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)
296 The eigth field is a unix timestamp which reflects the last time the room
297 was modified (created, edited, posted in, deleted from, etc.)
300 LKRO (List Known Rooms with Old [no new] messages)
302 This follows the same usage and format as LKRN.
305 LZRM (List Zapped RooMs)
307 This follows the same usage and format as LKRN and LKRO.
310 LKRA (List All Known Rooms)
312 Same format. Lists all known rooms, with or without new messages.
315 LRMS (List all accessible RooMS)
317 Again, same format. This command lists all accessible rooms, known and
318 forgotten, with and without new messages. It does not, however, list
319 inaccessible private rooms.
322 LPRM (List all Public RooMs)
324 Again, same format. This command lists all public rooms, and nothing else.
325 Unlike the other list rooms commands, this one can be executed without logging
329 GETU (GET User configuration)
331 This command retrieves the screen dimensions and user options for the
332 currently logged in account. ERROR + NOT_LOGGED_IN will be returned if no
333 user is logged in, of course. Otherwise, OK will be returned, followed by
334 four parameters. The first parameter is the user's screen width, the second
335 parameter is the user's screen height, and the third parameter is a bag of
336 bits with the following meanings:
338 #define US_LASTOLD 16 /* Print last old message with new */
339 #define US_EXPERT 32 /* Experienced user */
340 #define US_UNLISTED 64 /* Unlisted userlog entry */
341 #define US_NOPROMPT 128 /* Don't prompt after each message */
342 #define US_DISAPPEAR 512 /* Use "disappearing msg prompts" */
343 #define US_PAGINATOR 2048 /* Pause after each screen of text */
345 There are other bits, too, but they can't be changed by the user (see below).
348 SETU (SET User configuration)
350 This command does the opposite of SETU: it takes the screen dimensions and
351 user options (which were probably obtained with a GETU command, and perhaps
352 modified by the user) and writes them to the user account. This command
353 should be passed three parameters: the screen width, the screen height, and
354 the option bits (see above). It returns ERROR + NOT_LOGGED_IN if no user is
355 logged in, and ERROR + ILLEGAL_VALUE if the parameters are incorrect.
357 Note that there exist bits here which are not listed in this document. Some
358 are flags that can only be set by Aides or the system administrator. SETU
359 will ignore attempts to toggle these bits. There also may be more user
360 settable bits added at a later date. To maintain later downward compatibility,
361 the following procedure is suggested:
363 1. Execute GETU to read the current flags
364 2. Toggle the bits that we know we can toggle
365 3. Execute SETU to write the flags
367 If we are passed a bit whose meaning we don't know, it's best to leave it
368 alone, and pass it right back to the server. That way we can use an old
369 client on a server that uses an unknown bit without accidentally clearing
370 it every time we set the user's configuration.
375 This command is used to goto a new room. When the user first logs in (login
376 is completed after execution of the PASS command) this command is
377 automatically and silently executed to take the user to the first room in the
378 system (usually called the Lobby).
380 This command can be passed one or two parameters. The first parameter is,
381 of course, the name of the room. Although it is not case sensitive, the
382 full name of the room must be used. Wildcard matching or unique string
383 matching of room names should be the responsibility of the client.
385 Note that the reserved room name "_BASEROOM_" can be passed to the server
386 to cause the goto command to take the user to the first room in the system,
387 traditionally known as the Lobby>. As long as a user is logged in, a
388 GOTO command to _BASEROOM_ is guaranteed to succeed. This is useful to
389 allow client software to return to the base room when it doesn't know
392 There are also several additional reserved room names:
393 "_MAIL_" goes to the user's inbox (i.e. the Mail> room).
394 "_TRASH_" goes to the user's personal trashcan room (trash folder).
395 "_BITBUCKET_" goes to a room that has been chosen for messages without a home.
396 "_CALENDAR_" goes to the user's primary personal calendar.
397 "_CONTACTS_" goes to the user's primary personal address book.
398 "_NOTES_" goes to the user's primary personal notes room.
399 "_TASKS_" goes to the user's primary personal task list.
402 The second (and optional) parameter is a password, if one is required for
403 access to the room. This allows for all types of rooms to be accessed via
404 this command: for public rooms, invitation-only rooms to which the user
405 has access, and preferred users only rooms to which the user has access, the
406 room will appear in a room listing. For guess-name rooms, this command
407 will work transparently, adding the room to the user's known room list when
408 it completes. For passworded rooms, access will be denied if the password
409 is not supplied or is incorrect, or the command will complete successfully
410 if the password is correct.
412 The third (and also) optional parameter is a "transient" flag. Normally,
413 when a user enters a private and/or zapped room, the room is added to the
414 user's known rooms list. If the transient flag is set to non-zero, this is
415 called a "transient goto" which causes the user to enter the room without
416 adding the room to the known rooms list.
418 The possible result codes are:
420 OK - The command completed successfully. User is now in the room.
421 (See the list of returned parameters below)
423 ERROR - The command did not complete successfully. Check the second and
424 third positions of the result code to find out what happened:
426 NOT_LOGGED_IN - Of course you can't go there. You didn't log in.
427 PASSWORD_REQUIRED - Either a password was not supplied, or the supplied
428 password was incorrect.
429 ROOM_NOT_FOUND - The requested room does not exist.
431 The typical procedure for entering a passworded room would be:
433 1. Execute a GOTO command without supplying any password.
434 2. ERROR + PASSWORD_REQUIRED will be returned. The client now knows that
435 the room is passworded, and prompts the user for a password.
436 3. Execute a GOTO command, supplying both the room name and the password.
437 4. If OK is returned, the command is complete. If, however,
438 ERROR + PASSWORD_REQUIRED is still returned, tell the user that the supplied
439 password was incorrect. The user remains in the room he/she was previously
442 When the command succeeds, these parameters are returned:
443 0. The name of the room
444 1. Number of unread messages in this room
445 2. Total number of messages in this room
446 3. Info flag: set to nonzero if the user needs to read this room's info
447 file (see RINF command below)
448 4. Various flags associated with this room. (See LKRN cmd above)
449 5. The highest message number present in this room
450 6. The highest message number the user has read in this room
451 7. Boolean flag: 1 if this is a Mail> room, 0 otherwise.
452 8. Aide flag: 1 if the user is either the Room Aide for this room, *or* is
453 a regular Aide (this makes access checks easy).
454 9. The number of new Mail messages the user has (useful for alerting the
455 user to the arrival of new mail during a session)
456 10. The floor number this room resides on
457 11. The *current* "view" for this room (see views.txt for more info)
458 12. The *default* "view" for this room
459 13. Boolian flag: 1 if this is the user's Trash folder, 0 otherwise.
461 The default view gives the client a hint as to what views the user should
462 be allowed to select. For example, it would be confusing to allow messages
463 in a room intended for calendar items. The server does not enforce these
464 restrictions, though.
467 MSGS (get pointers to MeSsaGeS in this room)
469 This command obtains a listing of all the messages in the current room
470 which the client may request. This command may be passed a single parameter:
471 either "all", "old", or "new" to request all messages, only old messages, or
472 new messages. Or it may be passed two parameters: "last" plus a number, in
473 which case that many message pointers will be returned; "first" plus a
474 number, for the corresponding effect; or "gt" plus a number, to list all
475 messages in the current room with a message number greater than the one
476 specified. If no parameters are specified, "all" is assumed.
478 The third argument, may be either 0 or 1. If it is 1, this command behaves
479 differently: before a listing is returned, the client must transmit a list
480 of fields to search for. The field headers are listed below in the writeup
481 for the "MSG0" command.
483 The optional fourth argument may also be either 0 or 1. If it is 1, the
484 output of this command will include not only a list of message numbers, but
485 a simple header summary of each message as well. This is somewhat resource
486 intensive so you shouldn't do this unless you absolutely need all the headers
487 immediately. The fields which are output (in the usual delimited fashion, of
488 course) are: message number, timestamp, display name, node name, Internet
489 email address (if present), subject (if present).
491 This command can return three possible results. ERROR + NOT_LOGGED_IN will
492 be returned if no user is currently logged in. Otherwise, LISTING_FOLLOWS
493 will be returned, and the listing will consist of zero or more message
494 numbers, one per line. The listing ends, as always, with the string "000"
495 alone on a line by itself. The listed message numbers can be used to request
496 messages from the system. If "search mode" is being used, the server will
497 return START_CHAT_MODE, and the client is expected to transmit the search
498 criteria, and then read the message list.
500 Since this is somewhat complex, here are some examples:
502 Example 1: Read all new messages
505 Server: 100 Message list...
511 Example 2: Read the last five messages
514 Server: 100 Message list...
522 Example 3: Read all messages written by "IGnatius T Foobar"
525 Server: 800 Send template then receive message list
526 Client: from|IGnatius T Foobar
540 Note that in "search mode" the client may specify any number of search
541 criteria. These criteria are applied with an AND logic.
544 MSG0 (read MeSsaGe, mode 0)
546 This is a command used to read the text of a message. "Mode 0" implies that
547 other MSG commands (MSG1, MSG2, etc.) will probably be added later on to read
548 messages in more robust formats. This command should be passed two arguments.
549 The first is the message number of the message being requested. The second
550 argument specifies whether the client wants headers and/or message body:
554 3 = Headers only, with MIME information suppressed (this runs faster)
556 If the request is denied, ERROR + NOT_LOGGED_IN or ERROR + MESSAGE_NOT_FOUND
557 will be returned. Otherwise, LISTING_FOLLOWS will be returned, followed by
558 the contents of the message. The following fields may be sent:
560 type= Formatting type. The currently defined types are:
561 0 = "traditional" Citadel formatting. This means that newlines should be
562 treated as spaces UNLESS the first character on the next line is a space. In
563 other words, only indented lines should generate a newline on the user's screen
564 when the message is being displayed. This allows a message to be formatted to
565 the reader's screen width. It also allows the use of proportional fonts.
566 1 = a simple fixed-format message. The message should be displayed to
567 the user's screen as is, preferably in a fixed-width font that will fit 80
569 4 = MIME format message. The message text is expected to contain a header
570 with the "Content-type:" directive (and possibly others).
572 msgn= The message ID of this message on the system it originated on.
573 path= An e-mailable path back to the user who wrote the message.
575 time= The date and time of the message, in Unix format (the number of
576 seconds since midnight on January 1, 1970, GMT).
578 from= The name of the author of the message.
579 rcpt= If the message is a private e-mail, this is the recipient.
580 room= The name of the room the message originated in.
581 node= The short node name of the system this message originated on.
582 hnod= The long node name of the system this message originated on.
583 zaps= The id/node of a message which this one zaps (supersedes).
585 part= Information about a MIME part embedded in this message.
586 pref= Information about a multipart MIME prefix such as "multipart/mixed"
587 or "multipart/alternative". This will be output immediately prior
588 to the various "part=" lines which make up the multipart section.
589 suff= Information about a multipart MIME suffix. This will be output
590 immediately following the various "part=" lines which make up the
593 text Note that there is no "=" after the word "text". This string
594 signifies that the message text begins on the next line.
597 WHOK (WHO Knows room)
599 This command is available only to Aides. ERROR + HIGHER_ACCESS_REQUIRED
600 will be returned if the user is not an Aide. Otherwise, it returns
601 LISTING_FOLLOWS and then lists, one user per line, every user who has
602 access to the current room.
605 INFO (get server INFO)
607 This command will *always* return LISTING_FOLLOWS and then print out a
608 listing of zero or more strings. Client software should be written to expect
609 anywhere from a null listing to an infinite number of lines, to allow later
610 backward compatibility. The current implementation defines the following
611 parts of the listing:
613 Line 1 - Your unique session ID on the server
614 Line 2 - The node name of the Citadel server
615 Line 3 - Human-readable node name of the Citadel server
616 Line 4 - The fully-qualified domain name (FQDN) of the server
617 Line 5 - The name of the server software, i.e. "Citadel 4.00"
618 Line 6 - (The revision level of the server code) * 100
619 Line 7 - The geographical location of the site (city and state if in the US)
620 Line 8 - The name of the system administrator
621 Line 9 - A number identifying the server type (see below)
622 Line 10 - The text of the system's paginator prompt
623 Line 11 - Floor Flag. 1 if the system supports floors, 0 otherwise.
624 Line 12 - Paging level. 0 if the system only supports inline paging,
625 1 if the system supports "extended" paging (check-only and
626 multiline modes). See the SEXP command for further information.
627 Line 13 - The "nonce" for this session, for support of APOP-style
628 authentication. If this field is present, clients may authenticate
630 Line 14 - Set to nonzero if this server supports the QNOP command.
631 Line 15 - Set to nonzero if this server is capable of connecting to a
632 directory service using LDAP.
634 *** NOTE! *** The "server type" code is intended to promote global
635 compatibility in a scenario in which developers have added proprietary
636 features to their servers or clients. We are attempting to avoid a future
637 situation in which users need to keep different client software around for
638 each Citadel they use. *Please*, if you are a developer and plan to add
639 proprietary features:
641 -> Your client programs should still be able to utilize servers other than
643 -> Clients other than your own should still be able to utilize your server,
644 even if your proprietary extensions aren't supported.
645 -> Please contact Art Cancro <ajc@uncensored.citadel.org> and obtain a unique
646 server type code, which can be assigned to your server program.
647 -> If you document what you did in detail, perhaps it can be added to a
648 future release of the Citadel program, so everyone can enjoy it. Better
649 yet, just work with the Citadel development team on the main source tree.
651 If everyone follows this scheme, we can avoid a chaotic situation with lots
652 of confusion about which client program works with which server, etc. Client
653 software can simply check the server type (and perhaps the revision level)
654 to determine ahead of time what commands may be utilized.
656 Please refer to "developers.txt" for information on what codes belong to whom.
660 RDIR (Read room DIRectory)
662 Use this command to read the directory of a directory room. ERROR + NOT_HERE
663 will be returned if the room has no directory, ERROR + HIGHER_ACCESS_REQUIRED
664 will be returned if the room's directory is not visible and the user does not
665 have Aide or Room Aide privileges, ERROR + NOT_LOGGED_IN will be returned if
666 the user is not logged in; otherwise LISTING_FOLLOWS will be returned,
667 followed by the room's directory. Each line of the directory listing will
668 contain three fields: a filename, the length of the file, and a description.
670 The server message contained on the same line with LISTING_FOLLOWS will
671 contain the name of the system and the name of the directory, such as:
673 uncensored.citadel.org|/usr/local/citadel/files/my_room_directory
676 SLRP (Set Last-message-Read Pointer)
678 This command marks all messages in the current room as read (seen) up to and
679 including the specified number. Its sole parameter is the number of the last
680 message that has been read. This allows the pointer to be set at any
681 arbitrary point in the room. Optionally, the parameter "highest" may be used
682 instead of a message number, to set the pointer to the number of the highest
683 message in the room, effectively marking all messages in the room as having
684 been read (ala the Citadel <G>oto command).
686 The command will return OK if the pointer was set, or ERROR + NOT_LOGGED_IN
687 if the user is not logged in. If OK is returned, it will be followed by a
688 single argument containing the message number the last-read-pointer was set to.
691 INVT (INViTe a user to a room)
693 This command may only be executed by Aides, or by the room aide for the
694 current room. It is used primarily to add users to invitation-only rooms,
695 but it may also be used in other types of private rooms as well. Its sole
696 parameter is the name of the user to invite.
698 The command will return OK if the operation succeeded. ERROR + NO_SUCH_USER
699 will be returned if the user does not exist, ERROR + HIGHER_ACCESS_REQUIRED
700 will be returned if the operation would have been possible if the user had
701 higher access, and ERROR + NOT_HERE may be returned if the room is not a
705 KICK (KICK a user out of a room)
707 This is the opposite of INVT: it is used to kick a user out of a private
708 room. It can also be used to kick a user out of a public room, but the
709 effect will only be the same as if the user <Z>apped the room - a non-stupid
710 user can simply un-zap the room to get back in.
713 GETR (GET Room attributes)
715 This command is used for editing the various attributes associated with a
716 room. A typical "edit room" command would work like this:
717 1. Use the GETR command to get the current attributes
718 2. Change some of them around
719 3. Use SETR (see below) to save the changes
720 4. Possibly also change the room aide using the GETA and SETA commands
722 GETR takes no arguments. It will only return OK if the SETR command will
723 also return OK. This allows client software to tell the user that he/she
724 can't edit the room *before* going through the trouble of actually doing the
725 editing. Possible return codes are:
727 ERROR+NOT_LOGGED_IN - No user is logged in.
728 ERROR+HIGHER_ACCESS_REQUIRED - Not enough access. Typically, only aides
729 and the room aide associated with the current room, can access this command.
730 OK - Command succeeded. Parameters are returned.
732 If OK is returned, the following parameters will be returned as well:
734 0. The name of the room
735 1. The room's password (if it's a passworded room)
736 2. The name of the room's directory (if it's a directory room)
737 3. Various flags (bits) associated with the room (see LKRN cmd above)
738 4. The floor number on which the room resides
739 5. The room listing order
740 6. The default view for the room (see views.txt)
741 7. A second set of flags (bits) associated with the room
744 SETR (SET Room attributes)
746 This command sets various attributes associated with the current room. It
747 should be passed the following arguments:
749 0. The name of the room
750 1. The room's password (if it's a passworded room)
751 2. The name of the room's directory (if it's a directory room)
752 3. Various flags (bits) associated with the room (see LKRN cmd above)
753 4. "Bump" flag (see below)
754 5. The floor number on which the room should reside
755 6. The room listing order
756 7. The default view for the room (see views.txt)
757 8. A second set of flags (bits) associated with the room
759 *Important: You should always use GETR to retrieve the current attributes of
760 the room, then change what you want to change, and then use SETR to write it
761 all back. This is particularly important with respect to the flags: if a
762 particular bit is set, and you don't know what it means, LEAVE IT ALONE and
763 only toggle the bits you want to toggle. This will allow for upward
766 The _BASEROOM_, user's Mail> and Aide> rooms can only be partially edited.
767 Any changes which cannot be made will be silently ignored.
769 If the room is a private room, you have the option of causing all users who
770 currently have access, to forget the room. If you want to do this, set the
771 "bump" flag to 1, otherwise set it to 0.
776 This command is used to get the name of the Room Aide for the current room.
777 It will return ERROR + NOT_LOGGED_IN if no user is logged in, or OK if the
778 command succeeded. Along with OK there will be returned one parameter: the
779 name of the Room Aide. A conforming server must guarantee that the user is
785 The opposite of GETA, used to set the Room Aide for the current room. One
786 parameter should be passed, which is the name of the user who is to be the
787 new Room Aide. Under Citadel, this command may only be executed by Aides
788 and by the *current* Room Aide for the room. Return codes possible are:
789 ERROR + NOT_LOGGED_IN (Not logged in.)
790 ERROR + HIGHER_ACCESS_REQUIRED (Higher access required.)
791 ERROR + NOT_HERE (Room cannot be edited.)
792 OK (Command succeeded.)
795 ENT0 (ENTer message, mode 0)
797 This command is used to enter messages into the system. It accepts four
800 0 - Post flag. This should be set to 1 to post a message. If it is
801 set to 0, the server only returns OK or ERROR (plus any flags describing
802 the error) without reading in a message. Client software should, in fact,
803 perform this operation at the beginning of an "enter message" command
804 *before* starting up its editor, so the user does not end up typing a message
805 in vain that will not be permitted to be saved. If it is set to 2, the
806 server will accept an "apparent" post name if the user is privileged enough.
807 This post name is arg 5.
808 1 - Recipient (To: field). This argument is utilized only for private
809 mail. It is ignored for public messages. It contains, of course, the name
810 of the recipient(s) of the message.
811 2 - Anonymous flag. This argument is ignored unless the room allows
812 anonymous messages. In such rooms, this flag may be set to 1 to flag a
813 message as anonymous, otherwise 0 for a normal message.
814 3 - Format type. Any valid Citadel format type may be used (this will
815 typically be 0; see the MSG0 command above).
816 4 - Subject. If present, this argument will be used as the subject of
818 5 - Post name. When postflag is 2, this is the name you are posting as.
819 This is an Aide only command.
820 6 - Do Confirmation. NOTE: this changes the protocol semantics! When
821 you set this to nonzero, ENT0 will reply with a confirmation message after
822 you submit the message text. The reply code for the ENT0 command will be
823 START_CHAT_MODE instead of SEND_LISTING.
824 7 - Recipient (Cc: field). This argument is utilized only for private
825 mail. It is ignored for public messages. It contains, of course, the name
826 of the recipient(s) of the message.
827 8 - Recipient (Bcc: field). This argument is utilized only for private
828 mail. It is ignored for public messages. It contains, of course, the name
829 of the recipient(s) of the message.
830 9 - Exclusive message ID. When a message is submitted with an Exclusive
831 message ID, any existing messages with the same ID will automatically be
832 deleted. This is only applicable for Wiki rooms; other types of rooms either
833 ignore the supplied ID (such as message boards and mailboxes) or derive the
834 ID from a UUID native to the objects stored in them (such as calendars and
837 Possible result codes:
838 OK - The request is valid. (Client did not set the "post" flag, so the
839 server will not read in message text.) If the message is an e-mail with
840 a recipient, the text that follows the OK code will contain the exact name
841 to which mail is being sent. The client can display this to the user. The
842 implication here is that the name that the server returns will contain the
843 correct upper and lower case characters. In addition, if the recipient is
844 having his/her mail forwarded, the forwarding address will be returned.
845 SEND_LISTING - The request is valid. The client should now transmit
846 the text of the message (ending with a 000 on a line by itself, as usual).
847 START_CHAT_MODE - The request is valid. The client should now transmit
848 the text of the message, ending with a 000 on a line by itself. After
849 transmitting the 000 terminator, the client MUST read in the confirmation
850 from the server, which will also end with 000 on a line by itself. The format
851 of the confirmation appears below.
852 ERROR + NOT_LOGGED_IN - Not logged in.
853 ERROR + HIGHER_ACCESS_REQUIRED - Higher access is required. An
854 explanation follows, worded in a form that can be displayed to the user.
855 ERROR + NO_SUCH_USER - The specified recipient does not exist.
857 The format of the confirmation message, if requested, is as follows:
858 Line 1: The new message number on the server for the message. It will be
859 positive for a real message number, or negative to denote
860 that an error occurred. If an error occurred, the message was
862 Line 2: A human-readable confirmation or error message.
863 Line 3: The resulting Exclusive UID of the message, if present.
864 (More may be added to this in the future, so do not assume that there will
865 only be these lines output. Keep reading until 000 is received.)
868 RINF (read Room INFormation file)
870 Each room has associated with it a text file containing a description of
871 the room, perhaps containing its intended purpose or other important
872 information. The info file for the Lobby> (the system's base room) is
873 often used as a repository for system bulletins and the like.
875 This command, which accepts no arguments, is simply used to read the info
876 file for the current room. It will return LISTING_FOLLOWS followed by
877 the text of the message (always in format type 0) if the request can be
878 honored, or ERROR if no info file exists for the current room (which is
879 often the case). Other error description codes may accompany this result.
881 When should this command be used? This is, of course, up to the discretion
882 of client software authors, but in Citadel it is executed in two situations:
883 the first time the user ever enters a room; and whenever the contents of the
884 file change. The latter can be determined from the result of a GOTO command,
885 which will tell the client whether the file needs to be read (see GOTO above).
888 DELE (DELEte a message)
890 Delete a message from the current room. The one argument that should be
891 passed to this command is the message number of the message to be deleted.
892 The return value will be OK if the message was deleted, or an ERROR code.
893 If the delete is successful, the message's reference count is decremented, and
894 if the reference count reaches zero, the message is removed from the message
898 MOVE (MOVE or copy a message to a different room)
900 Move or copy a message to a different room. This command expects to be
901 passed three arguments:
902 0: the message number of the message to be moved or copied.
903 1: the name of the target room.
904 2: flag: 0 to move the message, 1 to copy it without deleting from the
907 This command never creates or deletes copies of a message; it merely moves
908 around links. When a message is moved, its reference count remains the same.
909 When a message is copied, its reference count is incremented.
912 KILL (KILL current room)
914 This command deletes the current room. It accepts a single argument, which
915 should be nonzero to actually delete the room, or zero to merely check
916 whether the room can be deleted.
918 Once the room is deleted, the current room is undefined. It is suggested
919 that client software immediately GOTO another room (usually _BASEROOM_)
920 after this command completes.
922 Possible return codes:
924 OK - room has been deleted (or, if checking only, request is valid).
925 ERROR+NOT_LOGGED_IN - no user is logged in.
926 ERROR+HIGHER_ACCESS_REQUIRED - not enough access to delete rooms.
927 ERROR+NOT_HERE - this room can not be deleted.
930 CRE8 (CRE[ate] a new room)
932 This command is used to create a new room. Like some of the other
933 commands, it provides a mechanism to first check to see if a room can be
934 created before actually executing the command. CRE8 accepts the following
937 0 - Create flag. Set this to 1 to actually create the room. If it is
938 set to 0, the server merely checks that there is a free slot in which to
939 create a new room, and that the user has enough access to create a room. It
940 returns OK if the client should go ahead and prompt the user for more info,
941 or ERROR or ERROR+HIGHER_ACCESS_REQUIRED if the command will not succeed.
942 1 - Name for new room.
943 2 - Access type for new room:
945 1 - Private; can be entered by guessing the room's name
946 2 - Private; can be entered by knowing the name *and* password
947 3 - Private; invitation only (sometimes called "exclusive")
948 4 - Personal (mailbox for this user only)
949 3 - Password for new room (if it is a type 2 room)
950 4 - Floor number on which the room should reside (optional)
951 5 - Set to 1 to avoid automatically gaining access to the created room.
952 6 - The default "view" for the room.
954 If the create flag is set to 1, the room is created (unless something
955 went wrong and an ERROR return is sent), and the server returns OK, but
956 the session is **not** automatically sent to that room. The client still
957 must perform a GOTO command to go to the new room.
960 FORG (FORGet the current room)
962 This command is used to forget (zap) the current room. For those not
963 familiar with Citadel, this terminology refers to removing the room from
964 a user's own known rooms list, *not* removing the room itself. After a
965 room is forgotten, it no longer shows up in the user's known room list,
966 but it will exist in the user's forgotten room list, and will return to the
967 known room list if the user goes to the room (in Citadel, this is
968 accomplished by explicitly typing the room's name in a <.G>oto command).
970 The command takes no arguments. If the command cannot execute for any
971 reason, ERROR will be returned. ERROR+NOT_LOGGED_IN or ERROR+NOT_HERE may
972 be returned as they apply.
974 If the command succeeds, OK will be returned. At this point, the current
975 room is **undefined**, and the client software is responsible for taking
976 the user to another room before executing any other room commands (usually
977 this will be _BASEROOM_ since it is always there).
980 MESG (read system MESsaGe)
982 This command is used to display system messages and/or help files. The
983 single argument it accepts is the name of the file to display. IT IS CASE
984 SENSITIVE. Citadel looks for these files first in the "messages"
985 subdirectory and then in the "help" subdirectory.
987 If the file is found, LISTING_FOLLOWS is returned, followed by a pathname
988 to the file being displayed. Then the message is printed, in format type 0
989 (see MSG0 command for more information on this). If the file is not found,
992 There are some "well known" names of system messages which client software
993 may expect most servers to carry:
995 hello - Welcome message, to be displayed before the user logs in.
996 changepw - To be displayed whenever the user is prompted for a new
997 password. Warns about picking guessable passwords and such.
998 register - Should be displayed prior to the user entering registration.
999 Warnings about not getting access if not registered, etc.
1000 help - Main system help file.
1001 goodbye - System logoff banner; display when user logs off.
1002 roomaccess - Information about how public rooms and different types of
1003 private rooms function with regards to access.
1004 unlisted - Tells users not to choose to be unlisted unless they're
1005 really paranoid, and warns that aides can still see
1006 unlisted userlog entries.
1008 Citadel provides these for the Citadel Unix text client. They are
1009 probably not very useful for other clients:
1011 mainmenu - Main menu (when in idiot mode).
1016 saveopt - Options to save a message, abort, etc.
1017 entermsg - Displayed just before a message is entered, when in
1021 GNUR (Get Next Unvalidated User)
1023 This command shows the name of a user that needs to be validated. If there
1024 are no unvalidated users, OK is returned. Otherwise, MORE_DATA is returned
1025 along with the name of the first unvalidated user the server finds. All of
1026 the usual ERROR codes may be returned as well (for example, if the user is
1027 not an Aide and cannot validate users).
1029 A typical "Validate New Users" command would keep executing this command,
1030 and then validating each user it returns, until it returns OK when all new
1031 users have been validated.
1034 GREG (Get REGistration for user)
1036 This command retrieves the registration info for a user, whose name is the
1037 command's sole argument. All the usual error messages can be returned. If
1038 the command succeeds, LISTING_FOLLOWS is returned, followed by the user's name
1039 (retrieved from the userlog, with the right upper and lower case etc.) The
1040 contents of the listing contains one field per line, followed by the usual
1041 000 on the last line.
1043 The following lines are defined. Others WILL be added in the futre, so all
1044 software should be written to read the lines it knows about and then ignore
1045 all remaining lines:
1050 Line 4: Street address or PO Box
1051 Line 5: City/town/village/etc.
1052 Line 6: State/province/etc.
1054 Line 8: Telephone number
1055 Line 9: Access level
1056 Line 10: Internet e-mail address
1059 Users without Aide privileges may retrieve their own registration using
1060 this command. This can be accomplished either by passing the user's own
1061 name as the argument, or the string "_SELF_". The command will always
1062 succeed when used in this manner, unless no user is logged in.
1065 VALI (VALIdate user)
1067 This command is used to validate users. Obviously, it can only be executed
1068 by users with Aide level access. It should be passed two parameters: the
1069 name of the user to validate, and the desired access level
1071 If the command succeeds, OK is returned. The user's access level is changed
1072 and the "need validation" bit is cleared. If the command fails for any
1073 reason, ERROR, ERROR+NO_SUCH_USER, or ERROR+HIGHER_ACCESS_REQUIRED will be
1077 EINF (Enter INFo file for room)
1079 Transmit the info file for the current room with this command. EINF uses
1080 a boolean flag (1 or 0 as the first and only argument to the command) to
1081 determine whether the client actually wishes to transmit a new info file, or
1082 is merely checking to see if it has permission to do so.
1084 If the command cannot succeed, it returns ERROR.
1085 If the client is only checking for permission, and permission will be
1086 granted, OK is returned.
1087 If the client wishes to transmit the new info file, SEND_LISTING is
1088 returned, and the client should transmit the text of the info file, ended
1089 by the usual 000 on a line by itself.
1094 This is a simple user listing. It always succeeds, returning
1095 LISTING_FOLLOWS followed by zero or more user records, 000 terminated. The
1096 fields on each line are as follows:
1101 4. Date/time of last login (Unix format)
1104 7. Password (listed only if the user requesting the list is an Aide)
1106 Unlisted entries will also be listed to Aides logged into the server, but
1107 not to ordinary users.
1109 The LIST command accepts an optional single argument, which is a simple,
1110 case-insensitive search string. If this argument is present, only usernames
1111 in which the search string is present will be returned. It is a simple
1112 substring search, not a regular expression search. If this string is empty
1113 or not present, all users will be returned.
1116 REGI (send REGIstration)
1118 Clients will use this command to transmit a user's registration info. If
1119 no user is logged in, ERROR+NOT_LOGGED_IN is returned. Otherwise,
1120 SEND_LISTING is returned, and the server will expect the following information
1121 (terminated by 000 on a line by itself):
1124 Line 2: Street address or PO Box
1125 Line 3: City/town/village/etc.
1126 Line 4: State/province/etc.
1128 Line 6: Telephone number
1129 Line 7: e-mail address
1133 CHEK (CHEcK various things)
1135 When logging in, there are various things that need to be checked. This
1136 command will return ERROR+NOT_LOGGED_IN if no user is logged in. Otherwise
1137 it returns OK and the following parameters:
1139 0: Number of new private messages in Mail>
1140 1: Nonzero if the user needs to register
1141 2: (Relevant to Aides only) Nonzero if new users require validation
1142 3: The user's preferred Internet e-mail address
1145 DELF (DELete a File)
1147 This command deletes a file from the room's directory, if there is one. The
1148 name of the file to delete is the only parameter to be supplied. Wildcards
1149 are not acceptable, and any slashes in the filename will be converted to
1150 underscores, to prevent unauthorized access to neighboring directories. The
1151 possible return codes are:
1153 OK - Command succeeded. The file was deleted.
1154 ERROR+NOT_LOGGED_IN - Not logged in.
1155 ERROR+HIGHER_ACCESS_REQUIRED - Not an Aide or Room Aide.
1156 ERROR+NOT_HERE - There is no directory in this room.
1157 ERROR+FILE_NOT_FOUND - Requested file was not found.
1162 This command is similar to DELF, except that it moves a file (and its
1163 associated file description) to another room. It should be passed two
1164 parameters: the name of the file to move, and the name of the room to move
1165 the file to. All of the same return codes as DELF may be returned, and also
1166 one additional one: ERROR+NO_SUCH_ROOM, which means that the target room
1167 does not exist. ERROR+NOT_HERE could also mean that the target room does
1168 not have a directory.
1171 NETF (NETwork send a File)
1173 This command is similar to MOVF, except that it attempts to send a file over
1174 the network to another system. It should be passed two parameters: the name
1175 of the file to send, and the node name of the system to send it to. All of
1176 the same return codes as MOVF may be returned, except for ERROR+NO_SUCH_ROOM.
1177 Instead, ERROR+NO_SUCH_SYSTEM may be returned if the name of the target
1180 The name of the originating room will be sent along with the file. Most
1181 implementations will look for a room with the same name at the receiving end
1182 and attempt to place the file there, otherwise it goes into a bit bucket room
1183 for miscellaneous files. This is, however, beyond the scope of this document;
1184 see elsewhere for more details.
1187 RWHO (Read WHO's online)
1189 Displays a list of all users connected to the server. No error codes are
1190 ever returned. LISTING_FOLLOWS will be returned, followed by zero or more
1191 lines containing the following three fields:
1193 0 - Session ID. Citadel fills this with the pid of a server program.
1195 2 - The name of the room the user is currently in. This field might not
1196 be displayed (for example, if the user is in a private room) or it might
1197 contain other information (such as the name of a file the user is
1199 3 - (server v4.03 and above) The name of the host the client is connecting
1200 from, or "localhost" if the client is local.
1201 4 - (server v4.04 and above) Description of the client software being used
1202 5 - The last time, locally to the server, that a command was received from
1203 this client (Note: NOOP's don't count)
1204 6 - The last command received from a client. (NOOP's don't count)
1205 7 - Session flags. These are: + (spoofed address), - (STEALTH mode), *
1206 (posting) and . (idle).
1207 8 - Actual user name, if user name is masqueraded and viewer is an Aide.
1208 9 - Actual room name, if room name is masqueraded and viewer is an Aide.
1209 10 - Actual host name, if host name is masqueraded and viewer is an Aide.
1210 11 - Nonzero if the session is a logged-in user, zero otherwise.
1212 The listing is terminated, as always, with the string "000" on a line by
1216 OPEN (OPEN a file for download)
1218 This command is used to open a file for downloading. Only one download
1219 file may be open at a time. The only argument to this command is the name
1220 of the file to be opened. The user should already be in the room where the
1221 file resides. Possible return codes are:
1224 ERROR+NOT_HERE (no directory in this room)
1225 ERROR+FILE_NOT_FOUND (could not open the file)
1229 If the file is successfully opened, OK will be returned, along with the
1230 size (in bytes) of the file, the time of last modification (if applicable),
1231 the filename (if known), and the MIME type of the file (if known).
1234 CLOS (CLOSe the download file)
1236 This command is used to close the download file. It returns OK if the
1237 file was successfully closed, or ERROR if there wasn't any file open in the
1241 READ (READ from the download file)
1243 Two arguments are passed to this command. The first is the starting position
1244 in the download file, and the second is the total number of bytes to be
1245 read. If the operation can be performed, BINARY_FOLLOWS will be returned,
1246 along with the number of bytes to follow. Then, immediately following the
1247 newline, will be that many bytes of binary data. The client *must* read
1248 exactly that number of bytes, otherwise the client and server will get out
1251 If the operation cannot be performed, any of the usual error codes will be
1255 UOPN (OPeN a file for Uploading)
1257 This command is similar to OPEN, except that this one is used when the
1258 client wishes to upload a file to the server. The first argument is the name
1259 of the file to create, and the second argument is a one-line comment
1260 describing the contents of the file. Only one upload file may be open at a
1261 time. Possible return codes are:
1264 ERROR+NOT_HERE (no directory in this room)
1265 ERROR+FILE_NOT_FOUND (a name must be specified)
1266 ERROR (miscellaneous errors)
1267 ERROR+ALREADY_EXISTS (a file with the same name already exists)
1270 If OK is returned, the command has succeeded and writes may be performed.
1273 UCLS (CLoSe the Upload file)
1275 Close the file opened with UOPN. An argument of "1" should be passed to
1276 this command to close and save the file; otherwise, the transfer will be
1277 considered aborted and the file will be deleted. This command returns OK
1278 if the operation succeeded or ERROR if it did not.
1281 WRIT (WRITe to the upload file)
1283 If an upload file is open, this command may be used to write to it. The
1284 argument passed to this command is the number of bytes the client wishes to
1285 transmit. An ERROR code will be returned if the operation cannot be
1288 If the operation can be performed, SEND_BINARY will be returned, followed
1289 by the number of bytes the server is expecting. The client must then transmit
1290 exactly that number of bytes. Note that in the current implementation, the
1291 number of bytes the server is expecting will always be the number of bytes
1292 the client requested to transmit, but the client software should never assume
1293 that this will always happen, in case changes are made later.
1296 QUSR (Query for a USeR)
1298 This command is used to check to see if a particular user exists. The only
1299 argument to this command is the name of the user being searched for. If
1300 the user exists, OK is returned, along with the name of the user in the userlog
1301 (so the client software can learn the correct upper/lower casing of the name
1302 if necessary). If the user does not exist, ERROR+NO_SUCH_USER is returned.
1303 No login or current room is required to utilize this command.
1306 OIMG (Open an IMaGe file)
1308 Open an image (graphics) file for downloading. Once opened, the file can be
1309 read as if it were a download file. This implies that an image and a download
1310 cannot be opened at the same time. OIMG returns the same result codes as OPEN.
1312 All images will be in GIF (Graphics Interchange Format). In the case of
1313 Citadel, the server will convert the supplied filename to all lower case,
1314 append the characters ".gif" to the filename, and look for it in the "images"
1315 subdirectory. As with the MESG command, there are several "well known"
1316 images which are likely to exist on most servers:
1318 hello - "Welcome" graphics to be displayed alongside MESG "hello"
1319 goodbye - Logoff banner graphics to be displayed alongside MESG "goodbye"
1320 background - Background image (usually tiled) for graphical clients
1322 The following "special" image names are defined in Citadel server version
1325 _userpic_ - Picture of a user (send the username as the second argument)
1326 _floorpic_ - A graphical floor label (send the floor number as the second
1327 argument). Clients which request a floor picture will display
1328 the picture *instead* of the floor name.
1329 _roompic_ - A graphic associated with the *current* room. Clients which
1330 request a room picture will display the picture in *addition*
1331 to the room name (i.e. it's used for a room banner, as
1332 opposed to the floor picture's use in a floor listing).
1335 NETP (authenticate as network session with connection NET Password)
1337 This command is used by client software to identify itself as a transport
1338 session for Citadel site-to-site networking. It should be called with
1339 two arguments: the node name of the calling system, and the "shared secret"
1340 password for that connection. If the authentication succeeds, NETP will
1341 return OK, otherwise, it returns ERROR.
1344 NSYN (Network SYNchronize room)
1346 This command can be used to synchronize the contents of a room on the
1347 network. It is only usable by Aides. It accepts one argument: the name of
1348 a network node (which must be a valid one).
1350 When NSYN is run, the *entire* contents of the current room will be spooled
1351 to the specified node, without regard to whether any of the messages have
1352 already undergone network processing. It is up to the receiving node to
1353 check for duplicates (the Citadel networker does handle this) and avoid
1356 The command returns OK upon success or ERROR if the user is not an Aide.
1359 NUOP (Network Upload OPen file)
1361 Open a network spool file for uploading. The client must have already
1362 identified itself as a network session using the NETP command. If the command
1363 returns OK, the client may begin transmitting IGnet/Open spool data using
1364 a series of WRIT commands. When a UCLS command is issued, the spooled data
1365 is entered into the server if the argument to UCLS is 1 or discarded if the
1366 argument to UCLS is 0. If the client has not authenticated itself with a
1367 NETP command, ERROR+HIGHER_ACCESS_REQUIRED will be returned.
1370 NDOP (Network Download OPen file)
1372 Open a network spool file for downloading. The client must have already
1373 identified itself as a network session using the NETP command. If the command
1374 returns OK, the client may begin receiving IGnet/Open spool data using
1375 a series of READ commands. When a CLOS command is issued, the spooled data
1376 is deleted from the server and may not be read again. If the client has not
1377 authenticated itself with a NETP command, ERROR+HIGHER_ACCESS_REQUIRED will
1381 LFLR (List all known FLooRs)
1383 On systems supporting floors, this command lists all known floors. The
1384 command accepts no parameters. It will return ERROR+NOT_LOGGED_IN if no
1385 user is logged in. Otherwise it returns LISTING_FOLLOWS and a list of
1386 the available floors, each line consisting of three fields:
1388 1. The floor number associated with the floor
1389 2. The name of the floor
1390 3. Reference count (number of rooms on this floor)
1393 CFLR (Create a new FLooR)
1395 This command is used to create a new floor. It should be passed two
1396 arguments: the name of the new floor to be created, and a 1 or 0 depending
1397 on whether the client is actually creating a floor or merely checking to
1398 see if it has permission to create the floor. The user must be logged in
1399 and have Aide privileges to create a floor.
1401 If the command succeeds, it will return OK followed by the floor number
1402 associated with the new floor. Otherwise, it will return ERROR (plus perhaps
1403 HIGHER_ACCESS_REQUIRED, ALREADY_EXISTS, or INVALID_FLOOR_OPERATION)
1404 followed by a description of why the command failed.
1409 This command is used to delete a floor. It should be passed two
1410 argument: the *number* of the floor to be deleted, and a 1 or 0 depending
1411 on whether the client is actually deleting the floor or merely checking to
1412 see if it has permission to delete the floor. The user must be logged in
1413 and have Aide privileges to delete a floor.
1415 Floors that contain rooms may not be deleted. If there are rooms on a floor,
1416 they must be either deleted or moved to different floors first. This implies
1417 that the Main Floor (floor 0) can never be deleted, since Lobby>, Mail>, and
1418 Aide> all reside on the Main Floor and cannot be deleted.
1420 If the command succeeds, it will return OK. Otherwise it will return
1421 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1422 followed by a description of why the command failed.
1427 Edit the parameters of a floor. The client may pass one or more parameters
1430 1. The number of the floor to be edited
1431 2. The desired new name
1433 More parameters may be added in the future. Any parameters not passed to
1434 the server will remain unchanged. A minimal command would be EFLR and a
1435 floor number -- which would do nothing. EFLR plus the floor number plus a
1436 floor name would change the floor's name.
1438 If the command succeeds, it will return OK. Otherwise it will return
1439 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1442 IDEN (IDENtify the client software)
1444 The client software has the option to identify itself to the server.
1445 Currently, the server does nothing with this information except to write
1446 it to the syslog to satisfy the system administrator's curiosity. Other
1447 uses might become apparent in the future.
1449 The IDEN command should contain five fields: a developer ID number (same as
1450 the server developer ID numbers in the INFO command -- please obtain one if
1451 you are a new developer), a client ID number (which does not have to be
1452 globally unique - only unique within the domain of the developer number),
1453 a version number, a free-form text string describing the client, and the name
1454 of the host the user is located at.
1456 It is up to the server to determine whether to accept the host name or to
1457 use the host name it has detected itself. Generally, if the client is
1458 running on a trusted host (either localhost or a well-known publically
1459 accessible client) it should use the host name transmitted by IDEN,
1460 otherwise it should use the host name it has detected itself.
1462 IDEN always returns OK, but since that's the only way it ever returns
1463 there's no point in checking the result code.
1466 IPGM (identify as an Internal ProGraM)
1468 IPGM is a low-level command that should not be used by normal user clients.
1469 It is used for various utilities to communicate with the server on the same
1470 host. For example, the "sendcommand" utility logs onto the server as an
1471 internal program in order to run arbitrary server commands. Since user clients
1472 do not utilize this command (or any of its companion commands), developers
1473 writing Citadel-compatible servers need not implement it.
1475 The sole argument to IPGM is the system's internal program password. This
1476 password is generated by the setup program and stored in the config file.
1477 Since internal programs have access to the config file, they know the correct
1480 IPGM returns OK for a correct authentication or ERROR otherwise.
1483 CHAT (enter CHAT mode)
1485 This command functions differently from every other command in the system. It
1486 is used to implement multi-user chat. For this to function, a new transfer
1487 mode, called START_CHAT_MODE, is implemented. If a client does not support
1488 chat mode, it should never send a CHAT command!
1490 In chat mode, messages may arrive asynchronously from the server at any
1491 time. The client may send messages at any time. This allows the arrival of
1492 messages without the client having to poll for them. Arriving messages will
1493 be of the form "user|message", where the "user" portion is, of course, the
1494 name of the user sending the message, and "message" is the message text.
1496 Chat mode ends when the server says it ends. The server will signal the end
1497 of chat mode by transmitting "000" on a line by itself. When the client reads
1498 this line, it must immediately exit from chat mode without sending any
1499 further traffic to the server. The next transmission sent to the server
1500 will be a regular server command.
1502 The Citadel server understands the following commands:
1503 /quit - Exit from chat mode (causes the server to do an 000 end)
1504 /who - List users currently in chat
1505 /whobbs - List users currently in chat and elsewhere
1506 /me - Do an irc-style action.
1507 /join - Join a new "room" in which all messages are only heard by
1508 people in that room.
1509 /msg - /msg <user> <msg> will send the msg to <user> only.
1510 /help - Print help information
1511 NOOP - Do nothing (silently)
1513 Any other non-empty string is treated as message text and will be broadcast
1514 to other users currently in chat.
1517 SEXP (Send instant message)
1519 This is one of two commands which implement instant messages (also known
1520 as "paging"). Commands ending in "...EXP" are so-named because we called
1521 them "express messages" before the industry standardized on the term
1522 "instant messages." When an instant message is sent, it will be
1523 logged in user to another. When an instant message is sent, it will be
1524 displayed the next time the target user executes a PEXP or GEXP command.
1526 The SEXP command accepts two arguments: the name of the user to send the
1527 message to, and the text of the message. If the message is successfully
1528 transmitted, OK is returned. If the target user is not logged in or if
1529 anything else goes wrong, ERROR is returned.
1531 If the server supports extended paging, sending a zero-length message
1532 merely checks for the presence of the requested user without actually sending
1533 a message. Sending a message consisting solely of a "-" (hyphen) will cause
1534 the server to return SEND_LISTING if the requested user is logged in, and the
1535 client can then transmit a multi-line page.
1537 The reserved name "broadcast" may be used instead of a user name, to
1538 broadcast an instant message to all users currently connected to the server.
1540 Do be aware that if an instant message is transmitted to a user who is logged
1541 in using a client that does not check for instant messages, the message will
1542 never be received. Also, instant messages are NOT sent via the following
1543 transports: SMTP, POP3.
1546 PEXP (Print instant messages) ***DEPRECATED***
1548 This command is deprecated; it will eventually disappear from the protocol and
1549 its use is not recommended. Please use the GEXP command instead.
1551 Called without any arguments, PEXP simply dumps out the contents
1552 of any waiting instant messages. It returns ERROR if there is a problem,
1553 otherwise it returns LISTING_FOLLOWS followed by all messages.
1555 So how does the client know there are instant messages waiting? It could
1556 execute a random PEXP every now and then. Or, it can check the byte in
1557 server return code messages, between the return code and the parameters. In
1558 much the same way as FTP uses "-" to signify a continuation, Citadel uses
1559 an "*" in this position to signify the presence of waiting instant messages.
1562 EBIO (Enter BIOgraphy)
1564 Transmit to the server a free-form text file containing a little bit of
1565 information about the user for other users to browse. This is typically
1566 referred to as a 'bio' online. EBIO returns SEND_LISTING if it succeeds,
1567 after which the client is expected to transmit the file, or any of the usual
1568 ERROR codes if it fails.
1571 RBIO (Read BIOgraphy)
1573 Receive from the server a named user's bio. This command should be passed
1574 a single argument - the name of the user whose bio is requested. RBIO returns
1575 LISTING_FOLLOWS plus the bio file if the user exists and has a bio on file.
1576 The return has the following parameters: the user name, user number, access
1577 level, date of last call, times called, and messages posted. This command
1578 returns ERROR+NO_SUCH_USER if the named user does not exist.
1580 RBIO no longer considers a user with no bio on file to be an error condition.
1581 It now returns a message saying the user has no bio on file as the text of the
1582 bio. This allows newer servers to operate with older clients.
1585 STEL (enter STEaLth mode)
1587 When in "stealth mode," a user will not show up in the "Who is online"
1588 listing (the RWHO server command). Only Aides may use stealth mode. The
1589 STEL command accepts one argument: a 1 indicating that the user wishes to
1590 enter stealth mode, or a 0 indicating that the user wishes to exit stealth
1591 mode. STEL returns OK if the command succeeded, ERROR+NOT_LOGGED_IN if no
1592 user is logged in, or ERROR+HIGHER_ACCESS_REQUIRED if the user is not an Aide;
1593 followed by a 1 or 0 indicating the new state.
1595 If any value other than 1 or 0 is sent by the client, the server simply
1596 replies with 1 or 0 to indicate the current state without changing it.
1598 The STEL command also makes it so a user does not show up in the chat room
1602 LBIO (List users who have BIOs on file)
1604 This command is self-explanatory. Any user who has used EBIO to place a bio
1605 on file is listed. LBIO almost always returns LISTING_FOLLOWS followed by
1606 this listing, unless it experiences an internal error in which case ERROR
1610 MSG2 (read MeSsaGe, mode 2)
1612 MSG2 follows the same calling convention as MSG0. The difference between
1613 the two commands is that MSG2 outputs messages in standard RFC822 format
1614 rather than in Citadel proprietary format.
1616 This command was implemented in order to make various gateway programs
1617 easier to implement, and to provide some sort of multimedia support in the
1618 future. Keep in mind that when this command is used, all messages will be
1619 output in fixed 80-column format.
1622 MSG3 (read MeSsaGe, mode 3 -- internal command)
1624 MSG3 is for use by internal programs only and should not be utilized by
1625 user-mode clients. It does require IPGM authentication. MSG3 follows the
1626 same calling convention as the other MSG commands, but upon success returns
1627 BINARY_FOLLOWS followed by a data block containing the _raw_ message format
1631 TERM (TERMinate another session)
1633 In a multithreaded environment, it sometimes becomes necessary to terminate
1634 a session that is unusable for whatever reason. The TERM command performs
1635 this task. Naturally, only Aides can execute TERM. The command should be
1636 called with a single argument: the session ID (obtained from an RWHO command)
1637 of the session to be terminated.
1639 TERM returns OK if the session was terminated, or ERROR otherwise. Note that
1640 a client program is prohibited from terminating the session it is currently
1646 DOWN (shut DOWN the server)
1648 This command, which may only be executed by an Aide, immediately shuts down
1649 the server. It is only implemented on servers on which such an operation is
1650 possible, such as a multithreaded Citadel engine. The server does not restart.
1651 DOWN returns OK if the user is allowed to shut down the server, in which case
1652 the client program should expect the connection to be immediately broken.
1655 SCDN (Schedule or Cancel a shutDowN)
1657 SCDN sets or clears the "scheduled shutdown" flag. Pass this command a 1 or
1658 0 to respectively set or clear the flag. When the "scheduled shutdown" flag is
1659 set, the server will be shut down when there are no longer any users logged in.
1660 Any value other than 0 or 1 will not change the flag, only report its state.
1661 No users will be kicked off the system, and in fact the server is still
1662 available for new connections. The command returns ERROR if it fails;
1663 otherwise, it returns OK followed by a number representing the current state
1667 EMSG (Enter a system MeSsaGe)
1669 This is the opposite of the MESG command - it allows the creation and editing
1670 of system messages. The only argument passed to EMSG is the name of the
1671 file being transmitted. If the file exists in any system message directory
1672 on the server it will be overwritten, otherwise a new file is created. EMSG
1673 returns SEND_LISTING on success or ERROR+HIGHER_ACCESS_REQUIRED if the user
1676 Typical client software would use MESG to retrieve any existing message into
1677 an edit buffer, then present an editor to the user and run EMSG if the changes
1681 UIMG (Upload an IMaGe file)
1683 UIMG is complemenary to OIMG; it is used to upload an image to the server.
1684 The first parameter supplied to UIMG should be 0 if the client is only checking
1685 for permission to upload, or 1 if the client is actually attempting to begin
1686 the upload operation. The second argument is the name of the file to be
1687 transmitted. In Citadel, the filename is converted to all lower case,
1688 appended with the characters ".gif", and stored in the "images" directory.
1690 UIMG returns OK if the client has permission to perform the requested upload,
1691 or ERROR+HIGHER_ACCESS_REQUIRED otherwise. If the client requested to begin
1692 the operation (first parameter set to 1), an upload file is opened, and the
1693 client should begin writing to it with WRIT commands, then close it with a
1696 The supplied filename should be one of:
1698 -> _userpic_ (Server will attempt to write to the user's online photo)
1699 -> Any of the "well known" filenames described in the writeup for the
1703 HCHG (Hostname CHanGe)
1705 HCHG is a command, usable by any user, that allows a user to change their RWHO
1706 host value. This will mask a client's originating hostname from normal
1707 users; access level 6 and higher can see, in an extended wholist, the actual
1708 hostname the user originates from.
1710 The format of an HCHG command is:
1714 If a HCHG command is successful, the value OK (200) is returned.
1717 RCHG (Roomname CHanGe)
1719 RCHG is a command, usable by any user, that allows a user to change their RWHO
1720 room value. This will mask a client's roomname from normal users; access
1721 level 6 and higher can see, in an extended wholist, the actual room the user
1724 The format of an RCHG command is:
1728 If a RCHG command is successful, the value OK (200) is returned.
1731 UCHG (Username CHanGe)
1733 UCHG is an aide-level command which allows an aide to effectively change their
1734 username. If this value is blank, the user goes into stealth mode (see
1736 will show up as being from the real username in this mode, however. In
1737 addition, the RWHO listing will include both the spoofed and real usernames.
1739 The format of an UCHG command is:
1743 If a UCHG command is successful, the value OK (200) is returned.
1746 TIME (get server local TIME)
1748 TIME returns OK followed by the current time measured in seconds since
1749 00:00:00 GMT, Jan 1, 1970 (standard Unix format).
1751 This is used in allowing a client to calculate idle times.
1754 AGUP (Administrative Get User Parameters)
1755 ASUP (Administrative Set User Parameters)
1757 These commands are only executable by Aides and by server extensions running
1758 at system-level. They are used to get/set any and all parameters relating to
1759 a user account. AGUP requires only one argument: the name of the user in
1760 question. SGUP requires all of the parameters to be set. The parameters are
1761 as follows, and are common to both commands:
1765 2 - Flags (see citadel.h)
1770 7 - Timestamp of last call
1771 8 - Purge time (in days) for this user (or 0 to use system default)
1773 Upon success, AGUP returns OK followed by all these parameters, and ASUP
1774 simply returns OK. If the client has insufficient access to perform the
1775 requested operation, ERROR+HIGHER_ACCESS_REQUIRED is returned. If the
1776 requested user does not exist, ERROR+NO_SUCH_USER is returned.
1780 GPEX (Get Policy for message EXpiration)
1782 Returns the policy of the current room, floor, or site regarding the automatic
1783 purging (expiration) of messages. The following policies are available:
1784 0 - Fall back to the policy of the next higher level. If this is a room,
1785 use the floor's default policy. If this is a floor, use the system
1786 default policy. This is an invalid value for the system policy.
1787 1 - Do not purge messages automatically.
1788 2 - Purge by message count. (Requires a value: number of messages)
1789 3 - Purge by message age. (Requires a value: number of days)
1791 The format of this command is: GPEX <which>
1792 The value of <which> must be one of: "room" "floor" "site" "mailboxes"
1794 If successful, GPEX returns OK followed by <policy>|<value>.
1798 SPEX (Set Policy for message EXpiration)
1800 Sets the policy of the current room, floor, or site regarding the automatic
1801 purging (expiration) of messages. See the writeup for the GPEX command for
1802 the list of available policies.
1804 The format of this command is: SPEX <which>|<policy>|<value>
1805 The value of <which> must be one of: "room" "floor" "site" "mailboxes"
1807 If successful, GPEX returns OK; otherwise, an ERROR code is returned.
1811 CONF (get or set global CONFiguration options)
1813 Retrieves or sets various system-wide configuration and policy options. This
1814 command is only available to Aides. The sole parameter accepted is a command,
1815 which should be either GET or SET. If the GET command succeeds, CONF will
1816 return LISTING_FOLLOWS followed by the fields described below, one line at a
1817 time. If the SET command succeeds, CONF will return SEND_LISTING and expect
1818 the fields described below, one line at a time (don't worry about other fields
1819 being added in the future; if a 'short' configuration list is sent, the missing
1820 values at the end will be left unchanged on the system). If either command
1821 fails for any reason, ERROR is returned.
1823 The configuration lines are as follows:
1826 1. Fully qualified domain name
1827 2. Human-readable node name
1828 3. Landline telephone number of this system
1829 4. Flag (0 or 1) - creator of private room automatically becomes room aide
1830 5. Server connection idle timeout (in seconds)
1831 6. Initial access level for new users
1832 7. Flag (0 or 1) - require registration for new users
1833 8. Flag (0 or 1) - automatically move Problem User messages to twit room
1834 9. Name of twit room
1835 10. Text of <more> prompt
1836 11. Flag (0 or 1) - restrict access to Internet mail
1837 12. Geographic location of this system
1838 13. Name of the system administrator
1839 14. Number of maximum concurrent sessions allowed on the server
1840 15. (placeholder -- this field is no longer in use)
1841 16. Default purge time (in days) for users
1842 17. Default purge time (in days) for rooms
1843 18. Name of room to log instant messages to (or a zero-length name for none)
1844 19. Access level required to create rooms
1845 20. Maximum message length which may be entered into the system
1846 21. Minimum number of worker threads
1847 22. Maximum number of worker threads
1848 23. Port number for POP3 service
1849 24. Port number for SMTP service
1850 25. Flag (0 or 1) - strict RFC822 adherence - don't correct From: forgeries
1851 26. Flag (0 or 1) - allow Aides to zap (forget) rooms
1852 27. Port number for IMAP service
1853 28. How often (in seconds) to run the networker
1854 29. Flag (0 or 1) - disable self-service new user registration
1855 30. (placeholder -- this field is no longer in use)
1856 31. Hour (0 through 23) during which database auto-purge jobs are run
1857 32. Name of host where an LDAP service may be found
1858 33. Port number of LDAP service on above host
1861 36. Password for LDAP Bind DN
1862 37. Server IP address to listen on (or "0.0.0.0" for all addresses)
1863 38. Port number for SMTP MSA service
1864 39. Port number for IMAPS (SSL-encrypted IMAP)
1865 40. Port number for POP3S (SSL-encrypted POP3)
1866 41. Port number for SMTPS (SSL-encrypted SMTP)
1867 42. Flag (0 or 1) - enable full text search index
1868 43. Flag (0 or 1) - automatically cull database log files
1869 44. Flag (0 or 1) - enable IMAP "instant expunge" of deleted messages
1870 45. Flag (0 or 1) - allow unauthenticated SMTP clients to spoof my domains
1871 46. Flag (0 or 1) - perform journaling of email messages
1872 47. Flag (0 or 1) - perform journaling of non-email messages
1873 48. Address to which journalized messages are to be sent
1875 CONF also accepts two additional commands: GETSYS and PUTSYS followed by an
1876 arbitrary MIME type (such as application/x-citadel-internet-config) which
1877 provides a means of storing generic configuration data in the Global System
1878 Configuration room without the need to add extra get/set commands to the
1881 Please note that the LDAP-specific configs have no effect on Citadel servers
1882 in which LDAP support is not enabled.
1886 MSG4 (read MeSsaGe, mode 4 -- output in preferred MIME format)
1888 This is the equivalent of MSG0, except it's a bit smarter about messages in
1889 rich text formats. Immediately following the "text" directive, the server
1890 will output RFC822-like MIME part headers such as "Content-type:" and
1891 "Content-length:". MIME formats are chosen and/or converted based on the
1892 client's preferred format settings, which are set using the MSGP command,
1895 The MSG4 command also accepts an optional second argument, which may be the
1896 MIME part specifier of an encapsulated message/rfc822 message. This is useful
1897 for fetching the encapsulated message instead of the top-level message, for
1898 example, when someone has forwarded a message as an attachment. Note that the
1899 only way for the client to know the part specifier is to fetch the top-level
1900 message and then look for attachments of type message/rfc822, and then call
1901 MSG4 again with that part specifier.
1906 MSGP (set MeSsaGe Preferred MIME format)
1908 Client tells the server what MIME content types it knows how to handle, and
1909 the order in which it prefers them. This is similar to an HTTP "Accept:"
1912 The parameters to a MSGP command are the client's acceptable MIME content
1913 types, in the order it prefers them (from most preferred to least preferred).
1914 For example: MSGP text/html|text/plain
1916 The MSGP command always returns OK.
1920 OPNA (OPeN Attachment)
1922 Opens, as a download file, a component of a MIME-encoded message. The two
1923 parameters which must be passed to this command are the message number and the
1924 name of the desired section. If the message or section does not exist, an
1925 appropriate ERROR code will be returned; otherwise, if the open is successful,
1926 this command will succeed returning the same information as an OPEN command.
1929 GEXP (Get instant messages)
1931 This is a more sophisticated way of retrieving instant messages than the old
1932 PEXP method. If there are no instant messages waiting, PEXP returns ERROR;
1933 otherwise, it returns LISTING_FOLLOWS and the following arguments:
1935 0 - a boolean value telling the client whether there are any additional
1936 instant messages waiting following this one
1937 1 - a Unix-style timestamp
1938 2 - flags (see server.h for more info)
1939 3 - the name of the sender
1940 4 - the node this message originated on (for future support of PIP, ICQ, etc.)
1942 The text sent to the client will be the body of the instant message.
1944 So how does the client know there are instant messages waiting? It could
1945 execute a random GEXP every now and then. Or, it can check the byte in
1946 server return code messages, between the return code and the parameters. In
1947 much the same way as FTP uses "-" to signify a continuation, Citadel uses
1948 an "*" in this position to signify the presence of waiting instant messages.
1951 FSCK (check message base reference counts)
1953 Verify, via the long way, that all message referenmce counts are correct. If
1954 the user has permission to do this then LISTING_FOLLOWS is returned, followed
1955 by a transcript of the run. Otherwise ERROR is returned.
1958 DEXP (Disable receiving instant messages)
1960 DEXP sets or clears the "disable instant messages" flag. Pass this command a
1961 1 or 0 to respectively set or clear the flag. When the "disable instant
1962 messages" flag is set, no one except Aides may send the user instant messages.
1963 Any value other than 0 or 1 will not change the flag, only report its state.
1964 The command returns ERROR if it fails; otherwise, it returns OK followed by a
1965 number representing the current state of the flag.
1968 REQT (REQuest client Termination)
1970 Request that the specified client (or all clients) log off. Aide level
1971 access is required to run this command, otherwise ERROR+HIGHER_ACCESS_REQUIRED
1974 The REQT command accepts one parameter: the session ID of the client which
1975 should be terminated, or 0 for all clients. When successful, the REQT command
1978 It should be noted that REQT simply transmits an instant message to the
1979 specified client(s) with the EM_GO_AWAY flag set. Older clients do not honor
1980 this flag, and it is certainly possible for users to re-program their client
1981 software to ignore it. Therefore the effects of the REQT command should be
1982 considered advisory only. The recommended implementation practice is to first
1983 issue a REQT command, then wait a little while (from 30 seconds up to a few
1984 minutes) for well-behaved clients to voluntarily terminate, and then issue a
1985 TERM command to forcibly disconnect the client (or perhaps a DOWN command, if
1986 you are logging off users for the purpose of shutting down the server).
1989 SEEN (set or clear the SEEN flag for a message)
1991 Beginning with version 5.80, Citadel supports the concept of setting or
1992 clearing the "seen" flag for each individual message, instead of only allowing
1993 a "last seen" pointer. In fact, the old semantics are implemented in terms
1994 of the new semantics. This command requires two arguments: the number of the
1995 message to be set, and a 1 or 0 to set or clear the "seen" bit.
1997 This command returns OK, unless the user is not logged in or a usage error
1998 occurred, in which case it returns ERROR. Please note that no checking is
1999 done on the supplied data; if the requested message does not exist, the SEEN
2000 command simply returns OK without doing anything.
2003 GTSN (GeT the list of SeeN messages)
2005 This command retrieves the list of "seen" (as opposed to unread) messages for
2006 the current room. It returns OK followed by an IMAP-format message list.
2009 SMTP (utility commands for the SMTP gateway)
2011 This command, accessible only by Aides, supports several utility operations
2012 which examine or manipulate Citadel's SMTP support. The first command argument
2013 is a subcommand telling the server what to do. The following subcommands are
2016 SMTP mx|hostname (display all MX hosts for 'hostname')
2017 SMTP runqueue (attempt immediate delivery of all messages
2018 in the outbound SMTP queue, ignoring any
2019 retry times stored there)
2022 STLS (Start Transport Layer Security)
2024 This command starts TLS on the current connection. The current
2025 implementation uses OpenSSL on both the client and server end. For future
2026 compatibility all clients must support at least TLSv1, and servers are
2027 guaranteed to support TLSv1. During TLS negotiation (see below) the server
2028 and client may agree to use a different protocol.
2030 The server returns ERROR if it does not support SSL or SSL initialization
2031 failed on the server; otherwise it returns OK. Once the server returns OK and
2032 the client has read the response, the server and client immediately negotiate
2033 TLS (in OpenSSL, using SSL_connect() on the client and SSL_accept() on the
2034 server). If negotiation fails, the server and client should attempt to resume
2035 the session unencrypted. If either end is unable to resume the session, the
2036 connection should be closed.
2038 This command may be run at any time.
2041 GTLS (Get Transport Layer Security Status)
2043 This command returns information about the current connection. The server
2044 returns OK plus several parameters if the connection is encrypted, and ERROR
2045 if the connection is not encrypted. It is primarily used for debugging. The
2046 command may be run at any time.
2048 0 - Protocol name, e.g. "SSLv3"
2049 1 - Cipher suite name, e.g. "ADH-RC4-MD5"
2050 2 - Cipher strength bits, e.g. 128
2051 3 - Cipher strength bits actually in use, e.g. 128
2054 IGAB (Initialize Global Address Book)
2056 This command creates, or re-creates, a database of Internet e-mail addresses
2057 using the vCard information in the Global Address Book room. This procedure
2058 is normally run internally when the server determines it necessary, but is
2059 also provided as a server command to be used as a troubleshooting/maintenenance
2060 tool. Only a system Aide can run the command. It returns OK on success or
2064 QDIR (Query global DIRectory)
2066 Look up an internet address in the global directory. Any logged-in user may
2067 call QDIR with one parameter, the Internet e-mail address to look up. QDIR
2068 returns OK followed by a Citadel address if there is a match, otherwise it
2069 returns ERROR+NOT_LOGGED_IN.
2072 ISME (find out if an e-mail address IS ME)
2074 This is a quickie shortcut command to find out if a given e-mail address
2075 belongs to the user currently logged in. Its sole argument is an address to
2076 parse. The supplied address may be in any format (local, IGnet, or Internet).
2077 The command returns OK if the address belongs to the user, ERROR otherwise.
2080 VIEW (set the VIEW for a room)
2082 Set the preferred view for the current user in the current room. Please see
2083 views.txt for more information on views. The sole parameter for this command
2084 is the type of view requested. VIEW returns OK on success or ERROR on failure.
2087 QNOP (Quiet No OPeration)
2089 This command does nothing, similar to the NOOP command. However, unlike the
2090 NOOP command, it returns *absolutely no response* at all. The client has no
2091 way of knowing that the command executed. It is intended for sending
2092 "keepalives" in situations where a full NOOP would cause the client protocol
2095 Naturally, sending this command to a server that doesn't support it is an
2096 easy way to mess things up. Therefore, client software should first check
2097 the output of an INFO command to ensure that the server supports quiet noops.
2101 ICAL (Internet CALendaring commands)
2103 This command supports a number of subcommands which are used to process the
2104 calendaring/scheduling support in Citadel. Here are the subcommands which
2108 Test server for calendaring support. Always returns OK unless the server
2109 does not have the calendar module enabled.
2111 ICAL respond|msgnum|partnum|action
2112 Respond to a meeting request. 'msgnum' and 'partnum' refer to a MIME-encoded
2113 meeting invitation in the current room. 'action' must be set to either
2114 "accept" or "decline" to determine the action to take. This subcommand will
2115 return either OK or ERROR.
2117 ICAL conflicts|msgnum|partnum
2118 Determine whether an incoming VEVENT will fit in the user's calendar by
2119 checking it against the existing VEVENTs. 'msgnum' and 'partnum' refer to
2120 a MIME-encoded meeting invitation in the current room (usually the inbox).
2121 This command may return ERROR if something went wrong, but usually it will
2122 return LISTING_FOLLOWS followed by a list of zero or more conflicting
2123 events. A zero-length list means that there were no conflicts.
2125 ICAL handle_rsvp|msgnum|partnum
2126 Handle an incoming "reply" (or RSVP) to a meeting request you sent out.
2127 'msgnum' and 'partnum' refer to a MIME-encoded reply in the current room.
2128 'action' must be set to either "update" or "ignore" to determine the action
2129 to take. If the action is "update" then the server will hunt for the meeting
2130 in the user's Calendar> room, and update the status for this attendee. Either
2131 way, the reply message is deleted from the current room. This subcommand will
2132 return either OK or ERROR.
2134 ICAL freebusy|username
2135 Output the free/busy times for the requested user. If the user specified
2136 has a calendar available, this command will return LISTING_FOLLOWS and a
2137 compound VCALENDAR object. That object, in turn, will contain VEVENT
2138 objects that have been stripped of all properties except for the bare
2139 minimum needed to learn free/busy times (such as DTSTART, DTEND, and
2140 TRANSP). If there is no such user, or no calendar available, the usual
2141 ERROR codes will be returned.
2145 Readers who are paying attention will notice that there is no subcommand to
2146 send out meeting invitations. This is because that task can be handled
2147 automatically by the Citadel server. Issue this command with <bool> set to 1
2148 to enable Server Generated Invitations. In this mode, when an event is saved
2149 to the user's Calendar> room and it contains attendees, Citadel will
2150 automatically turn the event into vCalendar REQUEST messages and mail them
2151 out to all listed attendees. If for some reason the client needs to disable
2152 Server Generated Invitations, the command may be sent again with <bool> = 0.
2156 MRTG (Multi Router Traffic Grapher)
2158 Multi Router Traffic Grapher (please see http://www.mrtg.org for more info) is
2159 a tool which creates pretty graphs of network activity, usually collected from
2160 routers using SNMP. However, its ability to call external scripts has spawned
2161 a small community of people using it to graph anything which can be graphed.
2162 The MRTG command can output Citadel server activity in the format MRTG expects.
2164 This format is as follows:
2169 Line 3: uptime of system
2170 Line 4: name of system
2173 MRTG accepts two different keywords. "MRTG users" will return two variables,
2174 the number of connected users and the number of active users. "MRTG messages"
2175 will return one variable (and a zero in the second field), showing the current
2176 highest message number on the system. Any other keyword, or a missing keyword,
2177 will cause the MRTG command to return an ERROR code.
2179 Please get in touch with the Citadel developers if you wish to experiment with
2184 GNET (Get NETwork configuration for this room)
2185 SNET (Set NETwork configuration for this room)
2187 These commands get/set the network configuration for the current room. Aide
2188 or Room Aide privileges are required, otherwise an ERROR code is returned.
2189 If the command succeeds, LISTING_FOLLOWS or SEND_LISTING is returned. The
2190 network configuration for a specific room includes neighbor nodes with whom
2191 the room is shared, and mailing list recipients. The format of the network
2192 configuration is described in the file "netconfigs.txt".
2196 ASYN (ASYNchronous message support)
2198 Negotiate the use of asynchronous, or unsolicited, protocol messages. The
2199 only parameter specified should be 1 or 0 to indicate that the client can or
2200 cannot handle this type of messages. The server will reply OK followed by a
2201 1 or 0 to tell the client which mode it is now operating in.
2203 If the command is not available on the server (i.e. it returns ERROR), or
2204 if the command has not been executed by the client, it should be assumed that
2205 this mode of operation is NOT in effect.
2207 The client may also send any value other than 0 or 1 to simply cause the
2208 server to output its current state without changing it.
2210 When asynchronous protocol mode is in effect, the client MUST handle any
2211 asynchronous messages as they arrive, before doing anything else.
2215 AUTO (AUTOcompletion of email addresses)
2217 The AUTO command is used by clients which want to request a list of email
2218 recipients whose names or email addresses match a partial string supplied by
2219 the client. This string is the only parameter passed to this command. The
2220 command will return ERROR if no user is logged in or if no address book could
2221 be found; otherwise, it returns LISTING_FOLLOWS followed by zero or more
2222 candidate recipients.
2226 SRCH (SeaRCH the message base)
2228 This command's implementation is incomplete and will be documented when it
2229 is finished. The current implementation accepts a search string as its sole
2230 argument, and will respond with LISTING_FOLLOWS followed by a list of
2231 messages (globally, not just in the current room) which contain ALL of the
2232 words in the search string. If the client desires an "exact phrase" match,
2233 it must then slow-search the text of each returned message for the exact
2234 string. The client should also compare the returned message numbers against
2235 those which actually exist in the room or rooms being searched. In
2236 particular, clients should avoid telling the user about messages which exist
2237 only in rooms to which the user does not have access.
2239 Again, keep in mind that this is a temporary implementation and is not
2240 guaranteed to continue to exist in this form.
2243 EUID (get message number using an EUID)}
2245 Returns the message number, if present, of the message in the current room
2246 which is indexed using the supplied EUID (exclusive message ID). There can be
2247 only one message in a room with any given EUID; if another message arrives
2248 with the same EUID, the existing one is replaced. This makes it possible to
2249 reference things like calendar items using an immutable URL that does not
2250 change even when the message number changes due to an update.
2252 The format of this command is: EUID <euid>
2254 If successful, EUID returns OK followed by a message number.
2255 If no message exists in the current room with the supplied EUID, the command
2256 returns ERROR+MESSAGE_NOT_FOUND.
2262 ASYNCHRONOUS MESSAGES
2263 ---------------------
2265 When the client protocol is operating in asynchronous mode (please refer to
2266 the writeup of the ASYN command above), the following messages may arrive at
2270 902 (instant message arriving)
2272 One or more instant messages have arrived for this client.