.\"
-.\" Copyright (C) 2004, 2005, 2006 Richard Kettlewell
+.\" Copyright (C) 2004-2008 Richard Kettlewell
.\"
-.\" This program is free software; you can redistribute it and/or modify
+.\" 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
+.\" 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.
-.\"
+.\"
+.\" 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
+.\" along with this program. If not, see <http://www.gnu.org/licenses/>.
.\"
.TH disorder_protocol 5
.SH NAME
The DisOrder client and server communicate via the protocol described
in this man page.
.PP
-The protocol is liable to change without notice. You are recommended to check
-the implementation before believing this document.
+The protocol is liable to change without notice.
+You are recommended to check the implementation before believing this document.
.SH "GENERAL SYNTAX"
Everything is encoded using UTF-8.
+See
+.B "CHARACTER ENCODING"
+below for more detail on character encoding issues.
.PP
-Commands and responses consist of a line followed (depending on the
-command or response) by a message.
+Commands and responses consist of a line perhaps followed (depending on the
+command or response) by a body.
.PP
The line syntax is the same as described in \fBdisorder_config\fR(5) except
that comments are prohibited.
consisting of a full stop and a line feed.
.SH COMMANDS
Commands always have a command name as the first field of the line; responses
-always have a 3-digit response code as the first field. See below for more
-details about this field.
+always have a 3-digit response code as the first field.
+See below for more details about this field.
.PP
All commands require the connection to have been already authenticated unless
stated otherwise.
+If not stated otherwise, the \fBread\fR right is sufficient to execute
+the command.
.PP
Neither commands nor responses have a body unless stated otherwise.
.TP
+.B adduser \fIUSERNAME PASSWORD \fR[\fIRIGHTS\fR]
+Create a new user with the given username and password.
+The new user's rights list can be specified; if it is not
+then the \fBdefault_rights\fR setting applies instead.
+Requires the \fBadmin\fR right, and only works on local
+connections.
+.TP
+.B adopt \fIID\fR
+Adopts a randomly picked track, leaving it in a similar state to if it was
+picked by this user. Requires the \fBplay\fR right.
+.TP
.B allfiles \fIDIRECTORY\fR [\fIREGEXP\fR]
-Lists all the files and directories in \fIDIRECTORY\fR in a response body.
+List all the files and directories in \fIDIRECTORY\fR in a response body.
If \fIREGEXP\fR is present only matching files and directories are returned.
.TP
-.B become \fIUSER\fR
-Instructs the server to treat the connection as if \fIUSER\fR had
-authenticated it. Only trusted users may issue this command.
+.B confirm \fICONFIRMATION
+Confirm user registration.
+\fICONFIRMATION\fR is as returned from \fBregister\fR below.
+This command can be used without logging in.
+.TP
+.B cookie \fICOOKIE
+Log a user back in using a cookie created with \fBmake\-cookie\fR.
+The response contains the username.
+.TP
+.B deluser \fIUSERNAME
+Delete the named user.
+Requires the \fBadmin\fR right, and only works on local connections.
.TP
.B dirs \fIDIRECTORY\fR [\fIREGEXP\fR]
-Lists all the directories in \fIDIRECTORY\fR in a response body.
+List all the directories in \fIDIRECTORY\fR in a response body.
If \fIREGEXP\fR is present only matching directories are returned.
.TP
.B disable \fR[\fBnow\fR]
-Disables further playing. If the optional \fBnow\fR argument is present then
-the current track is stopped.
+Disable further playing.
+If the optional \fBnow\fR argument is present then the current track
+is stopped.
+Requires the \fBglobal prefs\fR right.
+.TP
+.B edituser \fIUSERNAME PROPERTY VALUE
+Set a user property.
+With the \fBadmin\fR right any username and property may be specified.
+Otherwise the \fBuserinfo\fR right is required and only the
+\fBemail\fR and \fBpassword\fR properties may be set.
+.IP
+User properties are syntax-checked before setting. For instance \fBemail\fR
+must contain an "@" sign or you will get an error. (Setting an empty value for
+\fBemail\fR is allowed and removes the property.)
.TP
.B enable
-Re-enables further playing, and is the opposite of \fBdisable\fR.
+Re-enable further playing, and is the opposite of \fBdisable\fR.
+Requires the \fBglobal prefs\fR right.
.TP
.B enabled
-Reports whether playing is enabled. The second field of the response line will
-be \fByes\fR or \fBno\fR.
+Report whether playing is enabled.
+The second field of the response line will be \fByes\fR or \fBno\fR.
.TP
.B exists \fITRACK\fR
-Reports whether the named track exists. The second field of the response line
-will be \fByes\fR or \fBno\fR.
+Report whether the named track exists.
+The second field of the response line will be \fByes\fR or \fBno\fR.
.TP
.B files \fIDIRECTORY\fR [\fIREGEXP\fR]
-Lists all the files in \fIDIRECTORY\fR in a response body.
+List all the files in \fIDIRECTORY\fR in a response body.
If \fIREGEXP\fR is present only matching files are returned.
.TP
.B get \fITRACK\fR \fIPREF\fR
-Gets a preference value. On success the second field of the response line will
-have the value.
+Getsa preference value.
+On success the second field of the response line will have the value.
+.IP
+If the track or preference do not exist then the response code is 555.
.TP
-.B get-global \fIKEY\fR
+.B get\-global \fIKEY\fR
Get a global preference.
+.IP
+If the preference does not exist then the response code is 555.
.TP
.B length \fITRACK\fR
-Gets the length of the track in seconds. On success the second field of the
-response line will have the value.
+Get the length of the track in seconds.
+On success the second field of the response line will have the value.
.TP
.B log
-Sends event log messages in a response body. The command will only terminate (and
-close the response body with a final dot) when a further command is readable on
-the control connection.
+Send event log messages in a response body.
+The command will never terminate.
+Any further data sent to the server will be discarded (explicitly;
+i.e. it will not accumulate in a buffer somewhere).
.IP
See \fBEVENT LOG\fR below for more details.
.TP
+.B make\-cookie
+Returns an opaque string that can be used by the \fBcookie\fR command to log
+this user back in on another connection (until the cookie expires).
+.TP
.B move \fITRACK\fR \fIDELTA\fR
-Move a track in the queue. The track may be identified by ID (preferred) or
-name (which might cause confusion if it's there twice). \fIDELTA\fR should be
-an negative or positive integer and indicates how many steps towards the head
-of the queue the track should be moved.
+Move a track in the queue.
+The track may be identified by ID (preferred) or name (which might cause
+confusion if it's there twice).
+\fIDELTA\fR should be an negative or positive integer and indicates how
+many steps towards the head of the queue the track should be moved.
+.IP
+Requires one of the \fBmove mine\fR, \fBmove random\fR or \fBmove any\fR rights
+depending on how the track came to be added to the queue.
.TP
.B moveafter \fITARGET\fR \fIID\fR ...
-Move all the tracks in the \fIID\fR list after ID \fITARGET\fR. If
-\fITARGET\fR is the empty string then the listed tracks are put at the head of
-the queue. If \fITARGET\fR is listed in the ID list then the tracks are moved
+Move all the tracks in the \fIID\fR list after ID \fITARGET\fR.
+If \fITARGET\fR is the empty string then the listed tracks are put
+at the head of the queue.
+If \fITARGET\fR is listed in the ID list then the tracks are moved
to just after the first non-listed track before it, or to the head if there is
no such track.
+.IP
+Requires one of the \fBmove mine\fR, \fBmove random\fR or \fBmove any\fR rights
+depending on how the tracks came to be added to the queue.
+.TP
+.B new \fR[\fIMAX\fR]
+Send the most recently added \fIMAX\fR tracks in a response body.
+If the argument is ommitted, the \fBnew_max\fR most recent tracks are
+listed (see \fBdisorder_config\fR(5)).
+.TP
+.B nop
+Do nothing.
+Used by
+.BR disobedience (1)
+as a keepalive measure.
+This command does not require authentication.
.TP
.B part \fITRACK\fR \fICONTEXT\fI \fIPART\fR
-Get a track name part. Returns an empty string if a name part cannot be
-constructed.
+Get a track name part.
+Returns an empty string if a name part cannot be constructed.
.IP
.I CONTEXT
is one of
.TP
.B pause
Pause the current track.
+Requires the \fBpause\fR right.
.TP
.B play \fITRACK\fR
Add a track to the queue.
+The response contains the queue ID of the track.
+Requires the \fBplay\fR right.
.TP
.B playing
-Reports what track is playing.
+Report what track is playing.
.IP
If the response is \fB252\fR then the rest of the response line consists of
track information (see below).
If the response is \fB259\fR then nothing is playing.
.TP
.B prefs \fBTRACK\fR
-Sends back the preferences for \fITRACK\fR in a response body.
+Send back the preferences for \fITRACK\fR in a response body.
Each line of the response has the usual line syntax, the first field being the
name of the pref and the second the value.
.TP
.B queue
-Sends back the current queue in a response body, one track to a line, the track
-at the head of the queue (i.e. next to be be played) first. See below for the
-track information syntax.
+Send back the current queue in a response body, one track to a line, the track
+at the head of the queue (i.e. next to be be played) first.
+See below for the track information syntax.
.TP
-.B random-disable
+.B random\-disable
Disable random play (but don't stop the current track).
+Requires the \fBglobal prefs\fR right.
.TP
-.B random-enable
+.B random\-enable
Enable random play.
+Requires the \fBglobal prefs\fR right.
.TP
-.B random-enabled
-Reports whether random play is enabled. The second field of the response line
-will be \fByes\fR or \fBno\fR.
+.B random\-enabled
+Report whether random play is enabled.
+The second field of the response line will be \fByes\fR or \fBno\fR.
.TP
.B recent
-Sends back the current recently-played list in a response body, one track to a
-line, the track most recently played last. See below for the track
-information syntax.
+Send back the current recently-played list in a response body, one track to a
+line, the track most recently played last.
+See below for the track information syntax.
.TP
.B reconfigure
-Request that DisOrder reconfigure itself. Only trusted users may issue this
-command.
+Request that DisOrder reconfigure itself.
+Requires the \fBadmin\fR right.
+.TP
+.B register \fIUSERNAME PASSWORD EMAIL
+Register a new user.
+Requires the \fBregister\fR right.
+The result contains a confirmation string; the user will be be able
+to log in until this has been presented back to the server via the
+\fBconfirm\fR command.
+.TP
+.B reminder \fIUSERNAME\fR
+Send a password reminder to user \fIUSERNAME\fR.
+If the user has no valid email address, or no password, or a
+reminder has been sent too recently, then no reminder will be sent.
.TP
.B remove \fIID\fR
-Remove the track identified by \fIID\fR. If \fBrestrict remove\fR is enabled
-in the server's configuration then only the user that submitted the track may
-remove it.
+Remove the track identified by \fIID\fR.
+Requires one of the \fBremove mine\fR, \fBremove random\fR or
+\fBremove any\fR rights depending on how the
+track came to be added to the queue.
.TP
-.B rescan
+.B rescan \fR[\fBwait\fR] \fR[\fBfresh\fR]
Rescan all roots for new or obsolete tracks.
+Requires the \fBrescan\fR right.
+.IP
+If the \fBwait\fR flag is present then the response is delayed until the rescan
+completes.
+Otherwise the response arrives immediately.
+This is primarily intended for testing.
+.IP
+If the \fBfresh\fR flag is present a rescan is already underway then a second
+rescan will be started when it completes.
+The default behavior is to piggyback on the existing rescan.
+.IP
+NB that \fBfresh\fR is currently disabled in the server source, so using this
+flag will just provoke an error.
.TP
.B resolve \fITRACK\fR
Resolve a track name, i.e. if this is an alias then return the real track name.
.TP
.B resume
Resume the current track after a \fBpause\fR command.
+Requires the \fBpause\fR right.
+.TP
+.B revoke \fBcookie\fR
+Revoke a cookie previously created with \fBmake\-cookie\fR.
+It will not be possible to use this cookie in the future.
+.TP
+.B rtp\-address
+Report the RTP broadcast (or multicast) address, in the form \fIADDRESS
+PORT\fR.
+This command does not require authentication.
.TP
.B scratch \fR[\fIID\fR]
Remove the track identified by \fIID\fR, or the currently playing track if no
-\fIID\fR is specified. If \fBrestrict scratch\fR is enabled in the server's
-configuration then only the user that submitted the track may scratch it.
+\fIID\fR is specified.
+Requires one of the \fBscratch mine\fR, \fBscratch random\fR or
+\fBscratch any\fR rights depending on how the track came to be
+added to the queue.
+.TP
+.B schedule-add \fIWHEN\fR \fIPRIORITY\fR \fIACTION\fR ...
+Schedule an event for the future.
+.IP
+.I WHEN
+is the time when it should happen, as \fBtime_t\fR value.
+It must refer to a time in the future.
+.IP
+.I PRIORITY
+is the event priority.
+This can be \fBnormal\fR, in which case the event will be run at startup if its
+time has past, or \fBjunk\fR in which case it will be discarded if it is found
+to be in the past at startup.
+The meaning of other values is not defined.
+.IP
+.I ACTION
+is the action to perform.
+The choice of action determines the meaning of the remaining arguments.
+Possible actions are:
+.RS
+.TP
+.B play
+Play a track.
+The next argument is the track name.
+Requires the \fBplay\fR right.
+.TP
+.B set-global
+Set a global preference.
+The next argument is the preference name and the final argument is the value to
+set it to (omit it to unset it).
+Requires the \fBglobal prefs\fR right.
+.RE
+.IP
+You need the right at the point you create the event.
+It is not possible to create scheduled events in expectation of a future change
+in rights.
+.TP
+.B schedule-del \fIEVENT\fR
+Deletes a scheduled event.
+Users can always delete their own scheduled events; with the \fBadmin\fR
+right you can delete any event.
+.TP
+.B schedule-get \fIEVENT\fR
+Sends the details of scheduled event \fIEVENT\fR in a response body.
+Each line is a pair of strings quoted in the usual way, the first being the key
+ane the second the value.
+No particular order is used.
+.IP
+Scheduled events are considered public information.
+Right \fBread\fR is sufficient to see details of all events.
+.TP
+.B schedule-list
+Sends the event IDs of all scheduled events in a response body, in no
+particular order.
+Use \fBschedule-get\fR to get the details of each event.
.TP
.B search \fITERMS\fR
-Search for tracks matching the search terms. The results are put in a response
-body, one to a line.
+Search for tracks matching the search terms.
+The results are put in a response body, one to a line.
.IP
The search string is split in the usual way, with quoting supported, into a
-list of terms. Only tracks matching all terms are included in the results.
+list of terms.
+Only tracks matching all terms are included in the results.
.IP
Any terms of the form \fBtag:\fITAG\fR limits the search to tracks with that
tag.
.TP
.B \fBset\fR \fITRACK\fR \fIPREF\fR \fIVALUE\fR
Set a preference.
+Requires the \fBprefs\fR right.
.TP
-.B set-global \fIKEY\fR \fIVALUE\fR
+.B set\-global \fIKEY\fR \fIVALUE\fR
Set a global preference.
+Requires the \fBglobal prefs\fR right.
.TP
.B stats
Send server statistics in plain text in a response body.
.TP
.B \fBunset\fR \fITRACK\fR \fIPREF\fR
Unset a preference.
+Requires the \fBprefs\fR right.
.TP
-.B \fBunset-global\fR \fIKEY\fR
+.B \fBunset\-global\fR \fIKEY\fR
Unset a global preference.
+Requires the \fBglobal prefs\fR right.
.TP
-.B user \fIUSER\fR \fIRESPONSE\fR
-Authenticate as \fIUSER\fR.
-.IP
-When a connection is made the server sends a \fB221\fR response before any
-command is received. As its first field this contains a challenge string
-encoded in hex.
-.IP
-The \fIRESPONSE\fR consists of the SHA-1 hash of the user's password
-concatenated with the challenge, encoded in hex.
+.B user \fIUSERNAME\fR \fIRESPONSE\fR
+Authenticate as user \fIUSERNAME\fR.
+See
+.B AUTHENTICATION
+below.
+.TP
+.B userinfo \fIUSERNAME PROPERTY
+Get a user property.
+.TP
+.B users
+Send the list of currently known users in a response body.
.TP
.B version
Send back a response with the server version as the second field.
With zero parameters just gets the volume and reports the left and right sides
as the 2nd and 3rd fields of the response.
.IP
-With one parameter sets both sides to the same value. With two parameters sets
-each side independently.
+With one parameter sets both sides to the same value.
+With two parameters sets each side independently.
+Setting the volume requires the \fBvolume\fR right.
.SH RESPONSES
-Responses are three-digit codes. The first digit distinguishes errors from
-succesful responses:
+Responses are three-digit codes.
+The first digit distinguishes errors from succesful responses:
.TP
.B 2
Operation succeeded.
The second digit breaks down the origin of the response:
.TP
.B 0
-Generic responses not specific to the handling of the command. Mostly this is
-parse errors.
+Generic responses not specific to the handling of the command.
+Mostly this is parse errors.
+.TP
+.B 1
+51x errors indicate that the user had insufficient rights for the command.
.TP
.B 3
Authentication responses.
Text part is just commentary; a dot-stuffed body follows.
.TP
.B 4
-Text part is just commentary; an indefinite dot-stuffed body follows. (Used
-for \fBlog\fR.)
+Text part is just commentary; an indefinite dot-stuffed body follows.
+(Used for \fBlog\fR.)
.TP
-.B 4
-Text part is just commentary; an indefinite dot-stuffed body follows. (Used
-for \fBlog\fR.)
+.B 5
+Used with "normal" errors, for instance a preference not being found.
+The text part is commentary.
.TP
.B 9
The text part is just commentary (but would normally be a response for this
command) e.g. \fBplaying\fR.
+.PP
+Result strings (not bodies) intended for machine parsing (i.e. xx1 and xx2
+responses) are quoted.
.SH AUTHENTICATION
-The server starts by issuing a challenge line, with response code 231. This
-contains a random challenge encoded in hex.
+When a connection is made the server sends a \fB231\fR response before any
+command is received.
+This contains a protocol generation, an algorithm name and a
+challenge encoded in hex, all separated by whitespace.
+.PP
+The current protocol generation is \fB2\fR.
.PP
-The client should send back a \fBuser\fR command with username and a
-hex-encoded response. The response is the SHA-1 hash of the user's password
-and the challenge.
+The possible algorithms are (currently) \fBsha1\fR, \fBsha256\fR, \fBsha384\fR
+and \fBsha512\fR.
+\fBSHA1\fR etc work as synonyms.
+.PP
+The \fBuser\fR response consists of the selected hash of the user's password
+concatenated with the challenge, encoded in hex.
.SH "TRACK INFORMATION"
Track information is encoded in a line (i.e. using the usual line syntax) as
-pairs of fields. The first is a name, the second a value. The names have the
-following meanings:
+pairs of fields.
+The first is a name, the second a value.
+The names have the following meanings:
.TP 12
.B expected
The time the track is expected to be played at.
.B scratched
The user that scratched the track.
.TP
+.B origin
+The origin of the track. Valid origins are:
+.RS
+.TP 12
+.B adopted
+The track was originally randomly picked but has been adopted by a user.
+.TP
+.B picked
+The track was picked by a user.
+.TP
+.B random
+The track was randomly picked.
+.TP
+.B scheduled
+The track was played from a scheduled action.
+.TP
+.B scratch
+The track is a scratch sound.
+.RE
+.TP
.B state
-The current track state. Valid states are:
+The current track state.
+Valid states are:
.RS
.TP 12
.B failed
The player failed (exited with nonzero status but wasn't scratched).
.TP
-.B isscratch
-The track is actually a scratch.
-.TP
-.B no_player
-No player could be found for the track.
-.TP
.B ok
The track was played without any problems.
.TP
.B started
The track is currently playing.
.TP
+.B paused
+Track is playing but paused.
+.TP
.B unplayed
In the queue, hasn't been played yet.
.TP
.TP
.B wstat
The wait status of the player in decimal.
+.PP
+Note that \fBorigin\fR is new with DisOrder 4.3, and obsoletes some old
+\fBstate\fR values.
.SH NOTES
Times are decimal integers using the server's \fBtime_t\fR.
.PP
For file listings, the regexp applies to the basename of the returned file, not
-the whole filename, and letter case is ignored. \fBpcrepattern\fR(3) describes
-the regexp syntax.
+the whole filename, and letter case is ignored.
+\fBpcrepattern\fR(3) describes the regexp syntax.
.PP
Filenames are in UTF-8 even if the collection they come from uses some other
encoding - if you want to access the real file (in such cases as the filenames
right encoding is.
.SH "EVENT LOG"
The event log consists of lines starting with a hexadecimal timestamp and a
-keyword followed by (optionally) parameters. The parameters are quoted in the
-usual DisOrder way. Currently the following keywords are used:
+keyword followed by (optionally) parameters.
+The parameters are quoted in the usual DisOrder way.
+Currently the following keywords are used:
+.TP
+.B adopted \fIID\fR \fIUSERNAME\fR
+\fIUSERNAME\fR adopted track \fIID\fR.
.TP
.B completed \fITRACK\fR
Completed playing \fITRACK\fR
.B failed \fITRACK\fR \fIERROR\fR
Completed playing \fITRACK\fR with an error status
.TP
-.B moved \fIUSER\fR
-User \fIUSER\fR moved some track(s). Further details aren't included any
-more.
+.B moved \fIUSERNAME\fR
+User \fIUSERNAME\fR moved some track(s).
+Further details aren't included any more.
.TP
-.B playing \fITRACK\fR [\fIUSER\fR]
+.B playing \fITRACK\fR [\fIUSERNAME\fR]
Started playing \fITRACK\fR.
.TP
.B queue \fIQUEUE-ENTRY\fR...
.B recent_removed \fIID\fR
Removed \fIID\fR from the recently played list.
.TP
-.B removed \fIID\fR [\fIUSER\fR]
-Queue entry \fIID\fR was removed. This is used both for explicit removal (when
-\fIUSER\fR is present) and when playing a track (when it is absent).
+.B removed \fIID\fR [\fIUSERNAME\fR]
+Queue entry \fIID\fR was removed.
+This is used both for explicit removal (when \fIUSERNAME\fR is present)
+and when playing a track (when it is absent).
.TP
-.B scratched \fITRACK\fR \fIUSER\fR
-\fITRACK\fR was scratched by \fIUSER\fR.
+.B rescanned
+A rescan completed.
+.TP
+.B scratched \fITRACK\fR \fIUSERNAME\fR
+\fITRACK\fR was scratched by \fIUSERNAME\fR.
.TP
.B state \fIKEYWORD\fR
-Some state change occurred. The current set of keywords is:
+Some state change occurred.
+The current set of keywords is:
.RS
.TP
+.B completed
+The current track completed successfully.
+.TP
.B disable_play
Playing was disabled.
.TP
.B enable_random
Random play was enabled.
.TP
+.B failed
+The current track failed.
+.TP
.B pause
The current track was paused.
.TP
+.B playing
+A track started playing.
+.TP
.B resume
The current track was resumed.
+.TP
+.B rights_changed \fIRIGHTS\fR
+User's rights were changed.
+.TP
+.B scratched
+The current track was scratched.
+.PP
+To simplify client implementation, \fBstate\fR commands reflecting the current
+state are sent at the start of the log.
.RE
+.TB
+.B user_add \fIUSERNAME\fR
+A user was created.
+.TP
+.B user_delete \fIUSERNAME\fR
+A user was deleted.
+.TP
+.B user_edit \fIUSERNAME\fR \fIPROPERTY\fR
+Some property of a user was edited.
+.TP
+.B user_confirm \fIUSERNAME\fR
+A user's login was confirmed (via the web interface).
.TP
.B volume \fILEFT\fR \fIRIGHT\fR
The volume changed.
is as defined in
.B "TRACK INFORMATION"
above.
+.PP
+The \fBuser-*\fR messages are only sent to admin users, and are not sent over
+non-local connections unless \fBremote_userman\fR is enabled.
+.SH "CHARACTER ENCODING"
+All data sent by both server and client is encoded using UTF-8.
+Moreover it must be valid UTF-8, i.e. non-minimal sequences are not
+permitted, nor are surrogates, nor are code points outside the
+Unicode code space.
+.PP
+There are no particular normalization requirements on either side of the
+protocol.
+The server currently converts internally to NFC, the client must
+normalize the responses returned if it needs some normalized form for further
+processing.
+.PP
+The various characters which divide up lines may not be followed by combining
+characters.
+For instance all of the following are prohibited:
+.TP
+.B o
+LINE FEED followed by a combining character.
+For example the sequence LINE FEED, COMBINING GRAVE ACCENT is never permitted.
+.TP
+.B o
+APOSTROPHE or QUOTATION MARK followed by a combining character when used to
+delimit fields.
+For instance a line starting APOSTROPHE, COMBINING CEDILLA is prohibited.
+.IP
+Note that such sequences are not prohibited when the quote character cannot be
+interpreted as a field delimiter.
+For instance APOSTROPHE, REVERSE SOLIDUS, APOSTROPHE, COMBINING CEDILLA,
+APOSTROPHE would be permitted.
+.TP
+.B o
+REVERSE SOLIDUS (BACKSLASH) followed by a combining character in a quoted
+string when it is the first character of an escape sequence.
+For instance a line starting APOSTROPHE, REVERSE SOLIDUS, COMBINING TILDE
+is prohibited.
+.IP
+As above such sequences are not prohibited when the character is not being used
+to start an escape sequence.
+For instance APOSTROPHE, REVERSE SOLIDUS, REVERSE SOLIDS, COMBINING TILDE,
+APOSTROPHE is permitted.
+.TP
+.B o
+Any of the field-splitting whitespace characters followed by a combining
+character when not part of a quoted field.
+For instance a line starting COLON, SPACE, COMBINING CANDRABINDU is prohibited.
+.IP
+As above non-delimiter uses are fine.
+.TP
+.B o
+The FULL STOP characters used to quote or delimit a body.
+.PP
+Furthermore none of these characters are permitted to appear in the context of
+a canonical decomposition (i.e. they must still be present when converted to
+NFC).
+In practice however this is not an issue in Unicode 5.0.
+.PP
+These rules are consistent with the observation that the split() function is
+essentially a naive ASCII parser.
+The implication is not that these sequences never actually appear in
+the protocol, merely that the server is not required to honor them in
+any useful way nor be consistent between versions: in current
+versions the result will be lines and fields that start with combining
+characters and are not necessarily split where you expect, but future versions
+may remove them, reject them or ignore some or all of the delimiters that have
+following combining characters, and no notice will be given of any change.
.SH "SEE ALSO"
\fBdisorder\fR(1),
\fBtime\fR(2),
~mdw / disorder / blobdiff