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)
297 LKRO (List Known Rooms with Old [no new] messages)
299 This follows the same usage and format as LKRN.
302 LZRM (List Zapped RooMs)
304 This follows the same usage and format as LKRN and LKRO.
307 LKRA (List All Known Rooms)
309 Same format. Lists all known rooms, with or without new messages.
312 LRMS (List all accessible RooMS)
314 Again, same format. This command lists all accessible rooms, known and
315 forgotten, with and without new messages. It does not, however, list
316 inaccessible private rooms.
319 LPRM (List all Public RooMs)
321 Again, same format. This command lists all public rooms, and nothing else.
322 Unlike the other list rooms commands, this one can be executed without logging
326 GETU (GET User configuration)
328 This command retrieves the screen dimensions and user options for the
329 currently logged in account. ERROR + NOT_LOGGED_IN will be returned if no
330 user is logged in, of course. Otherwise, OK will be returned, followed by
331 four parameters. The first parameter is the user's screen width, the second
332 parameter is the user's screen height, and the third parameter is a bag of
333 bits with the following meanings:
335 #define US_LASTOLD 16 /* Print last old message with new */
336 #define US_EXPERT 32 /* Experienced user */
337 #define US_UNLISTED 64 /* Unlisted userlog entry */
338 #define US_NOPROMPT 128 /* Don't prompt after each message */
339 #define US_DISAPPEAR 512 /* Use "disappearing msg prompts" */
340 #define US_PAGINATOR 2048 /* Pause after each screen of text */
342 There are other bits, too, but they can't be changed by the user (see below).
345 SETU (SET User configuration)
347 This command does the opposite of SETU: it takes the screen dimensions and
348 user options (which were probably obtained with a GETU command, and perhaps
349 modified by the user) and writes them to the user account. This command
350 should be passed three parameters: the screen width, the screen height, and
351 the option bits (see above). It returns ERROR + NOT_LOGGED_IN if no user is
352 logged in, and ERROR + ILLEGAL_VALUE if the parameters are incorrect.
354 Note that there exist bits here which are not listed in this document. Some
355 are flags that can only be set by Aides or the system administrator. SETU
356 will ignore attempts to toggle these bits. There also may be more user
357 settable bits added at a later date. To maintain later downward compatibility,
358 the following procedure is suggested:
360 1. Execute GETU to read the current flags
361 2. Toggle the bits that we know we can toggle
362 3. Execute SETU to write the flags
364 If we are passed a bit whose meaning we don't know, it's best to leave it
365 alone, and pass it right back to the server. That way we can use an old
366 client on a server that uses an unknown bit without accidentally clearing
367 it every time we set the user's configuration.
372 This command is used to goto a new room. When the user first logs in (login
373 is completed after execution of the PASS command) this command is
374 automatically and silently executed to take the user to the first room in the
375 system (usually called the Lobby).
377 This command can be passed one or two parameters. The first parameter is,
378 of course, the name of the room. Although it is not case sensitive, the
379 full name of the room must be used. Wildcard matching or unique string
380 matching of room names should be the responsibility of the client.
382 Note that the reserved room name "_BASEROOM_" can be passed to the server
383 to cause the goto command to take the user to the first room in the system,
384 traditionally known as the Lobby>. As long as a user is logged in, a
385 GOTO command to _BASEROOM_ is guaranteed to succeed. This is useful to
386 allow client software to return to the base room when it doesn't know
389 There are also several additional reserved room names:
390 "_MAIL_" goes to the user's inbox (i.e. the Mail> room).
391 "_TRASH_" goes to the user's personal trashcan room (trash folder).
392 "_BITBUCKET_" goes to a room that has been chosen for messages without a home.
393 "_CALENDAR_" goes to the user's primary personal calendar.
394 "_CONTACTS_" goes to the user's primary personal address book.
395 "_NOTES_" goes to the user's primary personal notes room.
396 "_TASKS_" goes to the user's primary personal task list.
399 The second (and optional) parameter is a password, if one is required for
400 access to the room. This allows for all types of rooms to be accessed via
401 this command: for public rooms, invitation-only rooms to which the user
402 has access, and preferred users only rooms to which the user has access, the
403 room will appear in a room listing. For guess-name rooms, this command
404 will work transparently, adding the room to the user's known room list when
405 it completes. For passworded rooms, access will be denied if the password
406 is not supplied or is incorrect, or the command will complete successfully
407 if the password is correct.
409 The third (and also) optional parameter is a "transient" flag. Normally,
410 when a user enters a private and/or zapped room, the room is added to the
411 user's known rooms list. If the transient flag is set to non-zero, this is
412 called a "transient goto" which causes the user to enter the room without
413 adding the room to the known rooms list.
415 The possible result codes are:
417 OK - The command completed successfully. User is now in the room.
418 (See the list of returned parameters below)
420 ERROR - The command did not complete successfully. Check the second and
421 third positions of the result code to find out what happened:
423 NOT_LOGGED_IN - Of course you can't go there. You didn't log in.
424 PASSWORD_REQUIRED - Either a password was not supplied, or the supplied
425 password was incorrect.
426 ROOM_NOT_FOUND - The requested room does not exist.
428 The typical procedure for entering a passworded room would be:
430 1. Execute a GOTO command without supplying any password.
431 2. ERROR + PASSWORD_REQUIRED will be returned. The client now knows that
432 the room is passworded, and prompts the user for a password.
433 3. Execute a GOTO command, supplying both the room name and the password.
434 4. If OK is returned, the command is complete. If, however,
435 ERROR + PASSWORD_REQUIRED is still returned, tell the user that the supplied
436 password was incorrect. The user remains in the room he/she was previously
439 When the command succeeds, these parameters are returned:
440 0. The name of the room
441 1. Number of unread messages in this room
442 2. Total number of messages in this room
443 3. Info flag: set to nonzero if the user needs to read this room's info
444 file (see RINF command below)
445 4. Various flags associated with this room. (See LKRN cmd above)
446 5. The highest message number present in this room
447 6. The highest message number the user has read in this room
448 7. Boolean flag: 1 if this is a Mail> room, 0 otherwise.
449 8. Aide flag: 1 if the user is either the Room Aide for this room, *or* is
450 a regular Aide (this makes access checks easy).
451 9. The number of new Mail messages the user has (useful for alerting the
452 user to the arrival of new mail during a session)
453 10. The floor number this room resides on
454 11. The *current* "view" for this room (see views.txt for more info)
455 12. The *default* "view" for this room
456 13. Boolian flag: 1 if this is the user's Trash folder, 0 otherwise.
458 The default view gives the client a hint as to what views the user should
459 be allowed to select. For example, it would be confusing to allow messages
460 in a room intended for calendar items. The server does not enforce these
461 restrictions, though.
464 MSGS (get pointers to MeSsaGeS in this room)
466 This command obtains a listing of all the messages in the current room
467 which the client may request. This command may be passed a single parameter:
468 either "all", "old", or "new" to request all messages, only old messages, or
469 new messages. Or it may be passed two parameters: "last" plus a number, in
470 which case that many message pointers will be returned; "first" plus a
471 number, for the corresponding effect; or "gt" plus a number, to list all
472 messages in the current room with a message number greater than the one
473 specified. If no parameters are specified, "all" is assumed.
475 The third argument, may be either 0 or 1. If it is 1, this command behaves
476 differently: before a listing is returned, the client must transmit a list
477 of fields to search for. The field headers are listed below in the writeup
478 for the "MSG0" command.
480 The optional fourth argument may also be either 0 or 1. If it is 1, the
481 output of this command will include not only a list of message numbers, but
482 a simple header summary of each message as well. This is somewhat resource
483 intensive so you shouldn't do this unless you absolutely need all the headers
484 immediately. The fields which are output (in the usual delimited fashion, of
485 course) are: message number, timestamp, display name, node name, Internet
486 email address (if present), subject (if present).
488 This command can return three possible results. ERROR + NOT_LOGGED_IN will
489 be returned if no user is currently logged in. Otherwise, LISTING_FOLLOWS
490 will be returned, and the listing will consist of zero or more message
491 numbers, one per line. The listing ends, as always, with the string "000"
492 alone on a line by itself. The listed message numbers can be used to request
493 messages from the system. If "search mode" is being used, the server will
494 return START_CHAT_MODE, and the client is expected to transmit the search
495 criteria, and then read the message list.
497 Since this is somewhat complex, here are some examples:
499 Example 1: Read all new messages
502 Server: 100 Message list...
508 Example 2: Read the last five messages
511 Server: 100 Message list...
519 Example 3: Read all messages written by "IGnatius T Foobar"
522 Server: 800 Send template then receive message list
523 Client: from|IGnatius T Foobar
537 Note that in "search mode" the client may specify any number of search
538 criteria. These criteria are applied with an AND logic.
541 MSG0 (read MeSsaGe, mode 0)
543 This is a command used to read the text of a message. "Mode 0" implies that
544 other MSG commands (MSG1, MSG2, etc.) will probably be added later on to read
545 messages in more robust formats. This command should be passed two arguments.
546 The first is the message number of the message being requested. The second
547 argument specifies whether the client wants headers and/or message body:
551 3 = Headers only, with MIME information suppressed (this runs faster)
553 If the request is denied, ERROR + NOT_LOGGED_IN or ERROR + MESSAGE_NOT_FOUND
554 will be returned. Otherwise, LISTING_FOLLOWS will be returned, followed by
555 the contents of the message. The following fields may be sent:
557 type= Formatting type. The currently defined types are:
558 0 = "traditional" Citadel formatting. This means that newlines should be
559 treated as spaces UNLESS the first character on the next line is a space. In
560 other words, only indented lines should generate a newline on the user's screen
561 when the message is being displayed. This allows a message to be formatted to
562 the reader's screen width. It also allows the use of proportional fonts.
563 1 = a simple fixed-format message. The message should be displayed to
564 the user's screen as is, preferably in a fixed-width font that will fit 80
566 4 = MIME format message. The message text is expected to contain a header
567 with the "Content-type:" directive (and possibly others).
569 msgn= The message ID of this message on the system it originated on.
570 path= An e-mailable path back to the user who wrote the message.
572 time= The date and time of the message, in Unix format (the number of
573 seconds since midnight on January 1, 1970, GMT).
575 from= The name of the author of the message.
576 rcpt= If the message is a private e-mail, this is the recipient.
577 room= The name of the room the message originated in.
578 node= The short node name of the system this message originated on.
579 hnod= The long node name of the system this message originated on.
580 zaps= The id/node of a message which this one zaps (supersedes).
582 part= Information about a MIME part embedded in this message.
583 pref= Information about a multipart MIME prefix such as "multipart/mixed"
584 or "multipart/alternative". This will be output immediately prior
585 to the various "part=" lines which make up the multipart section.
586 suff= Information about a multipart MIME suffix. This will be output
587 immediately following the various "part=" lines which make up the
590 text Note that there is no "=" after the word "text". This string
591 signifies that the message text begins on the next line.
594 WHOK (WHO Knows room)
596 This command is available only to Aides. ERROR + HIGHER_ACCESS_REQUIRED
597 will be returned if the user is not an Aide. Otherwise, it returns
598 LISTING_FOLLOWS and then lists, one user per line, every user who has
599 access to the current room.
602 INFO (get server INFO)
604 This command will *always* return LISTING_FOLLOWS and then print out a
605 listing of zero or more strings. Client software should be written to expect
606 anywhere from a null listing to an infinite number of lines, to allow later
607 backward compatibility. The current implementation defines the following
608 parts of the listing:
610 Line 1 - Your unique session ID on the server
611 Line 2 - The node name of the Citadel server
612 Line 3 - Human-readable node name of the Citadel server
613 Line 4 - The fully-qualified domain name (FQDN) of the server
614 Line 5 - The name of the server software, i.e. "Citadel 4.00"
615 Line 6 - (The revision level of the server code) * 100
616 Line 7 - The geographical location of the site (city and state if in the US)
617 Line 8 - The name of the system administrator
618 Line 9 - A number identifying the server type (see below)
619 Line 10 - The text of the system's paginator prompt
620 Line 11 - Floor Flag. 1 if the system supports floors, 0 otherwise.
621 Line 12 - Paging level. 0 if the system only supports inline paging,
622 1 if the system supports "extended" paging (check-only and
623 multiline modes). See the SEXP command for further information.
624 Line 13 - The "nonce" for this session, for support of APOP-style
625 authentication. If this field is present, clients may authenticate
627 Line 14 - Set to nonzero if this server supports the QNOP command.
628 Line 15 - Set to nonzero if this server is capable of connecting to a
629 directory service using LDAP.
631 *** NOTE! *** The "server type" code is intended to promote global
632 compatibility in a scenario in which developers have added proprietary
633 features to their servers or clients. We are attempting to avoid a future
634 situation in which users need to keep different client software around for
635 each Citadel they use. *Please*, if you are a developer and plan to add
636 proprietary features:
638 -> Your client programs should still be able to utilize servers other than
640 -> Clients other than your own should still be able to utilize your server,
641 even if your proprietary extensions aren't supported.
642 -> Please contact Art Cancro <ajc@uncensored.citadel.org> and obtain a unique
643 server type code, which can be assigned to your server program.
644 -> If you document what you did in detail, perhaps it can be added to a
645 future release of the Citadel program, so everyone can enjoy it. Better
646 yet, just work with the Citadel development team on the main source tree.
648 If everyone follows this scheme, we can avoid a chaotic situation with lots
649 of confusion about which client program works with which server, etc. Client
650 software can simply check the server type (and perhaps the revision level)
651 to determine ahead of time what commands may be utilized.
653 Please refer to "developers.txt" for information on what codes belong to whom.
657 RDIR (Read room DIRectory)
659 Use this command to read the directory of a directory room. ERROR + NOT_HERE
660 will be returned if the room has no directory, ERROR + HIGHER_ACCESS_REQUIRED
661 will be returned if the room's directory is not visible and the user does not
662 have Aide or Room Aide privileges, ERROR + NOT_LOGGED_IN will be returned if
663 the user is not logged in; otherwise LISTING_FOLLOWS will be returned,
664 followed by the room's directory. Each line of the directory listing will
665 contain three fields: a filename, the length of the file, and a description.
667 The server message contained on the same line with LISTING_FOLLOWS will
668 contain the name of the system and the name of the directory, such as:
670 uncensored.citadel.org|/usr/local/citadel/files/my_room_directory
673 SLRP (Set Last-message-Read Pointer)
675 This command marks all messages in the current room as read (seen) up to and
676 including the specified number. Its sole parameter is the number of the last
677 message that has been read. This allows the pointer to be set at any
678 arbitrary point in the room. Optionally, the parameter "highest" may be used
679 instead of a message number, to set the pointer to the number of the highest
680 message in the room, effectively marking all messages in the room as having
681 been read (ala the Citadel <G>oto command).
683 The command will return OK if the pointer was set, or ERROR + NOT_LOGGED_IN
684 if the user is not logged in. If OK is returned, it will be followed by a
685 single argument containing the message number the last-read-pointer was set to.
688 INVT (INViTe a user to a room)
690 This command may only be executed by Aides, or by the room aide for the
691 current room. It is used primarily to add users to invitation-only rooms,
692 but it may also be used in other types of private rooms as well. Its sole
693 parameter is the name of the user to invite.
695 The command will return OK if the operation succeeded. ERROR + NO_SUCH_USER
696 will be returned if the user does not exist, ERROR + HIGHER_ACCESS_REQUIRED
697 will be returned if the operation would have been possible if the user had
698 higher access, and ERROR + NOT_HERE may be returned if the room is not a
702 KICK (KICK a user out of a room)
704 This is the opposite of INVT: it is used to kick a user out of a private
705 room. It can also be used to kick a user out of a public room, but the
706 effect will only be the same as if the user <Z>apped the room - a non-stupid
707 user can simply un-zap the room to get back in.
710 GETR (GET Room attributes)
712 This command is used for editing the various attributes associated with a
713 room. A typical "edit room" command would work like this:
714 1. Use the GETR command to get the current attributes
715 2. Change some of them around
716 3. Use SETR (see below) to save the changes
717 4. Possibly also change the room aide using the GETA and SETA commands
719 GETR takes no arguments. It will only return OK if the SETR command will
720 also return OK. This allows client software to tell the user that he/she
721 can't edit the room *before* going through the trouble of actually doing the
722 editing. Possible return codes are:
724 ERROR+NOT_LOGGED_IN - No user is logged in.
725 ERROR+HIGHER_ACCESS_REQUIRED - Not enough access. Typically, only aides
726 and the room aide associated with the current room, can access this command.
727 OK - Command succeeded. Parameters are returned.
729 If OK is returned, the following parameters will be returned as well:
731 0. The name of the room
732 1. The room's password (if it's a passworded room)
733 2. The name of the room's directory (if it's a directory room)
734 3. Various flags (bits) associated with the room (see LKRN cmd above)
735 4. The floor number on which the room resides
736 5. The room listing order
737 6. The default view for the room (see views.txt)
738 7. A second set of flags (bits) associated with the room
741 SETR (SET Room attributes)
743 This command sets various attributes associated with the current room. It
744 should be passed the following arguments:
746 0. The name of the room
747 1. The room's password (if it's a passworded room)
748 2. The name of the room's directory (if it's a directory room)
749 3. Various flags (bits) associated with the room (see LKRN cmd above)
750 4. "Bump" flag (see below)
751 5. The floor number on which the room should reside
752 6. The room listing order
753 7. The default view for the room (see views.txt)
754 8. A second set of flags (bits) associated with the room
756 *Important: You should always use GETR to retrieve the current attributes of
757 the room, then change what you want to change, and then use SETR to write it
758 all back. This is particularly important with respect to the flags: if a
759 particular bit is set, and you don't know what it means, LEAVE IT ALONE and
760 only toggle the bits you want to toggle. This will allow for upward
763 The _BASEROOM_, user's Mail> and Aide> rooms can only be partially edited.
764 Any changes which cannot be made will be silently ignored.
766 If the room is a private room, you have the option of causing all users who
767 currently have access, to forget the room. If you want to do this, set the
768 "bump" flag to 1, otherwise set it to 0.
773 This command is used to get the name of the Room Aide for the current room.
774 It will return ERROR + NOT_LOGGED_IN if no user is logged in, or OK if the
775 command succeeded. Along with OK there will be returned one parameter: the
776 name of the Room Aide. A conforming server must guarantee that the user is
782 The opposite of GETA, used to set the Room Aide for the current room. One
783 parameter should be passed, which is the name of the user who is to be the
784 new Room Aide. Under Citadel, this command may only be executed by Aides
785 and by the *current* Room Aide for the room. Return codes possible are:
786 ERROR + NOT_LOGGED_IN (Not logged in.)
787 ERROR + HIGHER_ACCESS_REQUIRED (Higher access required.)
788 ERROR + NOT_HERE (Room cannot be edited.)
789 OK (Command succeeded.)
792 ENT0 (ENTer message, mode 0)
794 This command is used to enter messages into the system. It accepts four
797 0 - Post flag. This should be set to 1 to post a message. If it is
798 set to 0, the server only returns OK or ERROR (plus any flags describing
799 the error) without reading in a message. Client software should, in fact,
800 perform this operation at the beginning of an "enter message" command
801 *before* starting up its editor, so the user does not end up typing a message
802 in vain that will not be permitted to be saved. If it is set to 2, the
803 server will accept an "apparent" post name if the user is privileged enough.
804 This post name is arg 5.
805 1 - Recipient (To: field). This argument is utilized only for private
806 mail. It is ignored for public messages. It contains, of course, the name
807 of the recipient(s) of the message.
808 2 - Anonymous flag. This argument is ignored unless the room allows
809 anonymous messages. In such rooms, this flag may be set to 1 to flag a
810 message as anonymous, otherwise 0 for a normal message.
811 3 - Format type. Any valid Citadel format type may be used (this will
812 typically be 0; see the MSG0 command above).
813 4 - Subject. If present, this argument will be used as the subject of
815 5 - Post name. When postflag is 2, this is the name you are posting as.
816 This is an Aide only command.
817 6 - Do Confirmation. NOTE: this changes the protocol semantics! When
818 you set this to nonzero, ENT0 will reply with a confirmation message after
819 you submit the message text. The reply code for the ENT0 command will be
820 START_CHAT_MODE instead of SEND_LISTING.
821 7 - Recipient (Cc: field). This argument is utilized only for private
822 mail. It is ignored for public messages. It contains, of course, the name
823 of the recipient(s) of the message.
824 8 - Recipient (Bcc: 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.
828 Possible result codes:
829 OK - The request is valid. (Client did not set the "post" flag, so the
830 server will not read in message text.) If the message is an e-mail with
831 a recipient, the text that follows the OK code will contain the exact name
832 to which mail is being sent. The client can display this to the user. The
833 implication here is that the name that the server returns will contain the
834 correct upper and lower case characters. In addition, if the recipient is
835 having his/her mail forwarded, the forwarding address will be returned.
836 SEND_LISTING - The request is valid. The client should now transmit
837 the text of the message (ending with a 000 on a line by itself, as usual).
838 START_CHAT_MODE - The request is valid. The client should now transmit
839 the text of the message, ending with a 000 on a line by itself. After
840 transmitting the 000 terminator, the client MUST read in the confirmation
841 from the server, which will also end with 000 on a line by itself. The format
842 of the confirmation appears below.
843 ERROR + NOT_LOGGED_IN - Not logged in.
844 ERROR + HIGHER_ACCESS_REQUIRED - Higher access is required. An
845 explanation follows, worded in a form that can be displayed to the user.
846 ERROR + NO_SUCH_USER - The specified recipient does not exist.
848 The format of the confirmation message, if requested, is as follows:
849 Line 1: The new message number on the server for the message. It will be
850 positive for a real message number, or negative to denote
851 that an error occurred. If an error occurred, the message was
853 Line 2: A human-readable confirmation or error message.
854 Line 3: The resulting Exclusive UID of the message, if present.
855 (More may be added to this in the future, so do not assume that there will
856 only be these lines output. Keep reading until 000 is received.)
859 RINF (read Room INFormation file)
861 Each room has associated with it a text file containing a description of
862 the room, perhaps containing its intended purpose or other important
863 information. The info file for the Lobby> (the system's base room) is
864 often used as a repository for system bulletins and the like.
866 This command, which accepts no arguments, is simply used to read the info
867 file for the current room. It will return LISTING_FOLLOWS followed by
868 the text of the message (always in format type 0) if the request can be
869 honored, or ERROR if no info file exists for the current room (which is
870 often the case). Other error description codes may accompany this result.
872 When should this command be used? This is, of course, up to the discretion
873 of client software authors, but in Citadel it is executed in two situations:
874 the first time the user ever enters a room; and whenever the contents of the
875 file change. The latter can be determined from the result of a GOTO command,
876 which will tell the client whether the file needs to be read (see GOTO above).
879 DELE (DELEte a message)
881 Delete a message from the current room. The one argument that should be
882 passed to this command is the message number of the message to be deleted.
883 The return value will be OK if the message was deleted, or an ERROR code.
884 If the delete is successful, the message's reference count is decremented, and
885 if the reference count reaches zero, the message is removed from the message
889 MOVE (MOVE or copy a message to a different room)
891 Move or copy a message to a different room. This command expects to be
892 passed three arguments:
893 0: the message number of the message to be moved or copied.
894 1: the name of the target room.
895 2: flag: 0 to move the message, 1 to copy it without deleting from the
898 This command never creates or deletes copies of a message; it merely moves
899 around links. When a message is moved, its reference count remains the same.
900 When a message is copied, its reference count is incremented.
903 KILL (KILL current room)
905 This command deletes the current room. It accepts a single argument, which
906 should be nonzero to actually delete the room, or zero to merely check
907 whether the room can be deleted.
909 Once the room is deleted, the current room is undefined. It is suggested
910 that client software immediately GOTO another room (usually _BASEROOM_)
911 after this command completes.
913 Possible return codes:
915 OK - room has been deleted (or, if checking only, request is valid).
916 ERROR+NOT_LOGGED_IN - no user is logged in.
917 ERROR+HIGHER_ACCESS_REQUIRED - not enough access to delete rooms.
918 ERROR+NOT_HERE - this room can not be deleted.
921 CRE8 (CRE[ate] a new room)
923 This command is used to create a new room. Like some of the other
924 commands, it provides a mechanism to first check to see if a room can be
925 created before actually executing the command. CRE8 accepts the following
928 0 - Create flag. Set this to 1 to actually create the room. If it is
929 set to 0, the server merely checks that there is a free slot in which to
930 create a new room, and that the user has enough access to create a room. It
931 returns OK if the client should go ahead and prompt the user for more info,
932 or ERROR or ERROR+HIGHER_ACCESS_REQUIRED if the command will not succeed.
933 1 - Name for new room.
934 2 - Access type for new room:
936 1 - Private; can be entered by guessing the room's name
937 2 - Private; can be entered by knowing the name *and* password
938 3 - Private; invitation only (sometimes called "exclusive")
939 4 - Personal (mailbox for this user only)
940 3 - Password for new room (if it is a type 2 room)
941 4 - Floor number on which the room should reside (optional)
942 5 - Set to 1 to avoid automatically gaining access to the created room.
943 6 - The default "view" for the room.
945 If the create flag is set to 1, the room is created (unless something
946 went wrong and an ERROR return is sent), and the server returns OK, but
947 the session is **not** automatically sent to that room. The client still
948 must perform a GOTO command to go to the new room.
951 FORG (FORGet the current room)
953 This command is used to forget (zap) the current room. For those not
954 familiar with Citadel, this terminology refers to removing the room from
955 a user's own known rooms list, *not* removing the room itself. After a
956 room is forgotten, it no longer shows up in the user's known room list,
957 but it will exist in the user's forgotten room list, and will return to the
958 known room list if the user goes to the room (in Citadel, this is
959 accomplished by explicitly typing the room's name in a <.G>oto command).
961 The command takes no arguments. If the command cannot execute for any
962 reason, ERROR will be returned. ERROR+NOT_LOGGED_IN or ERROR+NOT_HERE may
963 be returned as they apply.
965 If the command succeeds, OK will be returned. At this point, the current
966 room is **undefined**, and the client software is responsible for taking
967 the user to another room before executing any other room commands (usually
968 this will be _BASEROOM_ since it is always there).
971 MESG (read system MESsaGe)
973 This command is used to display system messages and/or help files. The
974 single argument it accepts is the name of the file to display. IT IS CASE
975 SENSITIVE. Citadel looks for these files first in the "messages"
976 subdirectory and then in the "help" subdirectory.
978 If the file is found, LISTING_FOLLOWS is returned, followed by a pathname
979 to the file being displayed. Then the message is printed, in format type 0
980 (see MSG0 command for more information on this). If the file is not found,
983 There are some "well known" names of system messages which client software
984 may expect most servers to carry:
986 hello - Welcome message, to be displayed before the user logs in.
987 changepw - To be displayed whenever the user is prompted for a new
988 password. Warns about picking guessable passwords and such.
989 register - Should be displayed prior to the user entering registration.
990 Warnings about not getting access if not registered, etc.
991 help - Main system help file.
992 goodbye - System logoff banner; display when user logs off.
993 roomaccess - Information about how public rooms and different types of
994 private rooms function with regards to access.
995 unlisted - Tells users not to choose to be unlisted unless they're
996 really paranoid, and warns that aides can still see
997 unlisted userlog entries.
999 Citadel provides these for the Citadel Unix text client. They are
1000 probably not very useful for other clients:
1002 mainmenu - Main menu (when in idiot mode).
1007 saveopt - Options to save a message, abort, etc.
1008 entermsg - Displayed just before a message is entered, when in
1012 GNUR (Get Next Unvalidated User)
1014 This command shows the name of a user that needs to be validated. If there
1015 are no unvalidated users, OK is returned. Otherwise, MORE_DATA is returned
1016 along with the name of the first unvalidated user the server finds. All of
1017 the usual ERROR codes may be returned as well (for example, if the user is
1018 not an Aide and cannot validate users).
1020 A typical "Validate New Users" command would keep executing this command,
1021 and then validating each user it returns, until it returns OK when all new
1022 users have been validated.
1025 GREG (Get REGistration for user)
1027 This command retrieves the registration info for a user, whose name is the
1028 command's sole argument. All the usual error messages can be returned. If
1029 the command succeeds, LISTING_FOLLOWS is returned, followed by the user's name
1030 (retrieved from the userlog, with the right upper and lower case etc.) The
1031 contents of the listing contains one field per line, followed by the usual
1032 000 on the last line.
1034 The following lines are defined. Others WILL be added in the futre, so all
1035 software should be written to read the lines it knows about and then ignore
1036 all remaining lines:
1041 Line 4: Street address or PO Box
1042 Line 5: City/town/village/etc.
1043 Line 6: State/province/etc.
1045 Line 8: Telephone number
1046 Line 9: Access level
1047 Line 10: Internet e-mail address
1050 Users without Aide privileges may retrieve their own registration using
1051 this command. This can be accomplished either by passing the user's own
1052 name as the argument, or the string "_SELF_". The command will always
1053 succeed when used in this manner, unless no user is logged in.
1056 VALI (VALIdate user)
1058 This command is used to validate users. Obviously, it can only be executed
1059 by users with Aide level access. It should be passed two parameters: the
1060 name of the user to validate, and the desired access level
1062 If the command succeeds, OK is returned. The user's access level is changed
1063 and the "need validation" bit is cleared. If the command fails for any
1064 reason, ERROR, ERROR+NO_SUCH_USER, or ERROR+HIGHER_ACCESS_REQUIRED will be
1068 EINF (Enter INFo file for room)
1070 Transmit the info file for the current room with this command. EINF uses
1071 a boolean flag (1 or 0 as the first and only argument to the command) to
1072 determine whether the client actually wishes to transmit a new info file, or
1073 is merely checking to see if it has permission to do so.
1075 If the command cannot succeed, it returns ERROR.
1076 If the client is only checking for permission, and permission will be
1077 granted, OK is returned.
1078 If the client wishes to transmit the new info file, SEND_LISTING is
1079 returned, and the client should transmit the text of the info file, ended
1080 by the usual 000 on a line by itself.
1085 This is a simple user listing. It always succeeds, returning
1086 LISTING_FOLLOWS followed by zero or more user records, 000 terminated. The
1087 fields on each line are as follows:
1092 4. Date/time of last login (Unix format)
1095 7. Password (listed only if the user requesting the list is an Aide)
1097 Unlisted entries will also be listed to Aides logged into the server, but
1098 not to ordinary users.
1100 The LIST command accepts an optional single argument, which is a simple,
1101 case-insensitive search string. If this argument is present, only usernames
1102 in which the search string is present will be returned. It is a simple
1103 substring search, not a regular expression search. If this string is empty
1104 or not present, all users will be returned.
1107 REGI (send REGIstration)
1109 Clients will use this command to transmit a user's registration info. If
1110 no user is logged in, ERROR+NOT_LOGGED_IN is returned. Otherwise,
1111 SEND_LISTING is returned, and the server will expect the following information
1112 (terminated by 000 on a line by itself):
1115 Line 2: Street address or PO Box
1116 Line 3: City/town/village/etc.
1117 Line 4: State/province/etc.
1119 Line 6: Telephone number
1120 Line 7: e-mail address
1124 CHEK (CHEcK various things)
1126 When logging in, there are various things that need to be checked. This
1127 command will return ERROR+NOT_LOGGED_IN if no user is logged in. Otherwise
1128 it returns OK and the following parameters:
1130 0: Number of new private messages in Mail>
1131 1: Nonzero if the user needs to register
1132 2: (Relevant to Aides only) Nonzero if new users require validation
1133 3: The user's preferred Internet e-mail address
1136 DELF (DELete a File)
1138 This command deletes a file from the room's directory, if there is one. The
1139 name of the file to delete is the only parameter to be supplied. Wildcards
1140 are not acceptable, and any slashes in the filename will be converted to
1141 underscores, to prevent unauthorized access to neighboring directories. The
1142 possible return codes are:
1144 OK - Command succeeded. The file was deleted.
1145 ERROR+NOT_LOGGED_IN - Not logged in.
1146 ERROR+HIGHER_ACCESS_REQUIRED - Not an Aide or Room Aide.
1147 ERROR+NOT_HERE - There is no directory in this room.
1148 ERROR+FILE_NOT_FOUND - Requested file was not found.
1153 This command is similar to DELF, except that it moves a file (and its
1154 associated file description) to another room. It should be passed two
1155 parameters: the name of the file to move, and the name of the room to move
1156 the file to. All of the same return codes as DELF may be returned, and also
1157 one additional one: ERROR+NO_SUCH_ROOM, which means that the target room
1158 does not exist. ERROR+NOT_HERE could also mean that the target room does
1159 not have a directory.
1162 NETF (NETwork send a File)
1164 This command is similar to MOVF, except that it attempts to send a file over
1165 the network to another system. It should be passed two parameters: the name
1166 of the file to send, and the node name of the system to send it to. All of
1167 the same return codes as MOVF may be returned, except for ERROR+NO_SUCH_ROOM.
1168 Instead, ERROR+NO_SUCH_SYSTEM may be returned if the name of the target
1171 The name of the originating room will be sent along with the file. Most
1172 implementations will look for a room with the same name at the receiving end
1173 and attempt to place the file there, otherwise it goes into a bit bucket room
1174 for miscellaneous files. This is, however, beyond the scope of this document;
1175 see elsewhere for more details.
1178 RWHO (Read WHO's online)
1180 Displays a list of all users connected to the server. No error codes are
1181 ever returned. LISTING_FOLLOWS will be returned, followed by zero or more
1182 lines containing the following three fields:
1184 0 - Session ID. Citadel fills this with the pid of a server program.
1186 2 - The name of the room the user is currently in. This field might not
1187 be displayed (for example, if the user is in a private room) or it might
1188 contain other information (such as the name of a file the user is
1190 3 - (server v4.03 and above) The name of the host the client is connecting
1191 from, or "localhost" if the client is local.
1192 4 - (server v4.04 and above) Description of the client software being used
1193 5 - The last time, locally to the server, that a command was received from
1194 this client (Note: NOOP's don't count)
1195 6 - The last command received from a client. (NOOP's don't count)
1196 7 - Session flags. These are: + (spoofed address), - (STEALTH mode), *
1197 (posting) and . (idle).
1198 8 - Actual user name, if user name is masqueraded and viewer is an Aide.
1199 9 - Actual room name, if room name is masqueraded and viewer is an Aide.
1200 10 - Actual host name, if host name is masqueraded and viewer is an Aide.
1201 11 - Nonzero if the session is a logged-in user, zero otherwise.
1203 The listing is terminated, as always, with the string "000" on a line by
1207 OPEN (OPEN a file for download)
1209 This command is used to open a file for downloading. Only one download
1210 file may be open at a time. The only argument to this command is the name
1211 of the file to be opened. The user should already be in the room where the
1212 file resides. Possible return codes are:
1215 ERROR+NOT_HERE (no directory in this room)
1216 ERROR+FILE_NOT_FOUND (could not open the file)
1220 If the file is successfully opened, OK will be returned, along with the
1221 size (in bytes) of the file, the time of last modification (if applicable),
1222 the filename (if known), and the MIME type of the file (if known).
1225 CLOS (CLOSe the download file)
1227 This command is used to close the download file. It returns OK if the
1228 file was successfully closed, or ERROR if there wasn't any file open in the
1232 READ (READ from the download file)
1234 Two arguments are passed to this command. The first is the starting position
1235 in the download file, and the second is the total number of bytes to be
1236 read. If the operation can be performed, BINARY_FOLLOWS will be returned,
1237 along with the number of bytes to follow. Then, immediately following the
1238 newline, will be that many bytes of binary data. The client *must* read
1239 exactly that number of bytes, otherwise the client and server will get out
1242 If the operation cannot be performed, any of the usual error codes will be
1246 UOPN (OPeN a file for Uploading)
1248 This command is similar to OPEN, except that this one is used when the
1249 client wishes to upload a file to the server. The first argument is the name
1250 of the file to create, and the second argument is a one-line comment
1251 describing the contents of the file. Only one upload file may be open at a
1252 time. Possible return codes are:
1255 ERROR+NOT_HERE (no directory in this room)
1256 ERROR+FILE_NOT_FOUND (a name must be specified)
1257 ERROR (miscellaneous errors)
1258 ERROR+ALREADY_EXISTS (a file with the same name already exists)
1261 If OK is returned, the command has succeeded and writes may be performed.
1264 UCLS (CLoSe the Upload file)
1266 Close the file opened with UOPN. An argument of "1" should be passed to
1267 this command to close and save the file; otherwise, the transfer will be
1268 considered aborted and the file will be deleted. This command returns OK
1269 if the operation succeeded or ERROR if it did not.
1272 WRIT (WRITe to the upload file)
1274 If an upload file is open, this command may be used to write to it. The
1275 argument passed to this command is the number of bytes the client wishes to
1276 transmit. An ERROR code will be returned if the operation cannot be
1279 If the operation can be performed, SEND_BINARY will be returned, followed
1280 by the number of bytes the server is expecting. The client must then transmit
1281 exactly that number of bytes. Note that in the current implementation, the
1282 number of bytes the server is expecting will always be the number of bytes
1283 the client requested to transmit, but the client software should never assume
1284 that this will always happen, in case changes are made later.
1287 QUSR (Query for a USeR)
1289 This command is used to check to see if a particular user exists. The only
1290 argument to this command is the name of the user being searched for. If
1291 the user exists, OK is returned, along with the name of the user in the userlog
1292 (so the client software can learn the correct upper/lower casing of the name
1293 if necessary). If the user does not exist, ERROR+NO_SUCH_USER is returned.
1294 No login or current room is required to utilize this command.
1297 OIMG (Open an IMaGe file)
1299 Open an image (graphics) file for downloading. Once opened, the file can be
1300 read as if it were a download file. This implies that an image and a download
1301 cannot be opened at the same time. OIMG returns the same result codes as OPEN.
1303 All images will be in GIF (Graphics Interchange Format). In the case of
1304 Citadel, the server will convert the supplied filename to all lower case,
1305 append the characters ".gif" to the filename, and look for it in the "images"
1306 subdirectory. As with the MESG command, there are several "well known"
1307 images which are likely to exist on most servers:
1309 hello - "Welcome" graphics to be displayed alongside MESG "hello"
1310 goodbye - Logoff banner graphics to be displayed alongside MESG "goodbye"
1311 background - Background image (usually tiled) for graphical clients
1313 The following "special" image names are defined in Citadel server version
1316 _userpic_ - Picture of a user (send the username as the second argument)
1317 _floorpic_ - A graphical floor label (send the floor number as the second
1318 argument). Clients which request a floor picture will display
1319 the picture *instead* of the floor name.
1320 _roompic_ - A graphic associated with the *current* room. Clients which
1321 request a room picture will display the picture in *addition*
1322 to the room name (i.e. it's used for a room banner, as
1323 opposed to the floor picture's use in a floor listing).
1326 NETP (authenticate as network session with connection NET Password)
1328 This command is used by client software to identify itself as a transport
1329 session for Citadel site-to-site networking. It should be called with
1330 two arguments: the node name of the calling system, and the "shared secret"
1331 password for that connection. If the authentication succeeds, NETP will
1332 return OK, otherwise, it returns ERROR.
1335 NSYN (Network SYNchronize room)
1337 This command can be used to synchronize the contents of a room on the
1338 network. It is only usable by Aides. It accepts one argument: the name of
1339 a network node (which must be a valid one).
1341 When NSYN is run, the *entire* contents of the current room will be spooled
1342 to the specified node, without regard to whether any of the messages have
1343 already undergone network processing. It is up to the receiving node to
1344 check for duplicates (the Citadel networker does handle this) and avoid
1347 The command returns OK upon success or ERROR if the user is not an Aide.
1350 NUOP (Network Upload OPen file)
1352 Open a network spool file for uploading. The client must have already
1353 identified itself as a network session using the NETP command. If the command
1354 returns OK, the client may begin transmitting IGnet/Open spool data using
1355 a series of WRIT commands. When a UCLS command is issued, the spooled data
1356 is entered into the server if the argument to UCLS is 1 or discarded if the
1357 argument to UCLS is 0. If the client has not authenticated itself with a
1358 NETP command, ERROR+HIGHER_ACCESS_REQUIRED will be returned.
1361 NDOP (Network Download OPen file)
1363 Open a network spool file for downloading. The client must have already
1364 identified itself as a network session using the NETP command. If the command
1365 returns OK, the client may begin receiving IGnet/Open spool data using
1366 a series of READ commands. When a CLOS command is issued, the spooled data
1367 is deleted from the server and may not be read again. If the client has not
1368 authenticated itself with a NETP command, ERROR+HIGHER_ACCESS_REQUIRED will
1372 LFLR (List all known FLooRs)
1374 On systems supporting floors, this command lists all known floors. The
1375 command accepts no parameters. It will return ERROR+NOT_LOGGED_IN if no
1376 user is logged in. Otherwise it returns LISTING_FOLLOWS and a list of
1377 the available floors, each line consisting of three fields:
1379 1. The floor number associated with the floor
1380 2. The name of the floor
1381 3. Reference count (number of rooms on this floor)
1384 CFLR (Create a new FLooR)
1386 This command is used to create a new floor. It should be passed two
1387 arguments: the name of the new floor to be created, and a 1 or 0 depending
1388 on whether the client is actually creating a floor or merely checking to
1389 see if it has permission to create the floor. The user must be logged in
1390 and have Aide privileges to create a floor.
1392 If the command succeeds, it will return OK followed by the floor number
1393 associated with the new floor. Otherwise, it will return ERROR (plus perhaps
1394 HIGHER_ACCESS_REQUIRED, ALREADY_EXISTS, or INVALID_FLOOR_OPERATION)
1395 followed by a description of why the command failed.
1400 This command is used to delete a floor. It should be passed two
1401 argument: the *number* of the floor to be deleted, and a 1 or 0 depending
1402 on whether the client is actually deleting the floor or merely checking to
1403 see if it has permission to delete the floor. The user must be logged in
1404 and have Aide privileges to delete a floor.
1406 Floors that contain rooms may not be deleted. If there are rooms on a floor,
1407 they must be either deleted or moved to different floors first. This implies
1408 that the Main Floor (floor 0) can never be deleted, since Lobby>, Mail>, and
1409 Aide> all reside on the Main Floor and cannot be deleted.
1411 If the command succeeds, it will return OK. Otherwise it will return
1412 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1413 followed by a description of why the command failed.
1418 Edit the parameters of a floor. The client may pass one or more parameters
1421 1. The number of the floor to be edited
1422 2. The desired new name
1424 More parameters may be added in the future. Any parameters not passed to
1425 the server will remain unchanged. A minimal command would be EFLR and a
1426 floor number -- which would do nothing. EFLR plus the floor number plus a
1427 floor name would change the floor's name.
1429 If the command succeeds, it will return OK. Otherwise it will return
1430 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1433 IDEN (IDENtify the client software)
1435 The client software has the option to identify itself to the server.
1436 Currently, the server does nothing with this information except to write
1437 it to the syslog to satisfy the system administrator's curiosity. Other
1438 uses might become apparent in the future.
1440 The IDEN command should contain five fields: a developer ID number (same as
1441 the server developer ID numbers in the INFO command -- please obtain one if
1442 you are a new developer), a client ID number (which does not have to be
1443 globally unique - only unique within the domain of the developer number),
1444 a version number, a free-form text string describing the client, and the name
1445 of the host the user is located at.
1447 It is up to the server to determine whether to accept the host name or to
1448 use the host name it has detected itself. Generally, if the client is
1449 running on a trusted host (either localhost or a well-known publically
1450 accessible client) it should use the host name transmitted by IDEN,
1451 otherwise it should use the host name it has detected itself.
1453 IDEN always returns OK, but since that's the only way it ever returns
1454 there's no point in checking the result code.
1457 IPGM (identify as an Internal ProGraM)
1459 IPGM is a low-level command that should not be used by normal user clients.
1460 It is used for various utilities to communicate with the server on the same
1461 host. For example, the "sendcommand" utility logs onto the server as an
1462 internal program in order to run arbitrary server commands. Since user clients
1463 do not utilize this command (or any of its companion commands), developers
1464 writing Citadel-compatible servers need not implement it.
1466 The sole argument to IPGM is the system's internal program password. This
1467 password is generated by the setup program and stored in the config file.
1468 Since internal programs have access to the config file, they know the correct
1471 IPGM returns OK for a correct authentication or ERROR otherwise.
1474 CHAT (enter CHAT mode)
1476 This command functions differently from every other command in the system. It
1477 is used to implement multi-user chat. For this to function, a new transfer
1478 mode, called START_CHAT_MODE, is implemented. If a client does not support
1479 chat mode, it should never send a CHAT command!
1481 In chat mode, messages may arrive asynchronously from the server at any
1482 time. The client may send messages at any time. This allows the arrival of
1483 messages without the client having to poll for them. Arriving messages will
1484 be of the form "user|message", where the "user" portion is, of course, the
1485 name of the user sending the message, and "message" is the message text.
1487 Chat mode ends when the server says it ends. The server will signal the end
1488 of chat mode by transmitting "000" on a line by itself. When the client reads
1489 this line, it must immediately exit from chat mode without sending any
1490 further traffic to the server. The next transmission sent to the server
1491 will be a regular server command.
1493 The Citadel server understands the following commands:
1494 /quit - Exit from chat mode (causes the server to do an 000 end)
1495 /who - List users currently in chat
1496 /whobbs - List users currently in chat and elsewhere
1497 /me - Do an irc-style action.
1498 /join - Join a new "room" in which all messages are only heard by
1499 people in that room.
1500 /msg - /msg <user> <msg> will send the msg to <user> only.
1501 /help - Print help information
1502 NOOP - Do nothing (silently)
1504 Any other non-empty string is treated as message text and will be broadcast
1505 to other users currently in chat.
1508 SEXP (Send instant message)
1510 This is one of two commands which implement instant messages (also known
1511 as "paging"). Commands ending in "...EXP" are so-named because we called
1512 them "express messages" before the industry standardized on the term
1513 "instant messages." When an instant message is sent, it will be
1514 logged in user to another. When an instant message is sent, it will be
1515 displayed the next time the target user executes a PEXP or GEXP command.
1517 The SEXP command accepts two arguments: the name of the user to send the
1518 message to, and the text of the message. If the message is successfully
1519 transmitted, OK is returned. If the target user is not logged in or if
1520 anything else goes wrong, ERROR is returned.
1522 If the server supports extended paging, sending a zero-length message
1523 merely checks for the presence of the requested user without actually sending
1524 a message. Sending a message consisting solely of a "-" (hyphen) will cause
1525 the server to return SEND_LISTING if the requested user is logged in, and the
1526 client can then transmit a multi-line page.
1528 The reserved name "broadcast" may be used instead of a user name, to
1529 broadcast an instant message to all users currently connected to the server.
1531 Do be aware that if an instant message is transmitted to a user who is logged
1532 in using a client that does not check for instant messages, the message will
1533 never be received. Also, instant messages are NOT sent via the following
1534 transports: SMTP, POP3.
1537 PEXP (Print instant messages) ***DEPRECATED***
1539 This command is deprecated; it will eventually disappear from the protocol and
1540 its use is not recommended. Please use the GEXP command instead.
1542 Called without any arguments, PEXP simply dumps out the contents
1543 of any waiting instant messages. It returns ERROR if there is a problem,
1544 otherwise it returns LISTING_FOLLOWS followed by all messages.
1546 So how does the client know there are instant messages waiting? It could
1547 execute a random PEXP every now and then. Or, it can check the byte in
1548 server return code messages, between the return code and the parameters. In
1549 much the same way as FTP uses "-" to signify a continuation, Citadel uses
1550 an "*" in this position to signify the presence of waiting instant messages.
1553 EBIO (Enter BIOgraphy)
1555 Transmit to the server a free-form text file containing a little bit of
1556 information about the user for other users to browse. This is typically
1557 referred to as a 'bio' online. EBIO returns SEND_LISTING if it succeeds,
1558 after which the client is expected to transmit the file, or any of the usual
1559 ERROR codes if it fails.
1562 RBIO (Read BIOgraphy)
1564 Receive from the server a named user's bio. This command should be passed
1565 a single argument - the name of the user whose bio is requested. RBIO returns
1566 LISTING_FOLLOWS plus the bio file if the user exists and has a bio on file.
1567 The return has the following parameters: the user name, user number, access
1568 level, date of last call, times called, and messages posted. This command
1569 returns ERROR+NO_SUCH_USER if the named user does not exist.
1571 RBIO no longer considers a user with no bio on file to be an error condition.
1572 It now returns a message saying the user has no bio on file as the text of the
1573 bio. This allows newer servers to operate with older clients.
1576 STEL (enter STEaLth mode)
1578 When in "stealth mode," a user will not show up in the "Who is online"
1579 listing (the RWHO server command). Only Aides may use stealth mode. The
1580 STEL command accepts one argument: a 1 indicating that the user wishes to
1581 enter stealth mode, or a 0 indicating that the user wishes to exit stealth
1582 mode. STEL returns OK if the command succeeded, ERROR+NOT_LOGGED_IN if no
1583 user is logged in, or ERROR+HIGHER_ACCESS_REQUIRED if the user is not an Aide;
1584 followed by a 1 or 0 indicating the new state.
1586 If any value other than 1 or 0 is sent by the client, the server simply
1587 replies with 1 or 0 to indicate the current state without changing it.
1589 The STEL command also makes it so a user does not show up in the chat room
1593 LBIO (List users who have BIOs on file)
1595 This command is self-explanatory. Any user who has used EBIO to place a bio
1596 on file is listed. LBIO almost always returns LISTING_FOLLOWS followed by
1597 this listing, unless it experiences an internal error in which case ERROR
1601 MSG2 (read MeSsaGe, mode 2)
1603 MSG2 follows the same calling convention as MSG0. The difference between
1604 the two commands is that MSG2 outputs messages in standard RFC822 format
1605 rather than in Citadel proprietary format.
1607 This command was implemented in order to make various gateway programs
1608 easier to implement, and to provide some sort of multimedia support in the
1609 future. Keep in mind that when this command is used, all messages will be
1610 output in fixed 80-column format.
1613 MSG3 (read MeSsaGe, mode 3 -- internal command)
1615 MSG3 is for use by internal programs only and should not be utilized by
1616 user-mode clients. It does require IPGM authentication. MSG3 follows the
1617 same calling convention as the other MSG commands, but upon success returns
1618 BINARY_FOLLOWS followed by a data block containing the _raw_ message format
1622 TERM (TERMinate another session)
1624 In a multithreaded environment, it sometimes becomes necessary to terminate
1625 a session that is unusable for whatever reason. The TERM command performs
1626 this task. Naturally, only Aides can execute TERM. The command should be
1627 called with a single argument: the session ID (obtained from an RWHO command)
1628 of the session to be terminated.
1630 TERM returns OK if the session was terminated, or ERROR otherwise. Note that
1631 a client program is prohibited from terminating the session it is currently
1637 DOWN (shut DOWN the server)
1639 This command, which may only be executed by an Aide, immediately shuts down
1640 the server. It is only implemented on servers on which such an operation is
1641 possible, such as a multithreaded Citadel engine. The server does not restart.
1642 DOWN returns OK if the user is allowed to shut down the server, in which case
1643 the client program should expect the connection to be immediately broken.
1646 SCDN (Schedule or Cancel a shutDowN)
1648 SCDN sets or clears the "scheduled shutdown" flag. Pass this command a 1 or
1649 0 to respectively set or clear the flag. When the "scheduled shutdown" flag is
1650 set, the server will be shut down when there are no longer any users logged in.
1651 Any value other than 0 or 1 will not change the flag, only report its state.
1652 No users will be kicked off the system, and in fact the server is still
1653 available for new connections. The command returns ERROR if it fails;
1654 otherwise, it returns OK followed by a number representing the current state
1658 EMSG (Enter a system MeSsaGe)
1660 This is the opposite of the MESG command - it allows the creation and editing
1661 of system messages. The only argument passed to EMSG is the name of the
1662 file being transmitted. If the file exists in any system message directory
1663 on the server it will be overwritten, otherwise a new file is created. EMSG
1664 returns SEND_LISTING on success or ERROR+HIGHER_ACCESS_REQUIRED if the user
1667 Typical client software would use MESG to retrieve any existing message into
1668 an edit buffer, then present an editor to the user and run EMSG if the changes
1672 UIMG (Upload an IMaGe file)
1674 UIMG is complemenary to OIMG; it is used to upload an image to the server.
1675 The first parameter supplied to UIMG should be 0 if the client is only checking
1676 for permission to upload, or 1 if the client is actually attempting to begin
1677 the upload operation. The second argument is the name of the file to be
1678 transmitted. In Citadel, the filename is converted to all lower case,
1679 appended with the characters ".gif", and stored in the "images" directory.
1681 UIMG returns OK if the client has permission to perform the requested upload,
1682 or ERROR+HIGHER_ACCESS_REQUIRED otherwise. If the client requested to begin
1683 the operation (first parameter set to 1), an upload file is opened, and the
1684 client should begin writing to it with WRIT commands, then close it with a
1687 The supplied filename should be one of:
1689 -> _userpic_ (Server will attempt to write to the user's online photo)
1690 -> Any of the "well known" filenames described in the writeup for the
1694 HCHG (Hostname CHanGe)
1696 HCHG is a command, usable by any user, that allows a user to change their RWHO
1697 host value. This will mask a client's originating hostname from normal
1698 users; access level 6 and higher can see, in an extended wholist, the actual
1699 hostname the user originates from.
1701 The format of an HCHG command is:
1705 If a HCHG command is successful, the value OK (200) is returned.
1708 RCHG (Roomname CHanGe)
1710 RCHG is a command, usable by any user, that allows a user to change their RWHO
1711 room value. This will mask a client's roomname from normal users; access
1712 level 6 and higher can see, in an extended wholist, the actual room the user
1715 The format of an RCHG command is:
1719 If a RCHG command is successful, the value OK (200) is returned.
1722 UCHG (Username CHanGe)
1724 UCHG is an aide-level command which allows an aide to effectively change their
1725 username. If this value is blank, the user goes into stealth mode (see
1727 will show up as being from the real username in this mode, however. In
1728 addition, the RWHO listing will include both the spoofed and real usernames.
1730 The format of an UCHG command is:
1734 If a UCHG command is successful, the value OK (200) is returned.
1737 TIME (get server local TIME)
1739 TIME returns OK followed by the current time measured in seconds since
1740 00:00:00 GMT, Jan 1, 1970 (standard Unix format).
1742 This is used in allowing a client to calculate idle times.
1745 AGUP (Administrative Get User Parameters)
1746 ASUP (Administrative Set User Parameters)
1748 These commands are only executable by Aides and by server extensions running
1749 at system-level. They are used to get/set any and all parameters relating to
1750 a user account. AGUP requires only one argument: the name of the user in
1751 question. SGUP requires all of the parameters to be set. The parameters are
1752 as follows, and are common to both commands:
1756 2 - Flags (see citadel.h)
1761 7 - Timestamp of last call
1762 8 - Purge time (in days) for this user (or 0 to use system default)
1764 Upon success, AGUP returns OK followed by all these parameters, and ASUP
1765 simply returns OK. If the client has insufficient access to perform the
1766 requested operation, ERROR+HIGHER_ACCESS_REQUIRED is returned. If the
1767 requested user does not exist, ERROR+NO_SUCH_USER is returned.
1771 GPEX (Get Policy for message EXpiration)
1773 Returns the policy of the current room, floor, or site regarding the automatic
1774 purging (expiration) of messages. The following policies are available:
1775 0 - Fall back to the policy of the next higher level. If this is a room,
1776 use the floor's default policy. If this is a floor, use the system
1777 default policy. This is an invalid value for the system policy.
1778 1 - Do not purge messages automatically.
1779 2 - Purge by message count. (Requires a value: number of messages)
1780 3 - Purge by message age. (Requires a value: number of days)
1782 The format of this command is: GPEX <which>
1783 The value of <which> must be one of: "room" "floor" "site" "mailboxes"
1785 If successful, GPEX returns OK followed by <policy>|<value>.
1789 SPEX (Set Policy for message EXpiration)
1791 Sets the policy of the current room, floor, or site regarding the automatic
1792 purging (expiration) of messages. See the writeup for the GPEX command for
1793 the list of available policies.
1795 The format of this command is: SPEX <which>|<policy>|<value>
1796 The value of <which> must be one of: "room" "floor" "site" "mailboxes"
1798 If successful, GPEX returns OK; otherwise, an ERROR code is returned.
1802 CONF (get or set global CONFiguration options)
1804 Retrieves or sets various system-wide configuration and policy options. This
1805 command is only available to Aides. The sole parameter accepted is a command,
1806 which should be either GET or SET. If the GET command succeeds, CONF will
1807 return LISTING_FOLLOWS followed by the fields described below, one line at a
1808 time. If the SET command succeeds, CONF will return SEND_LISTING and expect
1809 the fields described below, one line at a time (don't worry about other fields
1810 being added in the future; if a 'short' configuration list is sent, the missing
1811 values at the end will be left unchanged on the system). If either command
1812 fails for any reason, ERROR is returned.
1814 The configuration lines are as follows:
1817 1. Fully qualified domain name
1818 2. Human-readable node name
1819 3. Landline telephone number of this system
1820 4. Flag (0 or 1) - creator of private room automatically becomes room aide
1821 5. Server connection idle timeout (in seconds)
1822 6. Initial access level for new users
1823 7. Flag (0 or 1) - require registration for new users
1824 8. Flag (0 or 1) - automatically move Problem User messages to twit room
1825 9. Name of twit room
1826 10. Text of <more> prompt
1827 11. Flag (0 or 1) - restrict access to Internet mail
1828 12. Geographic location of this system
1829 13. Name of the system administrator
1830 14. Number of maximum concurrent sessions allowed on the server
1831 15. (placeholder -- this field is no longer in use)
1832 16. Default purge time (in days) for users
1833 17. Default purge time (in days) for rooms
1834 18. Name of room to log instant messages to (or a zero-length name for none)
1835 19. Access level required to create rooms
1836 20. Maximum message length which may be entered into the system
1837 21. Minimum number of worker threads
1838 22. Maximum number of worker threads
1839 23. Port number for POP3 service
1840 24. Port number for SMTP service
1841 25. Flag (0 or 1) - strict RFC822 adherence - don't correct From: forgeries
1842 26. Flag (0 or 1) - allow Aides to zap (forget) rooms
1843 27. Port number for IMAP service
1844 28. How often (in seconds) to run the networker
1845 29. Flag (0 or 1) - disable self-service new user registration
1846 30. (placeholder -- this field is no longer in use)
1847 31. Hour (0 through 23) during which database auto-purge jobs are run
1848 32. Name of host where an LDAP service may be found
1849 33. Port number of LDAP service on above host
1852 36. Password for LDAP Bind DN
1853 37. Server IP address to listen on (or "0.0.0.0" for all addresses)
1854 38. Port number for SMTP MSA service
1855 39. Port number for IMAPS (SSL-encrypted IMAP)
1856 40. Port number for POP3S (SSL-encrypted POP3)
1857 41. Port number for SMTPS (SSL-encrypted SMTP)
1858 42. Flag (0 or 1) - enable full text search index
1859 43. Flag (0 or 1) - automatically cull database log files
1860 44. Flag (0 or 1) - enable IMAP "instant expunge" of deleted messages
1861 45. Flag (0 or 1) - allow unauthenticated SMTP clients to spoof my domains
1862 46. Flag (0 or 1) - perform journaling of email messages
1863 47. Flag (0 or 1) - perform journaling of non-email messages
1864 48. Address to which journalized messages are to be sent
1866 CONF also accepts two additional commands: GETSYS and PUTSYS followed by an
1867 arbitrary MIME type (such as application/x-citadel-internet-config) which
1868 provides a means of storing generic configuration data in the Global System
1869 Configuration room without the need to add extra get/set commands to the
1872 Please note that the LDAP-specific configs have no effect on Citadel servers
1873 in which LDAP support is not enabled.
1877 MSG4 (read MeSsaGe, mode 4 -- output in preferred MIME format)
1879 This is the equivalent of MSG0, except it's a bit smarter about messages in
1880 rich text formats. Immediately following the "text" directive, the server
1881 will output RFC822-like MIME part headers such as "Content-type:" and
1882 "Content-length:". MIME formats are chosen and/or converted based on the
1883 client's preferred format settings, which are set using the MSGP command,
1886 The MSG4 command also accepts an optional second argument, which may be the
1887 MIME part specifier of an encapsulated message/rfc822 message. This is useful
1888 for fetching the encapsulated message instead of the top-level message, for
1889 example, when someone has forwarded a message as an attachment. Note that the
1890 only way for the client to know the part specifier is to fetch the top-level
1891 message and then look for attachments of type message/rfc822, and then call
1892 MSG4 again with that part specifier.
1897 MSGP (set MeSsaGe Preferred MIME format)
1899 Client tells the server what MIME content types it knows how to handle, and
1900 the order in which it prefers them. This is similar to an HTTP "Accept:"
1903 The parameters to a MSGP command are the client's acceptable MIME content
1904 types, in the order it prefers them (from most preferred to least preferred).
1905 For example: MSGP text/html|text/plain
1907 The MSGP command always returns OK.
1911 OPNA (OPeN Attachment)
1913 Opens, as a download file, a component of a MIME-encoded message. The two
1914 parameters which must be passed to this command are the message number and the
1915 name of the desired section. If the message or section does not exist, an
1916 appropriate ERROR code will be returned; otherwise, if the open is successful,
1917 this command will succeed returning the same information as an OPEN command.
1920 GEXP (Get instant messages)
1922 This is a more sophisticated way of retrieving instant messages than the old
1923 PEXP method. If there are no instant messages waiting, PEXP returns ERROR;
1924 otherwise, it returns LISTING_FOLLOWS and the following arguments:
1926 0 - a boolean value telling the client whether there are any additional
1927 instant messages waiting following this one
1928 1 - a Unix-style timestamp
1929 2 - flags (see server.h for more info)
1930 3 - the name of the sender
1931 4 - the node this message originated on (for future support of PIP, ICQ, etc.)
1933 The text sent to the client will be the body of the instant message.
1935 So how does the client know there are instant messages waiting? It could
1936 execute a random GEXP every now and then. Or, it can check the byte in
1937 server return code messages, between the return code and the parameters. In
1938 much the same way as FTP uses "-" to signify a continuation, Citadel uses
1939 an "*" in this position to signify the presence of waiting instant messages.
1942 FSCK (check message base reference counts)
1944 Verify, via the long way, that all message referenmce counts are correct. If
1945 the user has permission to do this then LISTING_FOLLOWS is returned, followed
1946 by a transcript of the run. Otherwise ERROR is returned.
1949 DEXP (Disable receiving instant messages)
1951 DEXP sets or clears the "disable instant messages" flag. Pass this command a
1952 1 or 0 to respectively set or clear the flag. When the "disable instant
1953 messages" flag is set, no one except Aides may send the user instant messages.
1954 Any value other than 0 or 1 will not change the flag, only report its state.
1955 The command returns ERROR if it fails; otherwise, it returns OK followed by a
1956 number representing the current state of the flag.
1959 REQT (REQuest client Termination)
1961 Request that the specified client (or all clients) log off. Aide level
1962 access is required to run this command, otherwise ERROR+HIGHER_ACCESS_REQUIRED
1965 The REQT command accepts one parameter: the session ID of the client which
1966 should be terminated, or 0 for all clients. When successful, the REQT command
1969 It should be noted that REQT simply transmits an instant message to the
1970 specified client(s) with the EM_GO_AWAY flag set. Older clients do not honor
1971 this flag, and it is certainly possible for users to re-program their client
1972 software to ignore it. Therefore the effects of the REQT command should be
1973 considered advisory only. The recommended implementation practice is to first
1974 issue a REQT command, then wait a little while (from 30 seconds up to a few
1975 minutes) for well-behaved clients to voluntarily terminate, and then issue a
1976 TERM command to forcibly disconnect the client (or perhaps a DOWN command, if
1977 you are logging off users for the purpose of shutting down the server).
1980 SEEN (set or clear the SEEN flag for a message)
1982 Beginning with version 5.80, Citadel supports the concept of setting or
1983 clearing the "seen" flag for each individual message, instead of only allowing
1984 a "last seen" pointer. In fact, the old semantics are implemented in terms
1985 of the new semantics. This command requires two arguments: the number of the
1986 message to be set, and a 1 or 0 to set or clear the "seen" bit.
1988 This command returns OK, unless the user is not logged in or a usage error
1989 occurred, in which case it returns ERROR. Please note that no checking is
1990 done on the supplied data; if the requested message does not exist, the SEEN
1991 command simply returns OK without doing anything.
1994 GTSN (GeT the list of SeeN messages)
1996 This command retrieves the list of "seen" (as opposed to unread) messages for
1997 the current room. It returns OK followed by an IMAP-format message list.
2000 SMTP (utility commands for the SMTP gateway)
2002 This command, accessible only by Aides, supports several utility operations
2003 which examine or manipulate Citadel's SMTP support. The first command argument
2004 is a subcommand telling the server what to do. The following subcommands are
2007 SMTP mx|hostname (display all MX hosts for 'hostname')
2008 SMTP runqueue (attempt immediate delivery of all messages
2009 in the outbound SMTP queue, ignoring any
2010 retry times stored there)
2013 STLS (Start Transport Layer Security)
2015 This command starts TLS on the current connection. The current
2016 implementation uses OpenSSL on both the client and server end. For future
2017 compatibility all clients must support at least TLSv1, and servers are
2018 guaranteed to support TLSv1. During TLS negotiation (see below) the server
2019 and client may agree to use a different protocol.
2021 The server returns ERROR if it does not support SSL or SSL initialization
2022 failed on the server; otherwise it returns OK. Once the server returns OK and
2023 the client has read the response, the server and client immediately negotiate
2024 TLS (in OpenSSL, using SSL_connect() on the client and SSL_accept() on the
2025 server). If negotiation fails, the server and client should attempt to resume
2026 the session unencrypted. If either end is unable to resume the session, the
2027 connection should be closed.
2029 This command may be run at any time.
2032 GTLS (Get Transport Layer Security Status)
2034 This command returns information about the current connection. The server
2035 returns OK plus several parameters if the connection is encrypted, and ERROR
2036 if the connection is not encrypted. It is primarily used for debugging. The
2037 command may be run at any time.
2039 0 - Protocol name, e.g. "SSLv3"
2040 1 - Cipher suite name, e.g. "ADH-RC4-MD5"
2041 2 - Cipher strength bits, e.g. 128
2042 3 - Cipher strength bits actually in use, e.g. 128
2045 IGAB (Initialize Global Address Book)
2047 This command creates, or re-creates, a database of Internet e-mail addresses
2048 using the vCard information in the Global Address Book room. This procedure
2049 is normally run internally when the server determines it necessary, but is
2050 also provided as a server command to be used as a troubleshooting/maintenenance
2051 tool. Only a system Aide can run the command. It returns OK on success or
2055 QDIR (Query global DIRectory)
2057 Look up an internet address in the global directory. Any logged-in user may
2058 call QDIR with one parameter, the Internet e-mail address to look up. QDIR
2059 returns OK followed by a Citadel address if there is a match, otherwise it
2060 returns ERROR+NOT_LOGGED_IN.
2063 ISME (find out if an e-mail address IS ME)
2065 This is a quickie shortcut command to find out if a given e-mail address
2066 belongs to the user currently logged in. Its sole argument is an address to
2067 parse. The supplied address may be in any format (local, IGnet, or Internet).
2068 The command returns OK if the address belongs to the user, ERROR otherwise.
2071 VIEW (set the VIEW for a room)
2073 Set the preferred view for the current user in the current room. Please see
2074 views.txt for more information on views. The sole parameter for this command
2075 is the type of view requested. VIEW returns OK on success or ERROR on failure.
2078 QNOP (Quiet No OPeration)
2080 This command does nothing, similar to the NOOP command. However, unlike the
2081 NOOP command, it returns *absolutely no response* at all. The client has no
2082 way of knowing that the command executed. It is intended for sending
2083 "keepalives" in situations where a full NOOP would cause the client protocol
2086 Naturally, sending this command to a server that doesn't support it is an
2087 easy way to mess things up. Therefore, client software should first check
2088 the output of an INFO command to ensure that the server supports quiet noops.
2092 ICAL (Internet CALendaring commands)
2094 This command supports a number of subcommands which are used to process the
2095 calendaring/scheduling support in Citadel. Here are the subcommands which
2099 Test server for calendaring support. Always returns OK unless the server
2100 does not have the calendar module enabled.
2102 ICAL respond|msgnum|partnum|action
2103 Respond to a meeting request. 'msgnum' and 'partnum' refer to a MIME-encoded
2104 meeting invitation in the current room. 'action' must be set to either
2105 "accept" or "decline" to determine the action to take. This subcommand will
2106 return either OK or ERROR.
2108 ICAL conflicts|msgnum|partnum
2109 Determine whether an incoming VEVENT will fit in the user's calendar by
2110 checking it against the existing VEVENTs. 'msgnum' and 'partnum' refer to
2111 a MIME-encoded meeting invitation in the current room (usually the inbox).
2112 This command may return ERROR if something went wrong, but usually it will
2113 return LISTING_FOLLOWS followed by a list of zero or more conflicting
2114 events. A zero-length list means that there were no conflicts.
2116 ICAL handle_rsvp|msgnum|partnum
2117 Handle an incoming "reply" (or RSVP) to a meeting request you sent out.
2118 'msgnum' and 'partnum' refer to a MIME-encoded reply in the current room.
2119 'action' must be set to either "update" or "ignore" to determine the action
2120 to take. If the action is "update" then the server will hunt for the meeting
2121 in the user's Calendar> room, and update the status for this attendee. Either
2122 way, the reply message is deleted from the current room. This subcommand will
2123 return either OK or ERROR.
2125 ICAL freebusy|username
2126 Output the free/busy times for the requested user. If the user specified
2127 has a calendar available, this command will return LISTING_FOLLOWS and a
2128 compound VCALENDAR object. That object, in turn, will contain VEVENT
2129 objects that have been stripped of all properties except for the bare
2130 minimum needed to learn free/busy times (such as DTSTART, DTEND, and
2131 TRANSP). If there is no such user, or no calendar available, the usual
2132 ERROR codes will be returned.
2136 Readers who are paying attention will notice that there is no subcommand to
2137 send out meeting invitations. This is because that task can be handled
2138 automatically by the Citadel server. Issue this command with <bool> set to 1
2139 to enable Server Generated Invitations. In this mode, when an event is saved
2140 to the user's Calendar> room and it contains attendees, Citadel will
2141 automatically turn the event into vCalendar REQUEST messages and mail them
2142 out to all listed attendees. If for some reason the client needs to disable
2143 Server Generated Invitations, the command may be sent again with <bool> = 0.
2147 MRTG (Multi Router Traffic Grapher)
2149 Multi Router Traffic Grapher (please see http://www.mrtg.org for more info) is
2150 a tool which creates pretty graphs of network activity, usually collected from
2151 routers using SNMP. However, its ability to call external scripts has spawned
2152 a small community of people using it to graph anything which can be graphed.
2153 The MRTG command can output Citadel server activity in the format MRTG expects.
2155 This format is as follows:
2160 Line 3: uptime of system
2161 Line 4: name of system
2164 MRTG accepts two different keywords. "MRTG users" will return two variables,
2165 the number of connected users and the number of active users. "MRTG messages"
2166 will return one variable (and a zero in the second field), showing the current
2167 highest message number on the system. Any other keyword, or a missing keyword,
2168 will cause the MRTG command to return an ERROR code.
2170 Please get in touch with the Citadel developers if you wish to experiment with
2175 GNET (Get NETwork configuration for this room)
2176 SNET (Set NETwork configuration for this room)
2178 These commands get/set the network configuration for the current room. Aide
2179 or Room Aide privileges are required, otherwise an ERROR code is returned.
2180 If the command succeeds, LISTING_FOLLOWS or SEND_LISTING is returned. The
2181 network configuration for a specific room includes neighbor nodes with whom
2182 the room is shared, and mailing list recipients. The format of the network
2183 configuration is described in the file "netconfigs.txt".
2187 ASYN (ASYNchronous message support)
2189 Negotiate the use of asynchronous, or unsolicited, protocol messages. The
2190 only parameter specified should be 1 or 0 to indicate that the client can or
2191 cannot handle this type of messages. The server will reply OK followed by a
2192 1 or 0 to tell the client which mode it is now operating in.
2194 If the command is not available on the server (i.e. it returns ERROR), or
2195 if the command has not been executed by the client, it should be assumed that
2196 this mode of operation is NOT in effect.
2198 The client may also send any value other than 0 or 1 to simply cause the
2199 server to output its current state without changing it.
2201 When asynchronous protocol mode is in effect, the client MUST handle any
2202 asynchronous messages as they arrive, before doing anything else.
2206 AUTO (AUTOcompletion of email addresses)
2208 The AUTO command is used by clients which want to request a list of email
2209 recipients whose names or email addresses match a partial string supplied by
2210 the client. This string is the only parameter passed to this command. The
2211 command will return ERROR if no user is logged in or if no address book could
2212 be found; otherwise, it returns LISTING_FOLLOWS followed by zero or more
2213 candidate recipients.
2217 SRCH (SeaRCH the message base)
2219 This command's implementation is incomplete and will be documented when it
2220 is finished. The current implementation accepts a search string as its sole
2221 argument, and will respond with LISTING_FOLLOWS followed by a list of
2222 messages (globally, not just in the current room) which contain ALL of the
2223 words in the search string. If the client desires an "exact phrase" match,
2224 it must then slow-search the text of each returned message for the exact
2225 string. The client should also compare the returned message numbers against
2226 those which actually exist in the room or rooms being searched. In
2227 particular, clients should avoid telling the user about messages which exist
2228 only in rooms to which the user does not have access.
2230 Again, keep in mind that this is a temporary implementation and is not
2231 guaranteed to continue to exist in this form.
2234 EUID (get message number using an EUID)}
2236 Returns the message number, if present, of the message in the current room
2237 which is indexed using the supplied EUID (exclusive message ID). There can be
2238 only one message in a room with any given EUID; if another message arrives
2239 with the same EUID, the existing one is replaced. This makes it possible to
2240 reference things like calendar items using an immutable URL that does not
2241 change even when the message number changes due to an update.
2243 The format of this command is: EUID <euid>
2245 If successful, EUID returns OK followed by a message number.
2246 If no message exists in the current room with the supplied EUID, the command
2247 returns ERROR+MESSAGE_NOT_FOUND.
2253 ASYNCHRONOUS MESSAGES
2254 ---------------------
2256 When the client protocol is operating in asynchronous mode (please refer to
2257 the writeup of the ASYN command above), the following messages may arrive at
2261 902 (instant message arriving)
2263 One or more instant messages have arrived for this client.