disobedience more robust against server restart

[disorder] / doc / disorder_config.5.in

.\"
.\" Copyright (C) 2004, 2005, 2006, 2007 Richard Kettlewell
.\"
.\" This program is free software; you can redistribute it and/or modify
.\" it under the terms of the GNU General Public License as published by
.\" the Free Software Foundation; either version 2 of the License, or
.\" (at your option) any later version.
.\"
.\" This program is distributed in the hope that it will be useful, but
.\" WITHOUT ANY WARRANTY; without even the implied warranty of
.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
.\" General Public License for more details.
.\"
.\" You should have received a copy of the GNU General Public License
.\" along with this program; if not, write to the Free Software
.\" Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
.\" USA
.\"
.TH disorder_config 5
.SH NAME
pkgconfdir/config - DisOrder jukebox configuration
.SH DESCRIPTION
The purpose of DisOrder is to organize and play digital audio files, under the
control of multiple users.  \fIpkgconfdir/config\fR is the primary
configuration file but this man page currently documents all of its various
configuration files.
.SS Tracks
DisOrder can be configured with multiple collections of tracks, indexing them
by their filename, and picking players on the basis of filename patterns (for
instance, "*.mp3").
.PP
Although the model is of filenames, it is not inherent that there are
corresponding real files - merely that they can be interpreted by the chosen
player.  See \fBdisorder\fR(3) for more details about this.
.PP
Each track can have a set of preferences associated with it.  These are simple
key-value pairs; they can be used for anything you like, but a number of keys
have specific meanings.  See \fBdisorder\fR(1) for more details about these.
.SS "Track Names"
Track names are derived from filenames under the control of regular
expressions, rather than attempting to interpret format-specific embedded name
information.  They can be overridden by setting preferences.
.PP
Names for display are distinguished from names for sorting, so with the right
underlying filenames an album can be displayed in its original order even if
the displayed track titles are not lexically sorted.
.SS "Server State"
A collection of global preferences define various bits of server state: whether
random play is enabled, what tags to check for when picking at random, etc.
.SS "Users And Access Control"
DisOrder distinguishes between multiple users.  This is for access control and
reporting, not to provide different views of the world: i.e. preferences and so
on are global.
.PP
It's possible to restrict a small number of operations to a specific subset of
users.  However, it is assumed that every user is supposed to be able to do
most operations - since the users are all sharing the same audio environment
they are expected to cooperate with each other.
.PP
Access control is entirely used-based.  If you configure DisOrder to listen for
TCP/IP connections then it will accept a connection from anywhere provided the
right password is available.  Passwords are never transmitted over TCP/IP
connections in clear, but everything else is.  The expected model is that
host-based access control is imposed at the network layer.
.SS "Web Interface"
The web interface is controlled by a collection of template files, one for each
kind of page, and a collection of option files.  These are split up and
separate from the main configuration file to make it more convenient to
override specific bits.
.PP
The web interface connects to the DisOrder server like any other user, though
it is given a special privilege to "become" any other user.  (Thus, any process
with the same UID as the web interface is very powerful as far as DisOrder
goes.)
.PP
Access control to the web interface is (currently) separate from DisOrder's own
access control (HTTP authentication is required) but uses the same user
namespace.
.SH "CONFIGURATION FILE"
.SS "General Syntax"
Lines are split into fields separated by whitespace (space, tab, line
feed, carriage return, form feed).  Comments are started by the number
sign ("#").
.PP
Fields may be unquoted (in which case they may not contain spaces and
may not start with a quotation mark or apostrophe) or quoted by either
quotation marks or apostrophes.  Inside quoted fields every character
stands for itself, except that a backslash can only appear as part of
one of the following escape sequences:
.TP
.B \e\e
Backslash
.TP
.B \e"
Quotation mark
.\" "
.TP
.B \e'
Apostrophe
.TP
.B \en
Line feed
.PP
No other escape sequences are allowed.
.PP
Within any line the first field is a configuration command and any
further fields are parameters.  Lines with no fields are ignored.
.PP
After editing the config file use \fBdisorder reconfigure\fR to make
it re-read it.  If there is anything wrong with it the daemon will
record a log message and ignore the new config file.  (You should fix
it before next terminating and restarting the daemon, as it cannot
start up without a valid config file.)
.SS "Global Configuration"
.TP
.B home \fIDIRECTORY\fR
The home directory for state files.  Defaults to
.IR pkgstatedir .
.TP
.B plugin \fIPATH\fR
Adds a directory to the plugin path.  (This is also used by the web
interface.)
.IP
Plugins are opened the first time they are required and never after,
so after changing a plugin you must restart the server before it is
guaranteed to take effect.
.SS "Server Configuration"
.TP
.B alias \fIPATTERN\fR
Defines the pattern use construct virtual filenames from \fBtrackname_\fR
preferences.
.IP
Most characters stand for themselves, the exception being \fB{\fR which is used
to insert a track name part in the form \fB{\fIname\fB}\fR or
\fB{/\fIname\fB}\fR.
.IP
The difference is that the first form just inserts the name part while the
second prefixes it with a \fB/\fR if it is nonempty.
.IP
The pattern should not attempt to include the collection root, which is
automatically included, but should include the proper extension.
.IP
The default is \fB{/artist}{/album}{/title}{ext}\fR.
.TP
.B channel \fICHANNEL\fR
The mixer channel that the volume control should use.  Valid names depend on
your operating system and hardware, but some standard ones that might be useful
are:
.RS
.TP 8
.B pcm
Output level for the audio device.  This is probably what you want.
.TP
.B speaker
Output level for the PC speaker, if that is connected to the sound card.
.TP
.B pcm2
Output level for alternative codec device.
.TP
.B vol
Master output level.  The OSS documentation recommends against using this, as
it affects all output devices.
.RE
.IP
You can also specify channels by number, if you know the right value.
.TP
.B collection \fIMODULE\fR \fIENCODING\fR \fIROOT\fR
Define a collection of tracks.
.IP
\fIMODULE\fR defines which plugin module should be used for this
collection.  Use the supplied \fBfs\fR module for tracks that exists
as ordinary files in the filesystem.
.IP
\fIENCODING\fR defines the encoding of filenames in this collection.
For \fBfs\fR this would be the encoding you use for filenames.
Examples might be \fBiso-8859-1\fR or \fButf-8\fR.
.IP
\fIROOT\fR is the root in the filesystem of the filenames and is
passed to the plugin module.
.TP
.B device \fINAME\fR
ALSA device to play raw-format audio.  Default is \fBdefault\fR, i.e. to use
the whatever the ALSA configured default is.
.TP
.B gap \fISECONDS\fR
Specifies the number of seconds to leave between tracks.  The default
is 2.
.TP
.B history \fIINTEGER\fR
Specifies the number of recently played tracks to remember (including
failed tracks and scratches).
.TP
.B listen \fR[\fIHOST\fR] \fISERVICE\fR
Listen for connections on the address specified by \fIHOST\fR and port
specified by \fISERVICE\fR.  If \fIHOST\fR is omitted then listens on all
local addresses.
.IP
Normally the server only listens on a UNIX domain socket.
.TP
.B lock yes\fR|\fBno
Determines whether the server locks against concurrent operation.  Default is
\fByes\fR.
.TP
.B mixer \fIPATH\fR
The path to the mixer device, if you want access to the volume control,
e.g. \fB/dev/mixer\fR.
.TP
.B namepart \fIPART\fR \fIREGEXP\fR \fISUBST\fR [\fICONTEXT\fR [\fIREFLAGS\fR]]
Determines how to extract trackname part \fIPART\fR from a 
track name (with the collection root part removed).
Used in \fB@recent@\fR, \fB@playing@\fR and \fB@search@\fR.
.IP
Track names can be different in different contexts.  For instance the sort
string might include an initial track number, but this would be stripped for
the display string.  \fICONTEXT\fR should be a glob pattern matching the
contexts in which this directive will be used.
.IP
Valid contexts are \fBsort\fR and \fBdisplay\fR.
.IP
All the \fBnamepart\fR directives are considered in order.  The
first directive for the right part, that matches the desired context,
and with a \fIREGEXP\fR that
matches the track is used, and the value chosen is constructed from
\fISUBST\fR according to the substitution rules below.
.IP
Note that searches use the raw track name and \fBtrackname_\fR preferences but
not (currently) the results of \fBnamepart\fR, so generating words via this option
that aren't in the original track name will lead to confusing results.
.IP
If you supply no \fBnamepart\fR directives at all then a default set will be
supplied automatically.  But if you supply even one then you must supply all of
them.  See the example config file for the defaults.
.TP
.B nice_rescan \fIPRIORITY\fR
Set the recan subprocess priority.  The default is 10.
.IP
(Note that higher values mean the process gets less CPU time; UNIX priority
values are the backwards.)
.TP
.B nice_server \fIPRIORITY\fR
Set the server priority.  This is applied to the server at startup time (and
not when you reload configuration).  The server does not use much CPU itself
but this value is inherited by programs it executes.  If you have limited CPU
then it might help to set this to a small negative value.  The default is 0.
.TP
.B nice_speaker \fIPRIORITY\fR
Set the speaker process priority.  This is applied to the speaker process at
startup time (and not when you reload the configuration).  The speaker process
is not massively CPU intensive by today's standards but depends on reasonably
timely scheduling.  If you have limited CPU then it might help to set this to a
small negative value.  The default is 0.
.TP
.B player \fIPATTERN\fR \fIMODULE\fR [\fIOPTIONS.. [\fB--\fR]] \fIARGS\fR...
Specifies the player for files matching the glob \fIPATTERN\fR.  \fIMODULE\fR
specifies which plugin module to use.
.IP
The following options are supported:
.RS
.TP
.B --wait-for-device\fR[\fB=\fIDEVICE\fR]
Waits (for up to a couple of seconds) for the default, or specified, libao
device to become openable.
.TP
.B --
Defines the end of the list of options.  Needed if the first argument to the
plugin starts with a "-".
.RE
.IP
The following are the standard modules:
.RS
.TP
.B exec \fICOMMAND\fR \fIARGS\fR...
The command is executed via \fBexecvp\fR(3), not via the shell.
The \fBPATH\fR environment variable is searched for the executable if it is not
an absolute path.
The command is expected to know how to open its own sound device.
.TP
.B execraw \fICOMMAND\fR \fIARGS\fR...
Identical to the \fBexec\fR except that the player is expected to use the
DisOrder raw player protocol (see notes below).
.TP
.B shell \fR[\fISHELL\fR] \fICOMMAND\fR
The command is executed using the shell.  If \fISHELL\fR is specified then that
is used, otherwise \fBsh\fR will be used.  In either case the \fBPATH\fR
environment variable is searched for the shell executable if it is not an
absolute path.  The track name is stored in the environment variable
\fBTRACK\fR.
.IP
Be careful of the interaction between the configuration file quoting rules and
the shell quoting rules.
.RE
.IP
If multiple player commands match a track then the first match is used.
.TP
.B prefsync \fISECONDS\fR
The interval at which the preferences log file will be synchronised.  Defaults
to 3600, i.e. one hour.
.TP
.B queue_pad \fICOUNT\fR
The target size of the queue.  If random play is enabled then randomly picked
tracks will be added until the queue is at least this big.
.TP
.B sample_format \fIBITS\fB/\fIRATE\fB/\fICHANNELS
Describes the sample format expected by the \fBspeaker_command\fR (below).  The
components of the format specification are as follows:
.RS
.TP 10
.I BITS
The number of bits per sample.  Optionally, may be suffixed by \fBb\fR or
\fBl\fR for big-endian and little-endian words.  If neither is used the native
byte order is assumed.
.TP
.I RATE
The number of samples per second.
.TP
.I CHANNELS
The number of channels.
.PP
The default is
.BR 16/44100/2 .
.RE
.TP
.B signal \fINAME\fR
Defines the signal to be sent to track player process groups when tracks are
scratched.  The default is \fBSIGKILL\fR.
.IP
Signals are specified by their full C name, i.e. \fBSIGINT\fR and not \fBINT\fR
or \fBInterrupted\fR or whatever.
.TP
.B sox_generation \fB0\fR|\fB1
Determines whether calls to \fBsox\fR(1) should use \fB-b\fR, \fB-x\fR, etc (if
the generation is 0) or \fB-\fIbits\fR, \fB-L\fR etc (if it is 1).  The default
is 0.
.TP
.B speaker_command \fICOMMAND
Causes the speaker subprocess to pipe audio data into shell command
\fICOMMAND\fR, rather than writing to a local sound card.  The sample format is
determine by
.B sample_format
above.
.IP
Note that if the sample format is wrong then
.BR sox (1)
is invoked to translate it.  If
.B sox
is not installed then this will not work.
.TP
.B restrict \fR[\fBscratch\fR] [\fBremove\fR] [\fBmove\fR]
Determine which operations are restricted to the submitter of a
track.  By default, no operations are restricted, i.e. anyone can
scratch or remove anything.
.IP
If \fBrestrict scratch\fR or \fBrestrict remove\fR are set then only the user
that submitted a track can scratch or remove it, respectively.
.IP
If \fBrestrict move\fR is set then only trusted users can move tracks around in
the queue.
.IP
If \fBrestrict\fR is used more than once then only the final use has any
effect.
.TP
.B scratch \fIPATH\fR
Specifies a scratch.  When a track is scratched, a scratch track is
played at random.
Scratches are played using the same logic as other tracks.
.IP
At least for the time being, path names of scratches must be encoded using
UTF-8 (which means that ASCII will do).
.TP
.B stopword \fIWORD\fR ...
Specifies one or more stopwords that should not take part in searches
over track names.
.SS "Client Configuration"
.TP
.B connect \fR[\fIHOST\fR] \fISERVICE\fR
Connect to the address specified by \fIHOST\fR and port specified by
\fISERVICE\fR.  If \fIHOST\fR is omitted then connects to the local host.
Normally the UNIX domain socket is used instead.
.SS "Web Interface Configuration"
.TP
.B refresh \fISECONDS\fR
Specifies the maximum refresh period in seconds.  Default 15.
.TP
.B templates \fIPATH\fR ...
Specifies the directory containing templates used by the web
interface.  If a template appears in more than one template directory
then the one in the earliest directory specified is chosen.
.IP
See below for further details.
.TP
.B transform \fITYPE\fR \fIREGEXP\fR \fISUBST\fR [\fICONTEXT\fR [\fIREFLAGS\fR]]
Determines how names are sorted and displayed in track choice displays.
.IP
\fITYPE\fR is the type of transformation; usually \fBtrack\fR or
\fBdir\fR but you can define your own.
.IP
\fICONTEXT\fR is a glob pattern matching the context.  Standard contexts are
\fBsort\fR (which determines how directory names are sorted) and \fBdisplay\fR
(which determines how they are displayed).  Again, you can define your
own.
.IP
All the \fBtransform\fR directives are considered in order.  If
the \fITYPE\fR, \fIREGEXP\fR and the \fICONTEXT\fR match
then a new track name is constructed from
\fISUBST\fR according to the substitution rules below.  If several
match then each is executed in order.
.IP
If you supply no \fBtransform\fR directives at all then a default set will be
supplied automatically.  But if you supply even one then you must supply all of
them.  See the example config file for the defaults.
.TP
.B url \fIURL\fR
Specifies the URL of the web interface.  This URL will be used in
generated web pages.
.IP
This must be the full URL, e.g. \fBhttp://myhost/cgi-bin/jukebox\fR and not
\fB/cgi-bin/jukebox\fR.
.SS "Authentication Configuration"
.TP
.B allow \fIUSERNAME\fR \fIPASSWORD\fR
Specify a username/password pair.
.TP
.B password \fIPASSWORD\fR
Specify password.
.TP
.B trust \fIUSERNAME\fR
Allow \fIUSERNAME\fR to perform privileged operations such as shutting
down or reconfiguring the daemon, or becoming another user.
.TP
.B user \fIUSER\fR
Specifies the user to run as.  Only makes sense if invoked as root (or
the target user).
.TP
.B username \fIUSERNAME\fR
Specify username.  The default is taken from the environment variable
\fBLOGNAME\fR.
.PP
Configuration files are read in the following order:
.TP
.I pkgconfdir/config
.TP
.I pkgconfdir/config.private
Should be readable only by the jukebox group, and contain \fBallow\fR
commands for authorised users.
.TP
.I pkgconfdir/config.\fRUSER
Per-user system-controlled client configuration.  Optional but if it
exists must be readable only by the relevant user.  Would normally
contain a \fBpassword\fR directive.
.TP
.I ~\fRUSER\fI/.disorder/passwd
Per-user client configuration.  Optional but if it exists must be
readable only by the relevant user.  Would normally contain a
\fBpassword\fR directive.
.SH "GLOBAL PREFERENCES"
These are the values set with \fBset-global\fR.
.TP
.B required-tags
If this is set an nonempty then randomly played tracks will always have at
least one of the listed tags.
.IP
Tags can contain any printing character except comma.  Leading and trailing
spaces are not significant but internal spaces are.  Tags in a list are
separated by commas.
.TP
.B prohibited-tags
If this is set an nonempty then randomly played tracks will never have any of
the listed tags.
.TP
.B playing
If unset or \fByes\fR then play is enabled.  Otherwise it is disabled.  Use
\fBdisable\fR rather than setting it directly.
.TP
.B random-play
If unset or \fByes\fR then random play is enabled.  Otherwise it is disabled.
Use \fBdisable\fR rather than setting it directly.
.SH "LIBAO DRIVER"
.SS "Raw Protocol Players"
Raw protocol players are expected to use the \fBdisorder\fR libao driver.
Programs that use libao generally have command line options to select the
driver and pass options to it.
.SS "Driver Options"
The known driver options are:
.TP
.B fd
The file descriptor to write to.  If this is not specified then the driver
looks like the environment variable \fBDISORDER_RAW_FD\fR.  If that is not set
then the default is 1 (i.e. standard output).
.TP
.B fragile
If this is set to a nonzero value then the driver will call \fB_exit\fR(2) if a
write to the output file descriptor fails.  This is a workaround for buggy
players such as \fBogg123\fR that ignore write errors.
.SH "WEB TEMPLATES"
When \fBdisorder.cgi\fR wants to generate a page for an action it searches the
directories specified with \fBtemplates\fR for a matching file.  It is
suggested that you leave the distributed templates unchanged and put
any customisations in an earlier entry in the template path.
.PP
The supplied templates are:
.TP
.B about.html
Display information about DisOrder.
.TP
.B choose.html
Navigates through the track database to choose a track to play.  The
\fBdir\fR argument gives the directory to look in; if it is missing
then the root directory is used.
.TP
.B choosealpha.html
Provides a front end to \fBchoose.html\fR which allows subsets of the top level
directories to be selected by initial letter.
.TP
.B playing.html
The "front page", which usually shows the currently playing tracks and
the queue.
Gets an HTTP \fBRefresh\fR header.
.IP
If the \fBmgmt\fR CGI argument is set to \fBtrue\fR then we include extra
buttons for moving tracks up and down in the queue.  There is some logic in
\fBdisorder.cgi\fR to ensure that \fBmgmt=true\fR is preserved across refreshes
and redirects back into itself, but URLs embedded in web pages must include it
explicitly.
.TP
.B prefs.html
Views preferences.  If the \fBfile\fR, \fBname\fR and \fBvalue\fR arguments are
all set then that preference is modified; if \fBfile\fR and \fBname\fR are set
but not \fBvalue\fR then the preference is deleted.
.TP
.B recent.html
Lists recently played tracks.
.TP
.B search.html
Presents search results.
.TP
.B volume.html
Primitive volume control.
.PP
Additionally, other standard files are included by these:
.TP
.B credits.html
Included at the end of the main content \fB<DIV>\fR element.
.TP
.B sidebar.html
Included at the start of the \fB<BODY>\fR element.
.TP
.B stdhead.html
Included in the \fB<HEAD>\fR element.
.TP
.B stylesheet.html
Contains the default DisOrder stylesheet.  You can override this by editing the
CSS or by replacing it all with a \fB<LINK>\fR to an external stylesheet.
.PP
Templates are ASCII files containing HTML documents, with an expansion
syntax to enable data supplied by the implementation to be inserted.
.PP
If you want to use characters outside the ASCII range, use either the
appropriate HTML entity, e.g. \fB&eacute;\fR, or an SGML numeric
character reference, e.g. \fB&#253;\fR.  Use \fB&#64;\fR to insert a
literal \fB@\fR without falling foul of the expansion syntax.
.SS "Expansion Syntax"
Expansions are surrounded by at ("@") symbols take the form of a keyword
followed by zero or more arguments.  Arguments may either be quoted by curly
brackets ("{" and "}") or separated by colons (":").  Both kinds may be mixed
in a single expansion, though doing so seems likely to cause confusion.
The descriptions below contain suggested forms for each
expansion.
.PP
Leading and trailing whitespace in unquoted arguments is ignored, as is
whitespace (including newlines) following a close bracket ("}").
.PP
Arguments are recursively expanded before being interpreted, except for
\fITEMPLATE\fR arguments.  These are expanded (possibly more than once) to
produce the final expansion.
(More than once means the same argument being expanded more than once
for different tracks or whatever, not the result of the first
expansion itself being re-expanded.)
.PP
Strings constructed by expansions (i.e. not literally copied from the template
text) are SGML-quoted: any character which does not stand for itself in #PCDATA
or a quoted attribute value is replaced by the appropriate numeric character
reference.
.PP
The exception to this is that such strings are \fInot\fR quoted when they are
generated in the expansion of a parameter.
.PP
In the descriptions below, the current track means the one set by
\fB@playing@\fR, \fB@recent@\fR or \fB@queue@\fR, not the one that is playing.
If none of these expansions are in force then there is no current track.
\fIBOOL\fR should always be either \fBtrue\fR or \fBfalse\fR.
.SS "Expansions"
The following expansion keywords are defined:
.TP
.B @#{\fICOMMENT\fB}@
Ignored.
.TP
.B @action@
The current action.  This reports
.B manage
if the action is really
.B playing
but
.B mgmt=true
was set.
.TP
.B @and{\fIBOOL\fB}{\fIBOOL\fB}\fR...\fB@
If there are no arguments, or all the arguments are \fBtrue\fB, then expands to
\fBtrue\fR, otherwise to \fBfalse\fR.
.TP
.B @arg:\fINAME\fB@
Expands to the value of CGI script argument \fINAME\fR.
.TP
.B @basename@
The basename of the current directory component, in \fB@navigate@\fR.
.TP
.B @basename{\fIPATH\fB}@
The base name part of \fIPATH\fR.
.TP
.B @choose{\fIWHAT\fB}{\fITEMPLATE\fB}@
Expands \fITEMPLATE\fR repeatedly for each file or directory under
\fB@arg:directory@\fR.
\fIWHAT\fR should be either \fBfile\fR or \fBdirectory\fR.
Use \fB@file@\fR to get the display name or filename of the file or
directory.
Usually used in \fBchoose.html\fR.
.TP
.B @dirname@
The directory of the current directory component, in \fB@navigate@\fR.
.TP
.B @dirname{\fIPATH\fB}@
The directory part of \fIPATH\fR.
.TP
.B @enabled@
Expands to \fBtrue\fR if play is currently enabled, otherwise to \fBfalse\fR.
.TP
.B @eq{\fIA\fB}{\fIB\fB}
Expands to \fBtrue\fR if \fIA\fR and \fIB\fR are identical, otherwise to
\fBfalse\fR.
.TP
.B @file@
Expands to the filename of the current file or directory, inside the template
argument to \fBchoose\fR.
.TP
.B @files{\fITEMPLATE\fB}
Expands \fITEMPLATE\fB once for each file indicated by the \fBdirectory\fR CGI
arg if it is present, or otherwise for the list of files counted by \fBfiles\fR
with names \fB0_file\fR, \fB1_file\fR etc.
.TP
.B @fullname@
The full path of the current directory component, in \fB@navigate@\fR.
.TP
.B @id@
The ID of the current track.
.TP
.B @if{\fIBOOL\fB}{\fITRUEPART\fB}{\fIFALSEPART\fB}@
If \fIBOOL\fR expands to \fBtrue\fR then expands to \fITRUEPART\fR, otherwise
to \fIFALSEPART\fR (which may be omitted).
.TP
.B @include:\fIPATH\fR@
Include the named file as if it were a template file.  If \fIPATH\fR
starts with a \fB/\fR then it is used as-is; otherwise, ".html" is
appended and the template path is searched.
.TP
.B @index@
Expands to the index of the current file in \fB@queue@\fR, \fB@recent@\fR or
\fB@files@\fR.
.TP
.B @isdirectories@
Expands to \fBtrue\fR if there are any directories in \fB@arg:directory@\fR,
otherwise to \fBfalse\fR.
.TP
.B @isfiles@
Expands to \fBtrue\fR if there are any files in \fB@arg:directory@\fR,
otherwise to \fBfalse\fR.
.TP
.B @isfirst@
Expands to \fBtrue\fR if this is the first repetition of a \fITEMPLATE\fR
argument in a loop (\fB@queue\fR or similar), otherwise to \fBfalse\fR.
.TP
.B @islast@
Expands to \fBtrue\fR if this is the last repetition of a \fITEMPLATE\fR in a
loop, otherwise to \fBfalse\fR.
.TP
.B @isplaying@
Expands to \fBtrue\fR if a track is playing, otherwise to \fBfalse\fR.
.TP
.B @isqueue@
Expands to \fBtrue\fR if there are any tracks in the queue, otherwise to
\fBfalse\fR.
.TP
.B @isrecent@
Expands to \fBtrue\fR if the recently played list has any tracks in it,
otherwise to \fBfalse\fR.
.TP
.B @label:\fINAME\fR\fB@
Expands to the value of label \fINAME\fR.  See the shipped \fIoptions.labels\fR
file for full documentation of the labels used by the standard templates.
.TP
.B @length@
Expands to the length of the current track.
.TP
.B @navigate{\fIDIRECTORY\fB}{\fITEMPLATE\fB}
Expands \fITEMPLATE\fR for each component of \fIDIRECTORY\fR in turn.
Use \fB@dirname\fR and \fB@basename@\fR to get the components of the path to
each component.
Usually used in \fBchoose.html\fR.
.TP
.B @ne{\fIA\fB}{\fIB\fB}
Expands to \fBtrue\fR if \fIA\fR and \fIB\fR differ, otherwise to \fBfalse\fR.
.TP
.B @nfiles@
Expands to the number of files from \fB@files\fR (above).
.TP
.B @nonce@
Expands to a string including the time and process ID, intended to be
unique across invocations.
.TP
.B @not{\fIBOOL\fB}@
Expands to \fBfalse\fR if \fIBOOL\fR is \fBtrue\fR, otherwise to
\fBfalse\fR.
.TP
.B @or{\fIBOOL\fB}{\fIBOOL\fB}\fR...\fB@
If at least one argument is \fBtrue\fB, then expands to \fBtrue\fR, otherwise
to \fBfalse\fR.
.TP
.B @parity@
Expands to \fBeven\fR or \fBodd\fR depending on whether the current track is at
an even or odd position in \fB@queue@\fR, \fB@recent@\fR or \fB@files@\fR.
.TP
.B @part{\fICONTEXT\fB}{\fIPART\fB}@
Expands to track name part \fIPART\fR using context \fICONTEXT\fR for the
current track.  The context may be omitted (and normally would be) and defaults
to \fBdisplay\fR.
.TP
.B @part{\fICONTEXT\fB}{\fIPART\fB}{\fITRACK\fB}@
Expands to track name part \fIPART\fR using context \fICONTEXT\fR for
\fITRACK\fR.  In this usage the context may not be omitted.
.TP
.B @paused@
Expands to \fBtrue\fR if the current track is paused, else \fBfalse\fR.
.TP
.B @playing{\fITEMPLATE\fB}@
Expands \fITEMPLATE\fR using the playing track as the current track.
.TP
.B @pref{\fITRACK\fB}{\fIKEY\fB}@
Expand to the track preference, or the empty string if it is not set.
.TP
.B @prefname@
Expands to the name of the current preference, in the template
argument of \fB@prefs@\fR.
.TP
.B @prefs{\fIFILE\fB}{\fITEMPLATE\fB}@
Expands \fITEMPLATE\fR repeatedly, for each preference of track
\fIFILE\fR.
Use \fB@prefname@\fR and \fB@prefvalue@\fR to get the name and value.
.TP
.B @prefvalue@
Expands to the value of the current preference, in the template
argument of \fB@prefs@\fR.
.TP
.B @queue{\fITEMPLATE\fB}@
Expands \fITEMPLATE\fR repeatedly using the each track on the queue in turn as
the current track.  The track at the head of the queue comes first.
.TP
.B @random-enabled@
Expands to \fBtrue\fR if random play is currently enabled, otherwise to
\fBfalse\fR.
.TP
.B @recent{\fITEMPLATE\fB}@
Expands \fITEMPLATE\fR repeatedly using the each recently played track in turn
as the current track.  The most recently played track comes first.
.TP
.B @resolve{\fITRACK\fB}@
Resolve aliases for \fITRACK\fR and expands to the result.
.TP
.B @search{\fIPART\fB}\fR[\fB{\fICONTEXT\fB}\fR]\fB{\fITEMPLATE\fB}@
Expands \fITEMPLATE\fR once for each group of search results that have
a common value of track part \fIPART\fR.
The groups are sorted by the value of the part.
.IP
.B @part@
and
.B @file@
within the template will apply to one of the tracks in the group.
.IP
If \fICONTEXT\fR is specified it should be either \fBsort\fR or \fBdisplay\fR,
and determines the context for \fIPART\fR.  The default is \fBsort\fR.  Usually
you want \fBdisplay\fR for everything except the title and \fBsort\fR for the
title.  If you use \fBsort\fR for artist and album then you are likely to get
strange effects.
.TP
.B @server-version@
Expands to the server's version string.
.TP
.B @shell{\fICOMMAND\fB}@
Expands to the output of \fICOMMAND\fR executed via the shell.  \fBsh\fR is
searched for using \fBPATH\fR.  If the command fails then this is logged but
otherwise ignored.
.TP
.B @state@
In \fB@queue@\fR and \fB@recent@\fR, expands to the state of the current
track.  Otherwise the empty string.  Known states are:
.RS
.TP 12
.B failed
The player terminated with nonzero status, but not because the track was
scratched.
.TP
.B isscratch
A scratch, in the queue.
.TP
.B no_player
No player could be found.
.TP
.B ok
Played successfully.
.TP
.B random
A randomly chosen track, in the queue.
.TP
.B scratched
This track was scratched.
.TP
.B unplayed
An explicitly queued track, in the queue.
.RE
.IP
Some additional states only apply to playing tracks, so will never be seen in
the queue or recently-played list:
.RS
.TP 12
.B paused
The track has been paused.
.TP
.B quitting
Interrupted because the server is shutting down.
.TP
.B started
This track is currently playing.
.RE
.TP
.B @stats@
Expands to the server statistics.
.TP
.B @thisurl@
Expands to the URL of the current page.  Typically used in
.B back
arguments.  If there is a
.B nonce
argument then it is changed to a fresh value.
.TP
.B @track@
The current track.
.TP
.B @trackstate{\fIPATH\fB}@
Expands to the current track state: \fBplaying\fR if the track is actually
playing now, \fBqueued\fR if it is queued or the empty string otherwise.
.TP
.B @transform{\fIPATH\fB}{\fITYPE\fB}{\fICONTEXT\fB}@
Transform a path according to \fBtransform\fR (see above).
\fIPATH\fR should be a raw filename (of a track or directory).
\fITYPE\fR should be the transform type (e.g. \fItrack\fR or \fIdir\fR).
\fICONTEXT\fR should be the context, and can be omitted (the default
is \fBdisplay\fR).
.TP
.B @url@
Expands to the canonical URL as defined in \fIpkgconfdir/config\fR.
.TP
.B @urlquote{\fISTRING\fB}@
URL-quote \fISTRING\fR.
.TP
.B @version@
Expands to \fBdisorder.cgi\fR's version string.
.TP
.B @volume:\fISPEAKER\fB@
The volume on the left or right speaker.  \fISPEAKER\fR must be \fBleft\fB or
\fBright\fR.
.TP
.B @when@
When the current track was played (or when it is expected to be played, if it
has not been played yet)
.TP
.B @who@
Who submitted the current track.
.SH "WEB OPTIONS"
This is a file called \fIoptions\fR, searched for in the same manner
as templates.  It includes numerous options for the control of the web
interface.  The general syntax is the same as the main configuration
file, except that it should be encoded using UTF-8 (though this might
change to the current locale's character encoding; stick to ASCII to
be safe).
.PP
The shipped \fIoptions\fR file includes four standard options files.
In order, they are:
.TP
.I options.labels
The default labels file.  You wouldn't normally edit this directly - instead
supply your own commands in \fIoptions.user\fR.  Have a look at the shipped
version of the file for documentation of labels used by the standard templates.
.TP
.I options.user
A user options file.  Here you should put any overrides for the default
labels and any extra labels required by your modified templates.
.PP
Valid directives are:
.TP
.B columns \fINAME\fR \fIHEADING\fR...
Defines the columns used in \fB@playing@\fR and \fB@recent@\fB.  \fINAME\fR
must be either \fBplaying\fR, \fBrecent\fR or \fBsearch\fR.
\fIHEADING\fR...  is a list of
heading names.  If a column is defined more than once then the last definitions
is used.
.IP
The heading names \fBbutton\fR, \fBlength\fR, \fBwhen\fR and \fBwho\fR
are built in.
.TP
.B include \fIPATH\fR
Includes another file.  If \fIPATH\fR starts with a \fB/\fR then it is
taken as is, otherwise it is searched for in the template path.
.TP
.B label \fINAME\fR \fIVALUE\fR
Define a label.  If a label is defined more than once then the last definition
is used.
.SS Labels
Some labels are defined inside \fBdisorder.cgi\fR and others by the
default templates.  You can define your own labels and use them inside
a template.
.PP
When an undefined label is expanded, if it has a dot in its name then
the part after the final dot is used as its value.  Otherwise the
whole name is used as the value.
.PP
Labels are no longer documented here, see the shipped \fIoptions.labels\fR file
instead.
.SH "REGEXP SUBSTITUTION RULES"
Regexps are PCRE regexps, as defined in \fBpcrepattern\fR(3).  The
only option used is \fBPCRE_UTF8\fR.  Remember that the configuration
file syntax means you have to escape backslashes and quotes inside
quoted strings.
.PP
In a \fISUBST\fR string the following sequences are interpreted
specially:
.TP
.B $1 \fR... \fB$9
These expand to the first to ninth bracketed subexpression.
.TP
.B $&
This expands to the matched part of the subject string.
.TP
.B $$
This expands to a single \fB$\fR symbol.
.PP
All other pairs starting with \fB$\fR are undefined (and might be used
for something else in the future, so don't rely on the current
behaviour.)
.PP
If \fBi\fR is present in \fIREFLAGS\fR then the match is case-independent.  If
\fBg\fR is present then all matches are replaced, otherwise only the first
match is replaced.
.SH "ACTIONS"
What the web interface actually does is terminated by the \fBaction\fR CGI
argument.  The values listed below are supported.
.PP
Except as specified, all actions redirect back to the \fBplaying.html\fR
template unless the \fBback\fR argument is present, in which case the URL it
gives is used instead.
.PP
Redirection to \fBplaying.html\fR preserves \fBmgmt=true\fR if it is present.
.TP 8
.B "move"
Move track \fBid\fR by offset \fBdelta\fR.
.TP
.B "play"
Play track \fBfile\fR, or if that is missing then play all the tracks in
\fBdirectory\fR.
.TP
.B "playing"
Don't change any state, but instead compute a suitable refresh time and include
that in an HTTP header.  Expands the \fBplaying.html\fR template rather than
redirecting.
.IP
This is the default if \fBaction\fR is missing.
.TP
.B "random-disable"
Disables random play.
.TP
.B "random-enable"
Enables random play.
.TP
.B "disable"
Disables play completely.
.TP
.B "enable"
Enables play.
.TP
.B "pause"
Pauses the current track.
.TP
.B "remove"
Remove track \fBid\fR.
.TP
.B "resume"
Resumes play after a pause.
.TP
.B "scratch"
Scratch the playing track.  If \fBid\fR is present it must match the playing
track.
.TP
.B "volume"
Change the volume by \fBdelta\fR, or if that is missing then set it to the
values of \fBleft\fR and \fBright\fR.  Expands to the \fBvolume.html\fR template
rather than redirecting.
.TP
.B "prefs"
Adjust preferences from the \fBprefs.html\fR template (which it then expands
rather than redirecting).
.IP
If
.B parts
is set then the cooked interface is assumed.  The value of
.B parts
is used to determine which trackname preferences are set.  By default the
.B display
context is adjusted but this can be overridden with the
.B context
argument.  Also the
.B random
argument is checked; if it is set then random play is enabled for that track,
otherwise it is disabled.
.IP
Otherwise if the
.B name
and
.B value
arguments are set then they are used to set a single preference.
.IP
Otherwise if just the
.B name
argument is set then that preference is deleted.
.IP
It is recommended that links to the \fBprefs\fR action use \fB@resolve@\fR to
enure that the real track name is always used.  Otherwise if the preferences
page is used to adjust a trackname_ preference, the alias may change, leading
to the URL going stale.
.TP
.B "error"
This action is generated automatically when an error occurs connecting to the
server.  The \fBerror\fR label is set to an indication of what the error is.
.SH "TRACK NAME PARTS"
The traditional track name parts are \fBartist\fR, \fBalbum\fR and \fBtitle\fR,
with the obvious intended meaning.  These are controlled by configuration and
by \fBtrackname_\fR preferences.
.PP
In addition there are two built-in parts, \fBpath\fR which is the whole path
name and \fBext\fR which is the filename extension, including the initial dot
(or the empty string if there is not extension).
.SH "SEE ALSO"
\fBdisorder\fR(1), \fBsox\fR(1), \fBdisorderd\fR(8), \fBdisorder-dump\fR(8),
\fBpcrepattern\fR(3)
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