1 APPLICATION LAYER PROTOCOL FOR THE CITADEL SYSTEM
2 (c) 1995-2006 by Art Cancro et. al. All Rights Reserved
8 This is an attempt to document the application layer protocol used by the
9 Citadel system, beginning with version 4.00, which is the first version
10 to implement a client/server paradigm. It is intended as a resource for
11 programmers who intend to develop their own Citadel clients, but it may have
15 IMPORTANT NOTE TO DEVELOPERS!
16 -----------------------------
18 Anyone who wants to add commands or other functionality to this protocol,
19 *please* get in touch so that these efforts can be coordinated. New
20 commands added by other developers can be added to this document, so we
21 don't end up with new server commands from multiple developers which have
22 the same name but perform different functions. If you don't coordinate new
23 developments ahead of time, please at least send in an e-mail documenting
24 what you did, so that your new commands can be added to this document.
26 The coordinator of the Citadel project is Art Cancro
27 <ajc@uncensored.citadel.org>.
30 CONNECTING TO A SERVER
31 ----------------------
33 The protocols used below the application layer are beyond the scope of this
34 document, but we will briefly cover the methodology employed by Citadel.
36 Citadel offers its client protocol using TCP/IP. It does so via a
37 multithreaded server listening on a TCP port. Local connections may also
38 be made using the same protocol using Unix domain sockets.
40 The port number officially assigned to Citadel by the IANA is 504/tcp. Since
41 our application layer assumes a clean, reliable, sequenced connection, the use
42 of UDP would render the server unstable and unusable, so we stick with TCP.
48 The native character set for the Citadel system is UTF-8. Unless otherwise
49 specified, all data elements are expected to be in the UTF-8 character set.
50 Specifically, all non-MIME messages should be assumed to be in UTF-8. MIME
51 messages may be in whatever character set is specified by the MIME header, of
52 course; however, some clients (such as WebCit) will automatically convert
53 messages from other character sets before displaying them.
56 GENERAL INFORMATION ABOUT THE SERVER
57 ------------------------------------
59 The server is connection-oriented and stateful: each client requires its own
60 connection to a server process, and when a command is sent, the client must
61 read the response, and then transfer data or change modes if necessary.
63 The application layer is very much like other Internet protocols such as SMTP
64 or NNTP. A client program sends one-line commands to the server, and the
65 server responds with a three-digit numeric result code followed by a message
66 describing what happened. This cycle continues until the end of the
69 Unlike protocols such as FTP, all data transfers occur in-band. This means
70 that the same connection that is used for exchange of client/server
71 messages, will also be used to transfer data back and forth. (FTP opens a
72 separate connection for data transfers.) This keeps protocol administration
73 straightforward, as it can traverse firewalls without any special protocol
74 support on the firewall except for opening the port number.
80 The server will respond to all commands with a 3-digit result code, which
81 will be the first three characters on the line. The rest of the line may
82 contain a human-readable string explaining what happened. (Some client
83 software will display some of these strings to the user.)
85 The first digit is the most important. The following codes are defined for
86 this position: ERROR, OK, MORE_DATA, LISTING_FOLLOWS, and SEND_LISTING.
88 The second and third digits may provide a reason as to why a command
89 succeeded or failed. See ipcdef.h for the available codes.
91 ERROR means the command did not complete.
92 OK means the command executed successfully.
93 MORE_DATA means the command executed partially. Usually this means that
94 another command needs to be executed to complete the operation. For example,
95 sending the USER command to log in a user usually results in a MORE_DATA
96 result code, because the client needs to execute a PASS command to send the
97 password and complete the login.
98 LISTING_FOLLOWS means that after the server response, the server will
99 output a listing of some sort. The client *must* read the listing, whether
100 it wants to or not. The end of the listing is signified by the string
101 "000" on a line by itself.
102 SEND_LISTING is the opposite of LISTING_FOLLOWS. It means that the client
103 should begin sending a listing of some sort. The client *must* send something,
104 even if it is an empty listing. Again, the listing ends with "000" on a line
106 BINARY_FOLLOWS and SEND_BINARY mean that the client must immediately send
107 or receive a block of binary data. The first parameter will always be the
109 ASYNC_MESSAGE_FOLLOWS means that an asynchronous, or unsolicited, message
110 follows. The next line will be one of the above codes, and if a data transfer
111 is involved it must be handled immediately. Note that the client will not
112 receive this type of response unless it indicates to the server that it is
113 capable of handling them; see the writeup of the ASYN command later in this
119 Zero or more parameters may be passed to a command. When more than one
120 parameter is passed to a command, they should be separated by the "|"
123 In this example, we're using the "SETU" command and passing three
124 parameters: 80, 24, and 260.
126 When the server spits out data that has parameters, if more than one
127 parameter is returned, they will be separated by the "|" symbol like
130 In this example, we just executed the "GETU" command, and it returned us
131 an OK result code (the '2' in the 200) and three parameters: 80, 24, and
138 This is a listing of all the commands that a Citadel server can execute.
143 This command does nothing. It takes no arguments and always returns
144 OK. It is intended primarily for testing and development, but it might also
145 be used as a "keep alive" command to prevent the server from timing out, if
146 it's running over a transport that needs this type of thing.
149 ECHO (ECHO something)
151 This command also does nothing. It simply returns OK followed by whatever
157 Terminate the server connection. This command takes no arguments. It
158 returns OK and closes the connection immediately.
163 Log out the user without closing the server connection. It always returns
164 OK even if no user is logged in.
167 USER (send USER name)
169 The first step in logging in a user. This command takes one argument: the
170 name of the user to be logged in. If the user exists, a MORE_DATA return
171 code will be sent, which means the client should execute PASS as the next
172 command. If the user does not exist, ERROR + NO_SUCH_USER is returned.
177 The second step in logging in a user. This command takes one argument: the
178 password for the user we are attempting to log in. If the password doesn't
179 match the correct password for the user we specified for the USER command,
180 ERROR + PASSWORD_REQUIRED is returned. If a USER command has not been
181 executed yet, ERROR + USERNAME_REQUIRED is returned. If a user is already
182 logged in, ERROR + ALREADY_LOGGED_IN is returned. If the password is
183 correct, OK is returned and the user is now logged in... and most of the
184 other server commands can now be executed. Along with OK, the following
185 parameters are returned:
187 0 - The user's name (in case the client wants the right upper/lower casing)
188 1 - The user's current access level
191 4 - Various flags (see citadel.h)
193 6 - Time of last call (UNIX timestamp)
196 NEWU (create NEW User account)
198 This command creates a new user account AND LOGS IT IN. The argument to
199 this command will be the name of the account. No case conversion is done
200 on the name. Note that the new account is installed with a default
201 configuration, and no password, so the client should immediately prompt the
202 user for a password and install it with the SETP command as soon as this
203 command completes. This command returns OK if the account was created and
204 logged in, ERROR + ALREADY_EXISTS if another user already exists with this
205 name, ERROR + NOT_HERE if self-service account creation is disabled,
206 ERROR + MAX_SESSIONS_EXCEEDED if too many users are logged in, ERROR +
207 USERNAME_REQUIRED if a username was not provided, or ERROR + ILELGAL_VALUE
208 if the username provided is invalid. If OK, it will also return the same
209 parameters that PASS returns.
211 Please note that the NEWU command should only be used for self-service
212 user account creation. For administratively creating user accounts, please
213 use the CREU command.
216 SETP (SET new Password)
218 This command sets a new password for the currently logged in user. The
219 argument to this command will be the new password. The command always
220 returns OK, unless the client is not logged in, in which case it will return
221 ERROR + NOT_LOGGED_IN, or if the user is an auto-login user, in which case
222 it will return ERROR + NOT_HERE.
225 CREU (CREate new User account)
227 This command creates a new user account AND DOES NOT LOG IT IN. The first
228 argument to this command will be the name of the account. No case conversion
229 is done on the name. Note that the new account is installed with a default
230 configuration, and no password. The second argument is optional, and will be
231 an initial password for the user. This command returns OK if the account was
232 created, ERROR + HIGHER_ACCESS_REQUIRED if the user is not an Aide, ERROR +
233 USERNAME_REQUIRED if no username was specified, or ERROR + ALREADY_EXISTS if
234 another user already exists with this name.
236 Please note that CREU is intended to be used for activities in which a
237 system administrator is creating user accounts. For self-service user
238 account creation, use the NEWU command.
241 LKRN (List Known Rooms with New messages)
243 List known rooms with new messages. If the client is not logged in, ERROR +
244 NOT_LOGGED_IN is returned. Otherwise, LISTING_FOLLOWS is returned, followed
245 by the room listing. Each line in the listing contains the full name of a
246 room, followed by the '|' symbol, and then a number that may contain the
249 #define QR_PERMANENT 1 /* Room does not purge */
250 #define QR_PRIVATE 4 /* Set for any type of private room */
251 #define QR_PASSWORDED 8 /* Set if there's a password too */
252 #define QR_GUESSNAME 16 /* Set if it's a guessname room */
253 #define QR_DIRECTORY 32 /* Directory room */
254 #define QR_UPLOAD 64 /* Allowed to upload */
255 #define QR_DOWNLOAD 128 /* Allowed to download */
256 #define QR_VISDIR 256 /* Visible directory */
257 #define QR_ANONONLY 512 /* Anonymous-Only room */
258 #define QR_ANON2 1024 /* Anonymous-Option room */
259 #define QR_NETWORK 2048 /* Shared network room */
260 #define QR_PREFONLY 4096 /* Preferred status needed to enter */
261 #define QR_READONLY 8192 /* Aide status required to post */
263 Then it returns another '|' symbol, followed by a second set of bits comprised
266 #define QR2_SYSTEM 1 /* System room; hide by default */
267 #define QR2_SELFLIST 2 /* Self-service mailing list mgmt */
269 Other bits may be defined in the future. The listing terminates, as with
270 all listings, with "000" on a line by itself.
272 Starting with version 4.01 and above, floors are supported. The first
273 argument to LKRN should be the number of the floor to list rooms from. Only
274 rooms from this floor will be listed. If no arguments are passed to LKRN, or
275 if the floor number requested is (-1), rooms on all floors will be listed.
277 The third field displayed on each line is the number of the floor the room
278 is on. The LFLR command should be used to associate floor numbers with
281 The fourth field displayed on each line is a "room listing order." Unless
282 there is a compelling reason not to, clients should sort any received room
283 listings by this value.
285 The fifth field is a special bit bucket containing fields which pertain to
286 room access controls:
288 #define UA_KNOWN 2 /* Known room */
289 #define UA_GOTOALLOWED 4 /* Access will be granted to this room
290 * if the user calls it up by name */
291 #define UA_HASNEWMSGS 8 /* Unread messages exist in room */
292 #define UA_ZAPPED 16 /* Zapped from known rooms list */
294 The sixth field is the user's current view for the room. (See VIEW command)
295 The seventh field is the *default* view for the room. (See VIEW command)
298 LKRO (List Known Rooms with Old [no new] messages)
300 This follows the same usage and format as LKRN.
303 LZRM (List Zapped RooMs)
305 This follows the same usage and format as LKRN and LKRO.
308 LKRA (List All Known Rooms)
310 Same format. Lists all known rooms, with or without new messages.
313 LRMS (List all accessible RooMS)
315 Again, same format. This command lists all accessible rooms, known and
316 forgotten, with and without new messages. It does not, however, list
317 inaccessible private rooms.
320 LPRM (List all Public RooMs)
322 Again, same format. This command lists all public rooms, and nothing else.
323 Unlike the other list rooms commands, this one can be executed without logging
327 GETU (GET User configuration)
329 This command retrieves the screen dimensions and user options for the
330 currently logged in account. ERROR + NOT_LOGGED_IN will be returned if no
331 user is logged in, of course. Otherwise, OK will be returned, followed by
332 four parameters. The first parameter is the user's screen width, the second
333 parameter is the user's screen height, and the third parameter is a bag of
334 bits with the following meanings:
336 #define US_LASTOLD 16 /* Print last old message with new */
337 #define US_EXPERT 32 /* Experienced user */
338 #define US_UNLISTED 64 /* Unlisted userlog entry */
339 #define US_NOPROMPT 128 /* Don't prompt after each message */
340 #define US_DISAPPEAR 512 /* Use "disappearing msg prompts" */
341 #define US_PAGINATOR 2048 /* Pause after each screen of text */
343 There are other bits, too, but they can't be changed by the user (see below).
346 SETU (SET User configuration)
348 This command does the opposite of SETU: it takes the screen dimensions and
349 user options (which were probably obtained with a GETU command, and perhaps
350 modified by the user) and writes them to the user account. This command
351 should be passed three parameters: the screen width, the screen height, and
352 the option bits (see above). It returns ERROR + NOT_LOGGED_IN if no user is
353 logged in, and ERROR + ILLEGAL_VALUE if the parameters are incorrect.
355 Note that there exist bits here which are not listed in this document. Some
356 are flags that can only be set by Aides or the system administrator. SETU
357 will ignore attempts to toggle these bits. There also may be more user
358 settable bits added at a later date. To maintain later downward compatibility,
359 the following procedure is suggested:
361 1. Execute GETU to read the current flags
362 2. Toggle the bits that we know we can toggle
363 3. Execute SETU to write the flags
365 If we are passed a bit whose meaning we don't know, it's best to leave it
366 alone, and pass it right back to the server. That way we can use an old
367 client on a server that uses an unknown bit without accidentally clearing
368 it every time we set the user's configuration.
373 This command is used to goto a new room. When the user first logs in (login
374 is completed after execution of the PASS command) this command is
375 automatically and silently executed to take the user to the first room in the
376 system (usually called the Lobby).
378 This command can be passed one or two parameters. The first parameter is,
379 of course, the name of the room. Although it is not case sensitive, the
380 full name of the room must be used. Wildcard matching or unique string
381 matching of room names should be the responsibility of the client.
383 Note that the reserved room name "_BASEROOM_" can be passed to the server
384 to cause the goto command to take the user to the first room in the system,
385 traditionally known as the Lobby>. As long as a user is logged in, a
386 GOTO command to _BASEROOM_ is guaranteed to succeed. This is useful to
387 allow client software to return to the base room when it doesn't know
390 There are also several additional reserved room names:
391 "_MAIL_" goes to the user's inbox (i.e. the Mail> room).
392 "_TRASH_" goes to the user's personal trashcan room (trash folder).
393 "_BITBUCKET_" goes to a room that has been chosen for messages without a home.
394 "_CALENDAR_" goes to the user's primary personal calendar.
395 "_CONTACTS_" goes to the user's primary personal address book.
396 "_NOTES_" goes to the user's primary personal notes room.
397 "_TASKS_" goes to the user's primary personal task list.
400 The second (and optional) parameter is a password, if one is required for
401 access to the room. This allows for all types of rooms to be accessed via
402 this command: for public rooms, invitation-only rooms to which the user
403 has access, and preferred users only rooms to which the user has access, the
404 room will appear in a room listing. For guess-name rooms, this command
405 will work transparently, adding the room to the user's known room list when
406 it completes. For passworded rooms, access will be denied if the password
407 is not supplied or is incorrect, or the command will complete successfully
408 if the password is correct.
410 The third (and also) optional parameter is a "transient" flag. Normally,
411 when a user enters a private and/or zapped room, the room is added to the
412 user's known rooms list. If the transient flag is set to non-zero, this is
413 called a "transient goto" which causes the user to enter the room without
414 adding the room to the known rooms list.
416 The possible result codes are:
418 OK - The command completed successfully. User is now in the room.
419 (See the list of returned parameters below)
421 ERROR - The command did not complete successfully. Check the second and
422 third positions of the result code to find out what happened:
424 NOT_LOGGED_IN - Of course you can't go there. You didn't log in.
425 PASSWORD_REQUIRED - Either a password was not supplied, or the supplied
426 password was incorrect.
427 ROOM_NOT_FOUND - The requested room does not exist.
429 The typical procedure for entering a passworded room would be:
431 1. Execute a GOTO command without supplying any password.
432 2. ERROR + PASSWORD_REQUIRED will be returned. The client now knows that
433 the room is passworded, and prompts the user for a password.
434 3. Execute a GOTO command, supplying both the room name and the password.
435 4. If OK is returned, the command is complete. If, however,
436 ERROR + PASSWORD_REQUIRED is still returned, tell the user that the supplied
437 password was incorrect. The user remains in the room he/she was previously
440 When the command succeeds, these parameters are returned:
441 0. The name of the room
442 1. Number of unread messages in this room
443 2. Total number of messages in this room
444 3. Info flag: set to nonzero if the user needs to read this room's info
445 file (see RINF command below)
446 4. Various flags associated with this room. (See LKRN cmd above)
447 5. The highest message number present in this room
448 6. The highest message number the user has read in this room
449 7. Boolean flag: 1 if this is a Mail> room, 0 otherwise.
450 8. Aide flag: 1 if the user is either the Room Aide for this room, *or* is
451 a regular Aide (this makes access checks easy).
452 9. The number of new Mail messages the user has (useful for alerting the
453 user to the arrival of new mail during a session)
454 10. The floor number this room resides on
455 11. The *current* "view" for this room (see views.txt for more info)
456 12. The *default* "view" for this room
457 13. Boolian flag: 1 if this is the user's Trash folder, 0 otherwise.
459 The default view gives the client a hint as to what views the user should
460 be allowed to select. For example, it would be confusing to allow messages
461 in a room intended for calendar items. The server does not enforce these
462 restrictions, though.
465 MSGS (get pointers to MeSsaGeS in this room)
467 This command obtains a listing of all the messages in the current room
468 which the client may request. This command may be passed a single parameter:
469 either "all", "old", or "new" to request all messages, only old messages, or
470 new messages. Or it may be passed two parameters: "last" plus a number, in
471 which case that many message pointers will be returned; "first" plus a
472 number, for the corresponding effect; or "gt" plus a number, to list all
473 messages in the current room with a message number greater than the one
474 specified. If no parameters are specified, "all" is assumed.
476 The third argument, may be either 0 or 1. If it is 1, this command behaves
477 differently: before a listing is returned, the client must transmit a list
478 of fields to search for. The field headers are listed below in the writeup
479 for the "MSG0" command.
481 The optional fourth argument may also be either 0 or 1. If it is 1, the
482 output of this command will include not only a list of message numbers, but
483 a simple header summary of each message as well. This is somewhat resource
484 intensive so you shouldn't do this unless you absolutely need all the headers
485 immediately. The fields which are output (in the usual delimited fashion, of
486 course) are: message number, timestamp, display name, node name, Internet
487 email address (if present), subject (if present).
489 This command can return three possible results. ERROR + NOT_LOGGED_IN will
490 be returned if no user is currently logged in. Otherwise, LISTING_FOLLOWS
491 will be returned, and the listing will consist of zero or more message
492 numbers, one per line. The listing ends, as always, with the string "000"
493 alone on a line by itself. The listed message numbers can be used to request
494 messages from the system. If "search mode" is being used, the server will
495 return START_CHAT_MODE, and the client is expected to transmit the search
496 criteria, and then read the message list.
498 Since this is somewhat complex, here are some examples:
500 Example 1: Read all new messages
503 Server: 100 Message list...
509 Example 2: Read the last five messages
512 Server: 100 Message list...
520 Example 3: Read all messages written by "IGnatius T Foobar"
523 Server: 800 Send template then receive message list
524 Client: from|IGnatius T Foobar
538 Note that in "search mode" the client may specify any number of search
539 criteria. These criteria are applied with an AND logic.
542 MSG0 (read MeSsaGe, mode 0)
544 This is a command used to read the text of a message. "Mode 0" implies that
545 other MSG commands (MSG1, MSG2, etc.) will probably be added later on to read
546 messages in more robust formats. This command should be passed two arguments.
547 The first is the message number of the message being requested. The second
548 argument specifies whether the client wants headers and/or message body:
552 3 = Headers only, with MIME information suppressed (this runs faster)
554 If the request is denied, ERROR + NOT_LOGGED_IN or ERROR + MESSAGE_NOT_FOUND
555 will be returned. Otherwise, LISTING_FOLLOWS will be returned, followed by
556 the contents of the message. The following fields may be sent:
558 type= Formatting type. The currently defined types are:
559 0 = "traditional" Citadel formatting. This means that newlines should be
560 treated as spaces UNLESS the first character on the next line is a space. In
561 other words, only indented lines should generate a newline on the user's screen
562 when the message is being displayed. This allows a message to be formatted to
563 the reader's screen width. It also allows the use of proportional fonts.
564 1 = a simple fixed-format message. The message should be displayed to
565 the user's screen as is, preferably in a fixed-width font that will fit 80
567 4 = MIME format message. The message text is expected to contain a header
568 with the "Content-type:" directive (and possibly others).
570 msgn= The message ID of this message on the system it originated on.
571 path= An e-mailable path back to the user who wrote the message.
573 time= The date and time of the message, in Unix format (the number of
574 seconds since midnight on January 1, 1970, GMT).
576 from= The name of the author of the message.
577 rcpt= If the message is a private e-mail, this is the recipient.
578 room= The name of the room the message originated in.
579 node= The short node name of the system this message originated on.
580 hnod= The long node name of the system this message originated on.
581 zaps= The id/node of a message which this one zaps (supersedes).
583 part= Information about a MIME part embedded in this message.
584 pref= Information about a multipart MIME prefix such as "multipart/mixed"
585 or "multipart/alternative". This will be output immediately prior
586 to the various "part=" lines which make up the multipart section.
587 suff= Information about a multipart MIME suffix. This will be output
588 immediately following the various "part=" lines which make up the
591 text Note that there is no "=" after the word "text". This string
592 signifies that the message text begins on the next line.
595 WHOK (WHO Knows room)
597 This command is available only to Aides. ERROR + HIGHER_ACCESS_REQUIRED
598 will be returned if the user is not an Aide. Otherwise, it returns
599 LISTING_FOLLOWS and then lists, one user per line, every user who has
600 access to the current room.
603 INFO (get server INFO)
605 This command will *always* return LISTING_FOLLOWS and then print out a
606 listing of zero or more strings. Client software should be written to expect
607 anywhere from a null listing to an infinite number of lines, to allow later
608 backward compatibility. The current implementation defines the following
609 parts of the listing:
611 Line 1 - Your unique session ID on the server
612 Line 2 - The node name of the Citadel server
613 Line 3 - Human-readable node name of the Citadel server
614 Line 4 - The fully-qualified domain name (FQDN) of the server
615 Line 5 - The name of the server software, i.e. "Citadel 4.00"
616 Line 6 - (The revision level of the server code) * 100
617 Line 7 - The geographical location of the site (city and state if in the US)
618 Line 8 - The name of the system administrator
619 Line 9 - A number identifying the server type (see below)
620 Line 10 - The text of the system's paginator prompt
621 Line 11 - Floor Flag. 1 if the system supports floors, 0 otherwise.
622 Line 12 - Paging level. 0 if the system only supports inline paging,
623 1 if the system supports "extended" paging (check-only and
624 multiline modes). See the SEXP command for further information.
625 Line 13 - The "nonce" for this session, for support of APOP-style
626 authentication. If this field is present, clients may authenticate
628 Line 14 - Set to nonzero if this server supports the QNOP command.
629 Line 15 - Set to nonzero if this server is capable of connecting to a
630 directory service using LDAP.
632 *** NOTE! *** The "server type" code is intended to promote global
633 compatibility in a scenario in which developers have added proprietary
634 features to their servers or clients. We are attempting to avoid a future
635 situation in which users need to keep different client software around for
636 each Citadel they use. *Please*, if you are a developer and plan to add
637 proprietary features:
639 -> Your client programs should still be able to utilize servers other than
641 -> Clients other than your own should still be able to utilize your server,
642 even if your proprietary extensions aren't supported.
643 -> Please contact Art Cancro <ajc@uncensored.citadel.org> and obtain a unique
644 server type code, which can be assigned to your server program.
645 -> If you document what you did in detail, perhaps it can be added to a
646 future release of the Citadel program, so everyone can enjoy it. Better
647 yet, just work with the Citadel development team on the main source tree.
649 If everyone follows this scheme, we can avoid a chaotic situation with lots
650 of confusion about which client program works with which server, etc. Client
651 software can simply check the server type (and perhaps the revision level)
652 to determine ahead of time what commands may be utilized.
654 Please refer to "developers.txt" for information on what codes belong to whom.
658 RDIR (Read room DIRectory)
660 Use this command to read the directory of a directory room. ERROR + NOT_HERE
661 will be returned if the room has no directory, ERROR + HIGHER_ACCESS_REQUIRED
662 will be returned if the room's directory is not visible and the user does not
663 have Aide or Room Aide privileges, ERROR + NOT_LOGGED_IN will be returned if
664 the user is not logged in; otherwise LISTING_FOLLOWS will be returned,
665 followed by the room's directory. Each line of the directory listing will
666 contain three fields: a filename, the length of the file, and a description.
668 The server message contained on the same line with LISTING_FOLLOWS will
669 contain the name of the system and the name of the directory, such as:
671 uncensored.citadel.org|/usr/local/citadel/files/my_room_directory
674 SLRP (Set Last-message-Read Pointer)
676 This command marks all messages in the current room as read (seen) up to and
677 including the specified number. Its sole parameter is the number of the last
678 message that has been read. This allows the pointer to be set at any
679 arbitrary point in the room. Optionally, the parameter "highest" may be used
680 instead of a message number, to set the pointer to the number of the highest
681 message in the room, effectively marking all messages in the room as having
682 been read (ala the Citadel <G>oto command).
684 The command will return OK if the pointer was set, or ERROR + NOT_LOGGED_IN
685 if the user is not logged in. If OK is returned, it will be followed by a
686 single argument containing the message number the last-read-pointer was set to.
689 INVT (INViTe a user to a room)
691 This command may only be executed by Aides, or by the room aide for the
692 current room. It is used primarily to add users to invitation-only rooms,
693 but it may also be used in other types of private rooms as well. Its sole
694 parameter is the name of the user to invite.
696 The command will return OK if the operation succeeded. ERROR + NO_SUCH_USER
697 will be returned if the user does not exist, ERROR + HIGHER_ACCESS_REQUIRED
698 will be returned if the operation would have been possible if the user had
699 higher access, and ERROR + NOT_HERE may be returned if the room is not a
703 KICK (KICK a user out of a room)
705 This is the opposite of INVT: it is used to kick a user out of a private
706 room. It can also be used to kick a user out of a public room, but the
707 effect will only be the same as if the user <Z>apped the room - a non-stupid
708 user can simply un-zap the room to get back in.
711 GETR (GET Room attributes)
713 This command is used for editing the various attributes associated with a
714 room. A typical "edit room" command would work like this:
715 1. Use the GETR command to get the current attributes
716 2. Change some of them around
717 3. Use SETR (see below) to save the changes
718 4. Possibly also change the room aide using the GETA and SETA commands
720 GETR takes no arguments. It will only return OK if the SETR command will
721 also return OK. This allows client software to tell the user that he/she
722 can't edit the room *before* going through the trouble of actually doing the
723 editing. Possible return codes are:
725 ERROR+NOT_LOGGED_IN - No user is logged in.
726 ERROR+HIGHER_ACCESS_REQUIRED - Not enough access. Typically, only aides
727 and the room aide associated with the current room, can access this command.
728 OK - Command succeeded. Parameters are returned.
730 If OK is returned, the following parameters will be returned as well:
732 0. The name of the room
733 1. The room's password (if it's a passworded room)
734 2. The name of the room's directory (if it's a directory room)
735 3. Various flags (bits) associated with the room (see LKRN cmd above)
736 4. The floor number on which the room resides
737 5. The room listing order
738 6. The default view for the room (see views.txt)
739 7. A second set of flags (bits) associated with the room
742 SETR (SET Room attributes)
744 This command sets various attributes associated with the current room. It
745 should be passed the following arguments:
747 0. The name of the room
748 1. The room's password (if it's a passworded room)
749 2. The name of the room's directory (if it's a directory room)
750 3. Various flags (bits) associated with the room (see LKRN cmd above)
751 4. "Bump" flag (see below)
752 5. The floor number on which the room should reside
753 6. The room listing order
754 7. The default view for the room (see views.txt)
755 8. A second set of flags (bits) associated with the room
757 *Important: You should always use GETR to retrieve the current attributes of
758 the room, then change what you want to change, and then use SETR to write it
759 all back. This is particularly important with respect to the flags: if a
760 particular bit is set, and you don't know what it means, LEAVE IT ALONE and
761 only toggle the bits you want to toggle. This will allow for upward
764 The _BASEROOM_, user's Mail> and Aide> rooms can only be partially edited.
765 Any changes which cannot be made will be silently ignored.
767 If the room is a private room, you have the option of causing all users who
768 currently have access, to forget the room. If you want to do this, set the
769 "bump" flag to 1, otherwise set it to 0.
774 This command is used to get the name of the Room Aide for the current room.
775 It will return ERROR + NOT_LOGGED_IN if no user is logged in, or OK if the
776 command succeeded. Along with OK there will be returned one parameter: the
777 name of the Room Aide. A conforming server must guarantee that the user is
783 The opposite of GETA, used to set the Room Aide for the current room. One
784 parameter should be passed, which is the name of the user who is to be the
785 new Room Aide. Under Citadel, this command may only be executed by Aides
786 and by the *current* Room Aide for the room. Return codes possible are:
787 ERROR + NOT_LOGGED_IN (Not logged in.)
788 ERROR + HIGHER_ACCESS_REQUIRED (Higher access required.)
789 ERROR + NOT_HERE (Room cannot be edited.)
790 OK (Command succeeded.)
793 ENT0 (ENTer message, mode 0)
795 This command is used to enter messages into the system. It accepts four
798 0 - Post flag. This should be set to 1 to post a message. If it is
799 set to 0, the server only returns OK or ERROR (plus any flags describing
800 the error) without reading in a message. Client software should, in fact,
801 perform this operation at the beginning of an "enter message" command
802 *before* starting up its editor, so the user does not end up typing a message
803 in vain that will not be permitted to be saved. If it is set to 2, the
804 server will accept an "apparent" post name if the user is privileged enough.
805 This post name is arg 5.
806 1 - Recipient (To: field). This argument is utilized only for private
807 mail. It is ignored for public messages. It contains, of course, the name
808 of the recipient(s) of the message.
809 2 - Anonymous flag. This argument is ignored unless the room allows
810 anonymous messages. In such rooms, this flag may be set to 1 to flag a
811 message as anonymous, otherwise 0 for a normal message.
812 3 - Format type. Any valid Citadel format type may be used (this will
813 typically be 0; see the MSG0 command above).
814 4 - Subject. If present, this argument will be used as the subject of
816 5 - Post name. When postflag is 2, this is the name you are posting as.
817 This is an Aide only command.
818 6 - Do Confirmation. NOTE: this changes the protocol semantics! When
819 you set this to nonzero, ENT0 will reply with a confirmation message after
820 you submit the message text. The reply code for the ENT0 command will be
821 START_CHAT_MODE instead of SEND_LISTING.
822 7 - Recipient (Cc: field). This argument is utilized only for private
823 mail. It is ignored for public messages. It contains, of course, the name
824 of the recipient(s) of the message.
825 8 - Recipient (Bcc: field). This argument is utilized only for private
826 mail. It is ignored for public messages. It contains, of course, the name
827 of the recipient(s) of the message.
828 9 - Exclusive message ID. When a message is submitted with an Exclusive
829 message ID, any existing messages with the same ID will automatically be
830 deleted. This is only applicable for Wiki rooms; other types of rooms either
831 ignore the supplied ID (such as message boards and mailboxes) or derive the
832 ID from a UUID native to the objects stored in them (such as calendars and
835 Possible result codes:
836 OK - The request is valid. (Client did not set the "post" flag, so the
837 server will not read in message text.) If the message is an e-mail with
838 a recipient, the text that follows the OK code will contain the exact name
839 to which mail is being sent. The client can display this to the user. The
840 implication here is that the name that the server returns will contain the
841 correct upper and lower case characters. In addition, if the recipient is
842 having his/her mail forwarded, the forwarding address will be returned.
843 SEND_LISTING - The request is valid. The client should now transmit
844 the text of the message (ending with a 000 on a line by itself, as usual).
845 START_CHAT_MODE - The request is valid. The client should now transmit
846 the text of the message, ending with a 000 on a line by itself. After
847 transmitting the 000 terminator, the client MUST read in the confirmation
848 from the server, which will also end with 000 on a line by itself. The format
849 of the confirmation appears below.
850 ERROR + NOT_LOGGED_IN - Not logged in.
851 ERROR + HIGHER_ACCESS_REQUIRED - Higher access is required. An
852 explanation follows, worded in a form that can be displayed to the user.
853 ERROR + NO_SUCH_USER - The specified recipient does not exist.
855 The format of the confirmation message, if requested, is as follows:
856 Line 1: The new message number on the server for the message. It will be
857 positive for a real message number, or negative to denote
858 that an error occurred. If an error occurred, the message was
860 Line 2: A human-readable confirmation or error message.
861 Line 3: The resulting Exclusive UID of the message, if present.
862 (More may be added to this in the future, so do not assume that there will
863 only be these lines output. Keep reading until 000 is received.)
866 RINF (read Room INFormation file)
868 Each room has associated with it a text file containing a description of
869 the room, perhaps containing its intended purpose or other important
870 information. The info file for the Lobby> (the system's base room) is
871 often used as a repository for system bulletins and the like.
873 This command, which accepts no arguments, is simply used to read the info
874 file for the current room. It will return LISTING_FOLLOWS followed by
875 the text of the message (always in format type 0) if the request can be
876 honored, or ERROR if no info file exists for the current room (which is
877 often the case). Other error description codes may accompany this result.
879 When should this command be used? This is, of course, up to the discretion
880 of client software authors, but in Citadel it is executed in two situations:
881 the first time the user ever enters a room; and whenever the contents of the
882 file change. The latter can be determined from the result of a GOTO command,
883 which will tell the client whether the file needs to be read (see GOTO above).
886 DELE (DELEte a message)
888 Delete a message from the current room. The one argument that should be
889 passed to this command is the message number of the message to be deleted.
890 The return value will be OK if the message was deleted, or an ERROR code.
891 If the delete is successful, the message's reference count is decremented, and
892 if the reference count reaches zero, the message is removed from the message
896 MOVE (MOVE or copy a message to a different room)
898 Move or copy a message to a different room. This command expects to be
899 passed three arguments:
900 0: the message number of the message to be moved or copied.
901 1: the name of the target room.
902 2: flag: 0 to move the message, 1 to copy it without deleting from the
905 This command never creates or deletes copies of a message; it merely moves
906 around links. When a message is moved, its reference count remains the same.
907 When a message is copied, its reference count is incremented.
910 KILL (KILL current room)
912 This command deletes the current room. It accepts a single argument, which
913 should be nonzero to actually delete the room, or zero to merely check
914 whether the room can be deleted.
916 Once the room is deleted, the current room is undefined. It is suggested
917 that client software immediately GOTO another room (usually _BASEROOM_)
918 after this command completes.
920 Possible return codes:
922 OK - room has been deleted (or, if checking only, request is valid).
923 ERROR+NOT_LOGGED_IN - no user is logged in.
924 ERROR+HIGHER_ACCESS_REQUIRED - not enough access to delete rooms.
925 ERROR+NOT_HERE - this room can not be deleted.
928 CRE8 (CRE[ate] a new room)
930 This command is used to create a new room. Like some of the other
931 commands, it provides a mechanism to first check to see if a room can be
932 created before actually executing the command. CRE8 accepts the following
935 0 - Create flag. Set this to 1 to actually create the room. If it is
936 set to 0, the server merely checks that there is a free slot in which to
937 create a new room, and that the user has enough access to create a room. It
938 returns OK if the client should go ahead and prompt the user for more info,
939 or ERROR or ERROR+HIGHER_ACCESS_REQUIRED if the command will not succeed.
940 1 - Name for new room.
941 2 - Access type for new room:
943 1 - Private; can be entered by guessing the room's name
944 2 - Private; can be entered by knowing the name *and* password
945 3 - Private; invitation only (sometimes called "exclusive")
946 4 - Personal (mailbox for this user only)
947 3 - Password for new room (if it is a type 2 room)
948 4 - Floor number on which the room should reside (optional)
949 5 - Set to 1 to avoid automatically gaining access to the created room.
950 6 - The default "view" for the room.
952 If the create flag is set to 1, the room is created (unless something
953 went wrong and an ERROR return is sent), and the server returns OK, but
954 the session is **not** automatically sent to that room. The client still
955 must perform a GOTO command to go to the new room.
958 FORG (FORGet the current room)
960 This command is used to forget (zap) the current room. For those not
961 familiar with Citadel, this terminology refers to removing the room from
962 a user's own known rooms list, *not* removing the room itself. After a
963 room is forgotten, it no longer shows up in the user's known room list,
964 but it will exist in the user's forgotten room list, and will return to the
965 known room list if the user goes to the room (in Citadel, this is
966 accomplished by explicitly typing the room's name in a <.G>oto command).
968 The command takes no arguments. If the command cannot execute for any
969 reason, ERROR will be returned. ERROR+NOT_LOGGED_IN or ERROR+NOT_HERE may
970 be returned as they apply.
972 If the command succeeds, OK will be returned. At this point, the current
973 room is **undefined**, and the client software is responsible for taking
974 the user to another room before executing any other room commands (usually
975 this will be _BASEROOM_ since it is always there).
978 MESG (read system MESsaGe)
980 This command is used to display system messages and/or help files. The
981 single argument it accepts is the name of the file to display. IT IS CASE
982 SENSITIVE. Citadel looks for these files first in the "messages"
983 subdirectory and then in the "help" subdirectory.
985 If the file is found, LISTING_FOLLOWS is returned, followed by a pathname
986 to the file being displayed. Then the message is printed, in format type 0
987 (see MSG0 command for more information on this). If the file is not found,
990 There are some "well known" names of system messages which client software
991 may expect most servers to carry:
993 hello - Welcome message, to be displayed before the user logs in.
994 changepw - To be displayed whenever the user is prompted for a new
995 password. Warns about picking guessable passwords and such.
996 register - Should be displayed prior to the user entering registration.
997 Warnings about not getting access if not registered, etc.
998 help - Main system help file.
999 goodbye - System logoff banner; display when user logs off.
1000 roomaccess - Information about how public rooms and different types of
1001 private rooms function with regards to access.
1002 unlisted - Tells users not to choose to be unlisted unless they're
1003 really paranoid, and warns that aides can still see
1004 unlisted userlog entries.
1006 Citadel provides these for the Citadel Unix text client. They are
1007 probably not very useful for other clients:
1009 mainmenu - Main menu (when in idiot mode).
1014 saveopt - Options to save a message, abort, etc.
1015 entermsg - Displayed just before a message is entered, when in
1019 GNUR (Get Next Unvalidated User)
1021 This command shows the name of a user that needs to be validated. If there
1022 are no unvalidated users, OK is returned. Otherwise, MORE_DATA is returned
1023 along with the name of the first unvalidated user the server finds. All of
1024 the usual ERROR codes may be returned as well (for example, if the user is
1025 not an Aide and cannot validate users).
1027 A typical "Validate New Users" command would keep executing this command,
1028 and then validating each user it returns, until it returns OK when all new
1029 users have been validated.
1032 GREG (Get REGistration for user)
1034 This command retrieves the registration info for a user, whose name is the
1035 command's sole argument. All the usual error messages can be returned. If
1036 the command succeeds, LISTING_FOLLOWS is returned, followed by the user's name
1037 (retrieved from the userlog, with the right upper and lower case etc.) The
1038 contents of the listing contains one field per line, followed by the usual
1039 000 on the last line.
1041 The following lines are defined. Others WILL be added in the futre, so all
1042 software should be written to read the lines it knows about and then ignore
1043 all remaining lines:
1048 Line 4: Street address or PO Box
1049 Line 5: City/town/village/etc.
1050 Line 6: State/province/etc.
1052 Line 8: Telephone number
1053 Line 9: Access level
1054 Line 10: Internet e-mail address
1057 Users without Aide privileges may retrieve their own registration using
1058 this command. This can be accomplished either by passing the user's own
1059 name as the argument, or the string "_SELF_". The command will always
1060 succeed when used in this manner, unless no user is logged in.
1063 VALI (VALIdate user)
1065 This command is used to validate users. Obviously, it can only be executed
1066 by users with Aide level access. It should be passed two parameters: the
1067 name of the user to validate, and the desired access level
1069 If the command succeeds, OK is returned. The user's access level is changed
1070 and the "need validation" bit is cleared. If the command fails for any
1071 reason, ERROR, ERROR+NO_SUCH_USER, or ERROR+HIGHER_ACCESS_REQUIRED will be
1075 EINF (Enter INFo file for room)
1077 Transmit the info file for the current room with this command. EINF uses
1078 a boolean flag (1 or 0 as the first and only argument to the command) to
1079 determine whether the client actually wishes to transmit a new info file, or
1080 is merely checking to see if it has permission to do so.
1082 If the command cannot succeed, it returns ERROR.
1083 If the client is only checking for permission, and permission will be
1084 granted, OK is returned.
1085 If the client wishes to transmit the new info file, SEND_LISTING is
1086 returned, and the client should transmit the text of the info file, ended
1087 by the usual 000 on a line by itself.
1092 This is a simple user listing. It always succeeds, returning
1093 LISTING_FOLLOWS followed by zero or more user records, 000 terminated. The
1094 fields on each line are as follows:
1099 4. Date/time of last login (Unix format)
1102 7. Password (listed only if the user requesting the list is an Aide)
1104 Unlisted entries will also be listed to Aides logged into the server, but
1105 not to ordinary users.
1107 The LIST command accepts an optional single argument, which is a simple,
1108 case-insensitive search string. If this argument is present, only usernames
1109 in which the search string is present will be returned. It is a simple
1110 substring search, not a regular expression search. If this string is empty
1111 or not present, all users will be returned.
1114 REGI (send REGIstration)
1116 Clients will use this command to transmit a user's registration info. If
1117 no user is logged in, ERROR+NOT_LOGGED_IN is returned. Otherwise,
1118 SEND_LISTING is returned, and the server will expect the following information
1119 (terminated by 000 on a line by itself):
1122 Line 2: Street address or PO Box
1123 Line 3: City/town/village/etc.
1124 Line 4: State/province/etc.
1126 Line 6: Telephone number
1127 Line 7: e-mail address
1131 CHEK (CHEcK various things)
1133 When logging in, there are various things that need to be checked. This
1134 command will return ERROR+NOT_LOGGED_IN if no user is logged in. Otherwise
1135 it returns OK and the following parameters:
1137 0: Number of new private messages in Mail>
1138 1: Nonzero if the user needs to register
1139 2: (Relevant to Aides only) Nonzero if new users require validation
1140 3: The user's preferred Internet e-mail address
1143 DELF (DELete a File)
1145 This command deletes a file from the room's directory, if there is one. The
1146 name of the file to delete is the only parameter to be supplied. Wildcards
1147 are not acceptable, and any slashes in the filename will be converted to
1148 underscores, to prevent unauthorized access to neighboring directories. The
1149 possible return codes are:
1151 OK - Command succeeded. The file was deleted.
1152 ERROR+NOT_LOGGED_IN - Not logged in.
1153 ERROR+HIGHER_ACCESS_REQUIRED - Not an Aide or Room Aide.
1154 ERROR+NOT_HERE - There is no directory in this room.
1155 ERROR+FILE_NOT_FOUND - Requested file was not found.
1160 This command is similar to DELF, except that it moves a file (and its
1161 associated file description) to another room. It should be passed two
1162 parameters: the name of the file to move, and the name of the room to move
1163 the file to. All of the same return codes as DELF may be returned, and also
1164 one additional one: ERROR+NO_SUCH_ROOM, which means that the target room
1165 does not exist. ERROR+NOT_HERE could also mean that the target room does
1166 not have a directory.
1169 NETF (NETwork send a File)
1171 This command is similar to MOVF, except that it attempts to send a file over
1172 the network to another system. It should be passed two parameters: the name
1173 of the file to send, and the node name of the system to send it to. All of
1174 the same return codes as MOVF may be returned, except for ERROR+NO_SUCH_ROOM.
1175 Instead, ERROR+NO_SUCH_SYSTEM may be returned if the name of the target
1178 The name of the originating room will be sent along with the file. Most
1179 implementations will look for a room with the same name at the receiving end
1180 and attempt to place the file there, otherwise it goes into a bit bucket room
1181 for miscellaneous files. This is, however, beyond the scope of this document;
1182 see elsewhere for more details.
1185 RWHO (Read WHO's online)
1187 Displays a list of all users connected to the server. No error codes are
1188 ever returned. LISTING_FOLLOWS will be returned, followed by zero or more
1189 lines containing the following three fields:
1191 0 - Session ID. Citadel fills this with the pid of a server program.
1193 2 - The name of the room the user is currently in. This field might not
1194 be displayed (for example, if the user is in a private room) or it might
1195 contain other information (such as the name of a file the user is
1197 3 - (server v4.03 and above) The name of the host the client is connecting
1198 from, or "localhost" if the client is local.
1199 4 - (server v4.04 and above) Description of the client software being used
1200 5 - The last time, locally to the server, that a command was received from
1201 this client (Note: NOOP's don't count)
1202 6 - The last command received from a client. (NOOP's don't count)
1203 7 - Session flags. These are: + (spoofed address), - (STEALTH mode), *
1204 (posting) and . (idle).
1205 8 - Actual user name, if user name is masqueraded and viewer is an Aide.
1206 9 - Actual room name, if room name is masqueraded and viewer is an Aide.
1207 10 - Actual host name, if host name is masqueraded and viewer is an Aide.
1208 11 - Nonzero if the session is a logged-in user, zero otherwise.
1210 The listing is terminated, as always, with the string "000" on a line by
1214 OPEN (OPEN a file for download)
1216 This command is used to open a file for downloading. Only one download
1217 file may be open at a time. The only argument to this command is the name
1218 of the file to be opened. The user should already be in the room where the
1219 file resides. Possible return codes are:
1222 ERROR+NOT_HERE (no directory in this room)
1223 ERROR+FILE_NOT_FOUND (could not open the file)
1227 If the file is successfully opened, OK will be returned, along with the
1228 size (in bytes) of the file, the time of last modification (if applicable),
1229 the filename (if known), and the MIME type of the file (if known).
1232 CLOS (CLOSe the download file)
1234 This command is used to close the download file. It returns OK if the
1235 file was successfully closed, or ERROR if there wasn't any file open in the
1239 READ (READ from the download file)
1241 Two arguments are passed to this command. The first is the starting position
1242 in the download file, and the second is the total number of bytes to be
1243 read. If the operation can be performed, BINARY_FOLLOWS will be returned,
1244 along with the number of bytes to follow. Then, immediately following the
1245 newline, will be that many bytes of binary data. The client *must* read
1246 exactly that number of bytes, otherwise the client and server will get out
1249 If the operation cannot be performed, any of the usual error codes will be
1253 UOPN (OPeN a file for Uploading)
1255 This command is similar to OPEN, except that this one is used when the
1256 client wishes to upload a file to the server. The first argument is the name
1257 of the file to create, and the second argument is a one-line comment
1258 describing the contents of the file. Only one upload file may be open at a
1259 time. Possible return codes are:
1262 ERROR+NOT_HERE (no directory in this room)
1263 ERROR+FILE_NOT_FOUND (a name must be specified)
1264 ERROR (miscellaneous errors)
1265 ERROR+ALREADY_EXISTS (a file with the same name already exists)
1268 If OK is returned, the command has succeeded and writes may be performed.
1271 UCLS (CLoSe the Upload file)
1273 Close the file opened with UOPN. An argument of "1" should be passed to
1274 this command to close and save the file; otherwise, the transfer will be
1275 considered aborted and the file will be deleted. This command returns OK
1276 if the operation succeeded or ERROR if it did not.
1279 WRIT (WRITe to the upload file)
1281 If an upload file is open, this command may be used to write to it. The
1282 argument passed to this command is the number of bytes the client wishes to
1283 transmit. An ERROR code will be returned if the operation cannot be
1286 If the operation can be performed, SEND_BINARY will be returned, followed
1287 by the number of bytes the server is expecting. The client must then transmit
1288 exactly that number of bytes. Note that in the current implementation, the
1289 number of bytes the server is expecting will always be the number of bytes
1290 the client requested to transmit, but the client software should never assume
1291 that this will always happen, in case changes are made later.
1294 QUSR (Query for a USeR)
1296 This command is used to check to see if a particular user exists. The only
1297 argument to this command is the name of the user being searched for. If
1298 the user exists, OK is returned, along with the name of the user in the userlog
1299 (so the client software can learn the correct upper/lower casing of the name
1300 if necessary). If the user does not exist, ERROR+NO_SUCH_USER is returned.
1301 No login or current room is required to utilize this command.
1304 OIMG (Open an IMaGe file)
1306 Open an image (graphics) file for downloading. Once opened, the file can be
1307 read as if it were a download file. This implies that an image and a download
1308 cannot be opened at the same time. OIMG returns the same result codes as OPEN.
1310 All images will be in GIF (Graphics Interchange Format). In the case of
1311 Citadel, the server will convert the supplied filename to all lower case,
1312 append the characters ".gif" to the filename, and look for it in the "images"
1313 subdirectory. As with the MESG command, there are several "well known"
1314 images which are likely to exist on most servers:
1316 hello - "Welcome" graphics to be displayed alongside MESG "hello"
1317 goodbye - Logoff banner graphics to be displayed alongside MESG "goodbye"
1318 background - Background image (usually tiled) for graphical clients
1320 The following "special" image names are defined in Citadel server version
1323 _userpic_ - Picture of a user (send the username as the second argument)
1324 _floorpic_ - A graphical floor label (send the floor number as the second
1325 argument). Clients which request a floor picture will display
1326 the picture *instead* of the floor name.
1327 _roompic_ - A graphic associated with the *current* room. Clients which
1328 request a room picture will display the picture in *addition*
1329 to the room name (i.e. it's used for a room banner, as
1330 opposed to the floor picture's use in a floor listing).
1333 NETP (authenticate as network session with connection NET Password)
1335 This command is used by client software to identify itself as a transport
1336 session for Citadel site-to-site networking. It should be called with
1337 two arguments: the node name of the calling system, and the "shared secret"
1338 password for that connection. If the authentication succeeds, NETP will
1339 return OK, otherwise, it returns ERROR.
1342 NSYN (Network SYNchronize room)
1344 This command can be used to synchronize the contents of a room on the
1345 network. It is only usable by Aides. It accepts one argument: the name of
1346 a network node (which must be a valid one).
1348 When NSYN is run, the *entire* contents of the current room will be spooled
1349 to the specified node, without regard to whether any of the messages have
1350 already undergone network processing. It is up to the receiving node to
1351 check for duplicates (the Citadel networker does handle this) and avoid
1354 The command returns OK upon success or ERROR if the user is not an Aide.
1357 NUOP (Network Upload OPen file)
1359 Open a network spool file for uploading. The client must have already
1360 identified itself as a network session using the NETP command. If the command
1361 returns OK, the client may begin transmitting IGnet/Open spool data using
1362 a series of WRIT commands. When a UCLS command is issued, the spooled data
1363 is entered into the server if the argument to UCLS is 1 or discarded if the
1364 argument to UCLS is 0. If the client has not authenticated itself with a
1365 NETP command, ERROR+HIGHER_ACCESS_REQUIRED will be returned.
1368 NDOP (Network Download OPen file)
1370 Open a network spool file for downloading. The client must have already
1371 identified itself as a network session using the NETP command. If the command
1372 returns OK, the client may begin receiving IGnet/Open spool data using
1373 a series of READ commands. When a CLOS command is issued, the spooled data
1374 is deleted from the server and may not be read again. If the client has not
1375 authenticated itself with a NETP command, ERROR+HIGHER_ACCESS_REQUIRED will
1379 LFLR (List all known FLooRs)
1381 On systems supporting floors, this command lists all known floors. The
1382 command accepts no parameters. It will return ERROR+NOT_LOGGED_IN if no
1383 user is logged in. Otherwise it returns LISTING_FOLLOWS and a list of
1384 the available floors, each line consisting of three fields:
1386 1. The floor number associated with the floor
1387 2. The name of the floor
1388 3. Reference count (number of rooms on this floor)
1391 CFLR (Create a new FLooR)
1393 This command is used to create a new floor. It should be passed two
1394 arguments: the name of the new floor to be created, and a 1 or 0 depending
1395 on whether the client is actually creating a floor or merely checking to
1396 see if it has permission to create the floor. The user must be logged in
1397 and have Aide privileges to create a floor.
1399 If the command succeeds, it will return OK followed by the floor number
1400 associated with the new floor. Otherwise, it will return ERROR (plus perhaps
1401 HIGHER_ACCESS_REQUIRED, ALREADY_EXISTS, or INVALID_FLOOR_OPERATION)
1402 followed by a description of why the command failed.
1407 This command is used to delete a floor. It should be passed two
1408 argument: the *number* of the floor to be deleted, and a 1 or 0 depending
1409 on whether the client is actually deleting the floor or merely checking to
1410 see if it has permission to delete the floor. The user must be logged in
1411 and have Aide privileges to delete a floor.
1413 Floors that contain rooms may not be deleted. If there are rooms on a floor,
1414 they must be either deleted or moved to different floors first. This implies
1415 that the Main Floor (floor 0) can never be deleted, since Lobby>, Mail>, and
1416 Aide> all reside on the Main Floor and cannot be deleted.
1418 If the command succeeds, it will return OK. Otherwise it will return
1419 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1420 followed by a description of why the command failed.
1425 Edit the parameters of a floor. The client may pass one or more parameters
1428 1. The number of the floor to be edited
1429 2. The desired new name
1431 More parameters may be added in the future. Any parameters not passed to
1432 the server will remain unchanged. A minimal command would be EFLR and a
1433 floor number -- which would do nothing. EFLR plus the floor number plus a
1434 floor name would change the floor's name.
1436 If the command succeeds, it will return OK. Otherwise it will return
1437 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1440 IDEN (IDENtify the client software)
1442 The client software has the option to identify itself to the server.
1443 Currently, the server does nothing with this information except to write
1444 it to the syslog to satisfy the system administrator's curiosity. Other
1445 uses might become apparent in the future.
1447 The IDEN command should contain five fields: a developer ID number (same as
1448 the server developer ID numbers in the INFO command -- please obtain one if
1449 you are a new developer), a client ID number (which does not have to be
1450 globally unique - only unique within the domain of the developer number),
1451 a version number, a free-form text string describing the client, and the name
1452 of the host the user is located at.
1454 It is up to the server to determine whether to accept the host name or to
1455 use the host name it has detected itself. Generally, if the client is
1456 running on a trusted host (either localhost or a well-known publically
1457 accessible client) it should use the host name transmitted by IDEN,
1458 otherwise it should use the host name it has detected itself.
1460 IDEN always returns OK, but since that's the only way it ever returns
1461 there's no point in checking the result code.
1464 IPGM (identify as an Internal ProGraM)
1466 IPGM is a low-level command that should not be used by normal user clients.
1467 It is used for various utilities to communicate with the server on the same
1468 host. For example, the "sendcommand" utility logs onto the server as an
1469 internal program in order to run arbitrary server commands. Since user clients
1470 do not utilize this command (or any of its companion commands), developers
1471 writing Citadel-compatible servers need not implement it.
1473 The sole argument to IPGM is the system's internal program password. This
1474 password is generated by the setup program and stored in the config file.
1475 Since internal programs have access to the config file, they know the correct
1478 IPGM returns OK for a correct authentication or ERROR otherwise.
1481 CHAT (enter CHAT mode)
1483 This command functions differently from every other command in the system. It
1484 is used to implement multi-user chat. For this to function, a new transfer
1485 mode, called START_CHAT_MODE, is implemented. If a client does not support
1486 chat mode, it should never send a CHAT command!
1488 In chat mode, messages may arrive asynchronously from the server at any
1489 time. The client may send messages at any time. This allows the arrival of
1490 messages without the client having to poll for them. Arriving messages will
1491 be of the form "user|message", where the "user" portion is, of course, the
1492 name of the user sending the message, and "message" is the message text.
1494 Chat mode ends when the server says it ends. The server will signal the end
1495 of chat mode by transmitting "000" on a line by itself. When the client reads
1496 this line, it must immediately exit from chat mode without sending any
1497 further traffic to the server. The next transmission sent to the server
1498 will be a regular server command.
1500 The Citadel server understands the following commands:
1501 /quit - Exit from chat mode (causes the server to do an 000 end)
1502 /who - List users currently in chat
1503 /whobbs - List users currently in chat and elsewhere
1504 /me - Do an irc-style action.
1505 /join - Join a new "room" in which all messages are only heard by
1506 people in that room.
1507 /msg - /msg <user> <msg> will send the msg to <user> only.
1508 /help - Print help information
1509 NOOP - Do nothing (silently)
1511 Any other non-empty string is treated as message text and will be broadcast
1512 to other users currently in chat.
1515 SEXP (Send instant message)
1517 This is one of two commands which implement instant messages (also known
1518 as "paging"). Commands ending in "...EXP" are so-named because we called
1519 them "express messages" before the industry standardized on the term
1520 "instant messages." When an instant message is sent, it will be
1521 logged in user to another. When an instant message is sent, it will be
1522 displayed the next time the target user executes a PEXP or GEXP command.
1524 The SEXP command accepts two arguments: the name of the user to send the
1525 message to, and the text of the message. If the message is successfully
1526 transmitted, OK is returned. If the target user is not logged in or if
1527 anything else goes wrong, ERROR is returned.
1529 If the server supports extended paging, sending a zero-length message
1530 merely checks for the presence of the requested user without actually sending
1531 a message. Sending a message consisting solely of a "-" (hyphen) will cause
1532 the server to return SEND_LISTING if the requested user is logged in, and the
1533 client can then transmit a multi-line page.
1535 The reserved name "broadcast" may be used instead of a user name, to
1536 broadcast an instant message to all users currently connected to the server.
1538 Do be aware that if an instant message is transmitted to a user who is logged
1539 in using a client that does not check for instant messages, the message will
1540 never be received. Also, instant messages are NOT sent via the following
1541 transports: SMTP, POP3.
1544 PEXP (Print instant messages) ***DEPRECATED***
1546 This command is deprecated; it will eventually disappear from the protocol and
1547 its use is not recommended. Please use the GEXP command instead.
1549 Called without any arguments, PEXP simply dumps out the contents
1550 of any waiting instant messages. It returns ERROR if there is a problem,
1551 otherwise it returns LISTING_FOLLOWS followed by all messages.
1553 So how does the client know there are instant messages waiting? It could
1554 execute a random PEXP every now and then. Or, it can check the byte in
1555 server return code messages, between the return code and the parameters. In
1556 much the same way as FTP uses "-" to signify a continuation, Citadel uses
1557 an "*" in this position to signify the presence of waiting instant messages.
1560 EBIO (Enter BIOgraphy)
1562 Transmit to the server a free-form text file containing a little bit of
1563 information about the user for other users to browse. This is typically
1564 referred to as a 'bio' online. EBIO returns SEND_LISTING if it succeeds,
1565 after which the client is expected to transmit the file, or any of the usual
1566 ERROR codes if it fails.
1569 RBIO (Read BIOgraphy)
1571 Receive from the server a named user's bio. This command should be passed
1572 a single argument - the name of the user whose bio is requested. RBIO returns
1573 LISTING_FOLLOWS plus the bio file if the user exists and has a bio on file.
1574 The return has the following parameters: the user name, user number, access
1575 level, date of last call, times called, and messages posted. This command
1576 returns ERROR+NO_SUCH_USER if the named user does not exist.
1578 RBIO no longer considers a user with no bio on file to be an error condition.
1579 It now returns a message saying the user has no bio on file as the text of the
1580 bio. This allows newer servers to operate with older clients.
1583 STEL (enter STEaLth mode)
1585 When in "stealth mode," a user will not show up in the "Who is online"
1586 listing (the RWHO server command). Only Aides may use stealth mode. The
1587 STEL command accepts one argument: a 1 indicating that the user wishes to
1588 enter stealth mode, or a 0 indicating that the user wishes to exit stealth
1589 mode. STEL returns OK if the command succeeded, ERROR+NOT_LOGGED_IN if no
1590 user is logged in, or ERROR+HIGHER_ACCESS_REQUIRED if the user is not an Aide;
1591 followed by a 1 or 0 indicating the new state.
1593 If any value other than 1 or 0 is sent by the client, the server simply
1594 replies with 1 or 0 to indicate the current state without changing it.
1596 The STEL command also makes it so a user does not show up in the chat room
1600 LBIO (List users who have BIOs on file)
1602 This command is self-explanatory. Any user who has used EBIO to place a bio
1603 on file is listed. LBIO almost always returns LISTING_FOLLOWS followed by
1604 this listing, unless it experiences an internal error in which case ERROR
1608 MSG2 (read MeSsaGe, mode 2)
1610 MSG2 follows the same calling convention as MSG0. The difference between
1611 the two commands is that MSG2 outputs messages in standard RFC822 format
1612 rather than in Citadel proprietary format.
1614 This command was implemented in order to make various gateway programs
1615 easier to implement, and to provide some sort of multimedia support in the
1616 future. Keep in mind that when this command is used, all messages will be
1617 output in fixed 80-column format.
1620 MSG3 (read MeSsaGe, mode 3 -- internal command)
1622 MSG3 is for use by internal programs only and should not be utilized by
1623 user-mode clients. It does require IPGM authentication. MSG3 follows the
1624 same calling convention as the other MSG commands, but upon success returns
1625 BINARY_FOLLOWS followed by a data block containing the _raw_ message format
1629 TERM (TERMinate another session)
1631 In a multithreaded environment, it sometimes becomes necessary to terminate
1632 a session that is unusable for whatever reason. The TERM command performs
1633 this task. Naturally, only Aides can execute TERM. The command should be
1634 called with a single argument: the session ID (obtained from an RWHO command)
1635 of the session to be terminated.
1637 TERM returns OK if the session was terminated, or ERROR otherwise. Note that
1638 a client program is prohibited from terminating the session it is currently
1644 DOWN (shut DOWN the server)
1646 This command, which may only be executed by an Aide, immediately shuts down
1647 the server. It is only implemented on servers on which such an operation is
1648 possible, such as a multithreaded Citadel engine. The server does not restart.
1649 DOWN returns OK if the user is allowed to shut down the server, in which case
1650 the client program should expect the connection to be immediately broken.
1653 SCDN (Schedule or Cancel a shutDowN)
1655 SCDN sets or clears the "scheduled shutdown" flag. Pass this command a 1 or
1656 0 to respectively set or clear the flag. When the "scheduled shutdown" flag is
1657 set, the server will be shut down when there are no longer any users logged in.
1658 Any value other than 0 or 1 will not change the flag, only report its state.
1659 No users will be kicked off the system, and in fact the server is still
1660 available for new connections. The command returns ERROR if it fails;
1661 otherwise, it returns OK followed by a number representing the current state
1665 EMSG (Enter a system MeSsaGe)
1667 This is the opposite of the MESG command - it allows the creation and editing
1668 of system messages. The only argument passed to EMSG is the name of the
1669 file being transmitted. If the file exists in any system message directory
1670 on the server it will be overwritten, otherwise a new file is created. EMSG
1671 returns SEND_LISTING on success or ERROR+HIGHER_ACCESS_REQUIRED if the user
1674 Typical client software would use MESG to retrieve any existing message into
1675 an edit buffer, then present an editor to the user and run EMSG if the changes
1679 UIMG (Upload an IMaGe file)
1681 UIMG is complemenary to OIMG; it is used to upload an image to the server.
1682 The first parameter supplied to UIMG should be 0 if the client is only checking
1683 for permission to upload, or 1 if the client is actually attempting to begin
1684 the upload operation. The second argument is the name of the file to be
1685 transmitted. In Citadel, the filename is converted to all lower case,
1686 appended with the characters ".gif", and stored in the "images" directory.
1688 UIMG returns OK if the client has permission to perform the requested upload,
1689 or ERROR+HIGHER_ACCESS_REQUIRED otherwise. If the client requested to begin
1690 the operation (first parameter set to 1), an upload file is opened, and the
1691 client should begin writing to it with WRIT commands, then close it with a
1694 The supplied filename should be one of:
1696 -> _userpic_ (Server will attempt to write to the user's online photo)
1697 -> Any of the "well known" filenames described in the writeup for the
1701 HCHG (Hostname CHanGe)
1703 HCHG is a command, usable by any user, that allows a user to change their RWHO
1704 host value. This will mask a client's originating hostname from normal
1705 users; access level 6 and higher can see, in an extended wholist, the actual
1706 hostname the user originates from.
1708 The format of an HCHG command is:
1712 If a HCHG command is successful, the value OK (200) is returned.
1715 RCHG (Roomname CHanGe)
1717 RCHG is a command, usable by any user, that allows a user to change their RWHO
1718 room value. This will mask a client's roomname from normal users; access
1719 level 6 and higher can see, in an extended wholist, the actual room the user
1722 The format of an RCHG command is:
1726 If a RCHG command is successful, the value OK (200) is returned.
1729 UCHG (Username CHanGe)
1731 UCHG is an aide-level command which allows an aide to effectively change their
1732 username. If this value is blank, the user goes into stealth mode (see
1734 will show up as being from the real username in this mode, however. In
1735 addition, the RWHO listing will include both the spoofed and real usernames.
1737 The format of an UCHG command is:
1741 If a UCHG command is successful, the value OK (200) is returned.
1744 TIME (get server local TIME)
1746 TIME returns OK followed by the current time measured in seconds since
1747 00:00:00 GMT, Jan 1, 1970 (standard Unix format).
1749 This is used in allowing a client to calculate idle times.
1752 AGUP (Administrative Get User Parameters)
1753 ASUP (Administrative Set User Parameters)
1755 These commands are only executable by Aides and by server extensions running
1756 at system-level. They are used to get/set any and all parameters relating to
1757 a user account. AGUP requires only one argument: the name of the user in
1758 question. SGUP requires all of the parameters to be set. The parameters are
1759 as follows, and are common to both commands:
1763 2 - Flags (see citadel.h)
1768 7 - Timestamp of last call
1769 8 - Purge time (in days) for this user (or 0 to use system default)
1771 Upon success, AGUP returns OK followed by all these parameters, and ASUP
1772 simply returns OK. If the client has insufficient access to perform the
1773 requested operation, ERROR+HIGHER_ACCESS_REQUIRED is returned. If the
1774 requested user does not exist, ERROR+NO_SUCH_USER is returned.
1778 GPEX (Get Policy for message EXpiration)
1780 Returns the policy of the current room, floor, or site regarding the automatic
1781 purging (expiration) of messages. The following policies are available:
1782 0 - Fall back to the policy of the next higher level. If this is a room,
1783 use the floor's default policy. If this is a floor, use the system
1784 default policy. This is an invalid value for the system policy.
1785 1 - Do not purge messages automatically.
1786 2 - Purge by message count. (Requires a value: number of messages)
1787 3 - Purge by message age. (Requires a value: number of days)
1789 The format of this command is: GPEX <which>
1790 The value of <which> must be one of: "room" "floor" "site" "mailboxes"
1792 If successful, GPEX returns OK followed by <policy>|<value>.
1796 SPEX (Set Policy for message EXpiration)
1798 Sets the policy of the current room, floor, or site regarding the automatic
1799 purging (expiration) of messages. See the writeup for the GPEX command for
1800 the list of available policies.
1802 The format of this command is: SPEX <which>|<policy>|<value>
1803 The value of <which> must be one of: "room" "floor" "site" "mailboxes"
1805 If successful, GPEX returns OK; otherwise, an ERROR code is returned.
1809 CONF (get or set global CONFiguration options)
1811 Retrieves or sets various system-wide configuration and policy options. This
1812 command is only available to Aides. The sole parameter accepted is a command,
1813 which should be either GET or SET. If the GET command succeeds, CONF will
1814 return LISTING_FOLLOWS followed by the fields described below, one line at a
1815 time. If the SET command succeeds, CONF will return SEND_LISTING and expect
1816 the fields described below, one line at a time (don't worry about other fields
1817 being added in the future; if a 'short' configuration list is sent, the missing
1818 values at the end will be left unchanged on the system). If either command
1819 fails for any reason, ERROR is returned.
1821 The configuration lines are as follows:
1824 1. Fully qualified domain name
1825 2. Human-readable node name
1826 3. Landline telephone number of this system
1827 4. Flag (0 or 1) - creator of private room automatically becomes room aide
1828 5. Server connection idle timeout (in seconds)
1829 6. Initial access level for new users
1830 7. Flag (0 or 1) - require registration for new users
1831 8. Flag (0 or 1) - automatically move Problem User messages to twit room
1832 9. Name of twit room
1833 10. Text of <more> prompt
1834 11. Flag (0 or 1) - restrict access to Internet mail
1835 12. Geographic location of this system
1836 13. Name of the system administrator
1837 14. Number of maximum concurrent sessions allowed on the server
1838 15. (placeholder -- this field is no longer in use)
1839 16. Default purge time (in days) for users
1840 17. Default purge time (in days) for rooms
1841 18. Name of room to log instant messages to (or a zero-length name for none)
1842 19. Access level required to create rooms
1843 20. Maximum message length which may be entered into the system
1844 21. Minimum number of worker threads
1845 22. Maximum number of worker threads
1846 23. Port number for POP3 service
1847 24. Port number for SMTP service
1848 25. Flag (0 or 1) - strict RFC822 adherence - don't correct From: forgeries
1849 26. Flag (0 or 1) - allow Aides to zap (forget) rooms
1850 27. Port number for IMAP service
1851 28. How often (in seconds) to run the networker
1852 29. Flag (0 or 1) - disable self-service new user registration
1853 30. (placeholder -- this field is no longer in use)
1854 31. Hour (0 through 23) during which database auto-purge jobs are run
1855 32. Name of host where an LDAP service may be found
1856 33. Port number of LDAP service on above host
1859 36. Password for LDAP Bind DN
1860 37. Server IP address to listen on (or "0.0.0.0" for all addresses)
1861 38. Port number for SMTP MSA service
1862 39. Port number for IMAPS (SSL-encrypted IMAP)
1863 40. Port number for POP3S (SSL-encrypted POP3)
1864 41. Port number for SMTPS (SSL-encrypted SMTP)
1865 42. Flag (0 or 1) - enable full text search index
1866 43. Flag (0 or 1) - automatically cull database log files
1867 44. Flag (0 or 1) - enable IMAP "instant expunge" of deleted messages
1868 45. Flag (0 or 1) - allow unauthenticated SMTP clients to spoof my domains
1869 46. Flag (0 or 1) - perform journaling of email messages
1870 47. Flag (0 or 1) - perform journaling of non-email messages
1871 48. Address to which journalized messages are to be sent
1873 CONF also accepts two additional commands: GETSYS and PUTSYS followed by an
1874 arbitrary MIME type (such as application/x-citadel-internet-config) which
1875 provides a means of storing generic configuration data in the Global System
1876 Configuration room without the need to add extra get/set commands to the
1879 Please note that the LDAP-specific configs have no effect on Citadel servers
1880 in which LDAP support is not enabled.
1884 MSG4 (read MeSsaGe, mode 4 -- output in preferred MIME format)
1886 This is the equivalent of MSG0, except it's a bit smarter about messages in
1887 rich text formats. Immediately following the "text" directive, the server
1888 will output RFC822-like MIME part headers such as "Content-type:" and
1889 "Content-length:". MIME formats are chosen and/or converted based on the
1890 client's preferred format settings, which are set using the MSGP command,
1893 The MSG4 command also accepts an optional second argument, which may be the
1894 MIME part specifier of an encapsulated message/rfc822 message. This is useful
1895 for fetching the encapsulated message instead of the top-level message, for
1896 example, when someone has forwarded a message as an attachment. Note that the
1897 only way for the client to know the part specifier is to fetch the top-level
1898 message and then look for attachments of type message/rfc822, and then call
1899 MSG4 again with that part specifier.
1904 MSGP (set MeSsaGe Preferred MIME format)
1906 Client tells the server what MIME content types it knows how to handle, and
1907 the order in which it prefers them. This is similar to an HTTP "Accept:"
1910 The parameters to a MSGP command are the client's acceptable MIME content
1911 types, in the order it prefers them (from most preferred to least preferred).
1912 For example: MSGP text/html|text/plain
1914 The MSGP command always returns OK.
1918 OPNA (OPeN Attachment)
1920 Opens, as a download file, a component of a MIME-encoded message. The two
1921 parameters which must be passed to this command are the message number and the
1922 name of the desired section. If the message or section does not exist, an
1923 appropriate ERROR code will be returned; otherwise, if the open is successful,
1924 this command will succeed returning the same information as an OPEN command.
1927 GEXP (Get instant messages)
1929 This is a more sophisticated way of retrieving instant messages than the old
1930 PEXP method. If there are no instant messages waiting, PEXP returns ERROR;
1931 otherwise, it returns LISTING_FOLLOWS and the following arguments:
1933 0 - a boolean value telling the client whether there are any additional
1934 instant messages waiting following this one
1935 1 - a Unix-style timestamp
1936 2 - flags (see server.h for more info)
1937 3 - the name of the sender
1938 4 - the node this message originated on (for future support of PIP, ICQ, etc.)
1940 The text sent to the client will be the body of the instant message.
1942 So how does the client know there are instant messages waiting? It could
1943 execute a random GEXP every now and then. Or, it can check the byte in
1944 server return code messages, between the return code and the parameters. In
1945 much the same way as FTP uses "-" to signify a continuation, Citadel uses
1946 an "*" in this position to signify the presence of waiting instant messages.
1949 FSCK (check message base reference counts)
1951 Verify, via the long way, that all message referenmce counts are correct. If
1952 the user has permission to do this then LISTING_FOLLOWS is returned, followed
1953 by a transcript of the run. Otherwise ERROR is returned.
1956 DEXP (Disable receiving instant messages)
1958 DEXP sets or clears the "disable instant messages" flag. Pass this command a
1959 1 or 0 to respectively set or clear the flag. When the "disable instant
1960 messages" flag is set, no one except Aides may send the user instant messages.
1961 Any value other than 0 or 1 will not change the flag, only report its state.
1962 The command returns ERROR if it fails; otherwise, it returns OK followed by a
1963 number representing the current state of the flag.
1966 REQT (REQuest client Termination)
1968 Request that the specified client (or all clients) log off. Aide level
1969 access is required to run this command, otherwise ERROR+HIGHER_ACCESS_REQUIRED
1972 The REQT command accepts one parameter: the session ID of the client which
1973 should be terminated, or 0 for all clients. When successful, the REQT command
1976 It should be noted that REQT simply transmits an instant message to the
1977 specified client(s) with the EM_GO_AWAY flag set. Older clients do not honor
1978 this flag, and it is certainly possible for users to re-program their client
1979 software to ignore it. Therefore the effects of the REQT command should be
1980 considered advisory only. The recommended implementation practice is to first
1981 issue a REQT command, then wait a little while (from 30 seconds up to a few
1982 minutes) for well-behaved clients to voluntarily terminate, and then issue a
1983 TERM command to forcibly disconnect the client (or perhaps a DOWN command, if
1984 you are logging off users for the purpose of shutting down the server).
1987 SEEN (set or clear the SEEN flag for a message)
1989 Beginning with version 5.80, Citadel supports the concept of setting or
1990 clearing the "seen" flag for each individual message, instead of only allowing
1991 a "last seen" pointer. In fact, the old semantics are implemented in terms
1992 of the new semantics. This command requires two arguments: the number of the
1993 message to be set, and a 1 or 0 to set or clear the "seen" bit.
1995 This command returns OK, unless the user is not logged in or a usage error
1996 occurred, in which case it returns ERROR. Please note that no checking is
1997 done on the supplied data; if the requested message does not exist, the SEEN
1998 command simply returns OK without doing anything.
2001 GTSN (GeT the list of SeeN messages)
2003 This command retrieves the list of "seen" (as opposed to unread) messages for
2004 the current room. It returns OK followed by an IMAP-format message list.
2007 SMTP (utility commands for the SMTP gateway)
2009 This command, accessible only by Aides, supports several utility operations
2010 which examine or manipulate Citadel's SMTP support. The first command argument
2011 is a subcommand telling the server what to do. The following subcommands are
2014 SMTP mx|hostname (display all MX hosts for 'hostname')
2015 SMTP runqueue (attempt immediate delivery of all messages
2016 in the outbound SMTP queue, ignoring any
2017 retry times stored there)
2020 STLS (Start Transport Layer Security)
2022 This command starts TLS on the current connection. The current
2023 implementation uses OpenSSL on both the client and server end. For future
2024 compatibility all clients must support at least TLSv1, and servers are
2025 guaranteed to support TLSv1. During TLS negotiation (see below) the server
2026 and client may agree to use a different protocol.
2028 The server returns ERROR if it does not support SSL or SSL initialization
2029 failed on the server; otherwise it returns OK. Once the server returns OK and
2030 the client has read the response, the server and client immediately negotiate
2031 TLS (in OpenSSL, using SSL_connect() on the client and SSL_accept() on the
2032 server). If negotiation fails, the server and client should attempt to resume
2033 the session unencrypted. If either end is unable to resume the session, the
2034 connection should be closed.
2036 This command may be run at any time.
2039 GTLS (Get Transport Layer Security Status)
2041 This command returns information about the current connection. The server
2042 returns OK plus several parameters if the connection is encrypted, and ERROR
2043 if the connection is not encrypted. It is primarily used for debugging. The
2044 command may be run at any time.
2046 0 - Protocol name, e.g. "SSLv3"
2047 1 - Cipher suite name, e.g. "ADH-RC4-MD5"
2048 2 - Cipher strength bits, e.g. 128
2049 3 - Cipher strength bits actually in use, e.g. 128
2052 IGAB (Initialize Global Address Book)
2054 This command creates, or re-creates, a database of Internet e-mail addresses
2055 using the vCard information in the Global Address Book room. This procedure
2056 is normally run internally when the server determines it necessary, but is
2057 also provided as a server command to be used as a troubleshooting/maintenenance
2058 tool. Only a system Aide can run the command. It returns OK on success or
2062 QDIR (Query global DIRectory)
2064 Look up an internet address in the global directory. Any logged-in user may
2065 call QDIR with one parameter, the Internet e-mail address to look up. QDIR
2066 returns OK followed by a Citadel address if there is a match, otherwise it
2067 returns ERROR+NOT_LOGGED_IN.
2070 ISME (find out if an e-mail address IS ME)
2072 This is a quickie shortcut command to find out if a given e-mail address
2073 belongs to the user currently logged in. Its sole argument is an address to
2074 parse. The supplied address may be in any format (local, IGnet, or Internet).
2075 The command returns OK if the address belongs to the user, ERROR otherwise.
2078 VIEW (set the VIEW for a room)
2080 Set the preferred view for the current user in the current room. Please see
2081 views.txt for more information on views. The sole parameter for this command
2082 is the type of view requested. VIEW returns OK on success or ERROR on failure.
2085 QNOP (Quiet No OPeration)
2087 This command does nothing, similar to the NOOP command. However, unlike the
2088 NOOP command, it returns *absolutely no response* at all. The client has no
2089 way of knowing that the command executed. It is intended for sending
2090 "keepalives" in situations where a full NOOP would cause the client protocol
2093 Naturally, sending this command to a server that doesn't support it is an
2094 easy way to mess things up. Therefore, client software should first check
2095 the output of an INFO command to ensure that the server supports quiet noops.
2099 ICAL (Internet CALendaring commands)
2101 This command supports a number of subcommands which are used to process the
2102 calendaring/scheduling support in Citadel. Here are the subcommands which
2106 Test server for calendaring support. Always returns OK unless the server
2107 does not have the calendar module enabled.
2109 ICAL respond|msgnum|partnum|action
2110 Respond to a meeting request. 'msgnum' and 'partnum' refer to a MIME-encoded
2111 meeting invitation in the current room. 'action' must be set to either
2112 "accept" or "decline" to determine the action to take. This subcommand will
2113 return either OK or ERROR.
2115 ICAL conflicts|msgnum|partnum
2116 Determine whether an incoming VEVENT will fit in the user's calendar by
2117 checking it against the existing VEVENTs. 'msgnum' and 'partnum' refer to
2118 a MIME-encoded meeting invitation in the current room (usually the inbox).
2119 This command may return ERROR if something went wrong, but usually it will
2120 return LISTING_FOLLOWS followed by a list of zero or more conflicting
2121 events. A zero-length list means that there were no conflicts.
2123 ICAL handle_rsvp|msgnum|partnum
2124 Handle an incoming "reply" (or RSVP) to a meeting request you sent out.
2125 'msgnum' and 'partnum' refer to a MIME-encoded reply in the current room.
2126 'action' must be set to either "update" or "ignore" to determine the action
2127 to take. If the action is "update" then the server will hunt for the meeting
2128 in the user's Calendar> room, and update the status for this attendee. Either
2129 way, the reply message is deleted from the current room. This subcommand will
2130 return either OK or ERROR.
2132 ICAL freebusy|username
2133 Output the free/busy times for the requested user. If the user specified
2134 has a calendar available, this command will return LISTING_FOLLOWS and a
2135 compound VCALENDAR object. That object, in turn, will contain VEVENT
2136 objects that have been stripped of all properties except for the bare
2137 minimum needed to learn free/busy times (such as DTSTART, DTEND, and
2138 TRANSP). If there is no such user, or no calendar available, the usual
2139 ERROR codes will be returned.
2143 Readers who are paying attention will notice that there is no subcommand to
2144 send out meeting invitations. This is because that task can be handled
2145 automatically by the Citadel server. Issue this command with <bool> set to 1
2146 to enable Server Generated Invitations. In this mode, when an event is saved
2147 to the user's Calendar> room and it contains attendees, Citadel will
2148 automatically turn the event into vCalendar REQUEST messages and mail them
2149 out to all listed attendees. If for some reason the client needs to disable
2150 Server Generated Invitations, the command may be sent again with <bool> = 0.
2154 MRTG (Multi Router Traffic Grapher)
2156 Multi Router Traffic Grapher (please see http://www.mrtg.org for more info) is
2157 a tool which creates pretty graphs of network activity, usually collected from
2158 routers using SNMP. However, its ability to call external scripts has spawned
2159 a small community of people using it to graph anything which can be graphed.
2160 The MRTG command can output Citadel server activity in the format MRTG expects.
2162 This format is as follows:
2167 Line 3: uptime of system
2168 Line 4: name of system
2171 MRTG accepts two different keywords. "MRTG users" will return two variables,
2172 the number of connected users and the number of active users. "MRTG messages"
2173 will return one variable (and a zero in the second field), showing the current
2174 highest message number on the system. Any other keyword, or a missing keyword,
2175 will cause the MRTG command to return an ERROR code.
2177 Please get in touch with the Citadel developers if you wish to experiment with
2182 GNET (Get NETwork configuration for this room)
2183 SNET (Set NETwork configuration for this room)
2185 These commands get/set the network configuration for the current room. Aide
2186 or Room Aide privileges are required, otherwise an ERROR code is returned.
2187 If the command succeeds, LISTING_FOLLOWS or SEND_LISTING is returned. The
2188 network configuration for a specific room includes neighbor nodes with whom
2189 the room is shared, and mailing list recipients. The format of the network
2190 configuration is described in the file "netconfigs.txt".
2194 ASYN (ASYNchronous message support)
2196 Negotiate the use of asynchronous, or unsolicited, protocol messages. The
2197 only parameter specified should be 1 or 0 to indicate that the client can or
2198 cannot handle this type of messages. The server will reply OK followed by a
2199 1 or 0 to tell the client which mode it is now operating in.
2201 If the command is not available on the server (i.e. it returns ERROR), or
2202 if the command has not been executed by the client, it should be assumed that
2203 this mode of operation is NOT in effect.
2205 The client may also send any value other than 0 or 1 to simply cause the
2206 server to output its current state without changing it.
2208 When asynchronous protocol mode is in effect, the client MUST handle any
2209 asynchronous messages as they arrive, before doing anything else.
2213 AUTO (AUTOcompletion of email addresses)
2215 The AUTO command is used by clients which want to request a list of email
2216 recipients whose names or email addresses match a partial string supplied by
2217 the client. This string is the only parameter passed to this command. The
2218 command will return ERROR if no user is logged in or if no address book could
2219 be found; otherwise, it returns LISTING_FOLLOWS followed by zero or more
2220 candidate recipients.
2224 SRCH (SeaRCH the message base)
2226 This command's implementation is incomplete and will be documented when it
2227 is finished. The current implementation accepts a search string as its sole
2228 argument, and will respond with LISTING_FOLLOWS followed by a list of
2229 messages (globally, not just in the current room) which contain ALL of the
2230 words in the search string. If the client desires an "exact phrase" match,
2231 it must then slow-search the text of each returned message for the exact
2232 string. The client should also compare the returned message numbers against
2233 those which actually exist in the room or rooms being searched. In
2234 particular, clients should avoid telling the user about messages which exist
2235 only in rooms to which the user does not have access.
2237 Again, keep in mind that this is a temporary implementation and is not
2238 guaranteed to continue to exist in this form.
2241 EUID (get message number using an EUID)}
2243 Returns the message number, if present, of the message in the current room
2244 which is indexed using the supplied EUID (exclusive message ID). There can be
2245 only one message in a room with any given EUID; if another message arrives
2246 with the same EUID, the existing one is replaced. This makes it possible to
2247 reference things like calendar items using an immutable URL that does not
2248 change even when the message number changes due to an update.
2250 The format of this command is: EUID <euid>
2252 If successful, EUID returns OK followed by a message number.
2253 If no message exists in the current room with the supplied EUID, the command
2254 returns ERROR+MESSAGE_NOT_FOUND.
2260 ASYNCHRONOUS MESSAGES
2261 ---------------------
2263 When the client protocol is operating in asynchronous mode (please refer to
2264 the writeup of the ASYN command above), the following messages may arrive at
2268 902 (instant message arriving)
2270 One or more instant messages have arrived for this client.