1 SESSION LAYER PROTOCOL FOR CITADEL/UX
2 (c) 1995-2004 by Art Cancro et. al. All Rights Reserved
8 This is an attempt to document the session layer protocol used by the
9 Citadel/UX 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/UX project is Art Cancro
27 <ajc@uncensored.citadel.org>.
30 CONNECTING TO A SERVER
31 ----------------------
33 The protocols used below the session layer are beyond the scope of this
34 document, but we will briefly cover the methodology employed by Citadel/UX.
36 Citadel/UX offers Citadel BBS service using TCP/IP. It does so via a
37 multithreaded server listening on a TCP port. Older (4.xx) versions employed
38 an inetd-based server.
40 The port number officially assigned to Citadel by the IANA is 504/tcp. Since
41 our session 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 session 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/UX 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 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 or if a USER command has not been executed yet, ERROR is returned. If the
170 password is correct, OK is returned and the user is now logged in... and
171 most of the other server commands can now be executed. Along with OK, the
172 following parameters are returned:
174 0 - The user's name (in case the client wants the right upper/lower casing)
175 1 - The user's current access level
178 4 - Various flags (see citadel.h)
180 6 - Time of last call (UNIX timestamp)
183 NEWU (create NEW User account)
185 This command creates a new user account AND LOGS IT IN. The argument to
186 this command will be the name of the account. No case conversion is done
187 on the name. Note that the new account is installed with a default
188 configuration, and no password, so the client should immediately prompt the
189 user for a password and install it with the SETP command as soon as this
190 command completes. This command returns OK if the account was created and
191 logged in, or ERROR if another user already exists with this name. If OK,
192 it will also return the same parameters that PASS returns.
194 Please note that the NEWU command should only be used for self-service user account
195 creation. For administratively creating user accounts, please use the CREU command.
198 SETP (SET new Password)
200 This command sets a new password for the currently logged in user. The
201 argument to this command will be the new password. The command always
202 returns OK, unless the client is not logged in, in which case it will return
206 CREU (CREate new User account)
208 This command creates a new user account AND DOES NOT LOG IT IN. The first
209 argument to this command will be the name of the account. No case conversion
210 is done on the name. Note that the new account is installed with a default
211 configuration, and no password. The second argument is optional, and will be
212 an initial password for the user. This command returns OK if the account was
213 created, or ERROR if another user already exists with this name.
215 Please note that CREU is intended to be used for activities in which a system
216 administrator is creating user accounts. For self-service user account
217 creation, use the NEWU command.
220 LKRN (List Known Rooms with New messages)
222 List known rooms with new messages. If the client is not logged in, ERROR
223 is returned. Otherwise, LISTING_FOLLOWS is returned, followed by the room
224 listing. Each line in the listing contains the full name of a room, followed
225 by the '|' symbol, and then a number that may contain the following bits:
228 #define QR_PERMANENT 1 /* Room does not purge */
229 #define QR_PRIVATE 4 /* Set for any type of private room */
230 #define QR_PASSWORDED 8 /* Set if there's a password too */
231 #define QR_GUESSNAME 16 /* Set if it's a guessname room */
232 #define QR_DIRECTORY 32 /* Directory room */
233 #define QR_UPLOAD 64 /* Allowed to upload */
234 #define QR_DOWNLOAD 128 /* Allowed to download */
235 #define QR_VISDIR 256 /* Visible directory */
236 #define QR_ANONONLY 512 /* Anonymous-Only room */
237 #define QR_ANON2 1024 /* Anonymous-Option room */
238 #define QR_NETWORK 2048 /* Shared network room */
239 #define QR_PREFONLY 4096 /* Preferred status needed to enter */
240 #define QR_READONLY 8192 /* Aide status required to post */
242 Then it returns another '|' symbol, followed by a second set of bits comprised
244 #define QR2_SYSTEM 1 /* System room; hide by default */
245 #define QR2_SELFLIST 2 /* Self-service mailing list mgmt */
247 Other bits may be defined in the future. The listing terminates, as with
248 all listings, with "000" on a line by itself.
250 Starting with version 4.01 and above, floors are supported. The first
251 argument to LKRN should be the number of the floor to list rooms from. Only
252 rooms from this floor will be listed. If no arguments are passed to LKRN, or
253 if the floor number requested is (-1), rooms on all floors will be listed.
255 The third field displayed on each line is the number of the floor the room
256 is on. The LFLR command should be used to associate floor numbers with
259 The fourth field displayed on each line is a "room listing order." Unless
260 there is a compelling reason not to, clients should sort any received room
261 listings by this value.
263 The fifth field is a special bit bucket containing fields which pertain to
264 room access controls:
266 #define UA_KNOWN 2 /* Known room */
267 #define UA_GOTOALLOWED 4 /* Access will be granted to this room
268 * if the user calls it up by name */
269 #define UA_HASNEWMSGS 8 /* Unread messages exist in room */
270 #define UA_ZAPPED 16 /* Zapped from known rooms list */
274 LKRO (List Known Rooms with Old [no new] messages)
276 This follows the same usage and format as LKRN.
279 LZRM (List Zapped RooMs)
281 This follows the same usage and format as LKRN and LKRO.
284 LKRA (List All Known Rooms)
286 Same format. Lists all known rooms, with or without new messages.
289 LRMS (List all accessible RooMS)
291 Again, same format. This command lists all accessible rooms, known and
292 forgotten, with and without new messages. It does not, however, list
293 inaccessible private rooms.
296 LPRM (List all Public RooMs)
298 Again, same format. This command lists all public rooms, and nothing else.
299 Unlike the other list rooms commands, this one can be executed without logging
303 GETU (GET User configuration)
305 This command retrieves the screen dimensions and user options for the
306 currently logged in account. ERROR will be returned if no user is logged
307 in, of course. Otherwise, OK will be returned, followed by four parameters.
308 The first parameter is the user's screen width, the second parameter is the
309 user's screen height, and the third parameter is a bag of bits with the
312 #define US_LASTOLD 16 /* Print last old message with new */
313 #define US_EXPERT 32 /* Experienced user */
314 #define US_UNLISTED 64 /* Unlisted userlog entry */
315 #define US_NOPROMPT 128 /* Don't prompt after each message */
316 #define US_DISAPPEAR 512 /* Use "disappearing msg prompts" */
317 #define US_PAGINATOR 2048 /* Pause after each screen of text */
319 There are other bits, too, but they can't be changed by the user (see below).
322 SETU (SET User configuration)
324 This command does the opposite of SETU: it takes the screen dimensions and
325 user options (which were probably obtained with a GETU command, and perhaps
326 modified by the user) and writes them to the user account. This command
327 should be passed three parameters: the screen width, the screen height, and
328 the option bits (see above).
330 Note that there exist bits here which are not listed in this document. Some
331 are flags that can only be set by Aides or the system administrator. SETU
332 will ignore attempts to toggle these bits. There also may be more user
333 settable bits added at a later date. To maintain later downward compatibility,
334 the following procedure is suggested:
336 1. Execute GETU to read the current flags
337 2. Toggle the bits that we know we can toggle
338 3. Execute SETU to write the flags
340 If we are passed a bit whose meaning we don't know, it's best to leave it
341 alone, and pass it right back to the server. That way we can use an old
342 client on a server that uses an unknown bit without accidentally clearing
343 it every time we set the user's configuration.
348 This command is used to goto a new room. When the user first logs in (login
349 is completed after execution of the PASS command) this command is
350 automatically and silently executed to take the user to the first room in the
351 system (usually called the Lobby).
353 This command can be passed one or two parameters. The first parameter is,
354 of course, the name of the room. Although it is not case sensitive, the
355 full name of the room must be used. Wildcard matching or unique string
356 matching of room names should be the responsibility of the client.
358 Note that the reserved room name "_BASEROOM_" can be passed to the server
359 to cause the goto command to take the user to the first room in the system,
360 traditionally known as the Lobby>. As long as a user is logged in, a
361 GOTO command to _BASEROOM_ is guaranteed to succeed. This is useful to
362 allow client software to return to the base room when it doesn't know
365 There are also two additional reserved room names:
366 "_MAIL_" translates to the system's designated room for e-mail messages.
367 "_BITBUCKET_" goes to whatever room has been chosen for messages
370 The second (and optional) parameter is a password, if one is required for
371 access to the room. This allows for all types of rooms to be accessed via
372 this command: for public rooms, invitation-only rooms to which the user
373 has access, and preferred users only rooms to which the user has access, the
374 room will appear in a room listing. For guess-name rooms, this command
375 will work transparently, adding the room to the user's known room list when
376 it completes. For passworded rooms, access will be denied if the password
377 is not supplied or is incorrect, or the command will complete successfully
378 if the password is correct.
380 The third (and also) optional parameter is a "transient" flag. Normally,
381 when a user enters a private and/or zapped room, the room is added to the
382 user's known rooms list. If the transient flag is set to non-zero, this is
383 called a "transient goto" which causes the user to enter the room without
384 adding the room to the known rooms list.
386 The possible result codes are:
388 OK - The command completed successfully. User is now in the room.
389 (See the list of returned parameters below)
391 ERROR - The command did not complete successfully. Check the second and
392 third positions of the result code to find out what happened:
394 NOT_LOGGED_IN - Of course you can't go there. You didn't log in.
395 PASSWORD_REQUIRED - Either a password was not supplied, or the supplied
396 password was incorrect.
397 NO_SUCH_ROOM - The requested room does not exist.
399 The typical procedure for entering a passworded room would be:
401 1. Execute a GOTO command without supplying any password.
402 2. ERROR+PASSWORD_REQUIRED will be returned. The client now knows that
403 the room is passworded, and prompts the user for a password.
404 3. Execute a GOTO command, supplying both the room name and the password.
405 4. If OK is returned, the command is complete. If, however,
406 ERROR+PASSWORD_REQUIRED is still returned, tell the user that the supplied
407 password was incorrect. The user remains in the room he/she was previously
410 When the command succeeds, these parameters are returned:
411 0. The name of the room
412 1. Number of unread messages in this room
413 2. Total number of messages in this room
414 3. Info flag: set to nonzero if the user needs to read this room's info
415 file (see RINF command below)
416 4. Various flags associated with this room. (See LKRN cmd above)
417 5. The highest message number present in this room
418 6. The highest message number the user has read in this room
419 7. Boolean flag: 1 if this is a Mail> room, 0 otherwise.
420 8. Aide flag: 1 if the user is either the Room Aide for this room, *or* is
421 a regular Aide (this makes access checks easy).
422 9. The number of new Mail messages the user has (useful for alerting the
423 user to the arrival of new mail during a session)
424 10. The floor number this room resides on
425 11. The *current* "view" for this room (see views.txt for more info)
426 12. The *default* "view" for this room
428 The default view gives the client a hint as to what views the user should
429 be allowed to select. For example, it would be confusing to allow messages
430 in a room intended for calendar items. The server does not enforce these
431 restrictions, though.
434 MSGS (get pointers to MeSsaGeS in this room)
436 This command obtains a listing of all the messages in the current room
437 which the client may request. This command may be passed a single parameter:
438 either "all", "old", or "new" to request all messages, only old messages, or
439 new messages. Or it may be passed two parameters: "last" plus a number, in
440 which case that many message pointers will be returned, or "first" plus a
441 number, for the corresponding effect. If no parameters are specified, "all"
444 In Citadel/UX 5.00 and above, the client may also specify "gt" plus a number,
445 to list all messages in the current room with a message number greater than
448 The third argument, valid only in Citadel/UX 5.60 and above, may be either
449 0 or 1. If it is 1, this command behaves differently: before a listing is
450 returned, the client must transmit a list of fields to search for. The field
451 headers are listed below in the writeup for the "MSG0" command.
453 This command can return three possible results. An ERROR code may be returned
454 if no user is currently logged in or if something else went wrong. Otherwise,
455 LISTING_FOLLOWS will be returned, and the listing will consist of zero or
456 more message numbers, one per line. The listing ends, as always, with the
457 string "000" alone on a line by itself. The listed message numbers can be used
458 to request messages from the system. If "search mode" is being used, the
459 server will return START_CHAT_MODE, and the client is expected to transmit
460 the search criteria, and then read the message list.
462 Since this is somewhat complex, here are some examples:
464 Example 1: Read all new messages
467 Server: 100 Message list...
473 Example 2: Read the last five messages
476 Server: 100 Message list...
484 Example 3: Read all messages written by "IGnatius T Foobar"
487 Server: 800 Send template then receive message list
488 Client: from|IGnatius T Foobar
502 Note that in "search mode" the client may specify any number of search
503 criteria. These criteria are applied with an AND logic.
507 MSG0 (read MeSsaGe, mode 0)
509 This is a command used to read the text of a message. "Mode 0" implies that
510 other MSG commands (MSG1, MSG2, etc.) will probably be added later on to read
511 messages in more robust formats. This command should be passed two arguments.
512 The first is the message number of the message being requested. The second
513 argument specifies whether the client wants headers and/or message body:
518 If the request is denied, an ERROR code will be returned. Otherwise, the
519 LISTING_FOLLOWS code will be returned, followed by the contents of the message.
520 The following fields may be sent:
522 type= Formatting type. The currently defined types are:
523 0 = "traditional" Citadel formatting. This means that newlines should be
524 treated as spaces UNLESS the first character on the next line is a space. In
525 other words, only indented lines should generate a newline on the user's screen
526 when the message is being displayed. This allows a message to be formatted to
527 the reader's screen width. It also allows the use of proportional fonts.
528 1 = a simple fixed-format message. The message should be displayed to
529 the user's screen as is, preferably in a fixed-width font that will fit 80
531 4 = MIME format message. The message text is expected to contain a header
532 with the "Content-type:" directive (and possibly others).
534 msgn= The message ID of this message on the system it originated on.
535 path= An e-mailable path back to the user who wrote the message.
537 time= The date and time of the message, in Unix format (the number of
538 seconds since midnight on January 1, 1970, GMT).
540 from= The name of the author of the message.
541 rcpt= If the message is a private e-mail, this is the recipient.
542 room= The name of the room the message originated in.
543 node= The short node name of the system this message originated on.
544 hnod= The long node name of the system this message originated on.
545 zaps= The id/node of a message which this one zaps (supersedes).
547 part= Information about a MIME part embedded in this message.
548 pref= Information about a multipart MIME prefix such as "multipart/mixed"
549 or "multipart/alternative". This will be output immediately prior
550 to the various "part=" lines which make up the multipart section.
551 suff= Information about a multipart MIME suffix. This will be output
552 immediately following the various "part=" lines which make up the
555 text Note that there is no "=" after the word "text". This string
556 signifies that the message text begins on the next line.
559 WHOK (WHO Knows room)
561 This command is available only to Aides. ERROR+HIGHER_ACCESS_REQUIRED will
562 be returned if the user is not an Aide. Otherwise, it returns
563 LISTING_FOLLOWS and then lists, one user per line, every user who has
564 access to the current room.
567 INFO (get server INFO)
569 This command will *always* return LISTING_FOLLOWS and then print out a
570 listing of zero or more strings. Client software should be written to expect
571 anywhere from a null listing to an infinite number of lines, to allow later
572 backward compatibility. The current implementation defines the following
573 parts of the listing:
575 Line 1 - Your unique session ID on the server
576 Line 2 - The node name of the server BBS
577 Line 3 - Human-readable node name of the server BBS
578 Line 4 - The fully-qualified domain name (FQDN) of the server
579 Line 5 - The name of the server software, i.e. "Citadel/UX 4.00"
580 Line 6 - (The revision level of the server code) * 100
581 Line 7 - The geographical location of the BBS (city and state if in the US)
582 Line 8 - The name of the system administrator
583 Line 9 - A number identifying the server type (see below)
584 Line 10 - The text of the system's paginator prompt
585 Line 11 - Floor Flag. 1 if the system supports floors, 0 otherwise.
586 Line 12 - Paging level. 0 if the system only supports inline paging,
587 1 if the system supports "extended" paging (check-only and
588 multiline modes). See the SEXP command for further information.
589 Line 13 - The "nonce" for this session, for support of APOP-style
590 authentication. If this field is present, clients may authenticate
592 Line 14 - Set to nonzero if this server supports the QNOP command.
593 Line 15 - Set to nonzero if this server is capable of connecting to a
594 directory service using LDAP.
596 *** NOTE! *** The "server type" code is intended to promote global
597 compatibility in a scenario in which developers have added proprietary
598 features to their servers or clients. We are attempting to avoid a future
599 situation in which users need to keep different client software around for
600 each BBS they use. *Please*, if you are a developer and plan to add
601 proprietary features:
603 -> Your client programs should still be able to utilize servers other than
605 -> Clients other than your own should still be able to utilize your server,
606 even if your proprietary extensions aren't supported.
607 -> Please contact Art Cancro <ajc@uncensored.citadel.org> and obtain a unique
608 server type code, which can be assigned to your server program.
609 -> If you document what you did in detail, perhaps it can be added to a
610 future release of the Citadel/UX program, so everyone can enjoy it. Better
611 yet, just work with the Citadel development team on the main source tree.
613 If everyone follows this scheme, we can avoid a chaotic situation with lots
614 of confusion about which client program works with which server, etc. Client
615 software can simply check the server type (and perhaps the revision level)
616 to determine ahead of time what commands may be utilized.
618 Please refer to "developers.txt" for information on what codes belong to whom.
622 RDIR (Read room DIRectory)
624 Use this command to read the directory of a directory room. ERROR+NOT_HERE
625 will be returned if the room has no directory, or some other error; ERROR +
626 HIGHER_ACCESS_REQUIRED will be returned if the room's directory is not
627 visible and the user does not have Aide or Room Aide privileges; otherwise
628 LISTING_FOLLOWS will be returned, followed by the room's directory. Each
629 line of the directory listing will contain three fields: a filename, the
630 length of the file, and a description.
632 The server message contained on the same line with LISTING_FOLLOWS will
633 contain the name of the system and the name of the directory, such as:
634 uncensored.citadel.org|/usr/bbs/files/my_room_directory
637 SLRP (Set Last-message-Read Pointer)
639 This command marks all messages in the current room as read (seen) up to and
640 including the specified number. Its sole parameter
641 is the number of the last message that has been read. This allows the pointer
642 to be set at any arbitrary point in the room. Optionally, the parameter
643 "highest" may be used instead of a message number, to set the pointer to the
644 number of the highest message in the room, effectively marking all messages
645 in the room as having been read (ala the Citadel <G>oto command).
647 The command will return OK if the pointer was set, or ERROR if something
648 went wrong. If OK is returned, it will be followed by a single argument
649 containing the message number the last-read-pointer was set to.
652 INVT (INViTe a user to a room)
654 This command may only be executed by Aides, or by the room aide for the
655 current room. It is used primarily to add users to invitation-only rooms,
656 but it may also be used in other types of private rooms as well. Its sole
657 parameter is the name of the user to invite.
659 The command will return OK if the operation succeeded, or ERROR if it did
660 not. ERROR+HIGHER_ACCESS_REQUIRED may also be returned if the operation
661 would have been possible if the user had higher access, and ERROR+NOT_HERE
662 may be returned if the room is not a private room.
665 KICK (KICK a user out of a room)
667 This is the opposite of INVT: it is used to kick a user out of a private
668 room. It can also be used to kick a user out of a public room, but the
669 effect will only be the same as if the user <Z>apped the room - a non-stupid
670 user can simply un-zap the room to get back in.
673 GETR (GET Room attributes)
675 This command is used for editing the various attributes associated with a
676 room. A typical "edit room" command would work like this:
677 1. Use the GETR command to get the current attributes
678 2. Change some of them around
679 3. Use SETR (see below) to save the changes
680 4. Possibly also change the room aide using the GETA and SETA commands
682 GETR takes no arguments. It will only return OK if the SETR command will
683 also return OK. This allows client software to tell the user that he/she
684 can't edit the room *before* going through the trouble of actually doing the
685 editing. Possible return codes are:
687 ERROR+NOT_LOGGED_IN - No user is logged in.
688 ERROR+HIGHER_ACCESS_REQUIRED - Not enough access. Typically, only aides
689 and the room aide associated with the current room, can access this command.
690 ERROR+NOT_HERE - Lobby>, Mail>, and Aide> cannot be edited.
691 OK - Command succeeded. Parameters are returned.
693 If OK is returned, the following parameters will be returned as well:
695 0. The name of the room
696 1. The room's password (if it's a passworded room)
697 2. The name of the room's directory (if it's a directory room)
698 3. Various flags (bits) associated with the room (see LKRN cmd above)
699 4. The floor number on which the room resides
700 5. The room listing order
701 6. The default view for the room (see views.txt)
702 7. A second set of flags (bits) associated with the room
705 SETR (SET Room attributes)
707 This command sets various attributes associated with the current room. It
708 should be passed the following arguments:
710 0. The name of the room
711 1. The room's password (if it's a passworded room)
712 2. The name of the room's directory (if it's a directory room)
713 3. Various flags (bits) associated with the room (see LKRN cmd above)
714 4. "Bump" flag (see below)
715 5. The floor number on which the room should reside
716 6. The room listing order
717 7. The default view for the room (see views.txt)
718 8. A second set of flags (buts) associated with the room
720 *Important: You should always use GETR to retrieve the current attributes of
721 the room, then change what you want to change, and then use SETR to write it
722 all back. This is particularly important with respect to the flags: if a
723 particular bit is set, and you don't know what it means, LEAVE IT ALONE and
724 only toggle the bits you want to toggle. This will allow for upward
727 If the room is a private room, you have the option of causing all users who
728 currently have access, to forget the room. If you want to do this, set the
729 "bump" flag to 1, otherwise set it to 0.
734 This command is used to get the name of the Room Aide for the current room.
735 It will return ERROR+NOT_LOGGED_IN if no user is logged in, ERROR if there
736 is no current room, or OK if the command succeeded. Along with OK there will
737 be returned one parameter: the name of the Room Aide.
742 The opposite of GETA, used to set the Room Aide for the current room. One
743 parameter should be passed, which is the name of the user who is to be the
744 new Room Aide. Under Citadel/UX, this command may only be executed by Aides
745 and by the *current* Room Aide for the room. Return codes possible are:
746 ERROR+NOT_LOGGED_IN (Not logged in.)
747 ERROR+HIGHER_ACCESS_REQUIRED (Higher access required.)
748 ERROR+NOT_HERE (No current room, or room cannot be edited.
749 Under Citadel/UX, the Lobby> Mail> and Aide> rooms are non-editable.)
750 OK (Command succeeded.)
753 ENT0 (ENTer message, mode 0)
755 This command is used to enter messages into the system. It accepts four
758 0 - Post flag. This should be set to 1 to post a message. If it is
759 set to 0, the server only returns OK or ERROR (plus any flags describing
760 the error) without reading in a message. Client software should, in fact,
761 perform this operation at the beginning of an "enter message" command
762 *before* starting up its editor, so the user does not end up typing a message
763 in vain that will not be permitted to be saved. If it is set to 2, the
764 server will accept an "apparent" post name if the user is privileged enough.
765 This post name is arg 5.
766 1 - Recipient. This argument is utilized only for private mail messages.
767 It is ignored for public messages. It contains, of course, the name of the
768 recipient of the message.
769 2 - Anonymous flag. This argument is ignored unless the room allows
770 anonymous messages. In such rooms, this flag may be set to 1 to flag a
771 message as anonymous, otherwise 0 for a normal message.
772 3 - Format type. Any valid Citadel/UX format type may be used (this will
773 typically be 0; see the MSG0 command above).
774 4 - Subject. If present, this argument will be used as the subject of
776 5 - Post name. When postflag is 2, this is the name you are posting as.
777 This is an Aide only command.
779 Possible result codes:
780 OK - The request is valid. (Client did not set the "post" flag, so the
781 server will not read in message text.) If the message is an e-mail with
782 a recipient, the text that follows the OK code will contain the exact name
783 to which mail is being sent. The client can display this to the user. The
784 implication here is that the name that the server returns will contain the
785 correct upper and lower case characters. In addition, if the recipient is
786 having his/her mail forwarded, the forwarding address will be returned.
787 SEND_LISTING - The request is valid. The client should now transmit
788 the text of the message (ending with a 000 on a line by itself, as usual).
789 ERROR - Miscellaneous error. (Explanation probably follows.)
790 ERROR + NOT_LOGGED_IN - Not logged in.
791 ERROR + HIGHER_ACCESS_REQUIRED - Higher access is required. An
792 explanation follows, worded in a form that can be displayed to the user.
793 ERROR + NO_SUCH_USER - The specified recipient does not exist.
796 RINF (read Room INFormation file)
798 Each room has associated with it a text file containing a description of
799 the room, perhaps containing its intended purpose or other important
800 information. The info file for the Lobby> (the system's base room) is
801 often used as a repository for system bulletins and the like.
803 This command, which accepts no arguments, is simply used to read the info
804 file for the current room. It will return LISTING_FOLLOWS followed by
805 the text of the message (always in format type 0) if the request can be
806 honored, or ERROR if no info file exists for the current room (which is
807 often the case). Other error description codes may accompany this result.
809 When should this command be used? This is, of course, up to the discretion
810 of client software authors, but in Citadel it is executed in two situations:
811 the first time the user ever enters a room; and whenever the contents of the
812 file change. The latter can be determined from the result of a GOTO command,
813 which will tell the client whether the file needs to be read (see GOTO above).
816 DELE (DELEte a message)
818 Delete a message from the current room. The one argument that should be
819 passed to this command is the message number of the message to be deleted.
820 The return value will be OK if the message was deleted, or an ERROR code.
821 If the delete is successful, the message's reference count is decremented, and
822 if the reference count reaches zero, the message is removed from the message
826 MOVE (MOVE or copy a message to a different room)
828 Move or copy a message to a different room. This command expects to be
829 passed three arguments:
830 0: the message number of the message to be moved or copied.
831 1: the name of the target room.
832 2: flag: 0 to move the message, 1 to copy it without deleting from the
835 This command never creates or deletes copies of a message; it merely moves
836 around links. When a message is moved, its reference count remains the same.
837 When a message is copied, its reference count is incremented.
840 KILL (KILL current room)
842 This command deletes the current room. It accepts a single argument, which
843 should be nonzero to actually delete the room, or zero to merely check
844 whether the room can be deleted.
846 Once the room is deleted, the current room is undefined. It is suggested
847 that client software immediately GOTO another room (usually _BASEROOM_)
848 after this command completes.
850 Possible return codes:
852 OK - room has been deleted (or, if checking only, request is valid).
853 ERROR+NOT_LOGGED_IN - no user is logged in.
854 ERROR+HIGHER_ACCESS_REQUIRED - not enough access to delete rooms.
855 ERROR+NOT_HERE - this room can not be deleted.
858 CRE8 (CRE[ate] a new room)
860 This command is used to create a new room. Like some of the other
861 commands, it provides a mechanism to first check to see if a room can be
862 created before actually executing the command. CRE8 accepts the following
865 0 - Create flag. Set this to 1 to actually create the room. If it is
866 set to 0, the server merely checks that there is a free slot in which to
867 create a new room, and that the user has enough access to create a room. It
868 returns OK if the client should go ahead and prompt the user for more info,
869 or ERROR or ERROR+HIGHER_ACCESS_REQUIRED if the command will not succeed.
870 1 - Name for new room.
871 2 - Access type for new room:
873 1 - Private; can be entered by guessing the room's name
874 2 - Private; can be entered by knowing the name *and* password
875 3 - Private; invitation only (sometimes called "exclusive")
876 4 - Personal (mailbox for this user only)
877 3 - Password for new room (if it is a type 2 room)
878 4 - Floor number on which the room should reside (optional)
879 5 - Set to 1 to avoid automatically gaining access to the created room.
881 If the create flag is set to 1, the room is created (unless something
882 went wrong and an ERROR return is sent), and the server returns OK, but
883 the session is **not** automatically sent to that room. The client still
884 must perform a GOTO command to go to the new room.
887 FORG (FORGet the current room)
889 This command is used to forget (zap) the current room. For those not
890 familiar with Citadel, this terminology refers to removing the room from
891 a user's own known rooms list, *not* removing the room itself. After a
892 room is forgotten, it no longer shows up in the user's known room list,
893 but it will exist in the user's forgotten room list, and will return to the
894 known room list if the user goes to the room (in Citadel, this is
895 accomplished by explicitly typing the room's name in a <.G>oto command).
897 The command takes no arguments. If the command cannot execute for any
898 reason, ERROR will be returned. ERROR+NOT_LOGGED_IN or ERROR+NOT_HERE may
899 be returned as they apply.
901 If the command succeeds, OK will be returned. At this point, the current
902 room is **undefined**, and the client software is responsible for taking
903 the user to another room before executing any other room commands (usually
904 this will be _BASEROOM_ since it is always there).
907 MESG (read system MESsaGe)
909 This command is used to display system messages and/or help files. The
910 single argument it accepts is the name of the file to display. IT IS CASE
911 SENSITIVE. Citadel/UX looks for these files first in the "messages"
912 subdirectory and then in the "help" subdirectory.
914 If the file is found, LISTING_FOLLOWS is returned, followed by a pathname
915 to the file being displayed. Then the message is printed, in format type 0
916 (see MSG0 command for more information on this). If the file is not found,
919 There are some "well known" names of system messages which client software
920 may expect most servers to carry:
922 hello - Welcome message, to be displayed before the user logs in.
923 changepw - To be displayed whenever the user is prompted for a new
924 password. Warns about picking guessable passwords and such.
925 register - Should be displayed prior to the user entering registration.
926 Warnings about not getting access if not registered, etc.
927 help - Main system help file.
928 goodbye - System logoff banner; display when user logs off.
929 roomaccess - Information about how public rooms and different types of
930 private rooms function with regards to access.
931 unlisted - Tells users not to choose to be unlisted unless they're
932 really paranoid, and warns that aides can still see
933 unlisted userlog entries.
935 Citadel/UX provides these for the Citadel/UX Unix text client. They are
936 probably not very useful for other clients:
938 mainmenu - Main menu (when in idiot mode).
943 saveopt - Options to save a message, abort, etc.
944 entermsg - Displayed just before a message is entered, when in
948 GNUR (Get Next Unvalidated User)
950 This command shows the name of a user that needs to be validated. If there
951 are no unvalidated users, OK is returned. Otherwise, MORE_DATA is returned
952 along with the name of the first unvalidated user the server finds. All of
953 the usual ERROR codes may be returned as well (for example, if the user is
954 not an Aide and cannot validate users).
956 A typical "Validate New Users" command would keep executing this command,
957 and then validating each user it returns, until it returns OK when all new
958 users have been validated.
961 GREG (Get REGistration for user)
963 This command retrieves the registration info for a user, whose name is the
964 command's sole argument. All the usual error messages can be returned. If
965 the command succeeds, LISTING_FOLLOWS is returned, followed by the user's name
966 (retrieved from the userlog, with the right upper and lower case etc.) The
967 contents of the listing contains one field per line, followed by the usual
968 000 on the last line.
970 The following lines are defined. Others WILL be added in the futre, so all
971 software should be written to read the lines it knows about and then ignore
977 Line 4: Street address or PO Box
978 Line 5: City/town/village/etc.
979 Line 6: State/province/etc.
981 Line 8: Telephone number
983 Line 10: Internet e-mail address
986 Users without Aide privileges may retrieve their own registration using
987 this command. This can be accomplished either by passing the user's own
988 name as the argument, or the string "_SELF_". The command will always
989 succeed when used in this manner, unless no user is logged in.
994 This command is used to validate users. Obviously, it can only be executed
995 by users with Aide level access. It should be passed two parameters: the
996 name of the user to validate, and the desired access level
998 If the command succeeds, OK is returned. The user's access level is changed
999 and the "need validation" bit is cleared. If the command fails for any
1000 reason, ERROR, ERROR+NO_SUCH_USER, or ERROR+HIGHER_ACCESS_REQUIRED will be
1004 EINF (Enter INFo file for room)
1006 Transmit the info file for the current room with this command. EINF uses
1007 a boolean flag (1 or 0 as the first and only argument to the command) to
1008 determine whether the client actually wishes to transmit a new info file, or
1009 is merely checking to see if it has permission to do so.
1011 If the command cannot succeed, it returns ERROR.
1012 If the client is only checking for permission, and permission will be
1013 granted, OK is returned.
1014 If the client wishes to transmit the new info file, SEND_LISTING is
1015 returned, and the client should transmit the text of the info file, ended
1016 by the usual 000 on a line by itself.
1021 This is a simple user listing. It always succeeds, returning
1022 LISTING_FOLLOWS followed by zero or more user records, 000 terminated. The
1023 fields on each line are as follows:
1028 4. Date/time of last login (Unix format)
1031 7. Password (listed only if the user requesting the list is an Aide)
1033 Unlisted entries will also be listed to Aides logged into the server, but
1034 not to ordinary users.
1037 REGI (send REGIstration)
1039 Clients will use this command to transmit a user's registration info. If
1040 no user is logged in, ERROR+NOT_LOGGED_IN is returned. Otherwise,
1041 SEND_LISTING is returned, and the server will expect the following information
1042 (terminated by 000 on a line by itself):
1045 Line 2: Street address or PO Box
1046 Line 3: City/town/village/etc.
1047 Line 4: State/province/etc.
1049 Line 6: Telephone number
1050 Line 7: e-mail address
1054 CHEK (CHEcK various things)
1056 When logging in, there are various things that need to be checked. This
1057 command will return ERROR+NOT_LOGGED_IN if no user is logged in. Otherwise
1058 it returns OK and the following parameters:
1060 0: Number of new private messages in Mail>
1061 1: Nonzero if the user needs to register
1062 2: (Relevant to Aides only) Nonzero if new users require validation
1063 3: The user's preferred Internet e-mail address
1066 DELF (DELete a File)
1068 This command deletes a file from the room's directory, if there is one. The
1069 name of the file to delete is the only parameter to be supplied. Wildcards
1070 are not acceptable, and any slashes in the filename will be converted to
1071 underscores, to prevent unauthorized access to neighboring directories. The
1072 possible return codes are:
1074 OK - Command succeeded. The file was deleted.
1075 ERROR+NOT_LOGGED_IN - Not logged in.
1076 ERROR+HIGHER_ACCESS_REQUIRED - Not an Aide or Room Aide.
1077 ERROR+NOT_HERE - There is no directory in this room.
1078 ERROR+FILE_NOT_FOUND - Requested file was not found.
1083 This command is similar to DELF, except that it moves a file (and its
1084 associated file description) to another room. It should be passed two
1085 parameters: the name of the file to move, and the name of the room to move
1086 the file to. All of the same return codes as DELF may be returned, and also
1087 one additional one: ERROR+NO_SUCH_ROOM, which means that the target room
1088 does not exist. ERROR+NOT_HERE could also mean that the target room does
1089 not have a directory.
1092 NETF (NETwork send a File)
1094 This command is similar to MOVF, except that it attempts to send a file over
1095 the network to another system. It should be passed two parameters: the name
1096 of the file to send, and the node name of the system to send it to. All of
1097 the same return codes as MOVF may be returned, except for ERROR+NO_SUCH_ROOM.
1098 Instead, ERROR+NO_SUCH_SYSTEM may be returned if the name of the target
1101 The name of the originating room will be sent along with the file. Most
1102 implementations will look for a room with the same name at the receiving end
1103 and attempt to place the file there, otherwise it goes into a bit bucket room
1104 for miscellaneous files. This is, however, beyond the scope of this document;
1105 see elsewhere for more details.
1108 RWHO (Read WHO's online)
1110 Displays a list of all users connected to the server. No error codes are
1111 ever returned. LISTING_FOLLOWS will be returned, followed by zero or more
1112 lines containing the following three fields:
1114 0 - Session ID. Citadel/UX fills this with the pid of a server program.
1116 2 - The name of the room the user is currently in. This field might not
1117 be displayed (for example, if the user is in a private room) or it might
1118 contain other information (such as the name of a file the user is
1120 3 - (server v4.03 and above) The name of the host the client is connecting
1121 from, or "localhost" if the client is local.
1122 4 - (server v4.04 and above) Description of the client software being used
1123 5 - The last time, locally to the server, that a command was received from
1124 this client (Note: NOOP's don't count)
1125 6 - The last command received from a client. (NOOP's don't count)
1126 7 - Session flags. These are: + (spoofed address), - (STEALTH mode), *
1127 (posting) and . (idle).
1128 8 - Actual user name, if user name is masqueraded and viewer is an Aide.
1129 9 - Actual room name, if room name is masqueraded and viewer is an Aide.
1130 10 - Actual host name, if host name is masqueraded and viewer is an Aide.
1131 11 - Nonzero if the session is a logged-in user, zero otherwise.
1133 The listing is terminated, as always, with the string "000" on a line by
1137 OPEN (OPEN a file for download)
1139 This command is used to open a file for downloading. Only one download
1140 file may be open at a time. The only argument to this command is the name
1141 of the file to be opened. The user should already be in the room where the
1142 file resides. Possible return codes are:
1145 ERROR+NOT_HERE (no directory in this room)
1146 ERROR+FILE_NOT_FOUND (could not open the file)
1150 If the file is successfully opened, OK will be returned, along with the
1151 size (in bytes) of the file, the time of last modification (if applicable),
1152 the filename (if known), and the MIME type of the file (if known).
1155 CLOS (CLOSe the download file)
1157 This command is used to close the download file. It returns OK if the
1158 file was successfully closed, or ERROR if there wasn't any file open in the
1162 READ (READ from the download file)
1164 Two arguments are passed to this command. The first is the starting position
1165 in the download file, and the second is the total number of bytes to be
1166 read. If the operation can be performed, BINARY_FOLLOWS will be returned,
1167 along with the number of bytes to follow. Then, immediately following the
1168 newline, will be that many bytes of binary data. The client *must* read
1169 exactly that number of bytes, otherwise the client and server will get out
1172 If the operation cannot be performed, any of the usual error codes will be
1176 UOPN (OPeN a file for Uploading)
1178 This command is similar to OPEN, except that this one is used when the
1179 client wishes to upload a file to the server. The first argument is the name
1180 of the file to create, and the second argument is a one-line comment
1181 describing the contents of the file. Only one upload file may be open at a
1182 time. Possible return codes are:
1185 ERROR+NOT_HERE (no directory in this room)
1186 ERROR+FILE_NOT_FOUND (a name must be specified)
1187 ERROR (miscellaneous errors)
1188 ERROR+ALREADY_EXISTS (a file with the same name already exists)
1191 If OK is returned, the command has succeeded and writes may be performed.
1194 UCLS (CLoSe the Upload file)
1196 Close the file opened with UOPN. An argument of "1" should be passed to
1197 this command to close and save the file; otherwise, the transfer will be
1198 considered aborted and the file will be deleted. This command returns OK
1199 if the operation succeeded or ERROR if it did not.
1202 WRIT (WRITe to the upload file)
1204 If an upload file is open, this command may be used to write to it. The
1205 argument passed to this command is the number of bytes the client wishes to
1206 transmit. An ERROR code will be returned if the operation cannot be
1209 If the operation can be performed, SEND_BINARY will be returned, followed
1210 by the number of bytes the server is expecting. The client must then transmit
1211 exactly that number of bytes. Note that in the current implementation, the
1212 number of bytes the server is expecting will always be the number of bytes
1213 the client requested to transmit, but the client software should never assume
1214 that this will always happen, in case changes are made later.
1217 QUSR (Query for a USeR)
1219 This command is used to check to see if a particular user exists. The only
1220 argument to this command is the name of the user being searched for. If
1221 the user exists, OK is returned, along with the name of the user in the userlog
1222 (so the client software can learn the correct upper/lower casing of the name
1223 if necessary). If the user does not exist, ERROR+NO_SUCH_USER is returned.
1224 No login or current room is required to utilize this command.
1227 OIMG (Open an IMaGe file)
1229 Open an image (graphics) file for downloading. Once opened, the file can be
1230 read as if it were a download file. This implies that an image and a download
1231 cannot be opened at the same time. OIMG returns the same result codes as OPEN.
1233 All images will be in GIF (Graphics Interchange Format). In the case of
1234 Citadel/UX, the server will convert the supplied filename to all lower case,
1235 append the characters ".gif" to the filename, and look for it in the "images"
1236 subdirectory. As with the MESG command, there are several "well known"
1237 images which are likely to exist on most servers:
1239 hello - "Welcome" graphics to be displayed alongside MESG "hello"
1240 goodbye - Logoff banner graphics to be displayed alongside MESG "goodbye"
1241 background - Background image (usually tiled) for graphical clients
1243 The following "special" image names are defined in Citadel/UX server version
1246 _userpic_ - Picture of a user (send the username as the second argument)
1247 _floorpic_ - A graphical floor label (send the floor number as the second
1248 argument). Clients which request a floor picture will display
1249 the picture *instead* of the floor name.
1250 _roompic_ - A graphic associated with the *current* room. Clients which
1251 request a room picture will display the picture in *addition*
1252 to the room name (i.e. it's used for a room banner, as
1253 opposed to the floor picture's use in a floor listing).
1256 NETP (authenticate as network session with connection NET Password)
1258 This command is used by client software to identify itself as a transport
1259 session for IGnet/Open BBS to BBS networking. It should be called with
1260 two arguments: the node name of the calling system, and the "shared secret"
1261 password for that connection. If the authentication succeeds, NETP will
1262 return OK, otherwise, it returns ERROR.
1265 NSYN (Network SYNchronize room)
1267 This command can be used to synchronize the contents of a room on the
1268 network. It is only usable by Aides. It accepts one argument: the name of
1269 a network node (which must be a valid one).
1271 When NSYN is run, the *entire* contents of the current room will be spooled
1272 to the specified node, without regard to whether any of the messages have
1273 already undergone network processing. It is up to the receiving node to
1274 check for duplicates (the Citadel networker does handle this) and avoid
1277 The command returns OK upon success or ERROR if the user is not an Aide.
1280 NUOP (Network Upload OPen file)
1282 Open a network spool file for uploading. The client must have already
1283 identified itself as a network session using the NETP command. If the command
1284 returns OK, the client may begin transmitting IGnet/Open spool data using
1285 a series of WRIT commands. When a UCLS command is issued, the spooled data
1286 is entered into the BBS if the argument to UCLS is 1 or discarded if the
1287 argument to UCLS is 0. If the client has not authenticated itself with a
1288 NETP command, ERROR+HIGHER_ACCESS_REQUIRED will be returned.
1291 NDOP (Network Download OPen file)
1293 Open a network spool file for downloading. The client must have already
1294 identified itself as a network session using the NETP command. If the command
1295 returns OK, the client may begin receiving IGnet/Open spool data using
1296 a series of READ commands. When a CLOS command is issued, the spooled data
1297 is deleted from the server and may not be read again. If the client has not
1298 authenticated itself with a NETP command, ERROR+HIGHER_ACCESS_REQUIRED will
1302 LFLR (List all known FLooRs)
1304 On systems supporting floors, this command lists all known floors. The
1305 command accepts no parameters. It will return ERROR+NOT_LOGGED_IN if no
1306 user is logged in. Otherwise it returns LISTING_FOLLOWS and a list of
1307 the available floors, each line consisting of three fields:
1309 1. The floor number associated with the floor
1310 2. The name of the floor
1311 3. Reference count (number of rooms on this floor)
1314 CFLR (Create a new FLooR)
1316 This command is used to create a new floor. It should be passed two
1317 arguments: the name of the new floor to be created, and a 1 or 0 depending
1318 on whether the client is actually creating a floor or merely checking to
1319 see if it has permission to create the floor. The user must be logged in
1320 and have Aide privileges to create a floor.
1322 If the command succeeds, it will return OK followed by the floor number
1323 associated with the new floor. Otherwise, it will return ERROR (plus perhaps
1324 HIGHER_ACCESS_REQUIRED, ALREADY_EXISTS, or INVALID_FLOOR_OPERATION)
1325 followed by a description of why the command failed.
1330 This command is used to delete a floor. It should be passed two
1331 argument: the *number* of the floor to be deleted, and a 1 or 0 depending
1332 on whether the client is actually deleting the floor or merely checking to
1333 see if it has permission to delete the floor. The user must be logged in
1334 and have Aide privileges to delete a floor.
1336 Floors that contain rooms may not be deleted. If there are rooms on a floor,
1337 they must be either deleted or moved to different floors first. This implies
1338 that the Main Floor (floor 0) can never be deleted, since Lobby>, Mail>, and
1339 Aide> all reside on the Main Floor and cannot be deleted.
1341 If the command succeeds, it will return OK. Otherwise it will return
1342 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1343 followed by a description of why the command failed.
1348 Edit the parameters of a floor. The client may pass one or more parameters
1351 1. The number of the floor to be edited
1352 2. The desired new name
1354 More parameters may be added in the future. Any parameters not passed to
1355 the server will remain unchanged. A minimal command would be EFLR and a
1356 floor number -- which would do nothing. EFLR plus the floor number plus a
1357 floor name would change the floor's name.
1359 If the command succeeds, it will return OK. Otherwise it will return
1360 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1363 IDEN (IDENtify the client software)
1365 The client software has the option to identify itself to the server.
1366 Currently, the server does nothing with this information except to write
1367 it to the syslog to satisfy the system administrator's curiosity. Other
1368 uses might become apparent in the future.
1370 The IDEN command should contain five fields: a developer ID number (same as
1371 the server developer ID numbers in the INFO command -- please obtain one if
1372 you are a new developer), a client ID number (which does not have to be
1373 globally unique - only unique within the domain of the developer number),
1374 a version number, a free-form text string describing the client, and the name
1375 of the host the user is located at.
1377 It is up to the server to determine whether to accept the host name or to
1378 use the host name it has detected itself. Generally, if the client is
1379 running on a trusted host (either localhost or a well-known publically
1380 accessible client) it should use the host name transmitted by IDEN,
1381 otherwise it should use the host name it has detected itself.
1383 IDEN always returns OK, but since that's the only way it ever returns
1384 there's no point in checking the result code.
1387 IPGM (identify as an Internal ProGraM)
1389 IPGM is a low-level command that should not be used by normal user clients.
1390 It is used for various utilities to communicate with the server on the same
1391 host. For example, the "sendcommand" utility logs onto the server as an
1392 internal program in order to run arbitrary server commands. Since user clients
1393 do not utilize this command (or any of its companion commands), developers
1394 writing Citadel-compatible servers need not implement it.
1396 The sole argument to IPGM is the system's internal program password. This
1397 password is generated by the setup program and stored in the config file.
1398 Since internal programs have access to the config file, they know the correct
1401 IPGM returns OK for a correct authentication or ERROR otherwise.
1404 CHAT (enter CHAT mode)
1406 This command functions differently from every other command in the system. It
1407 is used to implement multi-user chat. For this to function, a new transfer
1408 mode, called START_CHAT_MODE, is implemented. If a client does not support
1409 chat mode, it should never send a CHAT command!
1411 In chat mode, messages may arrive asynchronously from the server at any
1412 time. The client may send messages at any time. This allows the arrival of
1413 messages without the client having to poll for them. Arriving messages will
1414 be of the form "user|message", where the "user" portion is, of course, the
1415 name of the user sending the message, and "message" is the message text.
1417 Chat mode ends when the server says it ends. The server will signal the end
1418 of chat mode by transmitting "000" on a line by itself. When the client reads
1419 this line, it must immediately exit from chat mode without sending any
1420 further traffic to the server. The next transmission sent to the server
1421 will be a regular server command.
1423 The Citadel/UX server understands the following commands:
1424 /quit - Exit from chat mode (causes the server to do an 000 end)
1425 /who - List users currently in chat
1426 /whobbs - List users currently in chat and on the bbs
1427 /me - Do an irc-style action.
1428 /join - Join a new "room" in which all messages are only heard by
1429 people in that room.
1430 /msg - /msg <user> <msg> will send the msg to <user> only.
1431 /help - Print help information
1432 NOOP - Do nothing (silently)
1434 Any other non-empty string is treated as message text and will be broadcast
1435 to other users currently in chat.
1438 SEXP (Send EXPress messages)
1440 This is one of two commands which implement "express messages" (also known
1441 as "paging"). An express message is a near-real-time message sent from one
1442 logged in user to another. When an express message is sent, it will be
1443 displayed the next time the target user executes a PEXP or GEXP command.
1445 The SEXP command accepts two arguments: the name of the user to send the
1446 message to, and the text of the message. If the message is successfully
1447 transmitted, OK is returned. If the target user is not logged in or if
1448 anything else goes wrong, ERROR is returned.
1450 If the server supports extended paging, sending a zero-length message
1451 merely checks for the presence of the requested user without actually sending
1452 a message. Sending a message consisting solely of a "-" (hyphen) will cause
1453 the server to return SEND_LISTING if the requested user is logged in, and the
1454 client can then transmit a multi-line page.
1456 The reserved name "broadcast" may be used instead of a user name, to
1457 broadcast an express message to all users currently connected to the server.
1459 Do be aware that if an express message is transmitted to a user who is logged
1460 in using a client that does not check for express messages, the message will
1464 PEXP (Print EXPress messages) ***DEPRECATED***
1466 This command is deprecated; it will eventually disappear from the protocol and
1467 its use is not recommended. Please use the GEXP command instead.
1469 Called without any arguments, PEXP simply dumps out the contents
1470 of any waiting express messages. It returns ERROR if there is a problem,
1471 otherwise it returns LISTING_FOLLOWS followed by all messages.
1473 So how does the client know there are express messages waiting? It could
1474 execute a random PEXP every now and then. Or, it can check the byte in
1475 server return code messages, between the return code and the parameters. In
1476 much the same way as FTP uses "-" to signify a continuation, Citadel uses
1477 an "*" in this position to signify the presence of waiting express messages.
1480 EBIO (Enter BIOgraphy)
1482 Transmit to the server a free-form text file containing a little bit of
1483 information about the user for other users to browse. This is typically
1484 referred to as a 'bio' online. EBIO returns SEND_LISTING if it succeeds,
1485 after which the client is expected to transmit the file, or any of the usual
1486 ERROR codes if it fails.
1489 RBIO (Read BIOgraphy)
1491 Receive from the server a named user's bio. This command should be passed
1492 a single argument - the name of the user whose bio is requested. RBIO returns
1493 LISTING_FOLLOWS plus the bio file if the user exists and has a bio on file.
1494 The return has the following parameters: the user name, user number, access
1495 level, date of last call, times called, and messages posted. This command
1496 returns ERROR+NO_SUCH_USER if the named user does not exist.
1498 RBIO no longer considers a user with no bio on file to be an error condition.
1499 It now returns a message saying the user has no bio on file as the text of the
1500 bio. This allows newer servers to operate with older clients.
1503 STEL (enter STEaLth mode)
1505 When in "stealth mode," a user will not show up in the "Who is online"
1506 listing (the RWHO server command). Only Aides may use stealth mode. The
1507 STEL command accepts one argument: a 1 indicating that the user wishes to
1508 enter stealth mode, or a 0 indicating that the user wishes to exit stealth
1509 mode. STEL returns OK if the command succeeded, ERROR+NOT_LOGGED_IN if no
1510 user is logged in, or ERROR+HIGHER_ACCESS_REQUIRED if the user is not an Aide;
1511 followed by a 1 or 0 indicating the new state.
1513 If any value other than 1 or 0 is sent by the client, the server simply
1514 replies with 1 or 0 to indicate the current state without changing it.
1516 The STEL command also makes it so a user does not show up in the chat room
1520 LBIO (List users who have BIOs on file)
1522 This command is self-explanatory. Any user who has used EBIO to place a bio
1523 on file is listed. LBIO almost always returns LISTING_FOLLOWS followed by
1524 this listing, unless it experiences an internal error in which case ERROR
1528 MSG2 (read MeSsaGe, mode 2)
1530 MSG2 follows the same calling convention as MSG0. The difference between
1531 the two commands is that MSG2 outputs messages in standard RFC822 format
1532 rather than in Citadel/UX proprietary format.
1534 This command was implemented in order to make various gateway programs
1535 easier to implement, and to provide some sort of multimedia support in the
1536 future. Keep in mind that when this command is used, all messages will be
1537 output in fixed 80-column format.
1540 MSG3 (read MeSsaGe, mode 3 -- internal command)
1542 MSG3 is for use by internal programs only and should not be utilized by
1543 user-mode clients. It does require IPGM authentication. MSG3 follows the
1544 same calling convention as the other MSG commands, but upon success returns
1545 BINARY_FOLLOWS followed by a data block containing the _raw_ message format
1549 TERM (TERMinate another session)
1551 In a multithreaded environment, it sometimes becomes necessary to terminate
1552 a session that is unusable for whatever reason. The TERM command performs
1553 this task. Naturally, only Aides can execute TERM. The command should be
1554 called with a single argument: the session ID (obtained from an RWHO command)
1555 of the session to be terminated.
1557 TERM returns OK if the session was terminated, or ERROR otherwise. Note that
1558 a client program is prohibited from terminating the session it is currently
1564 DOWN (shut DOWN the server)
1566 This command, which may only be executed by an Aide, immediately shuts down
1567 the server. It is only implemented on servers on which such an operation is
1568 possible, such as a multithreaded Citadel engine. The server does not restart.
1569 DOWN returns OK if the user is allowed to shut down the server, in which case
1570 the client program should expect the connection to be immediately broken.
1573 SCDN (Schedule or Cancel a shutDowN)
1575 SCDN sets or clears the "scheduled shutdown" flag. Pass this command a 1 or
1576 0 to respectively set or clear the flag. When the "scheduled shutdown" flag is
1577 set, the server will be shut down when there are no longer any users logged in.
1578 Any value other than 0 or 1 will not change the flag, only report its state.
1579 No users will be kicked off the system, and in fact the server is still
1580 available for new connections. The command returns ERROR if it fails;
1581 otherwise, it returns OK followed by a number representing the current state
1585 EMSG (Enter a system MeSsaGe)
1587 This is the opposite of the MESG command - it allows the creation and editing
1588 of system messages. The only argument passed to EMSG is the name of the
1589 file being transmitted. If the file exists in any system message directory
1590 on the server it will be overwritten, otherwise a new file is created. EMSG
1591 returns SEND_LISTING on success or ERROR+HIGHER_ACCESS_REQUIRED if the user
1594 Typical client software would use MESG to retrieve any existing message into
1595 an edit buffer, then present an editor to the user and run EMSG if the changes
1599 UIMG (Upload an IMaGe file)
1601 UIMG is complemenary to OIMG; it is used to upload an image to the server.
1602 The first parameter supplied to UIMG should be 0 if the client is only checking
1603 for permission to upload, or 1 if the client is actually attempting to begin
1604 the upload operation. The second argument is the name of the file to be
1605 transmitted. In Citadel/UX, the filename is converted to all lower case,
1606 appended with the characters ".gif", and stored in the "images" directory.
1608 UIMG returns OK if the client has permission to perform the requested upload,
1609 or ERROR+HIGHER_ACCESS_REQUIRED otherwise. If the client requested to begin
1610 the operation (first parameter set to 1), an upload file is opened, and the
1611 client should begin writing to it with WRIT commands, then close it with a
1614 The supplied filename should be one of:
1616 -> _userpic_ (Server will attempt to write to the user's online photo)
1617 -> Any of the "well known" filenames described in the writeup for the
1621 HCHG (Hostname CHanGe)
1623 HCHG is a command, usable by any user, that allows a user to change their RWHO
1624 host value. This will mask a client's originating hostname from normal
1625 users; access level 6 and higher can see, in an extended wholist, the actual
1626 hostname the user originates from.
1628 The format of an HCHG command is:
1632 If a HCHG command is successful, the value OK (200) is returned.
1635 RCHG (Roomname CHanGe)
1637 RCHG is a command, usable by any user, that allows a user to change their RWHO
1638 room value. This will mask a client's roomname from normal users; access
1639 level 6 and higher can see, in an extended wholist, the actual room the user
1642 The format of an RCHG command is:
1646 If a RCHG command is successful, the value OK (200) is returned.
1649 UCHG (Username CHanGe)
1651 UCHG is an aide-level command which allows an aide to effectively change their
1652 username. If this value is blank, the user goes into stealth mode (see
1654 will show up as being from the real username in this mode, however. In
1655 addition, the RWHO listing will include both the spoofed and real usernames.
1657 The format of an UCHG command is:
1661 If a UCHG command is successful, the value OK (200) is returned.
1664 TIME (get server local TIME)
1666 TIME returns OK followed by the current time measured in seconds since
1667 00:00:00 GMT, Jan 1, 1970 (standard Unix format).
1669 This is used in allowing a client to calculate idle times.
1672 AGUP (Administrative Get User Parameters)
1673 ASUP (Administrative Set User Parameters)
1675 These commands are only executable by Aides and by server extensions running
1676 at system-level. They are used to get/set any and all parameters relating to
1677 a user account. AGUP requires only one argument: the name of the user in
1678 question. SGUP requires all of the parameters to be set. The parameters are
1679 as follows, and are common to both commands:
1683 2 - Flags (see citadel.h)
1688 7 - Timestamp of last call
1689 8 - Purge time (in days) for this user (or 0 to use system default)
1691 Upon success, AGUP returns OK followed by all these parameters, and ASUP
1692 simply returns OK. If the client has insufficient access to perform the
1693 requested operation, ERROR+HIGHER_ACCESS_REQUIRED is returned. If the
1694 requested user does not exist, ERROR+NO_SUCH_USER is returned.
1698 GPEX (Get Policy for message EXpiration)
1700 Returns the policy of the current room, floor, or site regarding the automatic
1701 purging (expiration) of messages. The following policies are available:
1702 0 - Fall back to the policy of the next higher level. If this is a room,
1703 use the floor's default policy. If this is a floor, use the system
1704 default policy. This is an invalid value for the system policy.
1705 1 - Do not purge messages automatically.
1706 2 - Purge by message count. (Requires a value: number of messages)
1707 3 - Purge by message age. (Requires a value: number of days)
1709 The format of this command is: GPEX <which>
1710 The value of <which> must be one of: "room" "floor" "site" "mailboxes"
1712 If successful, GPEX returns OK followed by <policy>|<value>.
1716 SPEX (Set Policy for message EXpiration)
1718 Sets the policy of the current room, floor, or site regarding the automatic
1719 purging (expiration) of messages. See the writeup for the GPEX command for
1720 the list of available policies.
1722 The format of this command is: SPEX <which>|<policy>|<value>
1723 The value of <which> must be one of: "room" "floor" "site" "mailboxes"
1725 If successful, GPEX returns OK; otherwise, an ERROR code is returned.
1729 CONF (get or set global CONFiguration options)
1731 Retrieves or sets various system-wide configuration and policy options. This
1732 command is only available to Aides. The sole parameter accepted is a command,
1733 which should be either GET or SET. If the GET command succeeds, CONF will
1734 return LISTING_FOLLOWS followed by the fields described below, one line at a
1735 time. If the SET command succeeds, CONF will return SEND_LISTING and expect
1736 the fields described below, one line at a time (don't worry about other fields
1737 being added in the future; if a 'short' configuration list is sent, the missing
1738 values at the end will be left unchanged on the system). If either command
1739 fails for any reason, ERROR is returned.
1741 The configuration lines are as follows:
1744 2. Fully qualified domain name
1745 3. Human-readable node name
1746 4. Landline telephone number of this system
1747 5. Flag (0 or 1) - creator of private room automatically becomes room aide
1748 6. Server connection idle timeout (in seconds)
1749 7. Initial access level for new users
1750 8. Flag (0 or 1) - require registration for new users
1751 9. Flag (0 or 1) - automatically move Problem User messages to twit room
1752 10. Name of twit room
1753 11. Text of <more> prompt
1754 12. Flag (0 or 1) - restrict access to Internet mail
1755 13. Geographic location of this system
1756 14. Name of the system administrator
1757 15. Number of maximum concurrent sessions allowed on the server
1758 16. (placeholder -- this field is no longer in use)
1759 17. Default purge time (in days) for users
1760 18. Default purge time (in days) for rooms
1761 19. Name of room to log express messages to (or a zero-length name for none)
1762 20. Access level required to create rooms
1763 21. Maximum message length which may be entered into the system
1764 22. Minimum number of worker threads
1765 23. Maximum number of worker threads
1766 24. Port number for POP3 service
1767 25. Port number for SMTP service
1768 26. Flag (0 or 1) - strict RFC822 adherence - don't correct From: forgeries
1769 27. Flag (0 or 1) - allow Aides to zap (forget) rooms
1770 28. Port number for IMAP service
1771 29. How often (in seconds) to run the networker
1772 30. Flag (0 or 1) - disable self-service new user registration
1773 31. Flag (0 or 1) - Aides are allowed access to all mailboxes
1774 32. Hour (0 through 23) during which database auto-purge jobs are run
1775 33. Name of host where an LDAP service may be found
1776 34. Port number of LDAP service on above host
1778 CONF also accepts two additional commands: GETSYS and PUTSYS followed by an
1779 arbitrary MIME type (such as application/x-citadel-internet-config) which
1780 provides a means of storing generic configuration data in the Global System
1781 Configuration room without the need to add extra get/set commands to the
1784 Please note that the LDAP-specific configs have no effect on Citadel servers
1785 in which LDAP support is not enabled.
1789 MSG4 (read MeSsaGe, mode 4 -- output in preferred MIME format)
1791 This is the equivalent of MSG0, except it's a bit smarter about messages in
1792 rich text formats. Immediately following the "text" directive, the server
1793 will output RFC822-like MIME part headers such as "Content-type:" and
1794 "Content-length:". MIME formats are chosen and/or converted based on the
1795 client's preferred format settings, which are set using the MSGP command,
1800 MSGP (set MeSsaGe Preferred MIME format)
1802 Client tells the server what MIME content types it knows how to handle, and
1803 the order in which it prefers them. This is similar to an HTTP "Accept:"
1806 The parameters to a MSGP command are the client's acceptable MIME content
1807 types, in the order it prefers them (from most preferred to least preferred).
1808 For example: MSGP text/html|text/plain
1810 The MSGP command always returns OK.
1814 OPNA (OPeN Attachment)
1816 Opens, as a download file, a component of a MIME-encoded message. The two
1817 parameters which must be passed to this command are the message number and the
1818 name of the desired section. If the message or section does not exist, an
1819 appropriate ERROR code will be returned; otherwise, if the open is successful,
1820 this command will succeed returning the same information as an OPEN command.
1823 GEXP (Get EXPress messages)
1825 This is a more sophisticated way of retrieving express messages than the old
1826 PEXP method. If there are no express messages waiting, PEXP returns ERROR;
1827 otherwise, it returns LISTING_FOLLOWS and the following arguments:
1829 0 - a boolean value telling the client whether there are any additional
1830 express messages waiting following this one
1831 1 - a Unix-style timestamp
1832 2 - flags (see server.h for more info)
1833 3 - the name of the sender
1834 4 - the node this message originated on (for future support of PIP, ICQ, etc.)
1836 The text sent to the client will be the body of the express message.
1838 So how does the client know there are express messages waiting? It could
1839 execute a random GEXP every now and then. Or, it can check the byte in
1840 server return code messages, between the return code and the parameters. In
1841 much the same way as FTP uses "-" to signify a continuation, Citadel uses
1842 an "*" in this position to signify the presence of waiting express messages.
1845 FSCK (check message base reference counts)
1847 Verify, via the long way, that all message referenmce counts are correct. If
1848 the user has permission to do this then LISTING_FOLLOWS is returned, followed
1849 by a transcript of the run. Otherwise ERROR is returned.
1852 DEXP (Disable EXPress messages)
1854 DEXP sets or clears the "disable express messages" flag. Pass this command a
1855 1 or 0 to respectively set or clear the flag. When the "disable express
1856 messages" flag is set, no one except Aides may send the user express messages.
1857 Any value other than 0 or 1 will not change the flag, only report its state.
1858 The command returns ERROR if it fails; otherwise, it returns OK followed by a
1859 number representing the current state of the flag.
1862 REQT (REQuest client Termination)
1864 Request that the specified client (or all clients) log off. Aide level
1865 access is required to run this command, otherwise ERROR+HIGHER_ACCESS_REQUIRED
1868 The REQT command accepts one parameter: the session ID of the client which
1869 should be terminated, or 0 for all clients. When successful, the REQT command
1872 It should be noted that REQT simply transmits an express message to the
1873 specified client(s) with the EM_GO_AWAY flag set. Older clients do not honor
1874 this flag, and it is certainly possible for users to re-program their client
1875 software to ignore it. Therefore the effects of the REQT command should be
1876 considered advisory only. The recommended implementation practice is to first
1877 issue a REQT command, then wait a little while (from 30 seconds up to a few
1878 minutes) for well-behaved clients to voluntarily terminate, and then issue a
1879 TERM command to forcibly disconnect the client (or perhaps a DOWN command, if
1880 you are logging off users for the purpose of shutting down the server).
1883 SEEN (set or clear the SEEN flag for a message)
1885 Beginning with version 5.80, Citadel supports the concept of setting or
1886 clearing the "seen" flag for each individual message, instead of only allowing
1887 a "last seen" pointer. In fact, the old semantics are implemented in terms
1888 of the new semantics. This command requires two arguments: the number of the
1889 message to be set, and a 1 or 0 to set or clear the "seen" bit.
1891 This command returns OK, unless the user is not logged in or a usage error
1892 occurred, in which case it returns ERROR. Please note that no checking is
1893 done on the supplied data; if the requested message does not exist, the SEEN
1894 command simply returns OK without doing anything.
1897 GTSN (GeT the list of SeeN messages)
1899 This command retrieves the list of "seen" (as opposed to unread) messages for
1900 the current room. It returns OK followed by an IMAP-format message list.
1903 SMTP (utility commands for the SMTP gateway)
1905 This command, accessible only by Aides, supports several utility operations
1906 which examine or manipulate Citadel's SMTP support. The first command argument
1907 is a subcommand telling the server what to do. The following subcommands are
1910 SMTP mx|hostname (display all MX hosts for 'hostname')
1911 SMTP runqueue (attempt immediate delivery of all messages
1912 in the outbound SMTP queue, ignoring any
1913 retry times stored there)
1916 STLS (Start Transport Layer Security)
1918 This command starts TLS on the current connection. The current
1919 implementation uses OpenSSL on both the client and server end. For future
1920 compatibility all clients must support at least TLSv1, and servers are
1921 guaranteed to support TLSv1. During TLS negotiation (see below) the server
1922 and client may agree to use a different protocol.
1924 The server returns ERROR if it does not support SSL or SSL initialization
1925 failed on the server; otherwise it returns OK. Once the server returns OK and
1926 the client has read the response, the server and client immediately negotiate
1927 TLS (in OpenSSL, using SSL_connect() on the client and SSL_accept() on the
1928 server). If negotiation fails, the server and client should attempt to resume
1929 the session unencrypted. If either end is unable to resume the session, the
1930 connection should be closed.
1932 This command may be run at any time.
1935 GTLS (Get Transport Layer Security Status)
1937 This command returns information about the current connection. The server
1938 returns OK plus several parameters if the connection is encrypted, and ERROR
1939 if the connection is not encrypted. It is primarily used for debugging. The
1940 command may be run at any time.
1942 0 - Protocol name, e.g. "SSLv3"
1943 1 - Cipher suite name, e.g. "ADH-RC4-MD5"
1944 2 - Cipher strength bits, e.g. 128
1945 3 - Cipher strength bits actually in use, e.g. 128
1948 IGAB (Initialize Global Address Book)
1950 This command creates, or re-creates, a database of Internet e-mail addresses
1951 using the vCard information in the Global Address Book room. This procedure
1952 is normally run internally when the server determines it necessary, but is
1953 also provided as a server command to be used as a troubleshooting/maintenenance
1954 tool. Only a system Aide can run the command. It returns OK on success or
1958 QDIR (Query global DIRectory)
1960 Look up an internet address in the global directory. Any logged-in user may
1961 call QDIR with one parameter, the Internet e-mail address to look up. QDIR
1962 returns OK followed by a Citadel address if there is a match, otherwise it
1963 returns ERROR+NOT_LOGGED_IN.
1966 ISME (find out if an e-mail address IS ME)
1968 This is a quickie shortcut command to find out if a given e-mail address
1969 belongs to the user currently logged in. Its sole argument is an address to
1970 parse. The supplied address may be in any format (local, IGnet, or Internet).
1971 The command returns OK if the address belongs to the user, ERROR otherwise.
1974 VIEW (set the VIEW for a room)
1976 Set the preferred view for the current user in the current room. Please see
1977 views.txt for more information on views. The sole parameter for this command
1978 is the type of view requested. VIEW returns OK on success or ERROR on failure.
1981 QNOP (Quiet No OPeration)
1983 This command does nothing, similar to the NOOP command. However, unlike the
1984 NOOP command, it returns *absolutely no response* at all. The client has no
1985 way of knowing that the command executed. It is intended for sending
1986 "keepalives" in situations where a full NOOP would cause the client protocol
1989 Naturally, sending this command to a server that doesn't support it is an
1990 easy way to mess things up. Therefore, client software should first check
1991 the output of an INFO command to ensure that the server supports quiet noops.
1995 ICAL (Internet CALendaring commands)
1997 This command supports a number of subcommands which are used to process the
1998 calendaring/scheduling support in Citadel. Here are the subcommands which
2002 Test server for calendaring support. Always returns OK unless the server
2003 does not have the calendar module enabled.
2005 ICAL respond|msgnum|partnum|action
2006 Respond to a meeting request. 'msgnum' and 'partnum' refer to a MIME-encoded
2007 meeting invitation in the current room. 'action' must be set to either
2008 "accept" or "decline" to determine the action to take. This subcommand will
2009 return either OK or ERROR.
2011 ICAL conflicts|msgnum|partnum
2012 Determine whether an incoming VEVENT will fit in the user's calendar by
2013 checking it against the existing VEVENTs. 'msgnum' and 'partnum' refer to
2014 a MIME-encoded meeting invitation in the current room (usually the inbox).
2015 This command may return ERROR if something went wrong, but usually it will
2016 return LISTING_FOLLOWS followed by a list of zero or more conflicting
2017 events. A zero-length list means that there were no conflicts.
2019 ICAL handle_rsvp|msgnum|partnum
2020 Handle an incoming "reply" (or RSVP) to a meeting request you sent out.
2021 'msgnum' and 'partnum' refer to a MIME-encoded reply in the current room.
2022 'action' must be set to either "update" or "ignore" to determine the action
2023 to take. If the action is "update" then the server will hunt for the meeting
2024 in the user's Calendar> room, and update the status for this attendee. Either
2025 way, the reply message is deleted from the current room. This subcommand will
2026 return either OK or ERROR.
2028 ICAL freebusy|username
2029 Output the free/busy times for the requested user. If the user specified
2030 has a calendar available, this command will return LISTING_FOLLOWS and a
2031 compound VCALENDAR object. That object, in turn, will contain VEVENT
2032 objects that have been stripped of all properties except for the bare
2033 minimum needed to learn free/busy times (such as DTSTART, DTEND, and
2034 TRANSP). If there is no such user, or no calendar available, the usual
2035 ERROR codes will be returned.
2037 Readers who are paying attention will notice that there is no subcommand to
2038 send out meeting invitations. This is because that task is handled
2039 automatically by the Citadel server. When an event is saved to the user's
2040 Calendar> room and it contains attendees, Citadel will automatically turn
2041 the event into vCalendar REQUEST messages and mail them out to all listed
2046 MRTG (Multi Router Traffic Grapher)
2048 Multi Router Traffic Grapher (please see http://www.mrtg.org for more info) is
2049 a tool which creates pretty graphs of network activity, usually collected from
2050 routers using SNMP. However, its ability to call external scripts has spawned
2051 a small community of people using it to graph anything which can be graphed.
2052 The MRTG command can output Citadel server activity in the format MRTG expects.
2054 This format is as follows:
2059 Line 3: uptime of system
2060 Line 4: name of system
2063 MRTG accepts two different keywords. "MRTG users" will return two variables,
2064 the number of connected users and the number of active users. "MRTG messages"
2065 will return one variable (and a zero in the second field), showing the current
2066 highest message number on the system. Any other keyword, or a missing keyword,
2067 will cause the MRTG command to return an ERROR code.
2069 Please get in touch with the Citadel developers if you wish to experiment with
2074 ASYN (ASYNchronous message support)
2076 Negotiate the use of asynchronous, or unsolicited, protocol messages. The
2077 only parameter specified should be 1 or 0 to indicate that the client can or
2078 cannot handle this type of messages. The server will reply OK followed by a
2079 1 or 0 to tell the client which mode it is now operating in.
2081 If the command is not available on the server (i.e. it returns ERROR), or
2082 if the command has not been executed by the client, it should be assumed that
2083 this mode of operation is NOT in effect.
2085 The client may also send any value other than 0 or 1 to simply cause the
2086 server to output its current state without changing it.
2088 When asynchronous protocol mode is in effect, the client MUST handle any
2089 asynchronous messages as they arrive, before doing anything else.
2094 ASYNCHRONOUS MESSAGES
2095 ---------------------
2097 When the client protocol is operating in asynchronous mode (please refer to
2098 the writeup of the ASYN command above), the following messages may arrive at
2102 901 (express message arriving)
2104 There is an express message intended for this client. When the client
2105 receives this message, it MUST act as if it just sent a GEXP command (the data
2106 following the 901 message WILL be a LISTING_FOLLOWS data transfer; in fact,
2107 the current implementation simply executes a GEXP command internally).