by clicking into
the <guilabel>Search for:</guilabel> text field and
entering the search string. You can then use the
<guilabel>Next</guilabel>
and <guilabel>Previous</guilabel> buttons
to find the next/previous occurrence. You can also type
<keycap>F3</keycap> inside the text area to get to the next
occurrence.</para>
<para>If you have a search string entered and you use
Ctrl-Up/Ctrl-Down to browse the results, the search is
initiated for each successive document. If the string is
found, the cursor will be positioned at the first
occurrence of the search string.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Walking the match lists</term>
<listitem><para>If the entry area is empty when you click
the <guilabel>Next</guilabel>
or <guilabel>Previous</guilabel> buttons, the editor will
be scrolled to show the next match to any search term
(the next highlighted zone). If you select a search group
from the dropdown list and click <guilabel>Next</guilabel>
or <guilabel>Previous</guilabel>, the match list for this
group will be walked. This is not the same as a text
search, because the occurences will include non-exact
matches (as caused by stemming or wildcards). The search
will revert to the text mode as soon as you edit the
entry area.</para></listitem>
</varlistentry>
</variablelist>
</sect3>
</sect2>
<sect2 id="rcl.search.gui.complex">
<title>Complex/advanced search</title>
<para>The advanced search dialog helps you build more complex queries
without memorizing the search language constructs. It can be opened
through the <guilabel>Tools</guilabel> menu or through the main
toolbar.</para>
<para>The dialog has two tabs:</para>
<orderedlist>
<listitem><para>The first tab lets you specify terms to search
for, and permits specifying multiple clauses which are combined
to build the search.</para>
</listitem>
<listitem><para>The second tab lets filter the results according
to file size, date of modification, mime type, or
location.</para>
</listitem>
</orderedlist>
<para>Click on the <guilabel>Start Search</guilabel> button in
the advanced search dialog, or type <keycap>Enter</keycap> in
any text field to start the search. The button in
the main window always performs a simple search.</para>
<para>Click on the <literal>Show query details</literal> link at
the top of the result page to see the query expansion.</para>
<sect3 id="rcl.search.gui.complex.terms">
<title>Avanced search: the "find" tab</title>
<para>This part of the dialog lets you constructc a query by
combining multiple clauses of different types. Each entry
field is configurable for the following modes:</para>
<itemizedlist>
<listitem><para>All terms.</para>
</listitem>
<listitem><para>Any term.</para>
</listitem>
<listitem><para>None of the terms.</para>
</listitem>
<listitem><para>Phrase (exact terms in order within an
adjustable window).</para>
</listitem>
<listitem><para>Proximity (terms in any order within an
adjustable window).</para>
</listitem>
<listitem><para>Filename search.</para>
</listitem>
</itemizedlist>
<para>Additional entry fields can be created by clicking the
<guilabel>Add clause</guilabel> button.</para>
<para>When searching, the non-empty clauses will be
combined either with an AND or an OR conjunction, depending on
the choice made on the left (<guilabel>All clauses</guilabel> or
<guilabel>Any clause</guilabel>).</para>
<para>Entries of all types except "Phrase" and "Near" accept
a mix of single words and phrases enclosed in double quotes.
Stemming and wildcard expansion will be performed as for simple
search. </para>
<formalpara><title>Phrases and Proximity searches</title>
<para>These two clauses work in similar ways, with the
difference that proximity searches do not impose an order on the
words. In both cases, an adjustable number (slack) of non-matched words
may be accepted between the searched ones (use the counter on
the left to adjust this count). For phrases, the default count
is zero (exact match). For proximity it is ten (meaning that two search
terms, would be matched if found within a window of twelve
words). Examples: a phrase search for <literal>quick
fox</literal> with a slack of 0 will match <literal>quick
fox</literal> but not <literal>quick brown fox</literal>. With
a slack of 1 it will match the latter, but not <literal>fox
quick</literal>. A proximity search for <literal>quick
fox</literal> with the default slack will match the
latter, and also <literal>a fox is a cunning and quick
animal</literal>.</para>
</formalpara>
</sect3>
<sect3 id="rcl.search.gui.complex.filter">
<title>Avanced search: the "filter" tab</title>
<para>This part of the dialog has several sections which allow
filtering the results of a search according to a number of
criteria</para>
<itemizedlist>
<listitem>
<para>The first section allows filtering by dates of last
modification. You can specify both a minimum and a maximum date. The
initial values are set according to the oldest and newest documents
found in the index.</para>
</listitem>
<listitem>
<para>The next section allows filtering the results by
file size. There are two entries for minimum and maximum
size. Enter decimal numbers. You can use suffix multipliers:
<literal>k/K</literal>, <literal>m/M</literal>,
<literal>g/G</literal>, <literal>t/T</literal> for 1E3, 1E6,
1E9, 1E12 respectively.</para>
</listitem>
<listitem>
<para>The next section allows filtering the results by their mime
types, or mime categories (ie: media/text/message/etc.).</para>
<para>You can transfer the types between two boxes, to define
which will be included or excluded by the search.</para>
<para>The state of the file type selection can be saved as
the default (the file type filter will not be activated at
program start-up, but the lists will be in the restored
state).</para>
</listitem>
<listitem>
<para>The bottom section allows restricting the search results to a
sub-tree of the indexed area. You can use the
<guilabel>Invert</guilabel> checkbox to search for files not in
the sub-tree instead. If you use directory filtering often and on
big subsets of the file system, you may think of setting up
multiple indexes instead, as the performance may be
better.</para>
<para>You can use relative/partial paths for filtering. Ie,
entering <literal>dirA/dirB</literal> would match either
<filename>/dir1/dirA/dirB/myfile1</filename> or
<filename>/dir2/dirA/dirB/someother/myfile2</filename>.</para>
</listitem>
</itemizedlist>
</sect3>
</sect2>
<sect2 id="rcl.search.gui.termexplorer">
<title>The term explorer tool</title>
<para>&RCL; automatically manages the expansion of search terms
to their derivatives (ie: plural/singular, verb
inflections). But there are other cases where the exact search
term is not known. For example, you may not remember the exact
spelling, or only know the beginning of the name.</para>
<para>The term explorer tool (started from the toolbar icon or
from the <guilabel>Term explorer</guilabel> entry of the
<guilabel>Tools</guilabel> menu) can be used to search the full index
terms list. It has three modes of operations:</para>
<variablelist>
<varlistentry>
<term>Wildcard</term>
<listitem><para>In this mode of operation, you can enter a
search string with shell-like wildcards (*, ?, []). ie:
<replaceable>xapi*</replaceable> would display all index terms
beginning with <replaceable>xapi</replaceable>. (More
about wildcards <link
linkend="rcl.search.wildcards">here</link>).</para></listitem>
</varlistentry>
<varlistentry>
<term>Regular expression</term>
<listitem><para>This mode will accept a regular expression
as input. Example:
<replaceable>word[0-9]+</replaceable>. The expression is
implicitely anchored at the beginning. Ie:
<replaceable>press</replaceable> will match
<replaceable>pression</replaceable> but not
<replaceable>expression</replaceable>. You can use
<replaceable>.*press</replaceable> to match the latter,
but be aware that this will cause a full index term list
scan, which can be quite long.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Stem expansion</term>
<listitem><para>This mode will perform the usual stem expansion
normally done as part user input processing. As such it is
probably mostly useful to demonstrate the process.
</para></listitem>
</varlistentry>
<varlistentry>
<term>Spelling/Phonetic</term> <listitem><para>In this
mode, you enter the term as you think it is spelled, and
&RCL; will do its best to find index terms that sound like
your entry. This mode uses the
<application>Aspell</application> spelling application,
which must be installed on your system for things to work
(if your documents contain non-ascii characters, &RCL;
needs an aspell version newer than 0.60 for UTF-8
support). The language which is used to build the
dictionary out of the index terms (which is done at the
end of an indexing pass) is the one defined by your NLS
environment. Weird things will probably happen if
languages are mixed up.</para></listitem>
</varlistentry>
</variablelist>
<para>Note that in cases where &RCL; does not know the beginning
of the string to search for (ie a wildcard expression like
<replaceable>*coll</replaceable>), the expansion can take quite
a long time because the full index term list will have to be
processed. The expansion is currently limited at 200 results for
wildcards and regular expressions.</para>
<para>Double-clicking on a term in the result list will insert
it into the simple search entry field. You can also cut/paste
between the result list and any entry field (the end of lines
will be taken care of).</para>
</sect2>
<sect2 id="rcl.search.gui.multidb">
<title>Multiple databases</title>
<para>See the <link linkend="rcl.search.multidb">section
describing the use of multiple indexes</link> for
generalities. Only the aspects concerning
the <command>recoll</command> GUI are described here.</para>
<para>A <command>recoll</command> program instance is always
associated with a specific index, which is the one to be updated
when requested from the <guimenu>File</guimenu> menu, but it can
use any number of &RCL; indexes for searching. The external
indexes can be selected through the <guilabel>external
indexes</guilabel> tab in the preferences dialog.</para>
<para>Index selection is performed in two phases. A set of all
usable indexes must first be defined, and then the subset of
indexes to be used for searching. Of course, these parameters
are retained across program executions (there are kept
separately for each &RCL; configuration). The set of all indexes
is usually quite stable, while the active ones might typically
be adjusted quite frequently.</para>
<para>The main index (defined by
<envar>RECOLL_CONFDIR</envar>) is always active. If this is
undesirable, you can set up your base configuration to index
an empty directory.</para>
<para>As building the set of all indexes can be a little tedious
when done through the user interface, you can use the
<envar>RECOLL_EXTRA_DBS</envar> environment
variable to provide an initial set. This might typically be
set up by a system administrator so that every user does not
have to do it. The variable should define a colon-separated list
of index directories, ie:
</para>
<screen>export RECOLL_EXTRA_DBS=/some/place/xapiandb:/some/other/db</screen>
<para>Another environment variable,
<envar>RECOLL_ACTIVE_EXTRA_DBS</envar> allows adding to the active
list of indexes. This variable was suggested and implemented by a
&RCL; user. It is mostly useful if you use scripts to mount
external volumes with &RCL; indexes. By using
<envar>RECOLL_EXTRA_DBS</envar> and
<envar>RECOLL_ACTIVE_EXTRA_DBS</envar>, you can add and activate
the index for the mounted volume when starting
<command>recoll</command>.
</para>
<para><envar>RECOLL_ACTIVE_EXTRA_DBS</envar> is available for
&RCL; versions 1.17.2 and later. A change was made in the same
update so that <command>recoll</command> will
automatically deactivate unreachable indexes when starting
up.</para>
</sect2>
<sect2 id="rcl.search.gui.history">
<title>Document history</title>
<para>Documents that you actually view (with the internal preview
or an external tool) are entered into the document history,
which is remembered.</para>
<para>You can display the history list by using
the <guilabel>Tools/</guilabel><guilabel>Doc History</guilabel> menu
entry.</para>
<para>You can erase the document history by using the
<guilabel>Erase document history</guilabel> entry in the
<guimenu>File</guimenu> menu.</para>
</sect2>
<sect2 id="rcl.search.gui.sort">
<title>Sorting search results and collapsing duplicates</title>
<para>The documents in a result list are normally sorted in
order of relevance. It is possible to specify a different sort
order, either by using the vertical arrows in the GUI toolbox to
sort by date, or switching to the result table display and clicking
on any header. The sort order chosen inside the result table
remains active if you switch back to the result list, until you
click one of the vertical arrows, until both are unchecked (you are
back to sort by relevance).</para>
<para>Sort parameters are remembered between program
invocations, but result sorting is normally always inactive
when the program starts. It is possible to keep the sorting
activation state between program invocations by checking the
<guilabel>Remember sort activation state</guilabel> option in
the preferences.</para>
<para>It is also possible to hide duplicate entries inside
the result list (documents with the exact same contents as the
displayed one). The test of identity is based on an MD5 hash
of the document container, not only of the text contents (so
that ie, a text document with an image added will not be a
duplicate of the text only). Duplicates hiding is controlled
by an entry in the <guilabel>Query configuration</guilabel>
dialog, and is off by default.</para>
</sect2>
<sect2 id="rcl.search.gui.tips">
<title>Search tips, shortcuts</title>
<sect3 id="rcl.search.gui.tips.terms">
<title>Terms and search expansion</title>
<formalpara><title>Term completion</title>
<para>Typing <keycap>Esc</keycap> <keycap>Space</keycap> in
the simple search entry field while entering a word will
either complete the current word if its beginning matches a
unique term in the index, or open a window to propose a list
of completions.</para>
</formalpara>
<formalpara><title>Picking up new terms from result or preview
text</title>
<para>Double-clicking on a word in the result list or in a
preview window will copy it to the simple search entry field.</para>
</formalpara>
<formalpara><title>Wildcards</title>
<para>Wildcards can be used inside search terms in all forms
of searches. <link linkend="rcl.search.wildcards">
More about wildcards</link>.
</para>
</formalpara>
<formalpara><title>Automatic suffixes</title>
<para>Words like <literal>odt</literal> or <literal>ods</literal>
can be automatically turned into query language
<literal>ext:xxx</literal> clauses. This can be enabled in the
<guilabel>Search preferences</guilabel> panel in the GUI.
</para>
</formalpara>
<formalpara><title>Disabling stem expansion</title>
<para>Entering a capitalized word in any search field will prevent
stem expansion (no search for
<literal>gardening</literal> if you enter
<literal>Garden</literal> instead of
<literal>garden</literal>). This is the only case where
character case should make a difference for a &RCL;
search. You can also disable stem expansion or change the
stemming language in the preferences.</para>
</formalpara>
<formalpara><title>Finding related documents</title>
<para>Selecting the <guilabel>Find similar documents</guilabel> entry
in the result list paragraph right-click menu will select a
set of "interesting" terms from the current result, and insert
them into the simple search entry field. You can then possibly
edit the list and start a search to find documents which may
be apparented to the current result.</para>
</formalpara>
<formalpara><title>File names</title>
<para>File names are added as terms during indexing, and you can
specify them as ordinary terms in normal search fields (&RCL; used
to index all directories in the file path as terms. This has been
abandoned as it did not seem really useful). Alternatively, you
can use the specific file name search which will
<emphasis>only</emphasis> look for file names, and may be
faster than the generic search especially when using wildcards.</para>
</formalpara>
</sect3>
<sect3 id="rcl.search.gui.tips.phrases">
<title>Working with phrases and proximity</title>
<formalpara><title>Phrases and Proximity searches</title>
<para>A phrase can be looked for by enclosing it in double
quotes. Example: <literal>"user manual"</literal> will look
only for occurrences of <literal>user</literal> immediately
followed by <literal>manual</literal>. You can use the
<guilabel>This phrase</guilabel> field of the advanced
search dialog to the same effect. Phrases can be entered along
simple terms in all simple or advanced search entry fields
(except <guilabel>This exact phrase</guilabel>).</para>
</formalpara>
<formalpara><title>AutoPhrases</title>
<para>This option can be set in the preferences dialog. If it is
set, a phrase will be automatically built and added to simple
searches when looking for <literal>Any terms</literal>. This
will not change radically the results, but will give a relevance
boost to the results where the search terms appear as a
phrase. Ie: searching for <literal>virtual reality</literal>
will still find all documents where either
<literal>virtual</literal> or <literal>reality</literal> or
both appear, but those which contain <literal>virtual
reality</literal> should appear sooner in the list.</para>
</formalpara>
<para>Phrase searches can strongly slow down a query if most of the
terms in the phrase are common. This is why the
<varname>autophrase</varname> option is off by default for &RCL;
versions before 1.17. As of version 1.17,
<varname>autophrase</varname> is on by default, but very common
terms will be removed from the constructed phrase. The removal
threshold can be adjusted from the search preferences.</para>
<formalpara><title>Phrases and abbreviations</title> <para>As of
&RCL; version 1.17, dotted abbreviations like
<literal>I.B.M.</literal> are also automatically indexed as a word
without the dots: <literal>IBM</literal>. Searching for the word
inside a phrase (ie: <literal>"the IBM company"</literal>) will only
match the dotted abrreviation if you increase the phrase slack (using the
advanced search panel control, or the <literal>o</literal> query
language modifier). Literal occurences of the word will be matched
normally.</para></formalpara>
</sect3>
<sect3 id="rcl.search.gui.tips.misc">
<title>Others</title>
<formalpara><title>Using fields</title>
<para>You can use the <link linkend="rcl.search.lang">query
language </link> and field specifications
to only search certain parts of documents. This can be
especially helpful with email, for example only searching
emails from a specific originator:
<literal>search tips from:helpfulgui</literal>
</para>
</formalpara>
<formalpara><title>Ajusting the result table columns</title>
<para>When displaying results in table mode, you can use a
right click on the table headers to activate a pop-up menu
which will let you adjust what columns are displayed. You can
drag the column headers to adjust their order. You can click
them to sort by the field displayed in the column. You can
also save the result list in CSV format.</para>
</formalpara>
<formalpara><title>Query explanation</title>
<para>You can get an exact description of what the query
looked for, including stem expansion, and Boolean operators
used, by clicking on the result list header.</para>
</formalpara>
<formalpara><title>Browsing the result list inside a preview
window</title>
<para>Entering <keycap>Shift-Down</keycap> or <keycap>Shift-Up</keycap>
(<keycap>Shift</keycap> + an arrow key) in a preview window will
display the next or the previous document from the result
list. Any secondary search currently active will be executed on
the new document.</para>
</formalpara>
<formalpara><title>Scrolling the result list from the keyboard</title>
<para>You can use <keycap>PageUp</keycap> and <keycap>PageDown</keycap>
to scroll the result list, <keycap>Shift+Home</keycap> to go back
to the first page. These work even while the focus is in the
search entry.</para>
</formalpara>
<formalpara><title>Forced opening of a preview window</title>
<para>You can use <keycap>Shift</keycap>+Click on a result list
<literal>Preview</literal> link to force the creation of a
preview window instead of a new tab in the existing one.</para>
</formalpara>
<formalpara><title>Closing previews</title>
<para>Entering <keycap>Ctrl-W</keycap> in a tab will
close it (and, for the last tab, close the preview
window). Entering <keycap>Esc</keycap> will close the preview
window and all its tabs.</para>
</formalpara>
<formalpara><title>Printing previews</title>
<para>Entering <keycap>Ctrl-P</keycap> in a preview window will print
the currently displayed text.</para>
</formalpara>
<formalpara><title>Quitting</title>
<para>Entering <keycap>Ctrl-Q</keycap> almost anywhere will
close the application.</para>
</formalpara>
</sect3>
</sect2>
<sect2 id="rcl.search.gui.custom">
<title>Customizing the search interface</title>
<para>You can customize some aspects of the search interface by using
the <guimenu>Query configuration</guimenu> entry in the
<guimenu>Preferences</guimenu> menu.</para>
<para>There are several tabs in the dialog, dealing with the
interface itself, the parameters used for searching and
returning results, and what indexes are searched.</para>
<formalpara id="rcl.search.gui.custom.ui">
<title>User interface parameters:</title>
<para>
<itemizedlist>
<listitem><para><guilabel>Highlight color for query
terms</guilabel>: Terms from the user query are highlighted in
the result list samples and the preview window. The color can
be chosen here. Any Qt color string should work (ie
<literal>red</literal>, <literal>#ff0000</literal>). The
default is <literal>blue</literal>.</para>
</listitem>
<listitem><para><guilabel>Style sheet</guilabel>:
The name of a <application>Qt</application> style sheet
text file which is applied to the whole Recoll application
on startup. The default value is empty, but there is a
skeleton style sheet (<filename>recoll.qss</filename>)
inside the <filename>/usr/share/recoll/examples</filename>
directory. Using a style sheet, you can change most
<command>recoll</command> graphical parameters: colors,
fonts, etc. See the sample file for a few simple
examples.</para>
</listitem>
<listitem><para><guilabel>Maximum text size highlighted for
preview</guilabel> Inserting highlights on search term inside
the text before inserting it in the preview window involves
quite a lot of processing, and can be disabled over the given
text size to speed up loading.</para>
</listitem>
<listitem><para><guilabel>Prefer HTML to plain text for
preview</guilabel> if set, Recoll will display HTML as such
inside the preview window. If this causes problems with the Qt
HTML display, you can uncheck it to display the plain text
version instead. </para>
</listitem>
<listitem><para><guilabel>Use <PRE> tags instead of
<BR> to display plain text as HTML in preview</guilabel>:
when displaying plain text inside the preview window, &RCL;
tries to preserve some of the original text line breaks and
indentation. It can either use PRE HTML tags, which will
well preserve the indentation but will force horizontal
scrolling for long lines, or use BR tags to break at the
original line breaks, which will let the editor introduce
other line breaks according to the window width, but will
lose some of the original indentation.</para>
</listitem>
<listitem><para><guilabel>Use desktop preferences to choose
document editor</guilabel>: if this is checked, the
<command>xdg-open</command> utility will be used to open files
when you click the <guilabel>Open</guilabel> link in the result
list, instead of the application defined in
<filename>mimeview</filename>. <command>xdg-open</command> will
in term use your desktop preferences to choose an appropriate
application.</para>
</listitem>
<listitem><para><guilabel>Choose editor applications</guilabel>
this will let you choose the command started by the
<guilabel>Open</guilabel> links inside the result list, for
specific document types.</para>
</listitem>
<listitem><para><guilabel>Display category filter as
toolbar...</guilabel> this will let you choose if the document
categories are displayed as a list or a set of buttons.</para>
</listitem>
<listitem><para><guilabel>Auto-start simple search on white
space entry</guilabel>: if this is checked, a search will be
executed each time you enter a space in the simple search input
field. This lets you look at the result list as you enter new
terms. This is off by default, you may like it or not...</para>
</listitem>
<listitem><para><guilabel>Start with advanced search dialog open
</guilabel> and <guilabel>Start with sort dialog
open</guilabel>: If you use these dialogs all the time, checking
these entries will get them to open when recoll starts.</para>
</listitem>
<listitem><para><guilabel>Remember sort activation
state</guilabel> if set, Recoll will remember the sort tool
stat between invocations. It normally starts with sorting
disabled.</para>
</listitem>
</itemizedlist>
</para>
</formalpara>
<formalpara id="rcl.search.gui.custom.rl">
<title>Result list parameters:</title>
<para>
<itemizedlist>
<listitem><para><guilabel>Number of results in a result
page</guilabel></para>
</listitem>
<listitem><para><guilabel>Result list font</guilabel>: There is
quite a lot of information shown in the result list, and you
may want to customize the font and/or font size. The rest of
the fonts used by &RCL; are determined by your generic Qt
config (try the <command>qtconfig</command> command).</para>
</listitem>
<listitem id="rcl.search.gui.custom.resultpara">
<para><guilabel>Edit result list paragraph format string</guilabel>:
allows you to change the presentation of each result list
entry. See the <link linkend="rcl.search.gui.custom.reslist">
result list customisation section</link>.</para>
</listitem>
<listitem id="rcl.search.gui.custom.resulthead">
<para><guilabel>Edit result page html header insert</guilabel>:
allows you to define text inserted at the end of the result
page html header.
More detail in the <link linkend="rcl.search.gui.custom.reslist">
result list customisation section.</link></para>
</listitem>
<listitem>
<para><guilabel>Date format</guilabel>: allows specifying the
format used for displaying dates inside the result list. This
should be specified as an strftime() string (man strftime).</para>
</listitem>
<listitem id="rcl.search.gui.custom.abssep">
<para><guilabel>Abstract snippet separator</guilabel>:
for synthetic abstracts built from index data, which are
usually made of several snippets from different parts of the
document, this defines the snippet separator, an ellipsis by
default. </para>
</listitem>
</itemizedlist></para>
</formalpara>
<formalpara id="rcl.search.gui.custom.search">
<title>Search parameters:</title>
<para>
<itemizedlist>
<listitem><para><guilabel>Hide duplicate results</guilabel>:
decides if result list entries are shown for identical
documents found in different places.</para>
</listitem>
<listitem><para><guilabel>Stemming language</guilabel>:
stemming obviously depends on the document's language. This
listbox will let you chose among the stemming databases which
were built during indexing (this is set in the <link
linkend="rcl.install.config.recollconf">main configuration
file</link>), or later added with <command>recollindex
-s</command> (See the recollindex manual). Stemming languages
which are dynamically added will be deleted at the next
indexing pass unless they are also added in the configuration
file.</para>
</listitem>
<listitem><para><guilabel>Automatically add phrase to simple
searches</guilabel>: a phrase will be automatically built and
added to simple searches when looking for <literal>Any
terms</literal>. This will give a relevance boost to the
results where the search terms appear as a phrase (consecutive
and in order).</para>
</listitem>
<listitem><para><guilabel>Autophrase term frequency threshold
percentage</guilabel>: very frequent terms should not be included
in automatic phrase searches for performance reasons. The
parameter defines the cutoff percentage (percentage of the
documents where the term appears).</para>
</listitem>
<listitem><para><guilabel>Replace abstracts from
documents</guilabel>: this decides if we should synthesize and
display an abstract in place of an explicit abstract found
within the document itself.</para>
</listitem>
<listitem><para><guilabel>Dynamically build
abstracts</guilabel>: this decides if &RCL; tries to build
document abstracts 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.</para>
</listitem>
<listitem><para><guilabel>Synthetic abstract size</guilabel>:
adjust to taste...</para>
</listitem>
<listitem><para><guilabel>Synthetic abstract context
words</guilabel>: how many words should be displayed around
each term occurrence.</para>
</listitem>
<listitem><para><guilabel>Query language magic file name
suffixes</guilabel>: a list of words which automatically get
turned into <literal>ext:xxx</literal> file name suffix clauses
when starting a query language query (ie: <literal>doc xls
xlsx...</literal>). This will save some typing for people who
use file types a lot when querying.</para>
</listitem>
</itemizedlist>
</para>
</formalpara>
<formalpara id="rcl.search.gui.custom.extradb">
<title>External indexes:</title>
<para>This panel will let you browse for additional indexes
that you may want to search. External indexes are designated by
their database directory (ie:
<filename>/home/someothergui/.recoll/xapiandb</filename>,
<filename>/usr/local/recollglobal/xapiandb</filename>).</para>
</formalpara>
<para>Once entered, the indexes will appear in the
<guilabel>External indexes</guilabel> list, and you can
chose which ones you want to use at any moment by checking or
unchecking their entries.</para>
<para>Your main database (the one the current configuration
indexes to), is always implicitly active. If this is not
desirable, you can set up your configuration so that it indexes,
for example, an empty directory. An alternative indexer may also
need to implement a way of purging the index from stale data,
</para>
<sect3 id="rcl.search.gui.custom.reslist">
<title>The result list format</title>
<para>The result list presentation can be exhaustively customized
by adjusting two elements:</para>
<itemizedlist>
<listitem><para>The paragraph format</para></listitem>
<listitem><para>Html code inside the header
section</para></listitem>
</itemizedlist>
<para>These can be edited from the <guilabel>Result list</guilabel>
tab of the <guilabel>Query configuration</guilabel>.</para>
<para>Newer versions of Recoll (from 1.17) use a WebKit HTML
object by default (this may be disabled at build time), and
total customisation is possible with full support for CSS and
Javascript. Conversely, there are limits to what you can do with
the older Qt QTextBrowser, but still, it is possible to decide
what data each result will contain, and how it will be
displayed.</para>
<para>No more detail will be given about the header part (only
useful with the WebKit build), if there are restrictions to
what you can do, they are beyond this author's HTML/CSS/Javascript
abilities... There are a few examples on the
<ulink url="http://www.recoll.org/custom.html">page about
customising the result list</ulink> on the &RCL; web site.</para>
<sect4 id="rcl.search.gui.custom.reslist.para">
<title>The paragraph format</title>
<para>This is an arbitrary HTML string where the following printf-like
<literal>%</literal> substitutions will be performed:
<itemizedlist>
<listitem>
<formalpara><title>%A</title><para>Abstract</para></formalpara>
</listitem>
<listitem><formalpara><title>%D</title><para>Date</para></formalpara>
</listitem>
<listitem><formalpara><title>%I</title><para>Icon image
name. This is normally determined from the mime type. The
associations are defined inside the
<link linkend="rcl.install.config.mimeconf">
<filename>mimeconf</filename> configuration file</link>.
If a thumbnail for the file is found at
the standard Freedesktop location, this will be displayed
instead.</para></formalpara>
</listitem>
<listitem><formalpara><title>%K</title><para>Keywords (if
any)</para></formalpara>
</listitem>
<listitem><formalpara><title>%L</title><para>Precooked Preview and
Edit links</para></formalpara>
</listitem>
<listitem><formalpara><title>%M</title><para>Mime
type</para></formalpara>
</listitem>
<listitem><formalpara><title>%N</title><para>result Number inside
the result page</para></formalpara>
</listitem>
<listitem><formalpara><title>%R</title><para>Relevance
percentage</para></formalpara>
</listitem>
<listitem><formalpara><title>%S</title><para>Size
information</para></formalpara>
</listitem>
<listitem><formalpara><title>%T</title><para>Title or Filename if
not set.</para></formalpara>
</listitem>
<listitem><formalpara><title>%t</title><para>Title or Filename if
not set.</para></formalpara>
</listitem>
<listitem><formalpara><title>%U</title><para>Url</para></formalpara>
</listitem>
</itemizedlist>
The format of the Preview and Edit links is
<literal><a href="P%N"></literal>
and
<literal><a href="E%N"></literal>
where <replaceable>docnum</replaceable> (%N) expands to the document
number inside the result page).</para>
<para>In addition to the predefined values above, all strings like
<literal>%(fieldname)</literal> will be replaced by the value of
the field named <literal>fieldname</literal> for this
document. Only stored fields can be accessed in this way, the value
of indexed but not stored fields is not known at this point in the
search process (see <link linkend="rcl.program.fields">field
configuration</link>). There are currently very few fields stored
by default, apart from the values above (only
<literal>author</literal> and <literal>filename</literal>), so this
feature will need some custom local configuration to be useful. 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 <literal>recipient</literal> field which is generated
by the message filters.</para>
<para>The default value for the paragraph format string is:
<screen><![CDATA[
<img src="%I" align="left">%R %S %L <b>%T</b><br>
%M %D <i>%U</i> %i<br>
%A %K
]]></screen>
You may, for example, try the following for a more web-like
experience:
<screen><![CDATA[
<u><b><a href="P%N">%T</a></b></u><br>
%A<font color=#008000>%U - %S</font> - %L
]]></screen>
Note that the P%N link in the above paragraph makes the title a
preview link. Or the clean looking:
<screen><![CDATA[
<img src="%I" align="left">%L <font color="#900000">%R</font>
<b>%T&</b><br>%S
<font color="#808080"><i>%U</i></font>
<table bgcolor="#e0e0e0">
<tr><td><div>%A</div></td></tr>
</table>%K
]]></screen>
</para>
<para>These samples, and some others are
<ulink url="http://www.recoll.org/custom.html">on the web
site, with pictures to show how they look.</ulink></para>
<para>It is also possible to
<link linkend="rcl.search.gui.custom.abssep">
define the value of the snippet separator inside the abstract
section</link>.</para>
</sect4>
</sect3>
</sect2>
</sect1> <!-- search GUI -->
<sect1 id="rcl.search.kio">
<title>Searching with the KDE KIO slave</title>
<sect2 id="rcl.search.kio.intro">
<title>What's this</title>
<para>The &RCL; KIO slave allows performing a &RCL; search
by entering an appropriate URL in a KDE open dialog, or with an
HTML-based interface displayed in
<command>Konqueror</command>.</para>
<para>The HTML-based interface is similar to the Qt-based
interface, but slightly less powerful for now. Its advantage is
that you can perform your search while staying fully within the
KDE framework: drag and drop from the result list works normally
and you have your normal choice of applications for opening
files.</para>
<para>The alternative interface uses a directory view of search
results. Due to limitations in the current KIO slave interface,
it is currently not obviously useful (to me).</para>
<para>The interface is described in more detail inside a help
file which you can access by entering
<filename>recoll:/</filename> inside the
<command>konqueror</command> URL line (this works only if the
recoll KIO slave has been previously installed).</para>
<para>The instructions for building this module are located in the
source tree. See:
<filename>kde/kio/recoll/00README.txt</filename>. Some Linux
distributions do package the kio-recoll module, so check before
diving into the build process, maybe it's already out there ready for
one-click installation.</para>
</sect2>
<sect2 id="rcl.search.kio.searchabledocs">
<title>Searchable documents</title>
<para>As a sample application, the &RCL; KIO slave could allow
preparing a set of HTML documents (for example a manual) so that
they become their own search interface inside
<command>konqueror</command>.</para>
<para>This can be done by either explicitly inserting
<literal><a href="recoll:/..."></literal> links
around some document areas, or automatically by adding a
very small <application>javascript</application> program to the
documents, like the following example, which would initiate a search by
double-clicking any term:</para>
<programlisting><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()">
</programlisting>
</sect2>
</sect1>
<sect1 id="rcl.search.commandline">
<title>Searching on the command line</title>
<para>There are several ways to obtain search results as a text
stream, without a graphical interface:</para>
<itemizedlist>
<listitem><para>By passing option <option>-t</option> to the
<command>recoll</command> program.</para>
</listitem>
<listitem><para>By using the <command>recollq</command> program.</para>
</listitem>
<listitem><para>By writing a custom
<application>Python</application> program, using the
<link linkend="rcl.program.api.python">Recoll Python API</link>.</para>
</listitem>
</itemizedlist>
<para>The first two methods work in the same way and accept/need the same
arguments (except for the additional <option>-t</option> to
<command>recoll</command>). The query to be executed is specified
as command line arguments.</para>
<para><command>recollq</command> is not built by default. You can
use the <filename>Makefile</filename> in the
<filename>query</filename> directory to build it. This is a very
simple program, and if you can program a little c++, you may find it
useful to taylor its output format to your needs.</para>
<para><command>recollq</command> has a man page (not installed by
default, look in the <filename>doc/man</filename> directory). The
Usage string is as follows:</para>
<programlisting>
recollq: usage:
-P: Show the date span for all the documents present in the index
[-o|-a|-f] [-q] <query string>
Runs a recoll query and displays result lines.
Default: will interpret the argument(s) as a xesam query string
query may be like:
implicit AND, Exclusion, field spec: t1 -t2 title:t3
OR has priority: t1 OR t2 t3 OR t4 means (t1 OR t2) AND (t3 OR t4)
Phrase: "t1 t2" (needs additional quoting on cmd line)
-o Emulate the GUI simple search in ANY TERM mode
-a Emulate the GUI simple search in ALL TERMS mode
-f Emulate the GUI simple search in filename mode
-q is just ignored (compatibility with the recoll GUI command line)
Common options:
-c <configdir> : specify config directory, overriding $RECOLL_CONFDIR
-d also dump file contents
-n [first-]<cnt> define the result slice. The default value for [first]
is 0. Without the option, the default max count is 2000.
Use n=0 for no limit
-b : basic. Just output urls, no mime types or titles
-Q : no result lines, just the processed query and result count
-m : dump the whole document meta[] array for each result
-A : output the document abstracts
-S fld : sort by field <fld>
-D : sort descending
-i <dbdir> : additional index, several can be given
-e use url encoding (%xx) for urls
-F <field name list> : output exactly these fields for each result.
The field values are encoded in base64, output in one line and
separated by one space character. This is the recommended format
for use by other programs. Use a normal query with option -m to
see the field names.
</programlisting>
<para>Sample execution:</para>
<programlisting>recollq 'ilur -nautique mime:text/html'
Recoll query: ((((ilur:(wqf=11) OR ilurs) AND_NOT (nautique:(wqf=11)
OR nautiques OR nautiqu OR nautiquement)) FILTER Ttext/html))
4 results
text/html [file:///Users/uncrypted-dockes/projets/bateaux/ilur/comptes.html] [comptes.html] 18593 bytes
text/html [file:///Users/uncrypted-dockes/projets/nautique/webnautique/articles/ilur1/index.html] [Constructio...
text/html [file:///Users/uncrypted-dockes/projets/pagepers/index.html] [psxtcl/writemime/recoll]...
text/html [file:///Users/uncrypted-dockes/projets/bateaux/ilur/factEtCie/recu-chasse-maree....
</programlisting>
</sect1>
<sect1 id="rcl.search.lang">
<title>The query language</title>
<para>The query language processor is activated in the GUI
simple search entry when the search mode selector is set to
<guilabel>Query Language</guilabel>. It can also be used with the KIO
slave or the command line search. It broadly has the same
capabilities as the complex search interface in the
GUI.</para>
<para>The language is roughly based on the (seemingly defunct)
<ulink url="http://www.xesam.org/main/XesamUserSearchLanguage95">
Xesam</ulink> user search language specification.</para>
<para>If the results of a query language search puzzle you and you
doubt what has been actually searched for, you can use the GUI
<literal>Show Query</literal> link at the top of the result list to
check the exact query which was finally executed by Xapian.</para>
<para>Here follows a sample request that we are going to
explain:</para>
<programlisting>
author:"john doe" Beatles OR Lennon Live OR Unplugged -potatoes
</programlisting>
<para>This would search for all documents with
<replaceable>John Doe</replaceable>
appearing as a phrase in the author field (exactly what this is
would depend on the document type, ie: the
<literal>From:</literal> header, for an email message),
and containing either <replaceable>beatles</replaceable> or
<replaceable>lennon</replaceable> and either
<replaceable>live</replaceable> or
<replaceable>unplugged</replaceable> but not
<replaceable>potatoes</replaceable> (in any part of the document).</para>
<para>An element is composed of an optional field specification,
and a value, separated by a colon. Example:
<replaceable>Beatles</replaceable>,
<replaceable>author:balzac</replaceable>,
<replaceable>dc:title:grandet</replaceable> </para>
<para>The colon, if present, means "contains". Xesam defines other
relations, which are not supported for now.</para>
<para>All elements in the search entry are normally combined
with an implicit AND. It is possible to specify that elements be
OR'ed instead, as in <replaceable>Beatles</replaceable>
<literal>OR</literal> <replaceable>Lennon</replaceable>. The
<literal>OR</literal> must be entered literally (capitals), and
it has priority over the AND associations:
<replaceable>word1</replaceable>
<replaceable>word2</replaceable> <literal>OR</literal>
<replaceable>word3</replaceable>
means
<replaceable>word1</replaceable> AND
(<replaceable>word2</replaceable> <literal>OR</literal>
<replaceable>word3</replaceable>)
not
(<replaceable>word1</replaceable> AND
<replaceable>word2</replaceable>) <literal>OR</literal>
<replaceable>word3</replaceable>. Do not enter explicit
parenthesis, they are not supported for now.</para>
<para>An element preceded by a <literal>-</literal> specifies a
term that should <emphasis>not</emphasis> appear. Pure negative
queries are forbidden.</para>
<para>As usual, words inside quotes define a phrase
(the order of words is significant), so that
<replaceable>title:"prejudice pride"</replaceable> is not the same as
<replaceable>title:prejudice title:pride</replaceable>, and is
unlikely to find a result.</para>
<para>Modifiers can be set on a phrase clause, for example to specify
a proximity search (unordered). See
<link linkend="rcl.search.lang.modifiers">the modifier
section</link>.</para>
<para>&RCL; currently manages the following default fields:</para>
<itemizedlist>
<listitem><para><literal>title</literal>,
<literal>subject</literal> or <literal>caption</literal> are
synonyms which specify data to be searched for in the
document title or subject.</para>
</listitem>
<listitem><para><literal>author</literal> or
<literal>from</literal> for searching the documents originators.</para>
</listitem>
<listitem><para><literal>recipient</literal> or
<literal>to</literal> for searching the documents recipients.</para>
</listitem>
<listitem><para><literal>keyword</literal> for searching the
document-specified keywords (few documents actually have any).</para>
</listitem>
<listitem><para><literal>filename</literal> for the document's
file name.</para></listitem>
<listitem><para><literal>ext</literal> specifies the file
name extension (Ex: <literal>ext:html</literal>)</para>
</listitem>
</itemizedlist>
<para>The field syntax also supports a few field-like, but
special, criteria:</para>
<itemizedlist>
<listitem><para><literal>dir</literal> for filtering the
results on file location (Ex:
<literal>dir:/home/me/somedir</literal>). <literal>-dir</literal>
also works to find results out of the specified directory, only
after release 1.15.8. A tilde inside the value will be expanded to
the home directory. <literal>dir</literal> is not a regular field
and only one value makes sense in a query (you can't use
<literal>dir:dir1 OR dir:dir2</literal>). Relative paths make
sense, for example,
<literal>dir:share/doc</literal> would match either
<filename>/usr/share/doc</filename> or
<filename>/usr/local/share/doc</filename> </para>
</listitem>
<listitem><para><literal>size</literal> for filtering the
results on file size. Example:
<literal>size<10000</literal>. You can use
<literal><</literal>, <literal>></literal> or
<literal>=</literal> as operators. You can specify a range like the
following: <literal>size>100 size<1000</literal>. The usual
<literal>k/K, m/M, g/G, t/T</literal> can be used as (decimal)
multipliers. Ex: <literal>size>1k</literal> to search for files
bigger than 1000 bytes.</para>
</listitem>
<listitem><para><literal>date</literal> for searching or filtering
on dates. The syntax for the argument is based on the ISO8601
standard for dates and time intervals. Only dates are supported, no
times. The general syntax is 2 elements separated by a
<literal>/</literal> character. Each element can be a date or a
period of time. Periods are specified as
<literal>P</literal><replaceable>n</replaceable><literal>Y</literal><replaceable>n</replaceable><literal>M</literal><replaceable>n</replaceable><literal>D</literal>.
The <replaceable>n</replaceable> numbers are the respective numbers
of years, months or days, any of which may be missing. Dates are
specified as
<replaceable>YYYY</replaceable>-<replaceable>MM</replaceable>-<replaceable>DD</replaceable>.
The days and months parts may be missing. If the
<literal>/</literal> is present but an element is missing, the
missing element is interpreted as the lowest or highest date in the
index. Examples:</para>
<itemizedlist>
<listitem><para><literal>2001-03-01/2002-05-01</literal> the
basic syntax for an interval of dates.</para>
</listitem>
<listitem><para><literal>2001-03-01/P1Y2M</literal> the
same specified with a period.</para>
</listitem>
<listitem><para><literal>2001/</literal> from the beginning of
2001 to the latest date in the index.</para>
</listitem>
<listitem><para><literal>2001</literal> the whole year of
2001</para></listitem>
<listitem><para><literal>P2D/</literal> means 2 days ago up to
now if there are no documents with dates in the future.</para>
</listitem>
<listitem><para><literal>/2003</literal> all documents from
2003 or older.</para>
</listitem>
</itemizedlist>
<para>Periods can also be specified with small letters (ie:
p2y).</para>
</listitem>
<listitem><para><literal>mime</literal> or
<literal>format</literal> for specifying the
mime type. 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: <literal>mime:text/plain
mime:text/html</literal>. Specifying an explicit boolean
operator before a
<literal>mime</literal> specification is not supported and
will produce strange results. You can filter out certain types
by using negation (<literal>-mime:some/type</literal>), and you can
use wildcards in the value (<literal>mime:text/*</literal>).
Note that <literal>mime</literal> is
the ONLY field with an OR default. You do need to use
<literal>OR</literal> with <literal>ext</literal> terms for
example.</para>
</listitem>
<listitem><para><literal>type</literal> or
<literal>rclcat</literal> for specifying the category (as in
text/media/presentation/etc.). The classification of mime
types in categories is defined in the &RCL; configuration
(<filename>mimeconf</filename>), and can be modified or
extended. The default category names are those which permit
filtering results in the main GUI screen. Categories are OR'ed
like mime types above. This can't be negated with
<literal>-</literal> either.</para>
</listitem>
</itemizedlist>
<para>Words inside phrases and capitalized words are not
stem-expanded. Wildcards may be used anywhere inside a term.
Specifying a wild-card on the left of a term can produce a very
slow search (or even an incorrect one if the expansion is
truncated because of excessive size). Also see <link
linkend="rcl.search.wildcards">More about wildcards</link>.</para>
<para>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.</para>
<sect2 id="rcl.search.lang.modifiers">
<title>Modifiers</title>
<para>Some characters are recognized as search modifiers when found
immediately after the closing double quote of a phrase, as in
<literal>"some term"modifierchars</literal>. The actual "phrase"
can be a single term of course. Supported modifiers:
<itemizedlist>
<listitem><para><literal>l</literal> can be used to turn off
stemming (mostly makes sense with <literal>p</literal> because
stemming is off by default for phrases).</para>
</listitem>
<listitem><para><literal>o</literal> can be used to specify a
"slack" for phrase and proximity searches: the number of
additional terms that may be found between the specified
ones. If <literal>o</literal> is followed by an integer number,
this is the slack, else the default is 10.</para>
</listitem>
<listitem><para><literal>p</literal> can be used to turn the
default phrase search into a proximity one
(unordered). Example:<literal>"order any in"p</literal></para>
</listitem>
<listitem><para>A weight can be specified for a query element
by specifying a decimal value at the start of the
modifiers. Example: <literal>"Important"2.5</literal>.</para>
</listitem>
</itemizedlist>
</para>
</sect2> <!-- search modifiers -->
</sect1> <!-- rcl.search.lang -->
<sect1 id="rcl.search.anchorwild">
<title>Anchored searches and wildcards</title>
<para>Some special characters are interpreted by &RCL; in search
strings to expand or specialize the search. Wildcards expand a root
term in controlled ways. Anchor characters can restrict a search to
succeed only if the match is found at or near the beginning of the
document or one of its fields.</para>
<sect2 id="rcl.search.wildcards">
<title>More about wildcards</title>
<para>All words entered in &RCL; search fields will be processed
for wildcard expansion before the request is finally
executed.</para>
<para>The wildcard characters are:</para>
<itemizedlist>
<listitem><para><literal>*</literal> which matches 0 or more
characters.</para>
</listitem>
<listitem><para><literal>?</literal> which matches
a single character.</para>
</listitem>
<listitem><para><literal>[]</literal> which allow
defining sets of characters to be matched (ex:
<literal>[</literal><userinput>abc</userinput><literal>]</literal>
matches a single character which may be 'a' or 'b' or 'c',
<literal>[</literal><userinput>0-9</userinput><literal>]</literal>
matches any number.</para>
</listitem>
</itemizedlist>
<para>You should be aware of a few things before using
wildcards.</para>
<itemizedlist>
<listitem><para>Using a wildcard character at the beginning of
a word can make for a slow search because &RCL; will have to
scan the whole index term list to find the matches.</para>
</listitem>
<listitem><para>Using a <literal>*</literal> at the end of a
word can produce more matches than you would think, and
strange search results. You can use the <link
linkend="rcl.search.gui.termexplorer">term explorer</link> tool to
check what completions exist for a given term. You can also
see exactly what search was performed by clicking on the link
at the top of the result list. In general, for natural
language terms, stem expansion will produce better results
than an ending <literal>*</literal> (stem expansion is turned
off when any wildcard character appears in the term).</para>
</listitem>
</itemizedlist>
</sect2> <!-- wildchars -->
<sect2 id="rcl.search.anchor">
<title>Anchored searches</title>
<para>Two characters are used to specify that a search hit should
occur at the beginning or at the end of the
text. <literal>^</literal> at the beginning of a term or phrase
constrains the search to happen at the start, <literal>$</literal>
at the end force it to happen at the end.</para>
<para>As this function is implemented as a phrase search it is
possible to specify a maximum distance at which the hit should
occur, either through the controls of the advanced search panel, or
using the query language, for example, as in:
<programlisting>"^someterm"o10</programlisting> which would force
<literal>someterm</literal> to be found within 10 terms of the
start of the text. This can be combined with a field search as in
<literal>somefield:"^someterm"o10</literal> or
<literal>somefield:someterm$</literal>.</para>
<para>This feature can also be used with an actual phrase search,
but in this case, the distance applies to the whole phrase and
anchor, so that, for example, <literal>bla bla my unexpected
term</literal> at the beginning of the text would be a match for
<literal>"^my term"o5</literal>.</para>
</sect2>
</sect1> <!-- wildchars and anchors -->
<sect1 id="rcl.search.desktop">
<title>Desktop integration</title>
<para>Being independant of the desktop type has its drawbacks: &RCL;
desktop integration is minimal. Here follow a few things that may
help.</para>
<sect2 id="rcl.search.shortcut">
<title>Hotkeying recoll</title>
<para>It is surprisingly convenient to be able to show or hide the
&RCL; GUI with a single keystroke. Recoll comes with a small
Python script, based on the <application>libwnck</application> window
manager interface library, which will allow you to do just
this. The detailed instructions are on
<ulink url="http://bitbucket.org/medoc/recoll/wiki/HotRecoll">
this wiki page</ulink>.</para>
</sect2>
<sect2 id="rcl.kicker-applet">
<title>The KDE Kicker Recoll applet</title>
<para>The &RCL; source tree contains the source code to the
<application>recoll_applet</application>, a small application derived
from the <application>find_applet</application>. This can be used to
add a small &RCL; launcher to the KDE panel.</para>
<para>The applet is not automatically built with the main &RCL;
programs, nor is it included with the main source distribution
(because the KDE build boilerplate makes it relatively big). You can
download its source from the recoll.org download page. Use the
omnipotent <userinput>configure;make;make install</userinput>
incantation to build and install.</para>
<para>You can then add the applet to the panel by right-clicking the
panel and choosing the <guilabel>Add applet</guilabel> entry.</para>
<para>The <application>recoll_applet</application> has a small text
window where you can type a &RCL; query (in query language form),
and an icon which can be used to restrict the search to certain
types of files. It is quite primitive, and launches a new recoll
GUI instance every time (even if it is already running). You may
find it useful anyway.</para>
</sect2>
</sect1> <!-- rcl.search.desktop -->
<sect1 id="rcl.search.multidb">
<title>Multiple databases</title>
<para>Multiple &RCL; 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
<envar>RECOLL_CONFDIR</envar> environment variable or the
<option>-c</option> option to <command>recoll</command> and
<command>recollindex</command>.</para>
<para>A typical usage scenario for the multiple index feature
would be for a system administrator to set up a central index
for shared data, that you choose to search or not in addition to
your personal data. Of course, there are other
possibilities. There are many cases where you know the subset of
files that should be searched, and where narrowing the search
can improve the results. You can achieve approximately the same
effect with the directory filter in advanced search, but
multiple indexes will have much better performance and may be
worth the trouble.</para>
<para>A <command>recollindex</command> program instance can only
update one specific index.</para>
<para>The main index (defined by
<envar>RECOLL_CONFDIR</envar> or <option>-c</option>) is
always active. If this is undesirable, you can set up your
base configuration to index an empty directory.</para>
<para>The different search interfaces (GUI, command line, ...)
have different methods to define the set of indexes to be
used, see the appropriate section.</para>
<para>If a set of multiple indexes are to be used together for
searches, some configuration parameters must be consistent
among the set. These are parameters which need to be the same
when indexing and searching. As the parameters come from the
main configuration when searching, they need to be compatible
with what was set when creating the other indexes (which came
from their respective configuration directories. Most of the
relevant parameters are described in the following
<link linkend="rcl.install.config.recollconf.terms">linked
section</link>.</para>
</sect1> <!-- multiple databases -->
</chapter> <!-- Search -->
<chapter id="rcl.program">
<title>Programming interface</title>
<para>&RCL; has an Application programming Interface, usable both
for indexing and searching, currently accessible from the
<application>Python</application> language.</para>
<para>Another less radical way to extend the application is to
write filters for new types of documents.</para>
<para>The processing of metadata attributes for documents
(<literal>fields</literal>) is highly configurable.</para>
<sect1 id="rcl.program.filters">
<title>Writing a document filter</title>
<para>&RCL; filters are executable programs which
translate from a specific format (ie:
<application>openoffice</application>,
<application>acrobat</application>, etc.) to the &RCL;
indexing input format, which may be
<literal>text/plain</literal> or
<literal>text/html</literal>.</para>
<para>As of &RCL; 1.13, there are two kinds of filters:
<itemizedlist>
<listitem><para>Simple filters (the old ones) run once and
exit. They can be bare programs like
<application>antiword</application>, or shell-scripts using other
programs. They are very simple to write, just having to write the
text to the standard output.</para>
</listitem>
<listitem><para>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
<application>Python</application>, using a common module to
handle the protocol.</para>
</listitem>
</itemizedlist>
The following will just describe the simple filters. If you can
program and want to write one of the other kind, it shouldn't be too
difficult to make sense of one of the existing modules. For example,
look at <command>rclzip</command> which uses Zip file paths as
internal identifiers (<literal>ipath</literal>), and
<command>rclinfo</command>, which uses an integer index.</para>
<sect2 id="rcl.program.filters.simple">
<title>Simple filters</title>
<para>&RCL; simple filters are usually shell-scripts, but this is in
no way necessary. Extracting the text from the native format is the
difficult part. Outputting the format expected by &RCL; is
trivial. Happily enough, most document formats have translators or
text extractors which can be called from the filter. In some cases
the output of the translating program is completely appropriate,
and no intermediate shell-script is needed.</para>
<para>Filters are called with a single argument which is the
source file name. They should output the result to stdout.</para>
<para>When writing a filter, you should decide if it will output
plain text or html. Plain text is simpler, but you will not be able
to add metadata or vary the output character encoding (this will be
defined in a configuration file). Additionally, some formatting may
easier to preserve when previewing html. Actually the deciding factor
is metadata: &RCL; has a way to <link linkend="rcl.program.filters.html">
extract metadata from the html header and use it for field
searches.</link>.</para>
<para>The <envar>RECOLL_FILTER_FORPREVIEW</envar> environment
variable (values <literal>yes</literal>, <literal>no</literal>)
tells the filter if the operation is for indexing or
previewing. Some filters use this to output a slightly different
format, for example stripping uninteresting repeated keywords (ie:
<literal>Subject:</literal> for email) when indexing. This is not
essential.</para>
<para>You should look at one of the simple filters, for example
<command>rclps</command> for a starting point.</para>
<para>Don't forget to make your filter executable before
testing !</para>
</sect2>
<sect2 id="rcl.program.filters.association">
<title>Telling &RCL; about the filter</title>
<para>There are two elements that link a file to the filter which
should process it: the association of file to mime type and the
association of a mime type with a filter.</para>
<para>The association of files to mime types is mostly based on
name suffixes. The types are defined inside the
<link linkend="rcl.install.config.mimemap">
<filename>mimemap</filename> file</link>. Example:
<programlisting>
.doc = application/msword
</programlisting>
If no suffix association is found for the file name, &RCL; will try
to execute the <command>file -i</command> command to determine a
mime type.</para>
<para>The association of file types to filters is performed in
the <link linkend="rcl.install.config.mimeconf">
<filename>mimeconf</filename> file</link>. A sample will probably be
of better help than a long explanation:</para>
<programlisting>
[index]
application/msword = exec antiword -t -i 1 -m UTF-8;\
mimetype = text/plain ; charset=utf-8
application/ogg = exec rclogg
text/rtf = exec unrtf --nopict --html; charset=iso-8859-1; mimetype=text/html
application/x-chm = execm rclchm
</programlisting>
<para>The fragment specifies that:
<itemizedlist>
<listitem><para><literal>application/msword</literal> files
are processed by executing the <command>antiword</command>
program, which outputs
<literal>text/plain</literal> encoded in
<literal>utf-8</literal>.</para>
</listitem>
<listitem><para><literal>application/ogg</literal> files are
processed by the <command>rclogg</command> script, with
default output type (<literal>text/html</literal>, with
encoding specified in the header, or <literal>utf-8</literal>
by default).</para>
</listitem>
<listitem><para><literal>text/rtf</literal> is processed by
<command>unrtf</command>, which outputs
<literal>text/html</literal>. The
<literal>iso-8859-1</literal> encoding is specified because it
is not the <literal>utf-8</literal> default, and not output by
<command>unrtf</command> in the HTML header section.</para>
</listitem>
<listitem><para><literal>application/x-chm</literal> is processed
by a persistant filter. This is determined by the
<literal>execm</literal> keyword.</para>
</listitem>
</itemizedlist>
</para>
</sect2>
<sect2 id="rcl.program.filters.html">
<title>Filter HTML output</title>
<para>The output HTML could be very minimal like the following
example:</para>
<programlisting><html><head>
<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
</head>
<body>some text content</body></html>
</programlisting>
<para>You should take care to escape some
characters inside
the text by transforming them into appropriate
entities. "<literal>&</literal>" should be transformed into
"<literal>&amp;</literal>", "<literal><</literal>"
should be transformed into
"<literal>&lt;</literal>". This is not always properly
done by translating programs which output HTML, and of
course nerver by those which output plain text.</para>
<para>The character set needs to be specified in the
header. It does not need to be UTF-8 (&RCL; will take care
of translating it), but it must be accurate for good
results.</para>
<para>&RCL; will also make use of other header fields if
they are present: <literal>title</literal>,
<literal>description</literal>,
<literal>keywords</literal>.</para>
<para>Filters also have the possibility to "invent" field
names. This should be output as meta tags:</para>
<programlisting>
<meta name="somefield" content="Some textual data" />
</programlisting>
<para> See the following section for details about configuring
how field data is processed by the indexer.</para>
</sect2>
</sect1>
<sect1 id="rcl.program.fields">
<title>Field data processing</title>
<para><literal>Fields</literal> are named pieces of information
in or about documents, like <literal>title</literal>,
<literal>author</literal>, <literal>abstract</literal>.</para>
<para>The field values for documents can appear in several ways
during indexing: either output by filters as
<literal>meta</literal> fields in the HTML header section, or
added as attributes of the <literal>Doc</literal> object when
using the API, or again synthetized internally by &RCL;.</para>
<para>The &RCL; query language allows searching for text in a
specific field.</para>
<para>&RCL; defines a number of default fields. Additional
ones can be output by filters, and described in the
<filename>fields</filename> configuration file.</para>
<para>Fields can be:</para>
<itemizedlist>
<listitem><para><literal>indexed</literal>, meaning that their
terms are separately stored in inverted lists (with a specific
prefix), and that a field-specific search is possible.</para>
</listitem>
<listitem><para><literal>stored</literal>, meaning that their
value is recorded in the index data record for the document,
and can be returned and displayed with search results.</para>
</listitem>
</itemizedlist>
<para>A field can be either or both indexed and stored. This and
other aspects of fields handling is defined inside the
<filename>fields</filename> configuration file.</para>
<para>You can find more information in the
<link linkend="rcl.install.config.fields">section about the
<filename>fields</filename> file</link>, or in comments inside the
file.</para>
</sect1>
<sect1 id="rcl.program.api">
<title>API</title>
<sect2 id="rcl.program.api.elements">
<title>Interface elements</title>
<para>A few elements in the interface are specific and and need
an explanation.</para>
<variablelist>
<varlistentry>
<term>udi</term> <listitem><para>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.</para> </listitem>
</varlistentry>
<varlistentry>
<term>ipath</term>
<listitem><para>This data value (set as a field in the Doc
object) is stored, along with the URL, but not indexed by
&RCL;. Its contents are not interpreted, and its use is up
to the application. For example, the &RCL; internal file
system indexer stores the part of the document access path
internal to the container file (<literal>ipath</literal> 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.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Stored and indexed fields</term>
<listitem><para>The <filename>fields</filename> file inside
the &RCL; configuration defines which document fields are
either "indexed" (searchable), "stored" (retrievable with
search results), or both.</para>
</listitem>
</varlistentry>
</variablelist>
<para>Data for an external indexer, should be stored in a
separate index, not the one for the &RCL; 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.</para>
</sect2>
<sect2 id="rcl.program.api.python">
<title>Python interface</title>
<sect3 id="rcl.program.python.intro">
<title>Introduction</title>
<para>&RCL; versions after 1.11 define a Python programming
interface, both for searching and indexing.</para>
<para>The Python interface is not built by default and can be
found in the source package,
under <filename>python/recoll</filename>.</para>
<para>In order to build the module, you should first build
or re-build the Recoll library using position-independant
objects:
<screen>
<userinput>cd recoll-xxx/</userinput>
<userinput>configure --enable-pic</userinput>
<userinput>make</userinput>
</screen>
There is no significant disadvantage in using PIC objects
for the main Recoll executables, so you can use the
<option>--enable-pic</option> option for the main build
too.</para>
<para>The <filename>python/recoll/</filename> directory
contains the usual <filename>setup.py</filename>
script which you can then use to build and install the
module:
<screen>
<userinput>cd recoll-xxx/python/recoll</userinput>
<userinput>python setup.py build</userinput>
<userinput>python setup.py install</userinput>
</screen>
</para>
</sect3>
<sect3 id="rcl.program.python.manual">
<title>Interface manual</title>
<literallayout>
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
</literallayout>
</sect3>
<sect3 id="rcl.program.python.examples">
<title>Example code</title>
<para>The following sample would query the index with a user
language string. See the <filename>python/samples</filename>
directory inside the &RCL; source for other examples.</para>
<programlisting>
#!/usr/bin/env python
<![CDATA[
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
]]>
</programlisting>
</sect3>
</sect2>
</sect1>
</chapter>
<chapter id="rcl.install">
<title>Installation and configuration</title>
<sect1 id="rcl.install.binary">
<title>Installing a binary copy</title>
<para>There are three types of binary &RCL; installations:
<itemizedlist>
<listitem><para>Through your system normal software distribution
framework (ie, <application>Debian/Ubuntu apt</application>,
<application>FreeBSD</application> ports, etc.).</para>
</listitem>
<listitem><para>From a package downloaded from the
&RCL; web site.</para>
</listitem>
<listitem><para>From a prebuilt tree downloaded from the &RCL;
web site.</para>
</listitem>
</itemizedlist>
In all cases, the strict software dependancies (ie on &XAP; or
<application>iconv</application>) will be automatically satisfied,
you should not have to worry about them.</para>
<para>You will only have to check or install <link
linkend="rcl.install.external">supporting applications</link>
for the file types that you want to index beyond those that are
natively processed by &RCL; (text, HTML, email files, and a few
others).</para>
<para>You should also maybe have a look at the
<link linkend="rcl.install.config">configuration section</link>
(but this may not be necessary for a quick test with default
parameters). Most parameters can be more conveniently set from the
GUI interface.</para>
<sect2 id="rcl.install.binary.package">
<title>Installing through a package system</title>
<para>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.</para>
</sect2>
<sect2 id="rcl.install.binary.rcl">
<title>Installing a prebuilt &RCL;</title>
<para>The unpackaged binary versions on the &RCL; web site are
just compressed tar files of a build tree, where only the
useful parts were kept (executables and sample
configuration).</para>
<para>The executable binary files are built with a static link to
libxapian and libiconv, to make installation easier (no
dependencies).</para>
<para>After extracting the tar file, you can proceed with
<link linkend="rcl.install.building.install">installation</link> as
if you had built the package from source (that is, just type
<literal>make install</literal>). The binary trees are built for
installation to <filename>/usr/local</filename>.</para>
</sect2>
</sect1>
<sect1 id="rcl.install.external">
<title>Supporting packages</title>
<para>&RCL; uses external applications to index some file
types. You need to install them for the file types that you wish to
have indexed (these are run-time optional dependencies. None is
needed for building or running &RCL; except for indexing their
specific file type).</para>
<para>After an indexing pass, the commands that were found
missing can be displayed from the <command>recoll</command>
<guilabel>File</guilabel> menu. The list is stored in the
<filename>missing</filename> text file inside the configuration
directory.</para>
<para>A list of common file types which need external
commands follows. Many of the filters need the
<command>iconv</command> command, which is not always listed as a
dependancy.</para>
<para>Please note that, due to the relatively dynamic nature of this
information, the most up to date version is now kept on the &RCLAPPS;
along with links to the home pages or best source/patches pages,
and misc tips. The list below is not updated often and may be quite
stale.</para>
<para>For many Linux distributions, most of the commands listed can
be installed from the package repositories. However, the packages
are sometimes outdated, or not the best version for &RCL;, so you
should take a look at the &RCLAPPS; if a file
type is important to you.</para>
<para>As of &RCL; release 1.14, a number of XML-based formats that
were handled by ad hoc filter code now use the
<command>xsltproc</command> command, which usually comes with
<application>libxslt</application>. These are: abiword, fb2
(ebooks), kword, openoffice, svg.</para>
<para>Now for the list:</para>
<itemizedlist>
<listitem><para>Openoffice files need <command>unzip</command> and
<command>xsltproc</command>.</para></listitem>
<listitem><para>PDF files need <command>pdftotext</command> which
is part of the <application>Xpdf</application> or
<application>Poppler</application> packages.</para></listitem>
<listitem><para>Postscript files need <command>pstotext</command>.
The original version has an issue with shell
character in file names, which is corrected in recent
packages. See the the &RCLAPPS; for more detail.</para>
</listitem>
<listitem><para>MS Word needs
<command>antiword</command>. It is also useful to have
<command>wvWare</command> installed as it may be
be used as a fallback for some files which
<command>antiword</command> does not handle.</para></listitem>
<listitem><para>MS Excel and PowerPoint need <command>
catdoc</command>.</para></listitem>
<listitem><para>MS Open XML (docx) needs <command>
xsltproc</command>.</para></listitem>
<listitem><para>Wordperfect files need <command>wpd2html</command>
from the <application>libwpd</application> (or
<application>libwpd-tools</application> on Ubuntu)
package.</para></listitem>
<listitem><para>RTF files need <command>unrtf</command>, which, in
its standard version, has much trouble with non-western character
sets. Check the &RCLAPPS;.</para></listitem>
<listitem><para>TeX files need <command>untex</command> or
<command>detex</command>. Check the &RCLAPPS; for sources if it's not
packaged for your distribution.</para></listitem>
<listitem><para>dvi files need <command>dvips</command>.</para>
</listitem>
<listitem><para>djvu files need <command>djvutxt</command> and
<command>djvused</command> from the
<application>DjVuLibre</application> package.</para></listitem>
<listitem><para>Audio files: &RCL; releases before 1.13
used the <command>id3info</command> command from the <application>
id3lib</application> package to extract mp3 tag information,
<command>metaflac</command> (standard flac tools) for flac files,
and <command>ogginfo</command> (vorbis tools) for ogg
files. Releases 1.14 and later use a single
<application>Python</application> filter based
on <application>mutagen</application> for all audio file
types.</para>
</listitem>
<listitem><para>Pictures: &RCL; uses the
<application>Exiftool</application>
<application>Perl</application> package to extract tag
information. Most image file formats are supported. Note that
there may not be much interest in indexing the technical tags
(image size, aperture, etc.). This is only of interest if you
store personal tags or textual descriptions inside the image
files.</para></listitem>
<listitem><para>chm: files in microsoft help format need Python and
the <application>pychm</application> module (which needs
<application>chmlib</application>).</para></listitem>
<listitem><para>ICS: up to &RCL; 1.13, iCalendar files need
<application>Python</application>
and the <application>icalendar</application>
module. <application>icalendar</application> is not needed for newer
versions, which use internal code.</para></listitem>
<listitem><para>Zip archives need <application>Python</application>
(and the standard zipfile module).</para></listitem>
<listitem><para>Rar archives need
<application>Python</application>, the
<application>rarfile</application> Python module and the
<command>unrar</command> utility.</para></listitem>
<listitem><para>Midi karaoke files need
<application>Python</application> and the
<ulink url="http://pypi.python.org/pypi/midi/0.2.1">
<application>Midi module</application></ulink></para>
</listitem>
<listitem><para>Konqueror webarchive format with Python (uses the
Tarfile module).</para></listitem>
<listitem><para>mimehtml web archive format (support based on the email
filter, which introduces some mild weirdness, but still
usable).</para></listitem>
</itemizedlist>
<para>Text, HTML, email folders, and Scribus files are
processed internally. <application>Lyx</application> is used to
index Lyx files. Many filters need <command>iconv</command> and the
standard <command>sed</command> and <command>awk</command>.
</para>
</sect1>
<sect1 id="rcl.install.building">
<title>Building from source</title>
<sect2 id="rcl.install.building.prereqs">
<title>Prerequisites</title>
<para>C++ compiler. Up to &RCL; version 1.13.04, its absence can
manifest itself by strange messages about a missing
iconv_open.</para>
<para>Development files for <ulink
url="http://www.xapian.org"> <application>Xapian
core</application></ulink>.</para> <important><para>If you are
building Xapian for an older CPU (before Pentium 4 or Athlon
64), you need to add the <option>--disable-sse</option> flag
to the configure command. Else all Xapian application will
crash with an <literal>illegal instruction</literal>
error.</para> </important>
<para>Development files for
<ulink url="http://www.trolltech.com/products/qt/index.html">
<application>Qt</application> </ulink>.</para>
<para>Development files for <application>X11</application> and
<application>zlib</application>.</para>
<para>Check the <ulink url="http://www.recoll.org/download.html">
&RCL; download page</ulink> for up to date version
information.</para>
<para>You will most probably be able to find a binary package for
<application>Qt</application> for your system. You may have to
compile &XAP; but this is not difficult (if you are using
<application>FreeBSD</application>, there is a port).</para>
<para>You may also need
<ulink
url="http://www.gnu.org/software/libiconv/">libiconv</ulink>. &RCL;
currently uses version 1.9 (this should not be critical). On
<application>Linux</application> systems, the iconv interface
is part of libc and you should not need to do anything
special.</para>
</sect2>
<sect2 id="rcl.install.building.build">
<title>Building</title>
<para>&RCL; has been built on Linux, FreeBSD, Mac OS X, and Solaris,
most versions after 2005 should be ok, maybe some older ones too
(Solaris 8 is ok). If you build on another system, and
need to modify things,
<ulink url="mailto:jfd@recoll.org">I would
very much welcome patches</ulink>.</para>
<para>Depending on the <application>Qt 3</application>
configuration on your system, you may have to set the
<envar>QTDIR</envar> and <envar>QMAKESPECS</envar>
variables in your environment:</para>
<itemizedlist>
<listitem><para><envar>QTDIR</envar> should point to the
directory above the one that holds the qt include files (ie:
if <filename>qt.h</filename> is
<filename>/usr/local/qt/include/qt.h</filename>, QTDIR
should be <filename>/usr/local/qt</filename>).</para>
</listitem>
<listitem><para><envar>QMAKESPECS</envar> should
be set to the name of one of the
<application>Qt</application> mkspecs sub-directories (ie:
<filename>linux-g++</filename>).</para>
</listitem>
</itemizedlist>
<para>On many Linux systems, <envar>QTDIR</envar> is set
by the login scripts, and <envar>QMAKESPECS</envar> is not
needed because there is a <filename>default</filename> link in
<filename>mkspecs/</filename>.</para>
<para>Neither <envar>QTDIR</envar> nor
<envar>QMAKESPECS</envar> should be needed with
Qt 4, configuration details are entirely determined by
<command>qmake</command> (which is quite often installed as
<command>qmake-qt4</command>).</para>
<formalpara><title>Configure options:</title>
<para>
<itemizedlist>
<listitem><para><option>--without-aspell</option>
will disable the code for phonetic matching of search
terms. </para>
</listitem>
<listitem><para><option>--with-fam</option> or
<option>--with-inotify</option> will enable the code for
real time indexing. Inotify support is enabled by default on
recent Linux systems.</para>
</listitem>
<listitem><para><option>--disable-webkit</option> is available
from version 1.17 to implement the result list with a
<application>Qt</application> QTextBrowser instead of a
WebKit widget if you do not or can't depend on the
latter.</para>
</listitem>
<listitem><para><option>--enable-xattr</option> 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
<filename>fields</filename> configuration file).</para>
</listitem>
<listitem><para><option>--enable-camelcase</option> will enable
splitting <replaceable>camelCase</replaceable> words. This
is not enabled by default as it has the unfortunate
side-effect of making some phrase searches quite
confusing: ie, <literal>"MySQL manual"</literal> would be
matched by <literal>"MySQL manual"</literal> and
<literal>"my sql manual"</literal> but not <literal>"mysql
manual"</literal> (only inside phrase searches).</para>
</listitem>
<listitem><para><option>--with-file-command</option> Specify
the version of the 'file' command to use (ie:
--with-file-command=/usr/local/bin/file). Can be useful to
enable the gnu version on systems where the native one is
bad.</para>
</listitem>
<listitem><para><option>--disable-qtgui</option> Disable the Qt
interface. Will allow building the indexer and the command line
search program in absence of a Qt environment.</para>
</listitem>
<listitem><para><option>--disable-x11mon</option> Disable
<application>X11</application> connection monitoring
inside recollindex. Together with --disable-qtgui, this
allows building recoll without
<application>Qt</application> and
<application>X11</application>.</para> </listitem>
<listitem><para>Of course the usual
<application>autoconf</application> <command>configure</command>
options, like <option>--prefix</option> apply.</para>
</listitem>
</itemizedlist>
</para>
</formalpara>
<para>Normal procedure:</para>
<screen>
<userinput>cd recoll-xxx</userinput>
<userinput>configure</userinput>
<userinput>make</userinput>
<userinput>(practices usual hardship-repelling invocations)</userinput>
</screen>
<para>There is little auto-configuration. The
<command>configure</command> script will mainly link one of
the system-specific files in the <filename>mk</filename>
directory to <filename>mk/sysconf</filename>. 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 <command>uname</command>
<option>-s</option>).</para>
</sect2>
<sect2 id="rcl.install.building.install">
<title>Installation</title>
<para>Either type <userinput>make install</userinput> or execute
<userinput>recollinstall
<replaceable>prefix</replaceable></userinput>, in the root
of the source tree. This will copy the commands to
<filename><replaceable>prefix</replaceable>/bin</filename>
and the sample configuration files, scripts and other shared
data to
<filename><replaceable>prefix</replaceable>/share/recoll</filename>.</para>
<para>If the installation prefix given to
<command>recollinstall</command> is different from either the
system default or the value which was
specified when executing <command>configure</command> (as in
<userinput>configure --prefix /some/path</userinput>), you
will have to set the <envar>RECOLL_DATADIR</envar>
environment variable to indicate where the shared data is to
be found (ie for (ba)sh:
<userinput>export RECOLL_DATADIR=/some/path/share/recoll</userinput>).
</para>
<para>You can then proceed to <link
linkend="rcl.install.config">configuration</link>. </para>
</sect2>
</sect1>
<sect1 id="rcl.install.config">
<title>Configuration overview</title>
<para>Most of the parameters specific to the
<command>recoll</command> GUI are set through the
<guilabel>Preferences</guilabel> menu and stored in the standard Qt
place (<filename>$HOME/.config/Recoll.org/recoll.conf</filename>).
You probably do not want to edit this by hand.</para>
<para>&RCL; indexing options are set inside text configuration
files located in a configuration directory. There can be
several such directories, each of which define the parameters
for one index.</para>
<para>The configuration files can be edited by hand or through
the <guilabel>Indexing configuration</guilabel> dialog
(<guilabel>Preferences</guilabel> menu). The GUI tool will try
to respect your formatting and comments as much as possible,
so it is quite possible to use both ways.</para>
<para>The most accurate documentation for the
configuration parameters is given by comments inside the default
files, and we will just give a general overview here.</para>
<para>For each index, there are two sets of configuration
files. System-wide configuration files are kept in a directory named
like <filename>/usr/[local/]share/recoll/examples</filename>,
and define default values, shared by all indexes. For each
index, a parallel set of files defines the customized
parameters.</para>
<para>The default location of the configuration is the
<filename>.recoll</filename>
directory in your home. Most people will only use this
directory.</para>
<para>This location can be changed, or others can be added with the
<envar>RECOLL_CONFDIR</envar> environment variable or the
<option>-c</option> option parameter to <command>recoll</command> and
<command>recollindex</command>.</para>
<para>If the <filename>.recoll</filename> directory does not
exist when <command>recoll</command> or
<command>recollindex</command> are started, it will be created
with a set of empty configuration files.
<command>recoll</command> will give you a chance to edit the
configuration file before starting
indexing. <command>recollindex</command> will proceed
immediately. To avoid mistakes, the automatic directory
creation will only occur for the
default location, not if <option>-c</option> or
<envar>RECOLL_CONFDIR</envar> were used (in the latter
cases, you will have to create the directory).</para>
<para>All configuration files share the same format. For
example, a short extract of the main configuration file might
look as follows:</para>
<programlisting>
# Space-separated list of directories to index.
topdirs = ~/docs /usr/share/doc
[~/somedirectory-with-utf8-txt-files]
defaultcharset = utf-8
</programlisting>
<para>There are three kinds of lines: </para>
<itemizedlist>
<listitem><para>Comment (starts with
<emphasis>#</emphasis>) or empty.</para>
</listitem>
<listitem><para>Parameter affectation (<emphasis>name =
value</emphasis>).</para>
</listitem>
<listitem><para>Section definition
([<emphasis>somedirname</emphasis>]).</para>
</listitem>
</itemizedlist>
<para>Depending on the type of configuration file, section
definitions either separate groups of parameters or allow
redefining some parameters for a directory sub-tree. They stay
in effect until another section definition, or the end of
file, is encountered. Some of the parameters used for indexing
are looked up hierarchically from the current directory
location upwards. Not all parameters can be meaningfully
redefined, this is specified for each in the next
section. </para>
<para>When found at the beginning of a file path, the tilde
character (~) is expanded to the name of the user's home
directory, as a shell would do.</para>
<para>White space is used for separation inside lists.
List elements with embedded spaces can be quoted using
double-quotes.</para>
<formalpara>
<title>Encoding issues</title>
<para>Most of the configuration parameters are plain ASCII. Two
particular sets of values may cause encoding issues:</para>
</formalpara>
<para>
<itemizedlist>
<listitem><para>File path parameters may contain non-ascii
characters and should use the exact same byte values as found in
the file system directory. Usually, this means that the
configuration file should use the system default locale
encoding.</para>
</listitem>
<listitem><para>The <envar>unac_except_trans</envar> parameter
should be encoded in UTF-8. If your system locale is not UTF-8, and
you need to also specify non-ascii file paths, this poses a
difficulty because common text editors cannot handle multiple
encodings in a single file. In this relatively unlikely case, you
can edit the configuration file as two separate text files with
appropriate encodings, and concatenate them to create the complete
configuration.</para>
</listitem>
</itemizedlist>
</para>
<sect2 id="rcl.install.config.recollconf">
<title>Main configuration file</title>
<para><filename>recoll.conf</filename> 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.</para>
<para>The default configuration will index your home
directory. If this is not appropriate, start
<command>recoll</command> to create a blank
configuration, click <guimenu>Cancel</guimenu>, and edit
the configuration file before restarting the command. This
will start the initial indexing, which may take some time.</para>
<para>Most of the following parameters can be changed from the
<guilabel>Index Configuration</guilabel> menu in the
<command>recoll</command> interface. Some can only be set by
editing the configuration file.</para>
<sect3 id="rcl.install.config.recollconf.files">
<title>Parameters affecting what documents we index:</title>
<variablelist>
<varlistentry id="rcl.install.config.recollconf.topdirs">
<term><varname>topdirs</varname></term>
<listitem><para>Specifies the list of directories or files to
index (recursively for directories). You can use symbolic links
as elements of this list. See the
<varname>followLinks</varname> option about following symbolic links
found under the top elements (not followed by default).</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>skippedNames</varname></term>
<listitem>
<para>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: </para>
<programlisting>
skippedNames = #* bin CVS Cache cache* caughtspam tmp .thumbnails .svn \
*~ .beagle .git .hg .bzr loop.ps .xsession-errors \
.recoll* xapiandb recollrc recoll.conf
</programlisting>
<para>The list can be redefined at any sub-directory in the
indexed area.</para>
<para>The top-level directories are not affected by this
list (that is, a directory in <varname>topdirs</varname>
might match and would still be indexed).</para>
<para>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, email user
agents like <application>thunderbird</application>
usually store messages in hidden directories, and you
probably want this indexed. One possible solution is to
have <filename>.*</filename> in
<varname>skippedNames</varname>, and add things like
<filename>~/.thunderbird</filename> or
<filename>~/.evolution</filename> in
<varname>topdirs</varname>.</para>
<para>Not even the file names are indexed for patterns
in this list. See the
<varname>recoll_noindex</varname> variable in
<filename>mimemap</filename> for an alternative
approach which indexes the file names.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>skippedPaths</varname> and
<varname>daemSkippedPaths</varname> </term>
<listitem>
<para>A space-separated list of patterns for
<emphasis>paths</emphasis> 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.</para>
<para><varname>skippedPaths</varname> is used both by
batch and real time
indexing. <varname>daemSkippedPaths</varname> can be
used to specify things that should be indexed at
startup, but not monitored.</para>
<para>Example of use for skipping text files only in a
specific directory:</para>
<programlisting>
skippedPaths = ~/somedir/∗.txt
</programlisting>
</listitem>
</varlistentry>
<varlistentry id="rcl.install.config.recollconf.skippedpathsfnmpathname">
<term><varname>skippedPathsFnmPathname</varname></term>
<listitem><para>The values in the
<varname>*skippedPaths</varname> variables are matched by
default with <literal>fnmatch(3)</literal>, with the
FNM_PATHNAME and FNM_LEADING_DIR flags. This means that '/'
characters must be matched explicitely. You can set
<varname>skippedPathsFnmPathname</varname> to 0 to disable
the use of FNM_PATHNAME (meaning that /*/dir3 will match
/dir1/dir2/dir3).</para>
</listitem>
</varlistentry>
<varlistentry id="rcl.install.config.recollconf.followlinks">
<term><varname>followLinks</varname></term>
<listitem><para>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 <varname>topdirs</varname>
members by using sections. It can not be changed below the
<varname>topdirs</varname> level.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>indexedmimetypes</varname></term>
<listitem><para>&RCL; 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.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>compressedfilemaxkbs</varname></term>
<listitem><para>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.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>textfilemaxmbs</varname></term>
<listitem><para>Maximum size for text files. Very big text
files are often uninteresting logs. Set to -1 to disable
(default 20MB).</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>textfilepagekbs</varname></term>
<listitem><para>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).</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>indexallfilenames</varname></term>
<listitem><para>&RCL; 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.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>usesystemfilecommand</varname></term>
<listitem><para>Decide if we use the
<command>file</command> <option>-i</option> system command
as a final step for determining the mime type for a file
(the main procedure uses suffix associations as defined in
the <filename>mimemap</filename> file). This can be useful
for files with suffix-less names, but it will also cause
the indexing of many bogus "text" files.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>processbeaglequeue</varname></term>
<listitem><para>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.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>beaglequeuedir</varname></term>
<listitem><para>The path to the Beagle indexing queue. This is
hard-coded in the Beagle plugin as
<filename>~/.beagle/ToIndex</filename> so there should be no
need to change it.</para>
</listitem>
</varlistentry>
</variablelist>
</sect3>
<sect3 id="rcl.install.config.recollconf.terms">
<title>Parameters affecting how we generate terms:</title>
<para>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.</para>
<variablelist>
<varlistentry><term><varname>nonumbers</varname></term>
<listitem><para>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.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>nocjk</varname></term>
<listitem><para>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 <varname>nocjk</varname> may be a significant time
and space saver.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>cjkngramlen</varname></term>
<listitem><para>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.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>indexstemminglanguages</varname></term>
<listitem><para>A list of languages for which the stem
expansion databases will be built. See <citerefentry>
<refentrytitle>recollindex</refentrytitle>
<manvolnum>1</manvolnum> </citerefentry> or use the
<command>recollindex</command> <option>-l</option> command
for possible values. You can add a stem expansion database
for a different language by using
<command>recollindex</command> <option>-s</option>, but it
will be deleted during the next indexing. Only languages
listed in the configuration file are permanent.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>defaultcharset</varname></term>
<listitem><para>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 (
<envar>LC_ALL</envar>, <envar>LC_CTYPE</envar>,
<envar>LANG</envar>), or <literal>iso8859-1</literal>
if nothing is set.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>unac_except_trans</varname></term>
<listitem><para>This is a list of characters, encoded in UTF-8,
which should be handled specially when converting text to
unaccented lowercase. For example, in Swedish, the letter
<literal>a with diaeresis</literal> has full alphabet
citizenship and should not be turned into an
<literal>a</literal>. Each element in the space-separated list
has the special character as first element and the translation
following. The handling of both the lowercase and upper-case
versions of a character should be specified, as appartenance to
the list will turn-off both standard accent and case
processing. Example for Swedish:</para>
<programlisting>
unac_except_trans = ĺĺ Ĺĺ ää Ää öö Öö
</programlisting>
<para>Note that the translation is not limited to a single
character, you could very well have something like
<literal>üue</literal> in the list.</para>
<para>This parameter can't be defined for subdirectories, it
is global, because there is no way to do otherwise when
querying. If you have document sets which would need different
values, you will have to index and query them separately.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>maildefcharset</varname></term>
<listitem><para>This can be used to define the default
character set specifically for email messages which don't
specify it. This is mainly useful for readpst (libpst) dumps,
which are utf-8 but do not say so.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>localfields</varname></term>
<listitem><para>This allows setting fields for all documents
under a given directory. Typical usage would be to set an
"rclaptg" field, to be used in <filename>mimeview</filename> 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:
<literal>localfields= rclaptg=gnus:other = val</literal>, then
select specifier viewer with
<literal>mimetype|tag=...</literal> in
<filename>mimeview</filename>.</para>
</listitem>
</varlistentry>
</variablelist>
</sect3>
<sect3 id="rcl.install.config.recollconf.storage">
<title>Parameters affecting where and how we store things:</title>
<variablelist>
<varlistentry><term><varname>dbdir</varname></term>
<listitem><para>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.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>idxstatusfile</varname></term>
<listitem><para>The name of the scratch file where the indexer
process updates its status. Default:
<filename>idxstatus.txt</filename> inside the configuration
directory.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>maxfsoccuppc</varname></term>
<listitem><para>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. </para>
</listitem>
</varlistentry>
<varlistentry><term><varname>mboxcachedir</varname></term>
<listitem><para>The directory where mbox message offsets cache
files are held. This is normally $RECOLL_CONFDIR/mboxcache, but
it may be useful to share a directory between different
configurations.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>mboxcacheminmbs</varname></term>
<listitem><para>The minimum mbox file size over which we
cache the offsets. There is really no sense in caching
offsets for small files. The default is 5 MB.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>webcachedir</varname></term>
<listitem><para>This is only used by the Beagle web browser
plugin indexing code, and defines where the cache for visited
pages will live. Default:
<filename>$RECOLL_CONFDIR/webcache</filename></para>
</listitem>
</varlistentry>
<varlistentry><term><varname>webcachemaxmbs</varname></term>
<listitem><para>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.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>idxflushmb</varname></term>
<listitem><para>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 (or
XAPIAN_FLUSH_THRESHOLD) documents, which gives little memory
usage control, as memory usage depends on average document
size. The default value is 10.</para>
</listitem>
</varlistentry>
</variablelist>
</sect3>
<sect3 id="rcl.install.config.recollconf.misc">
<title>Miscellaneous parameters:</title>
<variablelist>
<varlistentry><term><varname>loglevel,daemloglevel</varname></term>
<listitem><para>Verbosity level for recoll and
recollindex. A value of 4 lists quite a lot of
debug/information messages. 2 only lists errors. The
<literal>daem</literal>version is specific to the indexing monitor
daemon.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>logfilename,
daemlogfilename</varname></term>
<listitem><para>Where the messages should go. 'stderr' can
be used as a special value, and is the default. The
<literal>daem</literal>version is specific to the indexing monitor
daemon.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>mondelaypatterns</varname></term>
<listitem><para>This allows specify wildcard path patterns
(processed with fnmatch(3) with 0 flag), to match files which
change too often and for which a delay should be observed before
re-indexing. This is a space-separated list, each entry being a
pattern and a time in seconds, separated by a colon. You can
use double quotes if a path entry contains white
space. Example:</para>
<programlisting>
mondelaypatterns = *.log:20 "this one has spaces*:10"
</programlisting>
</listitem>
</varlistentry>
<varlistentry><term><varname>monixinterval</varname></term>
<listitem><para>Minimum interval (seconds) for processing the
indexing queue. The real time monitor does not process each
event when it comes in, but will wait this time for the queue
to accumulate to diminish overhead and in order to aggregate
multiple events to the same file. Default 30 S.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>monauxinterval</varname></term>
<listitem><para>Period (in seconds) at which the real time
monitor will regenerate the auxiliary databases (spelling,
stemming) if needed. The default is one hour.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>filtermaxseconds</varname></term>
<listitem><para>Maximum filter execution time, after which it
is aborted. Some postscript programs just loop...</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>filtersdir</varname></term>
<listitem><para>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. </para>
</listitem>
</varlistentry>
<varlistentry><term><varname>iconsdir</varname></term>
<listitem><para>The name of the directory where
<command>recoll</command> result list icons are
stored. You can change this if you want different
images.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>idxabsmlen</varname></term>
<listitem><para>&RCL; 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 <varname>idxabsmlen</varname> 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.
</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>aspellLanguage</varname></term>
<listitem><para>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.</para>
</listitem>
</varlistentry>
<varlistentry><term><varname>noaspell</varname></term>
<listitem><para>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.</para>
</listitem>
</varlistentry>
</variablelist>
</sect3>
</sect2>
<sect2 id="rcl.install.config.fields">
<title>The fields file</title>
<para>This file contains information about dynamic fields handling
in &RCL;. Some very basic fields have hard-wired behaviour,
and, mostly, you should not change the original data inside the
<filename>fields</filename> file. But you can create custom fields
fitting your data and handle them just like they were native
ones.</para>
<para>The <filename>fields</filename> file has several sections,
which each define an aspect of fields processing. Quite often,
you'll have to modify several sections to obtain the desired
behaviour.</para>
<para>We will only give a short description here, you should refer
to the comments inside the file for more detailed information.</para>
<para>Field names should be lowercase alphabetic ASCII.</para>
<variablelist>
<varlistentry>
<term>[prefixes]</term>
<listitem><para>A field becomes indexed (searchable) by having
a prefix defined in this section.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>[stored]</term>
<listitem><para>A field becomes stored (displayable inside
results) by having its name listed in this section (typically
with an empty value).</para>
</listitem>
</varlistentry>
<varlistentry>
<term>[aliases]</term>
<listitem><para>This section defines lists of synonyms for the
canonical names used inside the <literal>[prefixes]</literal>
and <literal>[stored]</literal> sections</para>
</listitem>
</varlistentry>
<varlistentry>
<term>filter-specific sections</term>
<listitem><para>Some filters may need specific
configuration for handling fields. Only the email message filter
currently has such a section (named
<literal>[mail]</literal>). It allows indexing arbitrary email
headers in addition to the ones indexed by default. Other such
sections may appear in the future.</para>
</listitem>
</varlistentry>
</variablelist>
<para>Here follows a small example of a personal
<filename>fields</filename>
file. This would extract a specific email header and
use it as a searchable field, with data displayable inside result
lists. (Side note: as the email 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).
<programlisting>[prefixes]
# Index mailmytag contents (with the given prefix)
mailmytag = XMTAG
[stored]
# Store mailmytag inside the document data record (so that it can be
# displayed - as %(mailmytag) - in result lists).
mailmytag =
[mail]
# Extract the X-My-Tag mail header, and use it internally with the
# mailmytag field name
x-my-tag = mailmytag
</programlisting>
</para>
</sect2>
<sect2 id="rcl.install.config.mimemap">
<title>The mimemap file</title>
<para><filename>mimemap</filename> specifies the
file name extension to mime type mappings.</para>
<para>For file names without an extension, or with an unknown
one, the system's <command>file</command> <option>-i</option>
command will be
executed to determine the mime type (this can be switched off
inside the main configuration file).</para>
<para>The mappings can be specified on a per-subtree basis,
which may be useful in some cases. Example:
<application>gaim</application> logs have a
<filename>.txt</filename> extension but
should be handled specially, which is possible because they
are usually all located in one place.</para>
<para><filename>mimemap</filename> also has a
<varname>recoll_noindex</varname> variable which is a list of
suffixes. Matching files will be skipped (which avoids
unnecessary decompressions or <command>file</command>
executions). This is partially redundant with
<varname>skippedNames</varname> 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 <varname>skippedNames</varname>.
<varname>recoll_noindex</varname> is used mostly for things
known to be unindexable by a given &RCL; version. Having it
there avoids cluttering the more user-oriented and locally
customized <varname>skippedNames</varname>.</para>
</sect2>
<sect2 id="rcl.install.config.mimeconf">
<title>The mimeconf file</title>
<para><filename>mimeconf</filename> specifies how the
different mime types are handled for indexing, and which icons
are displayed in the <command>recoll</command> result lists.</para>
<para>Changing the parameters in the [index] section is
probably not a good idea except if you are a &RCL;
developer.</para>
<para>The [icons] section allows you to change the icons which
are displayed by <command>recoll</command> in the result
lists (the values are the basenames of the png images inside
the <filename>iconsdir</filename> directory (specified in
<filename>recoll.conf</filename>).</para>
</sect2>
<sect2 id="rcl.install.config.mimeview">
<title>The mimeview file</title>
<para><filename>mimeview</filename> specifies which programs
are started when you click on an <guilabel>Open</guilabel>
link in a result list. Ie: HTML is normally displayed using
<application>firefox</application>, but you may prefer
<application>Konqueror</application>, your
<application>openoffice.org</application>
program might be named <command>oofice</command> instead of
<command>openoffice</command> etc.
</para>
<para>Changes to this file can be done by direct editing, or
through the <command>recoll</command> user preferences dialog.</para>
<para>If <guilabel>Use desktop preferences to choose document
editor</guilabel> is checked in the &RCL; GUI user preferences, all
<filename>mimeview</filename> entries will be ignored except the
one labelled <literal>application/x-all</literal> (which is set to
use <command>xdg-open</command> by default).</para>
<para>As for the other configuration files, the normal usage
is to have a <filename>mimeview</filename> inside your own
configuration directory, with just the non-default entries,
which will override those from the central configuration
file.</para>
<para>Please note that these entries must be placed under a
<literal>[view]</literal> section.</para>
<para>The keys in the file are normally mime types. You can add an
application tag to specialize the choice for an area of the
filesystem (using a <varname>localfields</varname> specification
in <filename>mimeconf</filename>). The syntax for the key is
<replaceable>mimetype</replaceable><literal>|</literal><replaceable>tag</replaceable></para>
<para>The <varname>nouncompforviewmts</varname> entry, (placed at
the top level, outside of the <literal>[view]</literal> section),
holds a list of mime types that should not be uncompressed before
starting the viewer (if they are found compressed, ie:
<replaceable>mydoc.doc.gz</replaceable>).</para>
<para>The right side of each assignment holds a command to be
executed for opening the file. The following substitutions are
performed:</para>
<itemizedlist>
<listitem>
<formalpara><title>%D</title><para>Document date</para></formalpara>
</listitem> <listitem><formalpara><title>%f</title><para>File
name. This may be the name of a temporary file if it was
necessary to create one (ie: to extract a subdocument from a
container).</para></formalpara>
</listitem>
<listitem><formalpara><title>%F</title><para>Original file name.
Same as %f except if a temporary file is used.</para></formalpara>
</listitem>
<listitem><formalpara><title>%i</title><para>Internal path, for
subdocuments of containers. The format depends on the container
type. If this appears in the command line, &RCL; will not create
a temporary file to extract the subdocument, expecting the called
application (possibly a script) to be able to handle
it.</para></formalpara>
</listitem>
<listitem><formalpara><title>%M</title><para>Mime
type</para></formalpara>
</listitem>
<listitem><formalpara><title>%U, %u</title><para>Url.
</para></formalpara>
</listitem>
</itemizedlist>
<para>In addition to the predefined values above, all strings like
<literal>%(fieldname)</literal> will be replaced by the value of
the field named <literal>fieldname</literal> for the
document. This could be used in combination with field
customisation to help with opening the document.</para>
</sect2>
<sect2 id="rcl.install.config.examples">
<title>Examples of configuration adjustments</title>
<sect3 id="rcl.install.config.examples.addview">
<title>Adding an external viewer for an non-indexed type</title>
<para>Imagine that you have some kind of file which does not
have indexable content, but for which you would like to have a
functional <guilabel>Open</guilabel> link in the result list
(when found by file name). The file names end in
<replaceable>.blob</replaceable> and can be displayed by
application <replaceable>blobviewer</replaceable>.</para>
<para>You need two entries in the configuration files for this
to work:</para>
<itemizedlist>
<listitem><para>In <filename>$RECOLL_CONFDIR/mimemap</filename>
(typically <filename>~/.recoll/mimemap</filename>), add the
following line:<programlisting>
.blob = application/x-blobapp
</programlisting>
Note that the mime type is made up here, and you could
call it <replaceable>diesel/oil</replaceable> just the
same.</para>
</listitem>
<listitem><para>In <filename>$RECOLL_CONFDIR/mimeview</filename>
under the <literal>[view]</literal> section, add:</para>
<programlisting>
application/x-blobapp = blobviewer %f
</programlisting>
<para>We are supposing
that <replaceable>blobviewer</replaceable> wants a file
name parameter here, you would use <literal>%u</literal> if
it liked URLs better.</para>
</listitem>
</itemizedlist>
<para>If you just wanted to change the application used by
&RCL; to display a mime type which it already knows, you
would just need to edit <filename>mimeview</filename>. The
entries you add in your personal file override those in the
central configuration, which you do not need to
alter. <filename>mimeview</filename> can also be modified
from the Gui.</para>
</sect3>
<sect3 id="rcl.install.config.examples.addindex">
<title>Adding indexing support for a new file type</title>
<para>Let us now imagine that the above
<replaceable>.blob</replaceable> files actually contain
indexable text and that you know how to extract it with a
command line program. Getting &RCL; to index the files is
easy. You need to perform the above alteration, and also to
add data to the <filename>mimeconf</filename> file
(typically in <filename>~/.recoll/mimeconf</filename>):</para>
<itemizedlist>
<listitem><para>Under the <literal>[index]</literal>
section, add the following line (more about the
<replaceable>rclblob</replaceable> indexing script
later):<programlisting>
application/x-blobapp = exec rclblob
</programlisting></para>
</listitem>
<listitem><para>Under the <literal>[icons]</literal>
section, you should choose an icon to be displayed for the
files inside the result lists. Icons are normally 64x64
pixels PNG files which live in
<filename>/usr/[local/]share/recoll/images</filename>.</para>
</listitem>
<listitem><para>Under the <literal>[categories]</literal>
section, you should add the mime type where it makes sense
(you can also create a category). Categories may be used
for filtering in advanced search.</para>
</listitem>
</itemizedlist>
<para>The <replaceable>rclblob</replaceable> filter should
be an executable program or script which exists inside
<filename>/usr/[local/]share/recoll/filters</filename>. It
will be given a file name as argument and should output the
text or html contents on the standard output.</para>
<para>The <link linkend="rcl.program.filters">filter
programming</link> section describes in more detail how
to write a filter.</para>
</sect3>
</sect2>
</sect1>
</chapter>
</book>