1 APPLICATION LAYER PROTOCOL FOR THE CITADEL SYSTEM
2 (c) 1995-2005 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.
45 GENERAL INFORMATION ABOUT THE SERVER
46 ------------------------------------
48 The server is connection-oriented and stateful: each client requires its own
49 connection to a server process, and when a command is sent, the client must
50 read the response, and then transfer data or change modes if necessary.
52 The application layer is very much like other Internet protocols such as SMTP
53 or NNTP. A client program sends one-line commands to the server, and the
54 server responds with a three-digit numeric result code followed by a message
55 describing what happened. This cycle continues until the end of the
58 Unlike protocols such as FTP, all data transfers occur in-band. This means
59 that the same connection that is used for exchange of client/server
60 messages, will also be used to transfer data back and forth. (FTP opens a
61 separate connection for data transfers.) This keeps protocol administration
62 straightforward, as it can traverse firewalls without any special protocol
63 support on the firewall except for opening the port number.
69 The server will respond to all commands with a 3-digit result code, which
70 will be the first three characters on the line. The rest of the line may
71 contain a human-readable string explaining what happened. (Some client
72 software will display some of these strings to the user.)
74 The first digit is the most important. The following codes are defined for
75 this position: ERROR, OK, MORE_DATA, LISTING_FOLLOWS, and SEND_LISTING.
77 The second and third digits may provide a reason as to why a command
78 succeeded or failed. See ipcdef.h for the available codes.
80 ERROR means the command did not complete.
81 OK means the command executed successfully.
82 MORE_DATA means the command executed partially. Usually this means that
83 another command needs to be executed to complete the operation. For example,
84 sending the USER command to log in a user usually results in a MORE_DATA
85 result code, because the client needs to execute a PASS command to send the
86 password and complete the login.
87 LISTING_FOLLOWS means that after the server response, the server will
88 output a listing of some sort. The client *must* read the listing, whether
89 it wants to or not. The end of the listing is signified by the string
90 "000" on a line by itself.
91 SEND_LISTING is the opposite of LISTING_FOLLOWS. It means that the client
92 should begin sending a listing of some sort. The client *must* send something,
93 even if it is an empty listing. Again, the listing ends with "000" on a line
95 BINARY_FOLLOWS and SEND_BINARY mean that the client must immediately send
96 or receive a block of binary data. The first parameter will always be the
98 ASYNC_MESSAGE_FOLLOWS means that an asynchronous, or unsolicited, message
99 follows. The next line will be one of the above codes, and if a data transfer
100 is involved it must be handled immediately. Note that the client will not
101 receive this type of response unless it indicates to the server that it is
102 capable of handling them; see the writeup of the ASYN command later in this
108 Zero or more parameters may be passed to a command. When more than one
109 parameter is passed to a command, they should be separated by the "|"
112 In this example, we're using the "SETU" command and passing three
113 parameters: 80, 24, and 260.
115 When the server spits out data that has parameters, if more than one
116 parameter is returned, they will be separated by the "|" symbol like
119 In this example, we just executed the "GETU" command, and it returned us
120 an OK result code (the '2' in the 200) and three parameters: 80, 24, and
127 This is a listing of all the commands that a Citadel server can execute.
132 This command does nothing. It takes no arguments and always returns
133 OK. It is intended primarily for testing and development, but it might also
134 be used as a "keep alive" command to prevent the server from timing out, if
135 it's running over a transport that needs this type of thing.
138 ECHO (ECHO something)
140 This command also does nothing. It simply returns OK followed by whatever
146 Terminate the server connection. This command takes no arguments. It
147 returns OK and closes the connection immediately.
152 Log out the user without closing the server connection. It always returns
153 OK even if no user is logged in.
156 USER (send USER name)
158 The first step in logging in a user. This command takes one argument: the
159 name of the user to be logged in. If the user exists, a MORE_DATA return
160 code will be sent, which means the client should execute PASS as the next
161 command. If the user does not exist, ERROR + NO_SUCH_USER is returned.
166 The second step in logging in a user. This command takes one argument: the
167 password for the user we are attempting to log in. If the password doesn't
168 match the correct password for the user we specified for the USER command,
169 ERROR + PASSWORD_REQUIRED is returned. If a USER command has not been
170 executed yet, ERROR + USERNAME_REQUIRED is returned. If a user is already
171 logged in, ERROR + ALREADY_LOGGED_IN is returned. If the password is
172 correct, OK is returned and the user is now logged in... and most of the
173 other server commands can now be executed. Along with OK, the following
174 parameters are returned:
176 0 - The user's name (in case the client wants the right upper/lower casing)
177 1 - The user's current access level
180 4 - Various flags (see citadel.h)
182 6 - Time of last call (UNIX timestamp)
185 NEWU (create NEW User account)
187 This command creates a new user account AND LOGS IT IN. The argument to
188 this command will be the name of the account. No case conversion is done
189 on the name. Note that the new account is installed with a default
190 configuration, and no password, so the client should immediately prompt the
191 user for a password and install it with the SETP command as soon as this
192 command completes. This command returns OK if the account was created and
193 logged in, ERROR + ALREADY_EXISTS if another user already exists with this
194 name, ERROR + NOT_HERE if self-service account creation is disabled,
195 ERROR + MAX_SESSIONS_EXCEEDED if too many users are logged in, ERROR +
196 USERNAME_REQUIRED if a username was not provided, or ERROR + ILELGAL_VALUE
197 if the username provided is invalid. If OK, it will also return the same
198 parameters that PASS returns.
200 Please note that the NEWU command should only be used for self-service
201 user account creation. For administratively creating user accounts, please
202 use the CREU command.
205 SETP (SET new Password)
207 This command sets a new password for the currently logged in user. The
208 argument to this command will be the new password. The command always
209 returns OK, unless the client is not logged in, in which case it will return
210 ERROR + NOT_LOGGED_IN, or if the user is an auto-login user, in which case
211 it will return ERROR + NOT_HERE.
214 CREU (CREate new User account)
216 This command creates a new user account AND DOES NOT LOG IT IN. The first
217 argument to this command will be the name of the account. No case conversion
218 is done on the name. Note that the new account is installed with a default
219 configuration, and no password. The second argument is optional, and will be
220 an initial password for the user. This command returns OK if the account was
221 created, ERROR + HIGHER_ACCESS_REQUIRED if the user is not an Aide, ERROR +
222 USERNAME_REQUIRED if no username was specified, or ERROR + ALREADY_EXISTS if
223 another user already exists with this name.
225 Please note that CREU is intended to be used for activities in which a
226 system administrator is creating user accounts. For self-service user
227 account creation, use the NEWU command.
230 LKRN (List Known Rooms with New messages)
232 List known rooms with new messages. If the client is not logged in, ERROR +
233 NOT_LOGGED_IN is returned. Otherwise, LISTING_FOLLOWS is returned, followed
234 by the room listing. Each line in the listing contains the full name of a
235 room, followed by the '|' symbol, and then a number that may contain the
238 #define QR_PERMANENT 1 /* Room does not purge */
239 #define QR_PRIVATE 4 /* Set for any type of private room */
240 #define QR_PASSWORDED 8 /* Set if there's a password too */
241 #define QR_GUESSNAME 16 /* Set if it's a guessname room */
242 #define QR_DIRECTORY 32 /* Directory room */
243 #define QR_UPLOAD 64 /* Allowed to upload */
244 #define QR_DOWNLOAD 128 /* Allowed to download */
245 #define QR_VISDIR 256 /* Visible directory */
246 #define QR_ANONONLY 512 /* Anonymous-Only room */
247 #define QR_ANON2 1024 /* Anonymous-Option room */
248 #define QR_NETWORK 2048 /* Shared network room */
249 #define QR_PREFONLY 4096 /* Preferred status needed to enter */
250 #define QR_READONLY 8192 /* Aide status required to post */
252 Then it returns another '|' symbol, followed by a second set of bits comprised
255 #define QR2_SYSTEM 1 /* System room; hide by default */
256 #define QR2_SELFLIST 2 /* Self-service mailing list mgmt */
258 Other bits may be defined in the future. The listing terminates, as with
259 all listings, with "000" on a line by itself.
261 Starting with version 4.01 and above, floors are supported. The first
262 argument to LKRN should be the number of the floor to list rooms from. Only
263 rooms from this floor will be listed. If no arguments are passed to LKRN, or
264 if the floor number requested is (-1), rooms on all floors will be listed.
266 The third field displayed on each line is the number of the floor the room
267 is on. The LFLR command should be used to associate floor numbers with
270 The fourth field displayed on each line is a "room listing order." Unless
271 there is a compelling reason not to, clients should sort any received room
272 listings by this value.
274 The fifth field is a special bit bucket containing fields which pertain to
275 room access controls:
277 #define UA_KNOWN 2 /* Known room */
278 #define UA_GOTOALLOWED 4 /* Access will be granted to this room
279 * if the user calls it up by name */
280 #define UA_HASNEWMSGS 8 /* Unread messages exist in room */
281 #define UA_ZAPPED 16 /* Zapped from known rooms list */
283 The sixth field is the user's current view for the room. (See VIEW command)
286 LKRO (List Known Rooms with Old [no new] messages)
288 This follows the same usage and format as LKRN.
291 LZRM (List Zapped RooMs)
293 This follows the same usage and format as LKRN and LKRO.
296 LKRA (List All Known Rooms)
298 Same format. Lists all known rooms, with or without new messages.
301 LRMS (List all accessible RooMS)
303 Again, same format. This command lists all accessible rooms, known and
304 forgotten, with and without new messages. It does not, however, list
305 inaccessible private rooms.
308 LPRM (List all Public RooMs)
310 Again, same format. This command lists all public rooms, and nothing else.
311 Unlike the other list rooms commands, this one can be executed without logging
315 GETU (GET User configuration)
317 This command retrieves the screen dimensions and user options for the
318 currently logged in account. ERROR + NOT_LOGGED_IN will be returned if no
319 user is logged in, of course. Otherwise, OK will be returned, followed by
320 four parameters. The first parameter is the user's screen width, the second
321 parameter is the user's screen height, and the third parameter is a bag of
322 bits with the following meanings:
324 #define US_LASTOLD 16 /* Print last old message with new */
325 #define US_EXPERT 32 /* Experienced user */
326 #define US_UNLISTED 64 /* Unlisted userlog entry */
327 #define US_NOPROMPT 128 /* Don't prompt after each message */
328 #define US_DISAPPEAR 512 /* Use "disappearing msg prompts" */
329 #define US_PAGINATOR 2048 /* Pause after each screen of text */
331 There are other bits, too, but they can't be changed by the user (see below).
334 SETU (SET User configuration)
336 This command does the opposite of SETU: it takes the screen dimensions and
337 user options (which were probably obtained with a GETU command, and perhaps
338 modified by the user) and writes them to the user account. This command
339 should be passed three parameters: the screen width, the screen height, and
340 the option bits (see above). It returns ERROR + NOT_LOGGED_IN if no user is
341 logged in, and ERROR + ILLEGAL_VALUE if the parameters are incorrect.
343 Note that there exist bits here which are not listed in this document. Some
344 are flags that can only be set by Aides or the system administrator. SETU
345 will ignore attempts to toggle these bits. There also may be more user
346 settable bits added at a later date. To maintain later downward compatibility,
347 the following procedure is suggested:
349 1. Execute GETU to read the current flags
350 2. Toggle the bits that we know we can toggle
351 3. Execute SETU to write the flags
353 If we are passed a bit whose meaning we don't know, it's best to leave it
354 alone, and pass it right back to the server. That way we can use an old
355 client on a server that uses an unknown bit without accidentally clearing
356 it every time we set the user's configuration.
361 This command is used to goto a new room. When the user first logs in (login
362 is completed after execution of the PASS command) this command is
363 automatically and silently executed to take the user to the first room in the
364 system (usually called the Lobby).
366 This command can be passed one or two parameters. The first parameter is,
367 of course, the name of the room. Although it is not case sensitive, the
368 full name of the room must be used. Wildcard matching or unique string
369 matching of room names should be the responsibility of the client.
371 Note that the reserved room name "_BASEROOM_" can be passed to the server
372 to cause the goto command to take the user to the first room in the system,
373 traditionally known as the Lobby>. As long as a user is logged in, a
374 GOTO command to _BASEROOM_ is guaranteed to succeed. This is useful to
375 allow client software to return to the base room when it doesn't know
378 There are also several additional reserved room names:
379 "_MAIL_" goes to the user's inbox (i.e. the Mail> room).
380 "_BITBUCKET_" goes to a room that has been chosen for messages without a home.
381 "_CALENDAR_" goes to the user's primary personal calendar.
382 "_CONTACTS_" goes to the user's primary personal address book.
383 "_NOTES_" goes to the user's primary personal notes room.
384 "_TASKS_" goes to the user's primary personal task list.
387 The second (and optional) parameter is a password, if one is required for
388 access to the room. This allows for all types of rooms to be accessed via
389 this command: for public rooms, invitation-only rooms to which the user
390 has access, and preferred users only rooms to which the user has access, the
391 room will appear in a room listing. For guess-name rooms, this command
392 will work transparently, adding the room to the user's known room list when
393 it completes. For passworded rooms, access will be denied if the password
394 is not supplied or is incorrect, or the command will complete successfully
395 if the password is correct.
397 The third (and also) optional parameter is a "transient" flag. Normally,
398 when a user enters a private and/or zapped room, the room is added to the
399 user's known rooms list. If the transient flag is set to non-zero, this is
400 called a "transient goto" which causes the user to enter the room without
401 adding the room to the known rooms list.
403 The possible result codes are:
405 OK - The command completed successfully. User is now in the room.
406 (See the list of returned parameters below)
408 ERROR - The command did not complete successfully. Check the second and
409 third positions of the result code to find out what happened:
411 NOT_LOGGED_IN - Of course you can't go there. You didn't log in.
412 PASSWORD_REQUIRED - Either a password was not supplied, or the supplied
413 password was incorrect.
414 ROOM_NOT_FOUND - The requested room does not exist.
416 The typical procedure for entering a passworded room would be:
418 1. Execute a GOTO command without supplying any password.
419 2. ERROR + PASSWORD_REQUIRED will be returned. The client now knows that
420 the room is passworded, and prompts the user for a password.
421 3. Execute a GOTO command, supplying both the room name and the password.
422 4. If OK is returned, the command is complete. If, however,
423 ERROR + PASSWORD_REQUIRED is still returned, tell the user that the supplied
424 password was incorrect. The user remains in the room he/she was previously
427 When the command succeeds, these parameters are returned:
428 0. The name of the room
429 1. Number of unread messages in this room
430 2. Total number of messages in this room
431 3. Info flag: set to nonzero if the user needs to read this room's info
432 file (see RINF command below)
433 4. Various flags associated with this room. (See LKRN cmd above)
434 5. The highest message number present in this room
435 6. The highest message number the user has read in this room
436 7. Boolean flag: 1 if this is a Mail> room, 0 otherwise.
437 8. Aide flag: 1 if the user is either the Room Aide for this room, *or* is
438 a regular Aide (this makes access checks easy).
439 9. The number of new Mail messages the user has (useful for alerting the
440 user to the arrival of new mail during a session)
441 10. The floor number this room resides on
442 11. The *current* "view" for this room (see views.txt for more info)
443 12. The *default* "view" for this room
445 The default view gives the client a hint as to what views the user should
446 be allowed to select. For example, it would be confusing to allow messages
447 in a room intended for calendar items. The server does not enforce these
448 restrictions, though.
451 MSGS (get pointers to MeSsaGeS in this room)
453 This command obtains a listing of all the messages in the current room
454 which the client may request. This command may be passed a single parameter:
455 either "all", "old", or "new" to request all messages, only old messages, or
456 new messages. Or it may be passed two parameters: "last" plus a number, in
457 which case that many message pointers will be returned; "first" plus a
458 number, for the corresponding effect; or "gt" plus a number, to list all
459 messages in the current room with a message number greater than the one
460 specified. If no parameters are specified, "all" is assumed.
462 The third argument, may be either 0 or 1. If it is 1, this command behaves
463 differently: before a listing is returned, the client must transmit a list
464 of fields to search for. The field headers are listed below in the writeup
465 for the "MSG0" command.
467 The optional fourth argument may also be either 0 or 1. If it is 1, the
468 output of this command will include not only a list of message numbers, but
469 a simple header summary of each message as well. This is somewhat resource
470 intensive so you shouldn't do this unless you absolutely need all the headers
471 immediately. The fields which are output (in the usual delimited fashion, of
472 course) are: message number, timestamp, display name, node name, Internet
473 email address (if present), subject (if present).
475 This command can return three possible results. ERROR + NOT_LOGGED_IN will
476 be returned if no user is currently logged in. Otherwise, LISTING_FOLLOWS
477 will be returned, and the listing will consist of zero or more message
478 numbers, one per line. The listing ends, as always, with the string "000"
479 alone on a line by itself. The listed message numbers can be used to request
480 messages from the system. If "search mode" is being used, the server will
481 return START_CHAT_MODE, and the client is expected to transmit the search
482 criteria, and then read the message list.
484 Since this is somewhat complex, here are some examples:
486 Example 1: Read all new messages
489 Server: 100 Message list...
495 Example 2: Read the last five messages
498 Server: 100 Message list...
506 Example 3: Read all messages written by "IGnatius T Foobar"
509 Server: 800 Send template then receive message list
510 Client: from|IGnatius T Foobar
524 Note that in "search mode" the client may specify any number of search
525 criteria. These criteria are applied with an AND logic.
528 MSG0 (read MeSsaGe, mode 0)
530 This is a command used to read the text of a message. "Mode 0" implies that
531 other MSG commands (MSG1, MSG2, etc.) will probably be added later on to read
532 messages in more robust formats. This command should be passed two arguments.
533 The first is the message number of the message being requested. The second
534 argument specifies whether the client wants headers and/or message body:
538 3 = Headers only, with MIME information suppressed (this runs faster)
540 If the request is denied, ERROR + NOT_LOGGED_IN or ERROR + MESSAGE_NOT_FOUND
541 will be returned. Otherwise, LISTING_FOLLOWS will be returned, followed by
542 the contents of the message. The following fields may be sent:
544 type= Formatting type. The currently defined types are:
545 0 = "traditional" Citadel formatting. This means that newlines should be
546 treated as spaces UNLESS the first character on the next line is a space. In
547 other words, only indented lines should generate a newline on the user's screen
548 when the message is being displayed. This allows a message to be formatted to
549 the reader's screen width. It also allows the use of proportional fonts.
550 1 = a simple fixed-format message. The message should be displayed to
551 the user's screen as is, preferably in a fixed-width font that will fit 80
553 4 = MIME format message. The message text is expected to contain a header
554 with the "Content-type:" directive (and possibly others).
556 msgn= The message ID of this message on the system it originated on.
557 path= An e-mailable path back to the user who wrote the message.
559 time= The date and time of the message, in Unix format (the number of
560 seconds since midnight on January 1, 1970, GMT).
562 from= The name of the author of the message.
563 rcpt= If the message is a private e-mail, this is the recipient.
564 room= The name of the room the message originated in.
565 node= The short node name of the system this message originated on.
566 hnod= The long node name of the system this message originated on.
567 zaps= The id/node of a message which this one zaps (supersedes).
569 part= Information about a MIME part embedded in this message.
570 pref= Information about a multipart MIME prefix such as "multipart/mixed"
571 or "multipart/alternative". This will be output immediately prior
572 to the various "part=" lines which make up the multipart section.
573 suff= Information about a multipart MIME suffix. This will be output
574 immediately following the various "part=" lines which make up the
577 text Note that there is no "=" after the word "text". This string
578 signifies that the message text begins on the next line.
581 WHOK (WHO Knows room)
583 This command is available only to Aides. ERROR + HIGHER_ACCESS_REQUIRED
584 will be returned if the user is not an Aide. Otherwise, it returns
585 LISTING_FOLLOWS and then lists, one user per line, every user who has
586 access to the current room.
589 INFO (get server INFO)
591 This command will *always* return LISTING_FOLLOWS and then print out a
592 listing of zero or more strings. Client software should be written to expect
593 anywhere from a null listing to an infinite number of lines, to allow later
594 backward compatibility. The current implementation defines the following
595 parts of the listing:
597 Line 1 - Your unique session ID on the server
598 Line 2 - The node name of the Citadel server
599 Line 3 - Human-readable node name of the Citadel server
600 Line 4 - The fully-qualified domain name (FQDN) of the server
601 Line 5 - The name of the server software, i.e. "Citadel 4.00"
602 Line 6 - (The revision level of the server code) * 100
603 Line 7 - The geographical location of the site (city and state if in the US)
604 Line 8 - The name of the system administrator
605 Line 9 - A number identifying the server type (see below)
606 Line 10 - The text of the system's paginator prompt
607 Line 11 - Floor Flag. 1 if the system supports floors, 0 otherwise.
608 Line 12 - Paging level. 0 if the system only supports inline paging,
609 1 if the system supports "extended" paging (check-only and
610 multiline modes). See the SEXP command for further information.
611 Line 13 - The "nonce" for this session, for support of APOP-style
612 authentication. If this field is present, clients may authenticate
614 Line 14 - Set to nonzero if this server supports the QNOP command.
615 Line 15 - Set to nonzero if this server is capable of connecting to a
616 directory service using LDAP.
618 *** NOTE! *** The "server type" code is intended to promote global
619 compatibility in a scenario in which developers have added proprietary
620 features to their servers or clients. We are attempting to avoid a future
621 situation in which users need to keep different client software around for
622 each Citadel they use. *Please*, if you are a developer and plan to add
623 proprietary features:
625 -> Your client programs should still be able to utilize servers other than
627 -> Clients other than your own should still be able to utilize your server,
628 even if your proprietary extensions aren't supported.
629 -> Please contact Art Cancro <ajc@uncensored.citadel.org> and obtain a unique
630 server type code, which can be assigned to your server program.
631 -> If you document what you did in detail, perhaps it can be added to a
632 future release of the Citadel program, so everyone can enjoy it. Better
633 yet, just work with the Citadel development team on the main source tree.
635 If everyone follows this scheme, we can avoid a chaotic situation with lots
636 of confusion about which client program works with which server, etc. Client
637 software can simply check the server type (and perhaps the revision level)
638 to determine ahead of time what commands may be utilized.
640 Please refer to "developers.txt" for information on what codes belong to whom.
644 RDIR (Read room DIRectory)
646 Use this command to read the directory of a directory room. ERROR + NOT_HERE
647 will be returned if the room has no directory, ERROR + HIGHER_ACCESS_REQUIRED
648 will be returned if the room's directory is not visible and the user does not
649 have Aide or Room Aide privileges, ERROR + NOT_LOGGED_IN will be returned if
650 the user is not logged in; otherwise LISTING_FOLLOWS will be returned,
651 followed by the room's directory. Each line of the directory listing will
652 contain three fields: a filename, the length of the file, and a description.
654 The server message contained on the same line with LISTING_FOLLOWS will
655 contain the name of the system and the name of the directory, such as:
657 uncensored.citadel.org|/usr/local/citadel/files/my_room_directory
660 SLRP (Set Last-message-Read Pointer)
662 This command marks all messages in the current room as read (seen) up to and
663 including the specified number. Its sole parameter is the number of the last
664 message that has been read. This allows the pointer to be set at any
665 arbitrary point in the room. Optionally, the parameter "highest" may be used
666 instead of a message number, to set the pointer to the number of the highest
667 message in the room, effectively marking all messages in the room as having
668 been read (ala the Citadel <G>oto command).
670 The command will return OK if the pointer was set, or ERROR + NOT_LOGGED_IN
671 if the user is not logged in. If OK is returned, it will be followed by a
672 single argument containing the message number the last-read-pointer was set to.
675 INVT (INViTe a user to a room)
677 This command may only be executed by Aides, or by the room aide for the
678 current room. It is used primarily to add users to invitation-only rooms,
679 but it may also be used in other types of private rooms as well. Its sole
680 parameter is the name of the user to invite.
682 The command will return OK if the operation succeeded. ERROR + NO_SUCH_USER
683 will be returned if the user does not exist, ERROR + HIGHER_ACCESS_REQUIRED
684 will be returned if the operation would have been possible if the user had
685 higher access, and ERROR + NOT_HERE may be returned if the room is not a
689 KICK (KICK a user out of a room)
691 This is the opposite of INVT: it is used to kick a user out of a private
692 room. It can also be used to kick a user out of a public room, but the
693 effect will only be the same as if the user <Z>apped the room - a non-stupid
694 user can simply un-zap the room to get back in.
697 GETR (GET Room attributes)
699 This command is used for editing the various attributes associated with a
700 room. A typical "edit room" command would work like this:
701 1. Use the GETR command to get the current attributes
702 2. Change some of them around
703 3. Use SETR (see below) to save the changes
704 4. Possibly also change the room aide using the GETA and SETA commands
706 GETR takes no arguments. It will only return OK if the SETR command will
707 also return OK. This allows client software to tell the user that he/she
708 can't edit the room *before* going through the trouble of actually doing the
709 editing. Possible return codes are:
711 ERROR+NOT_LOGGED_IN - No user is logged in.
712 ERROR+HIGHER_ACCESS_REQUIRED - Not enough access. Typically, only aides
713 and the room aide associated with the current room, can access this command.
714 OK - Command succeeded. Parameters are returned.
716 If OK is returned, the following parameters will be returned as well:
718 0. The name of the room
719 1. The room's password (if it's a passworded room)
720 2. The name of the room's directory (if it's a directory room)
721 3. Various flags (bits) associated with the room (see LKRN cmd above)
722 4. The floor number on which the room resides
723 5. The room listing order
724 6. The default view for the room (see views.txt)
725 7. A second set of flags (bits) associated with the room
728 SETR (SET Room attributes)
730 This command sets various attributes associated with the current room. It
731 should be passed the following arguments:
733 0. The name of the room
734 1. The room's password (if it's a passworded room)
735 2. The name of the room's directory (if it's a directory room)
736 3. Various flags (bits) associated with the room (see LKRN cmd above)
737 4. "Bump" flag (see below)
738 5. The floor number on which the room should reside
739 6. The room listing order
740 7. The default view for the room (see views.txt)
741 8. A second set of flags (bits) associated with the room
743 *Important: You should always use GETR to retrieve the current attributes of
744 the room, then change what you want to change, and then use SETR to write it
745 all back. This is particularly important with respect to the flags: if a
746 particular bit is set, and you don't know what it means, LEAVE IT ALONE and
747 only toggle the bits you want to toggle. This will allow for upward
750 The _BASEROOM_, user's Mail> and Aide> rooms can only be partially edited.
751 Any changes which cannot be made will be silently ignored.
753 If the room is a private room, you have the option of causing all users who
754 currently have access, to forget the room. If you want to do this, set the
755 "bump" flag to 1, otherwise set it to 0.
760 This command is used to get the name of the Room Aide for the current room.
761 It will return ERROR + NOT_LOGGED_IN if no user is logged in, or OK if the
762 command succeeded. Along with OK there will be returned one parameter: the
763 name of the Room Aide. A conforming server must guarantee that the user is
769 The opposite of GETA, used to set the Room Aide for the current room. One
770 parameter should be passed, which is the name of the user who is to be the
771 new Room Aide. Under Citadel, this command may only be executed by Aides
772 and by the *current* Room Aide for the room. Return codes possible are:
773 ERROR + NOT_LOGGED_IN (Not logged in.)
774 ERROR + HIGHER_ACCESS_REQUIRED (Higher access required.)
775 ERROR + NOT_HERE (Room cannot be edited.)
776 OK (Command succeeded.)
779 ENT0 (ENTer message, mode 0)
781 This command is used to enter messages into the system. It accepts four
784 0 - Post flag. This should be set to 1 to post a message. If it is
785 set to 0, the server only returns OK or ERROR (plus any flags describing
786 the error) without reading in a message. Client software should, in fact,
787 perform this operation at the beginning of an "enter message" command
788 *before* starting up its editor, so the user does not end up typing a message
789 in vain that will not be permitted to be saved. If it is set to 2, the
790 server will accept an "apparent" post name if the user is privileged enough.
791 This post name is arg 5.
792 1 - Recipient. This argument is utilized only for private mail messages.
793 It is ignored for public messages. It contains, of course, the name of the
794 recipient of the message.
795 2 - Anonymous flag. This argument is ignored unless the room allows
796 anonymous messages. In such rooms, this flag may be set to 1 to flag a
797 message as anonymous, otherwise 0 for a normal message.
798 3 - Format type. Any valid Citadel format type may be used (this will
799 typically be 0; see the MSG0 command above).
800 4 - Subject. If present, this argument will be used as the subject of
802 5 - Post name. When postflag is 2, this is the name you are posting as.
803 This is an Aide only command.
804 6 - Do Confirmation. NOTE: this changes the protocol semantics! When
805 you set this to nonzero, ENT0 will reply with a confirmation message after
806 you submit the message text. The reply code for the ENT0 command will be
807 START_CHAT_MODE instead of SEND_LISTING.
809 Possible result codes:
810 OK - The request is valid. (Client did not set the "post" flag, so the
811 server will not read in message text.) If the message is an e-mail with
812 a recipient, the text that follows the OK code will contain the exact name
813 to which mail is being sent. The client can display this to the user. The
814 implication here is that the name that the server returns will contain the
815 correct upper and lower case characters. In addition, if the recipient is
816 having his/her mail forwarded, the forwarding address will be returned.
817 SEND_LISTING - The request is valid. The client should now transmit
818 the text of the message (ending with a 000 on a line by itself, as usual).
819 START_CHAT_MODE - The request is valid. The client should now transmit
820 the text of the message, ending with a 000 on a line by itself. After
821 transmitting the 000 terminator, the client MUST read in the confirmation
822 from the server, which will also end with 000 on a line by itself. The format
823 of the confirmation appears below.
824 ERROR + NOT_LOGGED_IN - Not logged in.
825 ERROR + HIGHER_ACCESS_REQUIRED - Higher access is required. An
826 explanation follows, worded in a form that can be displayed to the user.
827 ERROR + NO_SUCH_USER - The specified recipient does not exist.
829 The format of the confirmation message, if requested, is as follows:
830 Line 1: The new message number on the server for the message. It will be
831 positive for a real message number, or negative to denote
832 that an error occurred. If an error occurred, the message was
834 Line 2: A human-readable confirmation or error message.
835 Line 3: The resulting Exclusive UID of the message, if present.
836 (More may be added to this in the future, so do not assume that there will
837 only be these lines output. Keep reading until 000 is received.)
840 RINF (read Room INFormation file)
842 Each room has associated with it a text file containing a description of
843 the room, perhaps containing its intended purpose or other important
844 information. The info file for the Lobby> (the system's base room) is
845 often used as a repository for system bulletins and the like.
847 This command, which accepts no arguments, is simply used to read the info
848 file for the current room. It will return LISTING_FOLLOWS followed by
849 the text of the message (always in format type 0) if the request can be
850 honored, or ERROR if no info file exists for the current room (which is
851 often the case). Other error description codes may accompany this result.
853 When should this command be used? This is, of course, up to the discretion
854 of client software authors, but in Citadel it is executed in two situations:
855 the first time the user ever enters a room; and whenever the contents of the
856 file change. The latter can be determined from the result of a GOTO command,
857 which will tell the client whether the file needs to be read (see GOTO above).
860 DELE (DELEte a message)
862 Delete a message from the current room. The one argument that should be
863 passed to this command is the message number of the message to be deleted.
864 The return value will be OK if the message was deleted, or an ERROR code.
865 If the delete is successful, the message's reference count is decremented, and
866 if the reference count reaches zero, the message is removed from the message
870 MOVE (MOVE or copy a message to a different room)
872 Move or copy a message to a different room. This command expects to be
873 passed three arguments:
874 0: the message number of the message to be moved or copied.
875 1: the name of the target room.
876 2: flag: 0 to move the message, 1 to copy it without deleting from the
879 This command never creates or deletes copies of a message; it merely moves
880 around links. When a message is moved, its reference count remains the same.
881 When a message is copied, its reference count is incremented.
884 KILL (KILL current room)
886 This command deletes the current room. It accepts a single argument, which
887 should be nonzero to actually delete the room, or zero to merely check
888 whether the room can be deleted.
890 Once the room is deleted, the current room is undefined. It is suggested
891 that client software immediately GOTO another room (usually _BASEROOM_)
892 after this command completes.
894 Possible return codes:
896 OK - room has been deleted (or, if checking only, request is valid).
897 ERROR+NOT_LOGGED_IN - no user is logged in.
898 ERROR+HIGHER_ACCESS_REQUIRED - not enough access to delete rooms.
899 ERROR+NOT_HERE - this room can not be deleted.
902 CRE8 (CRE[ate] a new room)
904 This command is used to create a new room. Like some of the other
905 commands, it provides a mechanism to first check to see if a room can be
906 created before actually executing the command. CRE8 accepts the following
909 0 - Create flag. Set this to 1 to actually create the room. If it is
910 set to 0, the server merely checks that there is a free slot in which to
911 create a new room, and that the user has enough access to create a room. It
912 returns OK if the client should go ahead and prompt the user for more info,
913 or ERROR or ERROR+HIGHER_ACCESS_REQUIRED if the command will not succeed.
914 1 - Name for new room.
915 2 - Access type for new room:
917 1 - Private; can be entered by guessing the room's name
918 2 - Private; can be entered by knowing the name *and* password
919 3 - Private; invitation only (sometimes called "exclusive")
920 4 - Personal (mailbox for this user only)
921 3 - Password for new room (if it is a type 2 room)
922 4 - Floor number on which the room should reside (optional)
923 5 - Set to 1 to avoid automatically gaining access to the created room.
924 6 - The default "view" for the room.
926 If the create flag is set to 1, the room is created (unless something
927 went wrong and an ERROR return is sent), and the server returns OK, but
928 the session is **not** automatically sent to that room. The client still
929 must perform a GOTO command to go to the new room.
932 FORG (FORGet the current room)
934 This command is used to forget (zap) the current room. For those not
935 familiar with Citadel, this terminology refers to removing the room from
936 a user's own known rooms list, *not* removing the room itself. After a
937 room is forgotten, it no longer shows up in the user's known room list,
938 but it will exist in the user's forgotten room list, and will return to the
939 known room list if the user goes to the room (in Citadel, this is
940 accomplished by explicitly typing the room's name in a <.G>oto command).
942 The command takes no arguments. If the command cannot execute for any
943 reason, ERROR will be returned. ERROR+NOT_LOGGED_IN or ERROR+NOT_HERE may
944 be returned as they apply.
946 If the command succeeds, OK will be returned. At this point, the current
947 room is **undefined**, and the client software is responsible for taking
948 the user to another room before executing any other room commands (usually
949 this will be _BASEROOM_ since it is always there).
952 MESG (read system MESsaGe)
954 This command is used to display system messages and/or help files. The
955 single argument it accepts is the name of the file to display. IT IS CASE
956 SENSITIVE. Citadel looks for these files first in the "messages"
957 subdirectory and then in the "help" subdirectory.
959 If the file is found, LISTING_FOLLOWS is returned, followed by a pathname
960 to the file being displayed. Then the message is printed, in format type 0
961 (see MSG0 command for more information on this). If the file is not found,
964 There are some "well known" names of system messages which client software
965 may expect most servers to carry:
967 hello - Welcome message, to be displayed before the user logs in.
968 changepw - To be displayed whenever the user is prompted for a new
969 password. Warns about picking guessable passwords and such.
970 register - Should be displayed prior to the user entering registration.
971 Warnings about not getting access if not registered, etc.
972 help - Main system help file.
973 goodbye - System logoff banner; display when user logs off.
974 roomaccess - Information about how public rooms and different types of
975 private rooms function with regards to access.
976 unlisted - Tells users not to choose to be unlisted unless they're
977 really paranoid, and warns that aides can still see
978 unlisted userlog entries.
980 Citadel provides these for the Citadel Unix text client. They are
981 probably not very useful for other clients:
983 mainmenu - Main menu (when in idiot mode).
988 saveopt - Options to save a message, abort, etc.
989 entermsg - Displayed just before a message is entered, when in
993 GNUR (Get Next Unvalidated User)
995 This command shows the name of a user that needs to be validated. If there
996 are no unvalidated users, OK is returned. Otherwise, MORE_DATA is returned
997 along with the name of the first unvalidated user the server finds. All of
998 the usual ERROR codes may be returned as well (for example, if the user is
999 not an Aide and cannot validate users).
1001 A typical "Validate New Users" command would keep executing this command,
1002 and then validating each user it returns, until it returns OK when all new
1003 users have been validated.
1006 GREG (Get REGistration for user)
1008 This command retrieves the registration info for a user, whose name is the
1009 command's sole argument. All the usual error messages can be returned. If
1010 the command succeeds, LISTING_FOLLOWS is returned, followed by the user's name
1011 (retrieved from the userlog, with the right upper and lower case etc.) The
1012 contents of the listing contains one field per line, followed by the usual
1013 000 on the last line.
1015 The following lines are defined. Others WILL be added in the futre, so all
1016 software should be written to read the lines it knows about and then ignore
1017 all remaining lines:
1022 Line 4: Street address or PO Box
1023 Line 5: City/town/village/etc.
1024 Line 6: State/province/etc.
1026 Line 8: Telephone number
1027 Line 9: Access level
1028 Line 10: Internet e-mail address
1031 Users without Aide privileges may retrieve their own registration using
1032 this command. This can be accomplished either by passing the user's own
1033 name as the argument, or the string "_SELF_". The command will always
1034 succeed when used in this manner, unless no user is logged in.
1037 VALI (VALIdate user)
1039 This command is used to validate users. Obviously, it can only be executed
1040 by users with Aide level access. It should be passed two parameters: the
1041 name of the user to validate, and the desired access level
1043 If the command succeeds, OK is returned. The user's access level is changed
1044 and the "need validation" bit is cleared. If the command fails for any
1045 reason, ERROR, ERROR+NO_SUCH_USER, or ERROR+HIGHER_ACCESS_REQUIRED will be
1049 EINF (Enter INFo file for room)
1051 Transmit the info file for the current room with this command. EINF uses
1052 a boolean flag (1 or 0 as the first and only argument to the command) to
1053 determine whether the client actually wishes to transmit a new info file, or
1054 is merely checking to see if it has permission to do so.
1056 If the command cannot succeed, it returns ERROR.
1057 If the client is only checking for permission, and permission will be
1058 granted, OK is returned.
1059 If the client wishes to transmit the new info file, SEND_LISTING is
1060 returned, and the client should transmit the text of the info file, ended
1061 by the usual 000 on a line by itself.
1066 This is a simple user listing. It always succeeds, returning
1067 LISTING_FOLLOWS followed by zero or more user records, 000 terminated. The
1068 fields on each line are as follows:
1073 4. Date/time of last login (Unix format)
1076 7. Password (listed only if the user requesting the list is an Aide)
1078 Unlisted entries will also be listed to Aides logged into the server, but
1079 not to ordinary users.
1081 The LIST command accepts an optional single argument, which is a simple,
1082 case-insensitive search string. If this argument is present, only usernames
1083 in which the search string is present will be returned. It is a simple
1084 substring search, not a regular expression search. If this string is empty
1085 or not present, all users will be returned.
1088 REGI (send REGIstration)
1090 Clients will use this command to transmit a user's registration info. If
1091 no user is logged in, ERROR+NOT_LOGGED_IN is returned. Otherwise,
1092 SEND_LISTING is returned, and the server will expect the following information
1093 (terminated by 000 on a line by itself):
1096 Line 2: Street address or PO Box
1097 Line 3: City/town/village/etc.
1098 Line 4: State/province/etc.
1100 Line 6: Telephone number
1101 Line 7: e-mail address
1105 CHEK (CHEcK various things)
1107 When logging in, there are various things that need to be checked. This
1108 command will return ERROR+NOT_LOGGED_IN if no user is logged in. Otherwise
1109 it returns OK and the following parameters:
1111 0: Number of new private messages in Mail>
1112 1: Nonzero if the user needs to register
1113 2: (Relevant to Aides only) Nonzero if new users require validation
1114 3: The user's preferred Internet e-mail address
1117 DELF (DELete a File)
1119 This command deletes a file from the room's directory, if there is one. The
1120 name of the file to delete is the only parameter to be supplied. Wildcards
1121 are not acceptable, and any slashes in the filename will be converted to
1122 underscores, to prevent unauthorized access to neighboring directories. The
1123 possible return codes are:
1125 OK - Command succeeded. The file was deleted.
1126 ERROR+NOT_LOGGED_IN - Not logged in.
1127 ERROR+HIGHER_ACCESS_REQUIRED - Not an Aide or Room Aide.
1128 ERROR+NOT_HERE - There is no directory in this room.
1129 ERROR+FILE_NOT_FOUND - Requested file was not found.
1134 This command is similar to DELF, except that it moves a file (and its
1135 associated file description) to another room. It should be passed two
1136 parameters: the name of the file to move, and the name of the room to move
1137 the file to. All of the same return codes as DELF may be returned, and also
1138 one additional one: ERROR+NO_SUCH_ROOM, which means that the target room
1139 does not exist. ERROR+NOT_HERE could also mean that the target room does
1140 not have a directory.
1143 NETF (NETwork send a File)
1145 This command is similar to MOVF, except that it attempts to send a file over
1146 the network to another system. It should be passed two parameters: the name
1147 of the file to send, and the node name of the system to send it to. All of
1148 the same return codes as MOVF may be returned, except for ERROR+NO_SUCH_ROOM.
1149 Instead, ERROR+NO_SUCH_SYSTEM may be returned if the name of the target
1152 The name of the originating room will be sent along with the file. Most
1153 implementations will look for a room with the same name at the receiving end
1154 and attempt to place the file there, otherwise it goes into a bit bucket room
1155 for miscellaneous files. This is, however, beyond the scope of this document;
1156 see elsewhere for more details.
1159 RWHO (Read WHO's online)
1161 Displays a list of all users connected to the server. No error codes are
1162 ever returned. LISTING_FOLLOWS will be returned, followed by zero or more
1163 lines containing the following three fields:
1165 0 - Session ID. Citadel fills this with the pid of a server program.
1167 2 - The name of the room the user is currently in. This field might not
1168 be displayed (for example, if the user is in a private room) or it might
1169 contain other information (such as the name of a file the user is
1171 3 - (server v4.03 and above) The name of the host the client is connecting
1172 from, or "localhost" if the client is local.
1173 4 - (server v4.04 and above) Description of the client software being used
1174 5 - The last time, locally to the server, that a command was received from
1175 this client (Note: NOOP's don't count)
1176 6 - The last command received from a client. (NOOP's don't count)
1177 7 - Session flags. These are: + (spoofed address), - (STEALTH mode), *
1178 (posting) and . (idle).
1179 8 - Actual user name, if user name is masqueraded and viewer is an Aide.
1180 9 - Actual room name, if room name is masqueraded and viewer is an Aide.
1181 10 - Actual host name, if host name is masqueraded and viewer is an Aide.
1182 11 - Nonzero if the session is a logged-in user, zero otherwise.
1184 The listing is terminated, as always, with the string "000" on a line by
1188 OPEN (OPEN a file for download)
1190 This command is used to open a file for downloading. Only one download
1191 file may be open at a time. The only argument to this command is the name
1192 of the file to be opened. The user should already be in the room where the
1193 file resides. Possible return codes are:
1196 ERROR+NOT_HERE (no directory in this room)
1197 ERROR+FILE_NOT_FOUND (could not open the file)
1201 If the file is successfully opened, OK will be returned, along with the
1202 size (in bytes) of the file, the time of last modification (if applicable),
1203 the filename (if known), and the MIME type of the file (if known).
1206 CLOS (CLOSe the download file)
1208 This command is used to close the download file. It returns OK if the
1209 file was successfully closed, or ERROR if there wasn't any file open in the
1213 READ (READ from the download file)
1215 Two arguments are passed to this command. The first is the starting position
1216 in the download file, and the second is the total number of bytes to be
1217 read. If the operation can be performed, BINARY_FOLLOWS will be returned,
1218 along with the number of bytes to follow. Then, immediately following the
1219 newline, will be that many bytes of binary data. The client *must* read
1220 exactly that number of bytes, otherwise the client and server will get out
1223 If the operation cannot be performed, any of the usual error codes will be
1227 UOPN (OPeN a file for Uploading)
1229 This command is similar to OPEN, except that this one is used when the
1230 client wishes to upload a file to the server. The first argument is the name
1231 of the file to create, and the second argument is a one-line comment
1232 describing the contents of the file. Only one upload file may be open at a
1233 time. Possible return codes are:
1236 ERROR+NOT_HERE (no directory in this room)
1237 ERROR+FILE_NOT_FOUND (a name must be specified)
1238 ERROR (miscellaneous errors)
1239 ERROR+ALREADY_EXISTS (a file with the same name already exists)
1242 If OK is returned, the command has succeeded and writes may be performed.
1245 UCLS (CLoSe the Upload file)
1247 Close the file opened with UOPN. An argument of "1" should be passed to
1248 this command to close and save the file; otherwise, the transfer will be
1249 considered aborted and the file will be deleted. This command returns OK
1250 if the operation succeeded or ERROR if it did not.
1253 WRIT (WRITe to the upload file)
1255 If an upload file is open, this command may be used to write to it. The
1256 argument passed to this command is the number of bytes the client wishes to
1257 transmit. An ERROR code will be returned if the operation cannot be
1260 If the operation can be performed, SEND_BINARY will be returned, followed
1261 by the number of bytes the server is expecting. The client must then transmit
1262 exactly that number of bytes. Note that in the current implementation, the
1263 number of bytes the server is expecting will always be the number of bytes
1264 the client requested to transmit, but the client software should never assume
1265 that this will always happen, in case changes are made later.
1268 QUSR (Query for a USeR)
1270 This command is used to check to see if a particular user exists. The only
1271 argument to this command is the name of the user being searched for. If
1272 the user exists, OK is returned, along with the name of the user in the userlog
1273 (so the client software can learn the correct upper/lower casing of the name
1274 if necessary). If the user does not exist, ERROR+NO_SUCH_USER is returned.
1275 No login or current room is required to utilize this command.
1278 OIMG (Open an IMaGe file)
1280 Open an image (graphics) file for downloading. Once opened, the file can be
1281 read as if it were a download file. This implies that an image and a download
1282 cannot be opened at the same time. OIMG returns the same result codes as OPEN.
1284 All images will be in GIF (Graphics Interchange Format). In the case of
1285 Citadel, the server will convert the supplied filename to all lower case,
1286 append the characters ".gif" to the filename, and look for it in the "images"
1287 subdirectory. As with the MESG command, there are several "well known"
1288 images which are likely to exist on most servers:
1290 hello - "Welcome" graphics to be displayed alongside MESG "hello"
1291 goodbye - Logoff banner graphics to be displayed alongside MESG "goodbye"
1292 background - Background image (usually tiled) for graphical clients
1294 The following "special" image names are defined in Citadel server version
1297 _userpic_ - Picture of a user (send the username as the second argument)
1298 _floorpic_ - A graphical floor label (send the floor number as the second
1299 argument). Clients which request a floor picture will display
1300 the picture *instead* of the floor name.
1301 _roompic_ - A graphic associated with the *current* room. Clients which
1302 request a room picture will display the picture in *addition*
1303 to the room name (i.e. it's used for a room banner, as
1304 opposed to the floor picture's use in a floor listing).
1307 NETP (authenticate as network session with connection NET Password)
1309 This command is used by client software to identify itself as a transport
1310 session for Citadel site-to-site networking. It should be called with
1311 two arguments: the node name of the calling system, and the "shared secret"
1312 password for that connection. If the authentication succeeds, NETP will
1313 return OK, otherwise, it returns ERROR.
1316 NSYN (Network SYNchronize room)
1318 This command can be used to synchronize the contents of a room on the
1319 network. It is only usable by Aides. It accepts one argument: the name of
1320 a network node (which must be a valid one).
1322 When NSYN is run, the *entire* contents of the current room will be spooled
1323 to the specified node, without regard to whether any of the messages have
1324 already undergone network processing. It is up to the receiving node to
1325 check for duplicates (the Citadel networker does handle this) and avoid
1328 The command returns OK upon success or ERROR if the user is not an Aide.
1331 NUOP (Network Upload OPen file)
1333 Open a network spool file for uploading. The client must have already
1334 identified itself as a network session using the NETP command. If the command
1335 returns OK, the client may begin transmitting IGnet/Open spool data using
1336 a series of WRIT commands. When a UCLS command is issued, the spooled data
1337 is entered into the server if the argument to UCLS is 1 or discarded if the
1338 argument to UCLS is 0. If the client has not authenticated itself with a
1339 NETP command, ERROR+HIGHER_ACCESS_REQUIRED will be returned.
1342 NDOP (Network Download OPen file)
1344 Open a network spool file for downloading. The client must have already
1345 identified itself as a network session using the NETP command. If the command
1346 returns OK, the client may begin receiving IGnet/Open spool data using
1347 a series of READ commands. When a CLOS command is issued, the spooled data
1348 is deleted from the server and may not be read again. If the client has not
1349 authenticated itself with a NETP command, ERROR+HIGHER_ACCESS_REQUIRED will
1353 LFLR (List all known FLooRs)
1355 On systems supporting floors, this command lists all known floors. The
1356 command accepts no parameters. It will return ERROR+NOT_LOGGED_IN if no
1357 user is logged in. Otherwise it returns LISTING_FOLLOWS and a list of
1358 the available floors, each line consisting of three fields:
1360 1. The floor number associated with the floor
1361 2. The name of the floor
1362 3. Reference count (number of rooms on this floor)
1365 CFLR (Create a new FLooR)
1367 This command is used to create a new floor. It should be passed two
1368 arguments: the name of the new floor to be created, and a 1 or 0 depending
1369 on whether the client is actually creating a floor or merely checking to
1370 see if it has permission to create the floor. The user must be logged in
1371 and have Aide privileges to create a floor.
1373 If the command succeeds, it will return OK followed by the floor number
1374 associated with the new floor. Otherwise, it will return ERROR (plus perhaps
1375 HIGHER_ACCESS_REQUIRED, ALREADY_EXISTS, or INVALID_FLOOR_OPERATION)
1376 followed by a description of why the command failed.
1381 This command is used to delete a floor. It should be passed two
1382 argument: the *number* of the floor to be deleted, and a 1 or 0 depending
1383 on whether the client is actually deleting the floor or merely checking to
1384 see if it has permission to delete the floor. The user must be logged in
1385 and have Aide privileges to delete a floor.
1387 Floors that contain rooms may not be deleted. If there are rooms on a floor,
1388 they must be either deleted or moved to different floors first. This implies
1389 that the Main Floor (floor 0) can never be deleted, since Lobby>, Mail>, and
1390 Aide> all reside on the Main Floor and cannot be deleted.
1392 If the command succeeds, it will return OK. Otherwise it will return
1393 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1394 followed by a description of why the command failed.
1399 Edit the parameters of a floor. The client may pass one or more parameters
1402 1. The number of the floor to be edited
1403 2. The desired new name
1405 More parameters may be added in the future. Any parameters not passed to
1406 the server will remain unchanged. A minimal command would be EFLR and a
1407 floor number -- which would do nothing. EFLR plus the floor number plus a
1408 floor name would change the floor's name.
1410 If the command succeeds, it will return OK. Otherwise it will return
1411 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1414 IDEN (IDENtify the client software)
1416 The client software has the option to identify itself to the server.
1417 Currently, the server does nothing with this information except to write
1418 it to the syslog to satisfy the system administrator's curiosity. Other
1419 uses might become apparent in the future.
1421 The IDEN command should contain five fields: a developer ID number (same as
1422 the server developer ID numbers in the INFO command -- please obtain one if
1423 you are a new developer), a client ID number (which does not have to be
1424 globally unique - only unique within the domain of the developer number),
1425 a version number, a free-form text string describing the client, and the name
1426 of the host the user is located at.
1428 It is up to the server to determine whether to accept the host name or to
1429 use the host name it has detected itself. Generally, if the client is
1430 running on a trusted host (either localhost or a well-known publically
1431 accessible client) it should use the host name transmitted by IDEN,
1432 otherwise it should use the host name it has detected itself.
1434 IDEN always returns OK, but since that's the only way it ever returns
1435 there's no point in checking the result code.
1438 IPGM (identify as an Internal ProGraM)
1440 IPGM is a low-level command that should not be used by normal user clients.
1441 It is used for various utilities to communicate with the server on the same
1442 host. For example, the "sendcommand" utility logs onto the server as an
1443 internal program in order to run arbitrary server commands. Since user clients
1444 do not utilize this command (or any of its companion commands), developers
1445 writing Citadel-compatible servers need not implement it.
1447 The sole argument to IPGM is the system's internal program password. This
1448 password is generated by the setup program and stored in the config file.
1449 Since internal programs have access to the config file, they know the correct
1452 IPGM returns OK for a correct authentication or ERROR otherwise.
1455 CHAT (enter CHAT mode)
1457 This command functions differently from every other command in the system. It
1458 is used to implement multi-user chat. For this to function, a new transfer
1459 mode, called START_CHAT_MODE, is implemented. If a client does not support
1460 chat mode, it should never send a CHAT command!
1462 In chat mode, messages may arrive asynchronously from the server at any
1463 time. The client may send messages at any time. This allows the arrival of
1464 messages without the client having to poll for them. Arriving messages will
1465 be of the form "user|message", where the "user" portion is, of course, the
1466 name of the user sending the message, and "message" is the message text.
1468 Chat mode ends when the server says it ends. The server will signal the end
1469 of chat mode by transmitting "000" on a line by itself. When the client reads
1470 this line, it must immediately exit from chat mode without sending any
1471 further traffic to the server. The next transmission sent to the server
1472 will be a regular server command.
1474 The Citadel server understands the following commands:
1475 /quit - Exit from chat mode (causes the server to do an 000 end)
1476 /who - List users currently in chat
1477 /whobbs - List users currently in chat and elsewhere
1478 /me - Do an irc-style action.
1479 /join - Join a new "room" in which all messages are only heard by
1480 people in that room.
1481 /msg - /msg <user> <msg> will send the msg to <user> only.
1482 /help - Print help information
1483 NOOP - Do nothing (silently)
1485 Any other non-empty string is treated as message text and will be broadcast
1486 to other users currently in chat.
1489 SEXP (Send instant message)
1491 This is one of two commands which implement instant messages (also known
1492 as "paging"). Commands ending in "...EXP" are so-named because we called
1493 them "express messages" before the industry standardized on the term
1494 "instant messages." When an instant message is sent, it will be
1495 logged in user to another. When an instant message is sent, it will be
1496 displayed the next time the target user executes a PEXP or GEXP command.
1498 The SEXP command accepts two arguments: the name of the user to send the
1499 message to, and the text of the message. If the message is successfully
1500 transmitted, OK is returned. If the target user is not logged in or if
1501 anything else goes wrong, ERROR is returned.
1503 If the server supports extended paging, sending a zero-length message
1504 merely checks for the presence of the requested user without actually sending
1505 a message. Sending a message consisting solely of a "-" (hyphen) will cause
1506 the server to return SEND_LISTING if the requested user is logged in, and the
1507 client can then transmit a multi-line page.
1509 The reserved name "broadcast" may be used instead of a user name, to
1510 broadcast an instant message to all users currently connected to the server.
1512 Do be aware that if an instant message is transmitted to a user who is logged
1513 in using a client that does not check for instant messages, the message will
1514 never be received. Also, instant messages are NOT sent via the following
1515 transports: SMTP, POP3.
1518 PEXP (Print instant messages) ***DEPRECATED***
1520 This command is deprecated; it will eventually disappear from the protocol and
1521 its use is not recommended. Please use the GEXP command instead.
1523 Called without any arguments, PEXP simply dumps out the contents
1524 of any waiting instant messages. It returns ERROR if there is a problem,
1525 otherwise it returns LISTING_FOLLOWS followed by all messages.
1527 So how does the client know there are instant messages waiting? It could
1528 execute a random PEXP every now and then. Or, it can check the byte in
1529 server return code messages, between the return code and the parameters. In
1530 much the same way as FTP uses "-" to signify a continuation, Citadel uses
1531 an "*" in this position to signify the presence of waiting instant messages.
1534 EBIO (Enter BIOgraphy)
1536 Transmit to the server a free-form text file containing a little bit of
1537 information about the user for other users to browse. This is typically
1538 referred to as a 'bio' online. EBIO returns SEND_LISTING if it succeeds,
1539 after which the client is expected to transmit the file, or any of the usual
1540 ERROR codes if it fails.
1543 RBIO (Read BIOgraphy)
1545 Receive from the server a named user's bio. This command should be passed
1546 a single argument - the name of the user whose bio is requested. RBIO returns
1547 LISTING_FOLLOWS plus the bio file if the user exists and has a bio on file.
1548 The return has the following parameters: the user name, user number, access
1549 level, date of last call, times called, and messages posted. This command
1550 returns ERROR+NO_SUCH_USER if the named user does not exist.
1552 RBIO no longer considers a user with no bio on file to be an error condition.
1553 It now returns a message saying the user has no bio on file as the text of the
1554 bio. This allows newer servers to operate with older clients.
1557 STEL (enter STEaLth mode)
1559 When in "stealth mode," a user will not show up in the "Who is online"
1560 listing (the RWHO server command). Only Aides may use stealth mode. The
1561 STEL command accepts one argument: a 1 indicating that the user wishes to
1562 enter stealth mode, or a 0 indicating that the user wishes to exit stealth
1563 mode. STEL returns OK if the command succeeded, ERROR+NOT_LOGGED_IN if no
1564 user is logged in, or ERROR+HIGHER_ACCESS_REQUIRED if the user is not an Aide;
1565 followed by a 1 or 0 indicating the new state.
1567 If any value other than 1 or 0 is sent by the client, the server simply
1568 replies with 1 or 0 to indicate the current state without changing it.
1570 The STEL command also makes it so a user does not show up in the chat room
1574 LBIO (List users who have BIOs on file)
1576 This command is self-explanatory. Any user who has used EBIO to place a bio
1577 on file is listed. LBIO almost always returns LISTING_FOLLOWS followed by
1578 this listing, unless it experiences an internal error in which case ERROR
1582 MSG2 (read MeSsaGe, mode 2)
1584 MSG2 follows the same calling convention as MSG0. The difference between
1585 the two commands is that MSG2 outputs messages in standard RFC822 format
1586 rather than in Citadel proprietary format.
1588 This command was implemented in order to make various gateway programs
1589 easier to implement, and to provide some sort of multimedia support in the
1590 future. Keep in mind that when this command is used, all messages will be
1591 output in fixed 80-column format.
1594 MSG3 (read MeSsaGe, mode 3 -- internal command)
1596 MSG3 is for use by internal programs only and should not be utilized by
1597 user-mode clients. It does require IPGM authentication. MSG3 follows the
1598 same calling convention as the other MSG commands, but upon success returns
1599 BINARY_FOLLOWS followed by a data block containing the _raw_ message format
1603 TERM (TERMinate another session)
1605 In a multithreaded environment, it sometimes becomes necessary to terminate
1606 a session that is unusable for whatever reason. The TERM command performs
1607 this task. Naturally, only Aides can execute TERM. The command should be
1608 called with a single argument: the session ID (obtained from an RWHO command)
1609 of the session to be terminated.
1611 TERM returns OK if the session was terminated, or ERROR otherwise. Note that
1612 a client program is prohibited from terminating the session it is currently
1618 DOWN (shut DOWN the server)
1620 This command, which may only be executed by an Aide, immediately shuts down
1621 the server. It is only implemented on servers on which such an operation is
1622 possible, such as a multithreaded Citadel engine. The server does not restart.
1623 DOWN returns OK if the user is allowed to shut down the server, in which case
1624 the client program should expect the connection to be immediately broken.
1627 SCDN (Schedule or Cancel a shutDowN)
1629 SCDN sets or clears the "scheduled shutdown" flag. Pass this command a 1 or
1630 0 to respectively set or clear the flag. When the "scheduled shutdown" flag is
1631 set, the server will be shut down when there are no longer any users logged in.
1632 Any value other than 0 or 1 will not change the flag, only report its state.
1633 No users will be kicked off the system, and in fact the server is still
1634 available for new connections. The command returns ERROR if it fails;
1635 otherwise, it returns OK followed by a number representing the current state
1639 EMSG (Enter a system MeSsaGe)
1641 This is the opposite of the MESG command - it allows the creation and editing
1642 of system messages. The only argument passed to EMSG is the name of the
1643 file being transmitted. If the file exists in any system message directory
1644 on the server it will be overwritten, otherwise a new file is created. EMSG
1645 returns SEND_LISTING on success or ERROR+HIGHER_ACCESS_REQUIRED if the user
1648 Typical client software would use MESG to retrieve any existing message into
1649 an edit buffer, then present an editor to the user and run EMSG if the changes
1653 UIMG (Upload an IMaGe file)
1655 UIMG is complemenary to OIMG; it is used to upload an image to the server.
1656 The first parameter supplied to UIMG should be 0 if the client is only checking
1657 for permission to upload, or 1 if the client is actually attempting to begin
1658 the upload operation. The second argument is the name of the file to be
1659 transmitted. In Citadel, the filename is converted to all lower case,
1660 appended with the characters ".gif", and stored in the "images" directory.
1662 UIMG returns OK if the client has permission to perform the requested upload,
1663 or ERROR+HIGHER_ACCESS_REQUIRED otherwise. If the client requested to begin
1664 the operation (first parameter set to 1), an upload file is opened, and the
1665 client should begin writing to it with WRIT commands, then close it with a
1668 The supplied filename should be one of:
1670 -> _userpic_ (Server will attempt to write to the user's online photo)
1671 -> Any of the "well known" filenames described in the writeup for the
1675 HCHG (Hostname CHanGe)
1677 HCHG is a command, usable by any user, that allows a user to change their RWHO
1678 host value. This will mask a client's originating hostname from normal
1679 users; access level 6 and higher can see, in an extended wholist, the actual
1680 hostname the user originates from.
1682 The format of an HCHG command is:
1686 If a HCHG command is successful, the value OK (200) is returned.
1689 RCHG (Roomname CHanGe)
1691 RCHG is a command, usable by any user, that allows a user to change their RWHO
1692 room value. This will mask a client's roomname from normal users; access
1693 level 6 and higher can see, in an extended wholist, the actual room the user
1696 The format of an RCHG command is:
1700 If a RCHG command is successful, the value OK (200) is returned.
1703 UCHG (Username CHanGe)
1705 UCHG is an aide-level command which allows an aide to effectively change their
1706 username. If this value is blank, the user goes into stealth mode (see
1708 will show up as being from the real username in this mode, however. In
1709 addition, the RWHO listing will include both the spoofed and real usernames.
1711 The format of an UCHG command is:
1715 If a UCHG command is successful, the value OK (200) is returned.
1718 TIME (get server local TIME)
1720 TIME returns OK followed by the current time measured in seconds since
1721 00:00:00 GMT, Jan 1, 1970 (standard Unix format).
1723 This is used in allowing a client to calculate idle times.
1726 AGUP (Administrative Get User Parameters)
1727 ASUP (Administrative Set User Parameters)
1729 These commands are only executable by Aides and by server extensions running
1730 at system-level. They are used to get/set any and all parameters relating to
1731 a user account. AGUP requires only one argument: the name of the user in
1732 question. SGUP requires all of the parameters to be set. The parameters are
1733 as follows, and are common to both commands:
1737 2 - Flags (see citadel.h)
1742 7 - Timestamp of last call
1743 8 - Purge time (in days) for this user (or 0 to use system default)
1745 Upon success, AGUP returns OK followed by all these parameters, and ASUP
1746 simply returns OK. If the client has insufficient access to perform the
1747 requested operation, ERROR+HIGHER_ACCESS_REQUIRED is returned. If the
1748 requested user does not exist, ERROR+NO_SUCH_USER is returned.
1752 GPEX (Get Policy for message EXpiration)
1754 Returns the policy of the current room, floor, or site regarding the automatic
1755 purging (expiration) of messages. The following policies are available:
1756 0 - Fall back to the policy of the next higher level. If this is a room,
1757 use the floor's default policy. If this is a floor, use the system
1758 default policy. This is an invalid value for the system policy.
1759 1 - Do not purge messages automatically.
1760 2 - Purge by message count. (Requires a value: number of messages)
1761 3 - Purge by message age. (Requires a value: number of days)
1763 The format of this command is: GPEX <which>
1764 The value of <which> must be one of: "room" "floor" "site" "mailboxes"
1766 If successful, GPEX returns OK followed by <policy>|<value>.
1770 SPEX (Set Policy for message EXpiration)
1772 Sets the policy of the current room, floor, or site regarding the automatic
1773 purging (expiration) of messages. See the writeup for the GPEX command for
1774 the list of available policies.
1776 The format of this command is: SPEX <which>|<policy>|<value>
1777 The value of <which> must be one of: "room" "floor" "site" "mailboxes"
1779 If successful, GPEX returns OK; otherwise, an ERROR code is returned.
1783 CONF (get or set global CONFiguration options)
1785 Retrieves or sets various system-wide configuration and policy options. This
1786 command is only available to Aides. The sole parameter accepted is a command,
1787 which should be either GET or SET. If the GET command succeeds, CONF will
1788 return LISTING_FOLLOWS followed by the fields described below, one line at a
1789 time. If the SET command succeeds, CONF will return SEND_LISTING and expect
1790 the fields described below, one line at a time (don't worry about other fields
1791 being added in the future; if a 'short' configuration list is sent, the missing
1792 values at the end will be left unchanged on the system). If either command
1793 fails for any reason, ERROR is returned.
1795 The configuration lines are as follows:
1798 2. Fully qualified domain name
1799 3. Human-readable node name
1800 4. Landline telephone number of this system
1801 5. Flag (0 or 1) - creator of private room automatically becomes room aide
1802 6. Server connection idle timeout (in seconds)
1803 7. Initial access level for new users
1804 8. Flag (0 or 1) - require registration for new users
1805 9. Flag (0 or 1) - automatically move Problem User messages to twit room
1806 10. Name of twit room
1807 11. Text of <more> prompt
1808 12. Flag (0 or 1) - restrict access to Internet mail
1809 13. Geographic location of this system
1810 14. Name of the system administrator
1811 15. Number of maximum concurrent sessions allowed on the server
1812 16. (placeholder -- this field is no longer in use)
1813 17. Default purge time (in days) for users
1814 18. Default purge time (in days) for rooms
1815 19. Name of room to log instant messages to (or a zero-length name for none)
1816 20. Access level required to create rooms
1817 21. Maximum message length which may be entered into the system
1818 22. Minimum number of worker threads
1819 23. Maximum number of worker threads
1820 24. Port number for POP3 service
1821 25. Port number for SMTP service
1822 26. Flag (0 or 1) - strict RFC822 adherence - don't correct From: forgeries
1823 27. Flag (0 or 1) - allow Aides to zap (forget) rooms
1824 28. Port number for IMAP service
1825 29. How often (in seconds) to run the networker
1826 30. Flag (0 or 1) - disable self-service new user registration
1827 31. (placeholder -- this field is no longer in use)
1828 32. Hour (0 through 23) during which database auto-purge jobs are run
1829 33. Name of host where an LDAP service may be found
1830 34. Port number of LDAP service on above host
1833 37. Password for LDAP Bind DN
1834 38. Server IP address to listen on (or "0.0.0.0" for all addresses)
1835 39. Port number for SMTP MSA service
1836 40. Port number for IMAPS (SSL-encrypted IMAP)
1837 41. Port number for POP3S (SSL-encrypted POP3)
1838 42. Port number for SMTPS (SSL-encrypted SMTP)
1839 43. Flag (0 or 1) - enable full text search index
1840 44. Flag (0 or 1) - automatically cull database log files
1841 45. Flag (0 or 1) - enable IMAP "instant expunge" of deleted messages
1842 46. Flag (0 or 1) - allow unauthenticated SMTP clients to spoof my domains
1844 CONF also accepts two additional commands: GETSYS and PUTSYS followed by an
1845 arbitrary MIME type (such as application/x-citadel-internet-config) which
1846 provides a means of storing generic configuration data in the Global System
1847 Configuration room without the need to add extra get/set commands to the
1850 Please note that the LDAP-specific configs have no effect on Citadel servers
1851 in which LDAP support is not enabled.
1855 MSG4 (read MeSsaGe, mode 4 -- output in preferred MIME format)
1857 This is the equivalent of MSG0, except it's a bit smarter about messages in
1858 rich text formats. Immediately following the "text" directive, the server
1859 will output RFC822-like MIME part headers such as "Content-type:" and
1860 "Content-length:". MIME formats are chosen and/or converted based on the
1861 client's preferred format settings, which are set using the MSGP command,
1866 MSGP (set MeSsaGe Preferred MIME format)
1868 Client tells the server what MIME content types it knows how to handle, and
1869 the order in which it prefers them. This is similar to an HTTP "Accept:"
1872 The parameters to a MSGP command are the client's acceptable MIME content
1873 types, in the order it prefers them (from most preferred to least preferred).
1874 For example: MSGP text/html|text/plain
1876 The MSGP command always returns OK.
1880 OPNA (OPeN Attachment)
1882 Opens, as a download file, a component of a MIME-encoded message. The two
1883 parameters which must be passed to this command are the message number and the
1884 name of the desired section. If the message or section does not exist, an
1885 appropriate ERROR code will be returned; otherwise, if the open is successful,
1886 this command will succeed returning the same information as an OPEN command.
1889 GEXP (Get instant messages)
1891 This is a more sophisticated way of retrieving instant messages than the old
1892 PEXP method. If there are no instant messages waiting, PEXP returns ERROR;
1893 otherwise, it returns LISTING_FOLLOWS and the following arguments:
1895 0 - a boolean value telling the client whether there are any additional
1896 instant messages waiting following this one
1897 1 - a Unix-style timestamp
1898 2 - flags (see server.h for more info)
1899 3 - the name of the sender
1900 4 - the node this message originated on (for future support of PIP, ICQ, etc.)
1902 The text sent to the client will be the body of the instant message.
1904 So how does the client know there are instant messages waiting? It could
1905 execute a random GEXP every now and then. Or, it can check the byte in
1906 server return code messages, between the return code and the parameters. In
1907 much the same way as FTP uses "-" to signify a continuation, Citadel uses
1908 an "*" in this position to signify the presence of waiting instant messages.
1911 FSCK (check message base reference counts)
1913 Verify, via the long way, that all message referenmce counts are correct. If
1914 the user has permission to do this then LISTING_FOLLOWS is returned, followed
1915 by a transcript of the run. Otherwise ERROR is returned.
1918 DEXP (Disable receiving instant messages)
1920 DEXP sets or clears the "disable instant messages" flag. Pass this command a
1921 1 or 0 to respectively set or clear the flag. When the "disable instant
1922 messages" flag is set, no one except Aides may send the user instant messages.
1923 Any value other than 0 or 1 will not change the flag, only report its state.
1924 The command returns ERROR if it fails; otherwise, it returns OK followed by a
1925 number representing the current state of the flag.
1928 REQT (REQuest client Termination)
1930 Request that the specified client (or all clients) log off. Aide level
1931 access is required to run this command, otherwise ERROR+HIGHER_ACCESS_REQUIRED
1934 The REQT command accepts one parameter: the session ID of the client which
1935 should be terminated, or 0 for all clients. When successful, the REQT command
1938 It should be noted that REQT simply transmits an instant message to the
1939 specified client(s) with the EM_GO_AWAY flag set. Older clients do not honor
1940 this flag, and it is certainly possible for users to re-program their client
1941 software to ignore it. Therefore the effects of the REQT command should be
1942 considered advisory only. The recommended implementation practice is to first
1943 issue a REQT command, then wait a little while (from 30 seconds up to a few
1944 minutes) for well-behaved clients to voluntarily terminate, and then issue a
1945 TERM command to forcibly disconnect the client (or perhaps a DOWN command, if
1946 you are logging off users for the purpose of shutting down the server).
1949 SEEN (set or clear the SEEN flag for a message)
1951 Beginning with version 5.80, Citadel supports the concept of setting or
1952 clearing the "seen" flag for each individual message, instead of only allowing
1953 a "last seen" pointer. In fact, the old semantics are implemented in terms
1954 of the new semantics. This command requires two arguments: the number of the
1955 message to be set, and a 1 or 0 to set or clear the "seen" bit.
1957 This command returns OK, unless the user is not logged in or a usage error
1958 occurred, in which case it returns ERROR. Please note that no checking is
1959 done on the supplied data; if the requested message does not exist, the SEEN
1960 command simply returns OK without doing anything.
1963 GTSN (GeT the list of SeeN messages)
1965 This command retrieves the list of "seen" (as opposed to unread) messages for
1966 the current room. It returns OK followed by an IMAP-format message list.
1969 SMTP (utility commands for the SMTP gateway)
1971 This command, accessible only by Aides, supports several utility operations
1972 which examine or manipulate Citadel's SMTP support. The first command argument
1973 is a subcommand telling the server what to do. The following subcommands are
1976 SMTP mx|hostname (display all MX hosts for 'hostname')
1977 SMTP runqueue (attempt immediate delivery of all messages
1978 in the outbound SMTP queue, ignoring any
1979 retry times stored there)
1982 STLS (Start Transport Layer Security)
1984 This command starts TLS on the current connection. The current
1985 implementation uses OpenSSL on both the client and server end. For future
1986 compatibility all clients must support at least TLSv1, and servers are
1987 guaranteed to support TLSv1. During TLS negotiation (see below) the server
1988 and client may agree to use a different protocol.
1990 The server returns ERROR if it does not support SSL or SSL initialization
1991 failed on the server; otherwise it returns OK. Once the server returns OK and
1992 the client has read the response, the server and client immediately negotiate
1993 TLS (in OpenSSL, using SSL_connect() on the client and SSL_accept() on the
1994 server). If negotiation fails, the server and client should attempt to resume
1995 the session unencrypted. If either end is unable to resume the session, the
1996 connection should be closed.
1998 This command may be run at any time.
2001 GTLS (Get Transport Layer Security Status)
2003 This command returns information about the current connection. The server
2004 returns OK plus several parameters if the connection is encrypted, and ERROR
2005 if the connection is not encrypted. It is primarily used for debugging. The
2006 command may be run at any time.
2008 0 - Protocol name, e.g. "SSLv3"
2009 1 - Cipher suite name, e.g. "ADH-RC4-MD5"
2010 2 - Cipher strength bits, e.g. 128
2011 3 - Cipher strength bits actually in use, e.g. 128
2014 IGAB (Initialize Global Address Book)
2016 This command creates, or re-creates, a database of Internet e-mail addresses
2017 using the vCard information in the Global Address Book room. This procedure
2018 is normally run internally when the server determines it necessary, but is
2019 also provided as a server command to be used as a troubleshooting/maintenenance
2020 tool. Only a system Aide can run the command. It returns OK on success or
2024 QDIR (Query global DIRectory)
2026 Look up an internet address in the global directory. Any logged-in user may
2027 call QDIR with one parameter, the Internet e-mail address to look up. QDIR
2028 returns OK followed by a Citadel address if there is a match, otherwise it
2029 returns ERROR+NOT_LOGGED_IN.
2032 ISME (find out if an e-mail address IS ME)
2034 This is a quickie shortcut command to find out if a given e-mail address
2035 belongs to the user currently logged in. Its sole argument is an address to
2036 parse. The supplied address may be in any format (local, IGnet, or Internet).
2037 The command returns OK if the address belongs to the user, ERROR otherwise.
2040 VIEW (set the VIEW for a room)
2042 Set the preferred view for the current user in the current room. Please see
2043 views.txt for more information on views. The sole parameter for this command
2044 is the type of view requested. VIEW returns OK on success or ERROR on failure.
2047 QNOP (Quiet No OPeration)
2049 This command does nothing, similar to the NOOP command. However, unlike the
2050 NOOP command, it returns *absolutely no response* at all. The client has no
2051 way of knowing that the command executed. It is intended for sending
2052 "keepalives" in situations where a full NOOP would cause the client protocol
2055 Naturally, sending this command to a server that doesn't support it is an
2056 easy way to mess things up. Therefore, client software should first check
2057 the output of an INFO command to ensure that the server supports quiet noops.
2061 ICAL (Internet CALendaring commands)
2063 This command supports a number of subcommands which are used to process the
2064 calendaring/scheduling support in Citadel. Here are the subcommands which
2068 Test server for calendaring support. Always returns OK unless the server
2069 does not have the calendar module enabled.
2071 ICAL respond|msgnum|partnum|action
2072 Respond to a meeting request. 'msgnum' and 'partnum' refer to a MIME-encoded
2073 meeting invitation in the current room. 'action' must be set to either
2074 "accept" or "decline" to determine the action to take. This subcommand will
2075 return either OK or ERROR.
2077 ICAL conflicts|msgnum|partnum
2078 Determine whether an incoming VEVENT will fit in the user's calendar by
2079 checking it against the existing VEVENTs. 'msgnum' and 'partnum' refer to
2080 a MIME-encoded meeting invitation in the current room (usually the inbox).
2081 This command may return ERROR if something went wrong, but usually it will
2082 return LISTING_FOLLOWS followed by a list of zero or more conflicting
2083 events. A zero-length list means that there were no conflicts.
2085 ICAL handle_rsvp|msgnum|partnum
2086 Handle an incoming "reply" (or RSVP) to a meeting request you sent out.
2087 'msgnum' and 'partnum' refer to a MIME-encoded reply in the current room.
2088 'action' must be set to either "update" or "ignore" to determine the action
2089 to take. If the action is "update" then the server will hunt for the meeting
2090 in the user's Calendar> room, and update the status for this attendee. Either
2091 way, the reply message is deleted from the current room. This subcommand will
2092 return either OK or ERROR.
2094 ICAL freebusy|username
2095 Output the free/busy times for the requested user. If the user specified
2096 has a calendar available, this command will return LISTING_FOLLOWS and a
2097 compound VCALENDAR object. That object, in turn, will contain VEVENT
2098 objects that have been stripped of all properties except for the bare
2099 minimum needed to learn free/busy times (such as DTSTART, DTEND, and
2100 TRANSP). If there is no such user, or no calendar available, the usual
2101 ERROR codes will be returned.
2105 Readers who are paying attention will notice that there is no subcommand to
2106 send out meeting invitations. This is because that task can be handled
2107 automatically by the Citadel server. Issue this command with <bool> set to 1
2108 to enable Server Generated Invitations. In this mode, when an event is saved
2109 to the user's Calendar> room and it contains attendees, Citadel will
2110 automatically turn the event into vCalendar REQUEST messages and mail them
2111 out to all listed attendees. If for some reason the client needs to disable
2112 Server Generated Invitations, the command may be sent again with <bool> = 0.
2116 MRTG (Multi Router Traffic Grapher)
2118 Multi Router Traffic Grapher (please see http://www.mrtg.org for more info) is
2119 a tool which creates pretty graphs of network activity, usually collected from
2120 routers using SNMP. However, its ability to call external scripts has spawned
2121 a small community of people using it to graph anything which can be graphed.
2122 The MRTG command can output Citadel server activity in the format MRTG expects.
2124 This format is as follows:
2129 Line 3: uptime of system
2130 Line 4: name of system
2133 MRTG accepts two different keywords. "MRTG users" will return two variables,
2134 the number of connected users and the number of active users. "MRTG messages"
2135 will return one variable (and a zero in the second field), showing the current
2136 highest message number on the system. Any other keyword, or a missing keyword,
2137 will cause the MRTG command to return an ERROR code.
2139 Please get in touch with the Citadel developers if you wish to experiment with
2144 GNET (Get NETwork configuration for this room)
2145 SNET (Set NETwork configuration for this room)
2147 These commands get/set the network configuration for the current room. Aide
2148 or Room Aide privileges are required, otherwise an ERROR code is returned.
2149 If the command succeeds, LISTING_FOLLOWS or SEND_LISTING is returned. The
2150 network configuration for a specific room includes neighbor nodes with whom
2151 the room is shared, and mailing list recipients. The format of the network
2152 configuration is described in the file "netconfigs.txt".
2156 ASYN (ASYNchronous message support)
2158 Negotiate the use of asynchronous, or unsolicited, protocol messages. The
2159 only parameter specified should be 1 or 0 to indicate that the client can or
2160 cannot handle this type of messages. The server will reply OK followed by a
2161 1 or 0 to tell the client which mode it is now operating in.
2163 If the command is not available on the server (i.e. it returns ERROR), or
2164 if the command has not been executed by the client, it should be assumed that
2165 this mode of operation is NOT in effect.
2167 The client may also send any value other than 0 or 1 to simply cause the
2168 server to output its current state without changing it.
2170 When asynchronous protocol mode is in effect, the client MUST handle any
2171 asynchronous messages as they arrive, before doing anything else.
2175 SRCH (SeaRCH the message base)
2177 This command's implementation is incomplete and will be documented when it
2183 ASYNCHRONOUS MESSAGES
2184 ---------------------
2186 When the client protocol is operating in asynchronous mode (please refer to
2187 the writeup of the ASYN command above), the following messages may arrive at
2191 902 (instant message arriving)
2193 One or more instant messages have arrived for this client.