Add many comments to server/play.c, in advance of possible

[disorder] / doc / disorder_config.5.in

.\"
.\" Copyright (C) 2004-2009 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 3 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, see <http://www.gnu.org/licenses/>.
.\"
.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; the web interface
uses a number of others (see \fBdisorder.cgi\fR(8)).
.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_preferences\fR(5) 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.
See \fBdisorder_preferences\fR(5) for more information.
.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
Each user has an associated set of rights which contorl which commands they may
execute.
Normally you would give all users most rights, and expect them to
cooperate (they are after all presumed to be in a shared sound environment).
.PP
The full set of rights are:
.TP
.B read
User can perform read-only operations
.TP
.B play
User can add tracks to the queue
.TP
.B "move any"
User can move any track
.TP
.B "move mine"
User can move their own tracks
.TP
.B "move random"
User can move randomly chosen tracks
.TP
.B "remove any"
User can remove any track
.TP
.B "remove mine"
User can remove their own tracks
.TP
.B "remove random"
User can remove randomly chosen tracks
.TP
.B "scratch any"
User can scratch any track
.TP
.B "scratch mine"
User can scratch their own tracks
.TP
.B "scratch random"
User can scratch randomly chosen tracks
.TP
.B volume
User can change the volume
.TP
.B admin
User can perform admin operations
.TP
.B rescan
User can initiate a rescan
.TP
.B register
User can register new users.
Normally only the
.B guest
user would have this right.
.TP
.B userinfo
User can edit their own userinfo
.TP
.B prefs
User can modify track preferences
.TP
.B "global prefs"
User can modify global preferences
.TP
.B pause
User can pause/resume 
.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
.PP
See \fBdisorder.cgi\fR(8) for more information.
.SS "Searching And Tags"
Search strings contain a list of search terms separated by spaces.
A search term can either be a single word or a tag, prefixed with "tag:".
.PP
Search words are compared without regard to letter case or accents; thus, all
of the following will be considered to be equal to one another:
.PP
.nf
  LATIN CAPITAL LETTER E
  LATIN SMALL LETTER E
  LATIN CAPITAL LETTER E WITH GRAVE
  LATIN SMALL LETTER E WITH GRAVE
  LATIN CAPITAL LETTER E plus COMBINING GRAVE ACCENT
  LATIN SMALL LETTER E plus COMBINING GRAVE ACCENT
.fi
.PP
The same rules apply to tags but in addition leading and trailing whitespace is
disregarded and all whitespace sequences are treated as equal when they appear
as internal whitespace.
.PP
Where several tags are listed, for instance the tags preference for a track,
the tags are separated by commas.
Therefore tags may not contain commas.
.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 "Configuration Files"
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.
Not really useful any more and will be abolished in future.
.TP
.I ~\fRUSERNAME\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.
.TP
.I pkgconfdir/config.\fRUSERNAME
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.
.IP
The prefererred location for per-user passwords is \fI~/.disorder/passwd\fR and
\fBdisorder authorize\fR writes there now.
.SS "Global Configuration"
.TP
.B home \fIDIRECTORY\fR
The home directory for state files.
Defaults to
.IR pkgstatedir .
The server will create this directory on startup if it does not exist.
.TP
.B plugins \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.
.IP
If
.B plugins
is used without arguments the plugin path is cleared.
.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 api \fINAME\fR
Selects the backend used to play sound and to set the volume.
The following options are available:
.RS
.TP
.B alsa
Use the ALSA API.
This is only available on Linux systems, on which it is the default.
.TP
.B coreaudio
Use Apple Core Audio.
This only available on OS X systems, on which it is the default.
.TP
.B oss
Use the OSS (/dev/dsp) API.
Not available on all platforms.
.TP
.B command
Execute a command.
This is the default if
.B speaker_command
is specified, or if no native is available.
.IP
You might want to set
.B pause_mode
with this backend.
.TP
.B rtp
Transmit audio over the network.
This is the default if \fBbroadcast\fR is specified.
You can use
.BR disorder-playrtp (1)
to receive and play the resulting stream on Linux and OS X.
.B network
is a deprecated synonym for this API.
.RE
.TP
.B authorization_algorithm \fIALGORITHM\fR
Defines the algorithm used to authenticate clients.
The valid options are sha1 (the default), sha256, sha384 and sha512.
See
.BR disorder_protocol (5)
for more details.
.TP
.B broadcast \fR[\fIFAMILY\fR] \fIADDRESS\fR \fIPORT\fR
Transmit sound data to \fIADDRESS\fR using UDP port \fIPORT\fR.
This implies \fBapi rtp\fR.
.IP
\fIFAMILY\fR can be \fB-4\fR or \fB-6\fR to force IPv4 or IPv6, if this is not
implied by \fIADDRESS\fR.
Note that IPv6 is not currently well tested.
.IP
See also \fBmulticast_loop\fR and \fBmulticast_ttl\fR.
.TP
.B broadcast_from \fR[\fIFAMILY\fR] \fIADDRESS\fR \fIPORT\fR
Sets the (local) source address used by \fBbroadcast\fR.
.IP
\fIFAMILY\fR can be \fB-4\fR or \fB-6\fR to force IPv4 or IPv6, if this is not
implied by \fIADDRESS\fR.
Note that IPv6 is not currently well tested.
.TP
.B channel \fICHANNEL\fR
The mixer channel that the volume control should use.
.IP
For \fBapi oss\fR the possible values are:
.RS
.TP 8
.B pcm

Output level for the audio device.
This is probably what you want and is the default.
.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.
.IP
For \fBapi alsa\fR, this is the name of the mixer control to use.
The default is \fBPCM\fR.
Use \fBamixer scontrols\fR or similar to get a full list.
.IP
For \fBapi coreaudio\fR, volume setting is not currently supported.
.TP
.B collection \fIMODULE\fR \fIENCODING\fR \fIROOT\fR
.TP
.B collection \fIMODULE\fR \fIROOT\fR
.TP
.B collection \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 exist as ordinary
files in the filesystem.
If no \fIMODULE\fR is specified then \fBfs\fR is assumed.
.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.
If no encoding is specified then the current locale's character encoding
is used.
.IP
NB that this default depends on the locale the server runs in, which is not
necessarily the same as that of ordinary users, depending how the system is
configured.
It's best to explicitly specify it to be certain.
.IP
\fIROOT\fR is the root in the filesystem of the filenames and is
passed to the plugin module.
It must be an absolute path and should not end with a "/".
.TP
.B cookie_key_lifetime \fISECONDS\fR
Lifetime of the signing key used in constructing cookies.  The default is one
week.
.TP
.B cookie_login_lifetime \fISECONDS\fR
Lifetime of a cookie enforced by the server.  When the cookie expires the user
will have to log in again even if their browser has remembered the cookie that
long.  The default is one day.
.TP
.B default_rights \fIRIGHTS\fR
Defines the set of rights given to new users.
The argument is a comma-separated list of rights.
For the possible values see
.B "Users And Access Control"
above.
.IP
The default is to allow everything except \fBadmin\fR and \fBregister\fR
(modified in legacy configurations by the obsolete \fBrestrict\fR directive).
.TP
.B device \fINAME\fR
Sound output device.
.IP
For \fBapi oss\fR this is the path to the device to use.
If it is set to \fBdefault\fR then \fI/dev/dsp\fR and \fI/dev/audio\fR
will be tried.
.IP
For \fBapi alsa\fR this is the device name to use.
.IP
For \fBapi coreaudio\fR this can be either the UID or the human-readable
name of the desired device.
For a list of names, visit System Preferences -> Sound and look at the Type column.
For example, you might use "Built-in Output" for the built-in speaker
or "Built-in Line Output" if you have connected external speakers.
Remember to quote the name.
.IP
The default is \fBdefault\fR, which is intended to map to whatever the system's
default is.
.TP
.B gap \fISECONDS\fR
Specifies the number of seconds to leave between tracks.
The default is 0.
.IP
NB this option currently DOES NOT WORK.  If there is genuine demand it might be
reinstated.
.TP
.B history \fIINTEGER\fR
Specifies the number of recently played tracks to remember (including
failed tracks and scratches).
.TP
.B listen \fR[\fIFAMILY\fR] \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, or is \fB*\fR, then listens on all local addresses.
.IP
\fIFAMILY\fR can be \fB-4\fR or \fB-6\fR to force IPv4 or IPv6, if this is not
implied by \fIHOST\fR.
Note that IPv6 is not currently well tested.
.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.
There is no good reason to set this to \fBno\fR and the option will
probably be removed in a future version.
.TP
.B mixer \fIDEVICE\fR
The mixer device name, if it needs to be specified separately from
\fBdevice\fR.
.IP
For \fBapi oss\fR this should be the path to the mixer device and the default
is \fI/dev/mixer\fR.
.IP
For \fBapi alsa\fR, this is the index of the mixer control to use.
The default is 0.
.IP
For \fBapi coreaudio\fR, volume setting is not currently supported.
.TP
.B multicast_loop yes\fR|\fBno
Determines whether multicast packets are loop backed to the sending host.
The default is \fByes\fR.
This only applies if \fBapi\fR is set to \fBrtp\fR and \fBbroadcast\fR
is actually a multicast address.
.TP
.B multicast_ttl \fIHOPS\fR
Set the maximum number of hops to send multicast packets.
This only applies if \fBapi\fR is set to \fBrtp\fR and
\fBbroadcast\fR is actually a multicast address.
The default is 1.
.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.
The defaults are equivalent to:
.PP
.nf
namepart title  "/([0-9]+ *[-:] *)?([^/]+)\\.[a-zA-Z0-9]+$" $2 display
namepart title  "/([^/]+)\\.[a-zA-Z0-9]+$"                  $1 sort
namepart album  "/([^/]+)/[^/]+$"                          $1 *
namepart artist "/([^/]+)/[^/]+/[^/]+$"                    $1 *
namepart ext    "(\\.[a-zA-Z0-9]+)$"                        $1 *
.fi
.TP
.B new_bias \fIWEIGHT\fR
The weight for new tracks.
The default is 450000, i.e. recently added tracks are a fifty times as likely
to be picked as normal.
.TP
.B new_bias_age \fISECONDS\fR
The maximum age of tracks that \fBnew_bias\fR applies to, in seconds.
The default is one week.
.TP
.B new_max \fIMAX\fR
The maximum number of tracks to list when reporting newly noticed tracks.
The default is 100.
.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 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 noticed_history
The maximum days that a track can survive in the database of newly added
tracks.
The default is 31.
.TP
.B pause_mode \fIMODE
Sets the pause mode for the \fBcommand\fR backend.
The possible values are:
.RS
.TP
.B silence
Send silent (0-value) samples when paused.
This is the default.
.TP
.B suspend
Stop writing when paused.
.RE
.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]
\fBThis option is deprecated\fR.
If you want gapless play use raw-format players and the speaker process instead.
(This the default in any case.)
.IP
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.
.BR disorder-decode (8)
can decode several common audio file formats to this format.
If your favourite format is not supported, but you have a player
which uses libao, there is also a libao driver which supports this format;
see below for more information about this.
.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.
.IP
For the server to be able to calculate track lengths, there should be a
.B tracklength
command corresponding to each
.B player
command.
.IP
If
.B player
is used without arguments, the list of players is cleared.
.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.
The default is 10.
.TP
.B reminder_interval \fISECONDS\fR
The minimum number of seconds that must elapse between password reminders.
The default is 600, i.e. 10 minutes.
.TP
.B remote_userman yes\fR|\fBno
User management over TCP connection is only allowed if this is set to
\fByes\fR.  By default it is set to \fBno\fR.
.TP
.B replay_min \fISECONDS\fR
The minimum number of seconds that must elapse after a track has been played
before it can be picked at random.  The default is 8 hours.  If this is set to
0 then there is no limit, though current \fBdisorder-choose\fR will not pick
anything currently listed in the recently-played list.
.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 .
.PP
With the
.B rtp
backend the sample format is forced to
.B 16b/44100/2
and with the
.B coreaudio
backend it is forced to
.BR 16/44100/2 ,
in both cases regardless of what is specified in the configuration file.
.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).
See the documentation for your installed copy of \fBsox\fR to determine
which you need.
The default is set according to the version of sox found when DisOrder was
built.
If you run on a system with a different version of sox, you will need to
set this option.
.TP
.B speaker_backend \fINAME
This is an alias for \fBapi\fR; see above.
.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 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).
.IP
If \fBscratch\fR is used without arguments then the list of scratches is
cleared.
.TP
.B stopword \fIWORD\fR ...
Specifies one or more stopwords that should not take part in searches
over track names.
.IP
If \fBstopword\fR is used without arguments then the list of stopwords is
cleared.
.IP
There is a default set of stopwords built in, but this option can be used to
augment or replace that list.
.TP
.B tracklength \fIPATTERN\fR \fIMODULE\fR
Specifies the module used to calculate the length of files matching
\fIPATTERN\fR.
\fIMODULE\fR specifies which plugin module to use.
.IP
If \fBtracklength\fR is used without arguments then the list of modules is
cleared.
.TP
.B user \fIUSERNAME\fR
Specifies the user to run as.
Only makes sense if invoked as root (or the target user).
.SS "Client Configuration"
These options would normally be used in \fI~\fRUSERNAME\fI/.disorder/passwd\fR
or
\fIpkgconfdir/config.\fRUSERNAME.
.TP
.B connect \fR[\fIFAMILY\fR] \fIHOST SERVICE\fR
Connect to the address specified by \fIHOST\fR and port specified by
\fISERVICE\fR.
.IP
\fIFAMILY\fR can be \fB-4\fR or \fB-6\fR to force IPv4 or IPv6, if this is not
implied by \fIHOST\fR.
Note that IPv6 is not currently well tested.
.TP
.B password \fIPASSWORD\fR
Specify password.
.TP
.B username \fIUSERNAME\fR
Specify username.
The default is inferred from the current UID.
.SS "Web Interface Configuration"
.\" TODO this section is misnamed really...
.TP
.B mail_sender \fIADDRESS\fR
The email address that appears in the From: field of any mail messages sent by
the web interface.
This must be set if you have online registration enabled.
.TP
.B refresh \fISECONDS\fR
Specifies the maximum refresh period in seconds.
Default 15.
.TP
.B sendmail \fIPATH\fR
The path to the Sendmail executable.
This must support the \fB-bs\fR option (Postfix, Exim and Sendmail should all
work).
The default is the sendmail executable found at compile time.
.TP
.B short_display \fICHARACTERS\fR
Defines the maximum number of characters to include in a \fBshort\fR name
part.
Default 30.
.TP
.B smtp_server \fIHOSTNAME\fR
The hostname (or address) of the SMTP server to use for sending mail.
The default is 127.0.0.1.
If \fBsendmail\fR is set then that is used instead.
.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.
The defaults are:
.PP
.nf
transform track "^.*/([0-9]+ *[-:] *)?([^/]+)\\.[a-zA-Z0-9]+$" $2 display
transform track "^.*/([^/]+)\\.[a-zA-Z0-9]+$"        $1 sort
transform dir   "^.*/([^/]+)$"                      $1 *
transform dir   "^(the) ([^/]*)"                    "$2 $1" sort i
transform dir   "[[:punct:]]"                       "" sort g
.fi
.TP
.B url \fIURL\fR
Specifies the URL of the web interface.
This URL will be used in generated web pages.
The default is inferred at runtime, so this option no
longer needs to be specified.
.IP
This must be the full URL, e.g. \fBhttp://myhost/cgi-bin/jukebox\fR and not
\fB/cgi-bin/jukebox\fR.
.SH "GLOBAL PREFERENCES"
.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 "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 "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), \fBdisorder_templates\fR(5), \fBdisorder_actions\fR(5),
\fBdisorder.cgi\fR(8), \fBdisorder_preferences\fR(5)
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