1 SESSION LAYER PROTOCOL FOR CITADEL/UX
2 (c) 1995-2003 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 argument to
209 this command will be the name of the account. No case conversion is done
210 on the name. Note that the new account is installed with a default
211 configuration, and no password. This command returns OK if the account was created,
212 or ERROR if another user already exists with this name.
214 Please note that CREU is intended to be used for activities in which a system
215 administrator is creating user accounts. For self-service user account creation,
216 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.
594 *** NOTE! *** The "server type" code is intended to promote global
595 compatibility in a scenario in which developers have added proprietary
596 features to their servers or clients. We are attempting to avoid a future
597 situation in which users need to keep different client software around for
598 each BBS they use. *Please*, if you are a developer and plan to add
599 proprietary features:
601 -> Your client programs should still be able to utilize servers other than
603 -> Clients other than your own should still be able to utilize your server,
604 even if your proprietary extensions aren't supported.
605 -> Please contact Art Cancro <ajc@uncensored.citadel.org> and obtain a unique
606 server type code, which can be assigned to your server program.
607 -> If you document what you did in detail, perhaps it can be added to a
608 future release of the Citadel/UX program, so everyone can enjoy it. Better
609 yet, just work with the Citadel development team on the main source tree.
611 If everyone follows this scheme, we can avoid a chaotic situation with lots
612 of confusion about which client program works with which server, etc. Client
613 software can simply check the server type (and perhaps the revision level)
614 to determine ahead of time what commands may be utilized.
616 Please refer to "developers.txt" for information on what codes belong to whom.
620 RDIR (Read room DIRectory)
622 Use this command to read the directory of a directory room. ERROR+NOT_HERE
623 will be returned if the room has no directory, or some other error; ERROR +
624 HIGHER_ACCESS_REQUIRED will be returned if the room's directory is not
625 visible and the user does not have Aide or Room Aide privileges; otherwise
626 LISTING_FOLLOWS will be returned, followed by the room's directory. Each
627 line of the directory listing will contain three fields: a filename, the
628 length of the file, and a description.
630 The server message contained on the same line with LISTING_FOLLOWS will
631 contain the name of the system and the name of the directory, such as:
632 uncensored.citadel.org|/usr/bbs/files/my_room_directory
635 SLRP (Set Last-message-Read Pointer)
637 This command marks all messages in the current room as read (seen) up to and
638 including the specified number. Its sole parameter
639 is the number of the last message that has been read. This allows the pointer
640 to be set at any arbitrary point in the room. Optionally, the parameter
641 "highest" may be used instead of a message number, to set the pointer to the
642 number of the highest message in the room, effectively marking all messages
643 in the room as having been read (ala the Citadel <G>oto command).
645 The command will return OK if the pointer was set, or ERROR if something
646 went wrong. If OK is returned, it will be followed by a single argument
647 containing the message number the last-read-pointer was set to.
650 INVT (INViTe a user to a room)
652 This command may only be executed by Aides, or by the room aide for the
653 current room. It is used primarily to add users to invitation-only rooms,
654 but it may also be used in other types of private rooms as well. Its sole
655 parameter is the name of the user to invite.
657 The command will return OK if the operation succeeded, or ERROR if it did
658 not. ERROR+HIGHER_ACCESS_REQUIRED may also be returned if the operation
659 would have been possible if the user had higher access, and ERROR+NOT_HERE
660 may be returned if the room is not a private room.
663 KICK (KICK a user out of a room)
665 This is the opposite of INVT: it is used to kick a user out of a private
666 room. It can also be used to kick a user out of a public room, but the
667 effect will only be the same as if the user <Z>apped the room - a non-stupid
668 user can simply un-zap the room to get back in.
671 GETR (GET Room attributes)
673 This command is used for editing the various attributes associated with a
674 room. A typical "edit room" command would work like this:
675 1. Use the GETR command to get the current attributes
676 2. Change some of them around
677 3. Use SETR (see below) to save the changes
678 4. Possibly also change the room aide using the GETA and SETA commands
680 GETR takes no arguments. It will only return OK if the SETR command will
681 also return OK. This allows client software to tell the user that he/she
682 can't edit the room *before* going through the trouble of actually doing the
683 editing. Possible return codes are:
685 ERROR+NOT_LOGGED_IN - No user is logged in.
686 ERROR+HIGHER_ACCESS_REQUIRED - Not enough access. Typically, only aides
687 and the room aide associated with the current room, can access this command.
688 ERROR+NOT_HERE - Lobby>, Mail>, and Aide> cannot be edited.
689 OK - Command succeeded. Parameters are returned.
691 If OK is returned, the following parameters will be returned as well:
693 0. The name of the room
694 1. The room's password (if it's a passworded room)
695 2. The name of the room's directory (if it's a directory room)
696 3. Various flags (bits) associated with the room (see LKRN cmd above)
697 4. The floor number on which the room resides
698 5. The room listing order
699 6. The default view for the room (see views.txt)
700 7. A second set of flags (bits) associated with the room
703 SETR (SET Room attributes)
705 This command sets various attributes associated with the current room. It
706 should be passed the following arguments:
708 0. The name of the room
709 1. The room's password (if it's a passworded room)
710 2. The name of the room's directory (if it's a directory room)
711 3. Various flags (bits) associated with the room (see LKRN cmd above)
712 4. "Bump" flag (see below)
713 5. The floor number on which the room should reside
714 6. The room listing order
715 7. The default view for the room (see views.txt)
716 8. A second set of flags (buts) associated with the room
718 *Important: You should always use GETR to retrieve the current attributes of
719 the room, then change what you want to change, and then use SETR to write it
720 all back. This is particularly important with respect to the flags: if a
721 particular bit is set, and you don't know what it means, LEAVE IT ALONE and
722 only toggle the bits you want to toggle. This will allow for upward
725 If the room is a private room, you have the option of causing all users who
726 currently have access, to forget the room. If you want to do this, set the
727 "bump" flag to 1, otherwise set it to 0.
732 This command is used to get the name of the Room Aide for the current room.
733 It will return ERROR+NOT_LOGGED_IN if no user is logged in, ERROR if there
734 is no current room, or OK if the command succeeded. Along with OK there will
735 be returned one parameter: the name of the Room Aide.
740 The opposite of GETA, used to set the Room Aide for the current room. One
741 parameter should be passed, which is the name of the user who is to be the
742 new Room Aide. Under Citadel/UX, this command may only be executed by Aides
743 and by the *current* Room Aide for the room. Return codes possible are:
744 ERROR+NOT_LOGGED_IN (Not logged in.)
745 ERROR+HIGHER_ACCESS_REQUIRED (Higher access required.)
746 ERROR+NOT_HERE (No current room, or room cannot be edited.
747 Under Citadel/UX, the Lobby> Mail> and Aide> rooms are non-editable.)
748 OK (Command succeeded.)
751 ENT0 (ENTer message, mode 0)
753 This command is used to enter messages into the system. It accepts four
756 0 - Post flag. This should be set to 1 to post a message. If it is
757 set to 0, the server only returns OK or ERROR (plus any flags describing
758 the error) without reading in a message. Client software should, in fact,
759 perform this operation at the beginning of an "enter message" command
760 *before* starting up its editor, so the user does not end up typing a message
761 in vain that will not be permitted to be saved. If it is set to 2, the
762 server will accept an "apparent" post name if the user is privileged enough.
763 This post name is arg 5.
764 1 - Recipient. This argument is utilized only for private mail messages.
765 It is ignored for public messages. It contains, of course, the name of the
766 recipient of the message.
767 2 - Anonymous flag. This argument is ignored unless the room allows
768 anonymous messages. In such rooms, this flag may be set to 1 to flag a
769 message as anonymous, otherwise 0 for a normal message.
770 3 - Format type. Any valid Citadel/UX format type may be used (this will
771 typically be 0; see the MSG0 command above).
772 4 - Subject. If present, this argument will be used as the subject of
774 5 - Post name. When postflag is 2, this is the name you are posting as.
775 This is an Aide only command.
777 Possible result codes:
778 OK - The request is valid. (Client did not set the "post" flag, so the
779 server will not read in message text.) If the message is an e-mail with
780 a recipient, the text that follows the OK code will contain the exact name
781 to which mail is being sent. The client can display this to the user. The
782 implication here is that the name that the server returns will contain the
783 correct upper and lower case characters. In addition, if the recipient is
784 having his/her mail forwarded, the forwarding address will be returned.
785 SEND_LISTING - The request is valid. The client should now transmit
786 the text of the message (ending with a 000 on a line by itself, as usual).
787 ERROR - Miscellaneous error. (Explanation probably follows.)
788 ERROR + NOT_LOGGED_IN - Not logged in.
789 ERROR + HIGHER_ACCESS_REQUIRED - Higher access is required. An
790 explanation follows, worded in a form that can be displayed to the user.
791 ERROR + NO_SUCH_USER - The specified recipient does not exist.
794 RINF (read Room INFormation file)
796 Each room has associated with it a text file containing a description of
797 the room, perhaps containing its intended purpose or other important
798 information. The info file for the Lobby> (the system's base room) is
799 often used as a repository for system bulletins and the like.
801 This command, which accepts no arguments, is simply used to read the info
802 file for the current room. It will return LISTING_FOLLOWS followed by
803 the text of the message (always in format type 0) if the request can be
804 honored, or ERROR if no info file exists for the current room (which is
805 often the case). Other error description codes may accompany this result.
807 When should this command be used? This is, of course, up to the discretion
808 of client software authors, but in Citadel it is executed in two situations:
809 the first time the user ever enters a room; and whenever the contents of the
810 file change. The latter can be determined from the result of a GOTO command,
811 which will tell the client whether the file needs to be read (see GOTO above).
814 DELE (DELEte a message)
816 Delete a message from the current room. The one argument that should be
817 passed to this command is the message number of the message to be deleted.
818 The return value will be OK if the message was deleted, or an ERROR code.
819 If the delete is successful, the message's reference count is decremented, and
820 if the reference count reaches zero, the message is removed from the message
824 MOVE (MOVE or copy a message to a different room)
826 Move or copy a message to a different room. This command expects to be
827 passed three arguments:
828 0: the message number of the message to be moved or copied.
829 1: the name of the target room.
830 2: flag: 0 to move the message, 1 to copy it without deleting from the
833 This command never creates or deletes copies of a message; it merely moves
834 around links. When a message is moved, its reference count remains the same.
835 When a message is copied, its reference count is incremented.
838 KILL (KILL current room)
840 This command deletes the current room. It accepts a single argument, which
841 should be nonzero to actually delete the room, or zero to merely check
842 whether the room can be deleted.
844 Once the room is deleted, the current room is undefined. It is suggested
845 that client software immediately GOTO another room (usually _BASEROOM_)
846 after this command completes.
848 Possible return codes:
850 OK - room has been deleted (or, if checking only, request is valid).
851 ERROR+NOT_LOGGED_IN - no user is logged in.
852 ERROR+HIGHER_ACCESS_REQUIRED - not enough access to delete rooms.
853 ERROR+NOT_HERE - this room can not be deleted.
856 CRE8 (CRE[ate] a new room)
858 This command is used to create a new room. Like some of the other
859 commands, it provides a mechanism to first check to see if a room can be
860 created before actually executing the command. CRE8 accepts the following
863 0 - Create flag. Set this to 1 to actually create the room. If it is
864 set to 0, the server merely checks that there is a free slot in which to
865 create a new room, and that the user has enough access to create a room. It
866 returns OK if the client should go ahead and prompt the user for more info,
867 or ERROR or ERROR+HIGHER_ACCESS_REQUIRED if the command will not succeed.
868 1 - Name for new room.
869 2 - Access type for new room:
871 1 - Private; can be entered by guessing the room's name
872 2 - Private; can be entered by knowing the name *and* password
873 3 - Private; invitation only (sometimes called "exclusive")
874 4 - Personal (mailbox for this user only)
875 3 - Password for new room (if it is a type 2 room)
876 4 - Floor number on which the room should reside (optional)
877 5 - Set to 1 to avoid automatically gaining access to the created room.
879 If the create flag is set to 1, the room is created (unless something
880 went wrong and an ERROR return is sent), and the server returns OK, but
881 the session is **not** automatically sent to that room. The client still
882 must perform a GOTO command to go to the new room.
885 FORG (FORGet the current room)
887 This command is used to forget (zap) the current room. For those not
888 familiar with Citadel, this terminology refers to removing the room from
889 a user's own known rooms list, *not* removing the room itself. After a
890 room is forgotten, it no longer shows up in the user's known room list,
891 but it will exist in the user's forgotten room list, and will return to the
892 known room list if the user goes to the room (in Citadel, this is
893 accomplished by explicitly typing the room's name in a <.G>oto command).
895 The command takes no arguments. If the command cannot execute for any
896 reason, ERROR will be returned. ERROR+NOT_LOGGED_IN or ERROR+NOT_HERE may
897 be returned as they apply.
899 If the command succeeds, OK will be returned. At this point, the current
900 room is **undefined**, and the client software is responsible for taking
901 the user to another room before executing any other room commands (usually
902 this will be _BASEROOM_ since it is always there).
905 MESG (read system MESsaGe)
907 This command is used to display system messages and/or help files. The
908 single argument it accepts is the name of the file to display. IT IS CASE
909 SENSITIVE. Citadel/UX looks for these files first in the "messages"
910 subdirectory and then in the "help" subdirectory.
912 If the file is found, LISTING_FOLLOWS is returned, followed by a pathname
913 to the file being displayed. Then the message is printed, in format type 0
914 (see MSG0 command for more information on this). If the file is not found,
917 There are some "well known" names of system messages which client software
918 may expect most servers to carry:
920 hello - Welcome message, to be displayed before the user logs in.
921 changepw - To be displayed whenever the user is prompted for a new
922 password. Warns about picking guessable passwords and such.
923 register - Should be displayed prior to the user entering registration.
924 Warnings about not getting access if not registered, etc.
925 help - Main system help file.
926 goodbye - System logoff banner; display when user logs off.
927 roomaccess - Information about how public rooms and different types of
928 private rooms function with regards to access.
929 unlisted - Tells users not to choose to be unlisted unless they're
930 really paranoid, and warns that aides can still see
931 unlisted userlog entries.
933 Citadel/UX provides these for the Citadel/UX Unix text client. They are
934 probably not very useful for other clients:
936 mainmenu - Main menu (when in idiot mode).
941 saveopt - Options to save a message, abort, etc.
942 entermsg - Displayed just before a message is entered, when in
946 GNUR (Get Next Unvalidated User)
948 This command shows the name of a user that needs to be validated. If there
949 are no unvalidated users, OK is returned. Otherwise, MORE_DATA is returned
950 along with the name of the first unvalidated user the server finds. All of
951 the usual ERROR codes may be returned as well (for example, if the user is
952 not an Aide and cannot validate users).
954 A typical "Validate New Users" command would keep executing this command,
955 and then validating each user it returns, until it returns OK when all new
956 users have been validated.
959 GREG (Get REGistration for user)
961 This command retrieves the registration info for a user, whose name is the
962 command's sole argument. All the usual error messages can be returned. If
963 the command succeeds, LISTING_FOLLOWS is returned, followed by the user's name
964 (retrieved from the userlog, with the right upper and lower case etc.) The
965 contents of the listing contains one field per line, followed by the usual
966 000 on the last line.
968 The following lines are defined. Others WILL be added in the futre, so all
969 software should be written to read the lines it knows about and then ignore
975 Line 4: Street address or PO Box
976 Line 5: City/town/village/etc.
977 Line 6: State/province/etc.
979 Line 8: Telephone number
981 Line 10: Internet e-mail address
984 Users without Aide privileges may retrieve their own registration using
985 this command. This can be accomplished either by passing the user's own
986 name as the argument, or the string "_SELF_". The command will always
987 succeed when used in this manner, unless no user is logged in.
992 This command is used to validate users. Obviously, it can only be executed
993 by users with Aide level access. It should be passed two parameters: the
994 name of the user to validate, and the desired access level
996 If the command succeeds, OK is returned. The user's access level is changed
997 and the "need validation" bit is cleared. If the command fails for any
998 reason, ERROR, ERROR+NO_SUCH_USER, or ERROR+HIGHER_ACCESS_REQUIRED will be
1002 EINF (Enter INFo file for room)
1004 Transmit the info file for the current room with this command. EINF uses
1005 a boolean flag (1 or 0 as the first and only argument to the command) to
1006 determine whether the client actually wishes to transmit a new info file, or
1007 is merely checking to see if it has permission to do so.
1009 If the command cannot succeed, it returns ERROR.
1010 If the client is only checking for permission, and permission will be
1011 granted, OK is returned.
1012 If the client wishes to transmit the new info file, SEND_LISTING is
1013 returned, and the client should transmit the text of the info file, ended
1014 by the usual 000 on a line by itself.
1019 This is a simple user listing. It always succeeds, returning
1020 LISTING_FOLLOWS followed by zero or more user records, 000 terminated. The
1021 fields on each line are as follows:
1026 4. Date/time of last login (Unix format)
1029 7. Password (listed only if the user requesting the list is an Aide)
1031 Unlisted entries will also be listed to Aides logged into the server, but
1032 not to ordinary users.
1035 REGI (send REGIstration)
1037 Clients will use this command to transmit a user's registration info. If
1038 no user is logged in, ERROR+NOT_LOGGED_IN is returned. Otherwise,
1039 SEND_LISTING is returned, and the server will expect the following information
1040 (terminated by 000 on a line by itself):
1043 Line 2: Street address or PO Box
1044 Line 3: City/town/village/etc.
1045 Line 4: State/province/etc.
1047 Line 6: Telephone number
1048 Line 7: e-mail address
1052 CHEK (CHEcK various things)
1054 When logging in, there are various things that need to be checked. This
1055 command will return ERROR+NOT_LOGGED_IN if no user is logged in. Otherwise
1056 it returns OK and the following parameters:
1058 0: Number of new private messages in Mail>
1059 1: Nonzero if the user needs to register
1060 2: (Relevant to Aides only) Nonzero if new users require validation
1061 3: The user's preferred Internet e-mail address
1064 DELF (DELete a File)
1066 This command deletes a file from the room's directory, if there is one. The
1067 name of the file to delete is the only parameter to be supplied. Wildcards
1068 are not acceptable, and any slashes in the filename will be converted to
1069 underscores, to prevent unauthorized access to neighboring directories. The
1070 possible return codes are:
1072 OK - Command succeeded. The file was deleted.
1073 ERROR+NOT_LOGGED_IN - Not logged in.
1074 ERROR+HIGHER_ACCESS_REQUIRED - Not an Aide or Room Aide.
1075 ERROR+NOT_HERE - There is no directory in this room.
1076 ERROR+FILE_NOT_FOUND - Requested file was not found.
1081 This command is similar to DELF, except that it moves a file (and its
1082 associated file description) to another room. It should be passed two
1083 parameters: the name of the file to move, and the name of the room to move
1084 the file to. All of the same return codes as DELF may be returned, and also
1085 one additional one: ERROR+NO_SUCH_ROOM, which means that the target room
1086 does not exist. ERROR+NOT_HERE could also mean that the target room does
1087 not have a directory.
1090 NETF (NETwork send a File)
1092 This command is similar to MOVF, except that it attempts to send a file over
1093 the network to another system. It should be passed two parameters: the name
1094 of the file to send, and the node name of the system to send it to. All of
1095 the same return codes as MOVF may be returned, except for ERROR+NO_SUCH_ROOM.
1096 Instead, ERROR+NO_SUCH_SYSTEM may be returned if the name of the target
1099 The name of the originating room will be sent along with the file. Most
1100 implementations will look for a room with the same name at the receiving end
1101 and attempt to place the file there, otherwise it goes into a bit bucket room
1102 for miscellaneous files. This is, however, beyond the scope of this document;
1103 see elsewhere for more details.
1106 RWHO (Read WHO's online)
1108 Displays a list of all users connected to the server. No error codes are
1109 ever returned. LISTING_FOLLOWS will be returned, followed by zero or more
1110 lines containing the following three fields:
1112 0 - Session ID. Citadel/UX fills this with the pid of a server program.
1114 2 - The name of the room the user is currently in. This field might not
1115 be displayed (for example, if the user is in a private room) or it might
1116 contain other information (such as the name of a file the user is
1118 3 - (server v4.03 and above) The name of the host the client is connecting
1119 from, or "localhost" if the client is local.
1120 4 - (server v4.04 and above) Description of the client software being used
1121 5 - The last time, locally to the server, that a command was received from
1122 this client (Note: NOOP's don't count)
1123 6 - The last command received from a client. (NOOP's don't count)
1124 7 - Session flags. These are: + (spoofed address), - (STEALTH mode), *
1125 (posting) and . (idle).
1126 8 - Actual user name, if user name is masqueraded and viewer is an Aide.
1127 9 - Actual room name, if room name is masqueraded and viewer is an Aide.
1128 10 - Actual host name, if host name is masqueraded and viewer is an Aide.
1129 11 - Nonzero if the session is a logged-in user, zero otherwise.
1131 The listing is terminated, as always, with the string "000" on a line by
1135 OPEN (OPEN a file for download)
1137 This command is used to open a file for downloading. Only one download
1138 file may be open at a time. The only argument to this command is the name
1139 of the file to be opened. The user should already be in the room where the
1140 file resides. Possible return codes are:
1143 ERROR+NOT_HERE (no directory in this room)
1144 ERROR+FILE_NOT_FOUND (could not open the file)
1148 If the file is successfully opened, OK will be returned, along with the
1149 size (in bytes) of the file, the time of last modification (if applicable),
1150 the filename (if known), and the MIME type of the file (if known).
1153 CLOS (CLOSe the download file)
1155 This command is used to close the download file. It returns OK if the
1156 file was successfully closed, or ERROR if there wasn't any file open in the
1160 READ (READ from the download file)
1162 Two arguments are passed to this command. The first is the starting position
1163 in the download file, and the second is the total number of bytes to be
1164 read. If the operation can be performed, BINARY_FOLLOWS will be returned,
1165 along with the number of bytes to follow. Then, immediately following the
1166 newline, will be that many bytes of binary data. The client *must* read
1167 exactly that number of bytes, otherwise the client and server will get out
1170 If the operation cannot be performed, any of the usual error codes will be
1174 UOPN (OPeN a file for Uploading)
1176 This command is similar to OPEN, except that this one is used when the
1177 client wishes to upload a file to the server. The first argument is the name
1178 of the file to create, and the second argument is a one-line comment
1179 describing the contents of the file. Only one upload file may be open at a
1180 time. Possible return codes are:
1183 ERROR+NOT_HERE (no directory in this room)
1184 ERROR+FILE_NOT_FOUND (a name must be specified)
1185 ERROR (miscellaneous errors)
1186 ERROR+ALREADY_EXISTS (a file with the same name already exists)
1189 If OK is returned, the command has succeeded and writes may be performed.
1192 UCLS (CLoSe the Upload file)
1194 Close the file opened with UOPN. An argument of "1" should be passed to
1195 this command to close and save the file; otherwise, the transfer will be
1196 considered aborted and the file will be deleted. This command returns OK
1197 if the operation succeeded or ERROR if it did not.
1200 WRIT (WRITe to the upload file)
1202 If an upload file is open, this command may be used to write to it. The
1203 argument passed to this command is the number of bytes the client wishes to
1204 transmit. An ERROR code will be returned if the operation cannot be
1207 If the operation can be performed, SEND_BINARY will be returned, followed
1208 by the number of bytes the server is expecting. The client must then transmit
1209 exactly that number of bytes. Note that in the current implementation, the
1210 number of bytes the server is expecting will always be the number of bytes
1211 the client requested to transmit, but the client software should never assume
1212 that this will always happen, in case changes are made later.
1215 QUSR (Query for a USeR)
1217 This command is used to check to see if a particular user exists. The only
1218 argument to this command is the name of the user being searched for. If
1219 the user exists, OK is returned, along with the name of the user in the userlog
1220 (so the client software can learn the correct upper/lower casing of the name
1221 if necessary). If the user does not exist, ERROR+NO_SUCH_USER is returned.
1222 No login or current room is required to utilize this command.
1225 OIMG (Open an IMaGe file)
1227 Open an image (graphics) file for downloading. Once opened, the file can be
1228 read as if it were a download file. This implies that an image and a download
1229 cannot be opened at the same time. OIMG returns the same result codes as OPEN.
1231 All images will be in GIF (Graphics Interchange Format). In the case of
1232 Citadel/UX, the server will convert the supplied filename to all lower case,
1233 append the characters ".gif" to the filename, and look for it in the "images"
1234 subdirectory. As with the MESG command, there are several "well known"
1235 images which are likely to exist on most servers:
1237 hello - "Welcome" graphics to be displayed alongside MESG "hello"
1238 goodbye - Logoff banner graphics to be displayed alongside MESG "goodbye"
1239 background - Background image (usually tiled) for graphical clients
1241 The following "special" image names are defined in Citadel/UX server version
1244 _userpic_ - Picture of a user (send the username as the second argument)
1245 _floorpic_ - A graphical floor label (send the floor number as the second
1246 argument). Clients which request a floor picture will display
1247 the picture *instead* of the floor name.
1248 _roompic_ - A graphic associated with the *current* room. Clients which
1249 request a room picture will display the picture in *addition*
1250 to the room name (i.e. it's used for a room banner, as
1251 opposed to the floor picture's use in a floor listing).
1254 NETP (authenticate as network session with connection NET Password)
1256 This command is used by client software to identify itself as a transport
1257 session for IGnet/Open BBS to BBS networking. It should be called with
1258 two arguments: the node name of the calling system, and the "shared secret"
1259 password for that connection. If the authentication succeeds, NETP will
1260 return OK, otherwise, it returns ERROR.
1263 NUOP (Network Upload OPen file)
1265 Open a network spool file for uploading. The client must have already
1266 identified itself as a network session using the NETP command. If the command
1267 returns OK, the client may begin transmitting IGnet/Open spool data using
1268 a series of WRIT commands. When a UCLS command is issued, the spooled data
1269 is entered into the BBS if the argument to UCLS is 1 or discarded if the
1270 argument to UCLS is 0. If the client has not authenticated itself with a
1271 NETP command, ERROR+HIGHER_ACCESS_REQUIRED will be returned.
1274 NDOP (Network Download OPen file)
1276 Open a network spool file for downloading. The client must have already
1277 identified itself as a network session using the NETP command. If the command
1278 returns OK, the client may begin receiving IGnet/Open spool data using
1279 a series of READ commands. When a CLOS command is issued, the spooled data
1280 is deleted from the server and may not be read again. If the client has not
1281 authenticated itself with a NETP command, ERROR+HIGHER_ACCESS_REQUIRED will
1285 LFLR (List all known FLooRs)
1287 On systems supporting floors, this command lists all known floors. The
1288 command accepts no parameters. It will return ERROR+NOT_LOGGED_IN if no
1289 user is logged in. Otherwise it returns LISTING_FOLLOWS and a list of
1290 the available floors, each line consisting of three fields:
1292 1. The floor number associated with the floor
1293 2. The name of the floor
1294 3. Reference count (number of rooms on this floor)
1297 CFLR (Create a new FLooR)
1299 This command is used to create a new floor. It should be passed two
1300 arguments: the name of the new floor to be created, and a 1 or 0 depending
1301 on whether the client is actually creating a floor or merely checking to
1302 see if it has permission to create the floor. The user must be logged in
1303 and have Aide privileges to create a floor.
1305 If the command succeeds, it will return OK followed by the floor number
1306 associated with the new floor. Otherwise, it will return ERROR (plus perhaps
1307 HIGHER_ACCESS_REQUIRED, ALREADY_EXISTS, or INVALID_FLOOR_OPERATION)
1308 followed by a description of why the command failed.
1313 This command is used to delete a floor. It should be passed two
1314 argument: the *number* of the floor to be deleted, and a 1 or 0 depending
1315 on whether the client is actually deleting the floor or merely checking to
1316 see if it has permission to delete the floor. The user must be logged in
1317 and have Aide privileges to delete a floor.
1319 Floors that contain rooms may not be deleted. If there are rooms on a floor,
1320 they must be either deleted or moved to different floors first. This implies
1321 that the Main Floor (floor 0) can never be deleted, since Lobby>, Mail>, and
1322 Aide> all reside on the Main Floor and cannot be deleted.
1324 If the command succeeds, it will return OK. Otherwise it will return
1325 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1326 followed by a description of why the command failed.
1331 Edit the parameters of a floor. The client may pass one or more parameters
1334 1. The number of the floor to be edited
1335 2. The desired new name
1337 More parameters may be added in the future. Any parameters not passed to
1338 the server will remain unchanged. A minimal command would be EFLR and a
1339 floor number -- which would do nothing. EFLR plus the floor number plus a
1340 floor name would change the floor's name.
1342 If the command succeeds, it will return OK. Otherwise it will return
1343 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1346 IDEN (IDENtify the client software)
1348 The client software has the option to identify itself to the server.
1349 Currently, the server does nothing with this information except to write
1350 it to the syslog to satisfy the system administrator's curiosity. Other
1351 uses might become apparent in the future.
1353 The IDEN command should contain five fields: a developer ID number (same as
1354 the server developer ID numbers in the INFO command -- please obtain one if
1355 you are a new developer), a client ID number (which does not have to be
1356 globally unique - only unique within the domain of the developer number),
1357 a version number, a free-form text string describing the client, and the name
1358 of the host the user is located at.
1360 It is up to the server to determine whether to accept the host name or to
1361 use the host name it has detected itself. Generally, if the client is
1362 running on a trusted host (either localhost or a well-known publically
1363 accessible client) it should use the host name transmitted by IDEN,
1364 otherwise it should use the host name it has detected itself.
1366 IDEN always returns OK, but since that's the only way it ever returns
1367 there's no point in checking the result code.
1370 IPGM (identify as an Internal ProGraM)
1372 IPGM is a low-level command that should not be used by normal user clients.
1373 It is used for various utilities to communicate with the server on the same
1374 host. For example, the "sendcommand" utility logs onto the server as an
1375 internal program in order to run arbitrary server commands. Since user clients
1376 do not utilize this command (or any of its companion commands), developers
1377 writing Citadel-compatible servers need not implement it.
1379 The sole argument to IPGM is the system's internal program password. This
1380 password is generated by the setup program and stored in the config file.
1381 Since internal programs have access to the config file, they know the correct
1384 IPGM returns OK for a correct authentication or ERROR otherwise.
1387 CHAT (enter CHAT mode)
1389 This command functions differently from every other command in the system. It
1390 is used to implement multi-user chat. For this to function, a new transfer
1391 mode, called START_CHAT_MODE, is implemented. If a client does not support
1392 chat mode, it should never send a CHAT command!
1394 In chat mode, messages may arrive asynchronously from the server at any
1395 time. The client may send messages at any time. This allows the arrival of
1396 messages without the client having to poll for them. Arriving messages will
1397 be of the form "user|message", where the "user" portion is, of course, the
1398 name of the user sending the message, and "message" is the message text.
1400 Chat mode ends when the server says it ends. The server will signal the end
1401 of chat mode by transmitting "000" on a line by itself. When the client reads
1402 this line, it must immediately exit from chat mode without sending any
1403 further traffic to the server. The next transmission sent to the server
1404 will be a regular server command.
1406 The Citadel/UX server understands the following commands:
1407 /quit - Exit from chat mode (causes the server to do an 000 end)
1408 /who - List users currently in chat
1409 /whobbs - List users currently in chat and on the bbs
1410 /me - Do an irc-style action.
1411 /join - Join a new "room" in which all messages are only heard by
1412 people in that room.
1413 /msg - /msg <user> <msg> will send the msg to <user> only.
1414 /help - Print help information
1415 NOOP - Do nothing (silently)
1417 Any other non-empty string is treated as message text and will be broadcast
1418 to other users currently in chat.
1421 SEXP (Send EXPress messages)
1423 This is one of two commands which implement "express messages" (also known
1424 as "paging"). An express message is a near-real-time message sent from one
1425 logged in user to another. When an express message is sent, it will be
1426 displayed the next time the target user executes a PEXP or GEXP command.
1428 The SEXP command accepts two arguments: the name of the user to send the
1429 message to, and the text of the message. If the message is successfully
1430 transmitted, OK is returned. If the target user is not logged in or if
1431 anything else goes wrong, ERROR is returned.
1433 If the server supports extended paging, sending a zero-length message
1434 merely checks for the presence of the requested user without actually sending
1435 a message. Sending a message consisting solely of a "-" (hyphen) will cause
1436 the server to return SEND_LISTING if the requested user is logged in, and the
1437 client can then transmit a multi-line page.
1439 The reserved name "broadcast" may be used instead of a user name, to
1440 broadcast an express message to all users currently connected to the server.
1442 Do be aware that if an express message is transmitted to a user who is logged
1443 in using a client that does not check for express messages, the message will
1447 PEXP (Print EXPress messages) ***DEPRECATED***
1449 This command is deprecated; it will eventually disappear from the protocol and
1450 its use is not recommended. Please use the GEXP command instead.
1452 Called without any arguments, PEXP simply dumps out the contents
1453 of any waiting express messages. It returns ERROR if there is a problem,
1454 otherwise it returns LISTING_FOLLOWS followed by all messages.
1456 So how does the client know there are express messages waiting? It could
1457 execute a random PEXP every now and then. Or, it can check the byte in
1458 server return code messages, between the return code and the parameters. In
1459 much the same way as FTP uses "-" to signify a continuation, Citadel uses
1460 an "*" in this position to signify the presence of waiting express messages.
1463 EBIO (Enter BIOgraphy)
1465 Transmit to the server a free-form text file containing a little bit of
1466 information about the user for other users to browse. This is typically
1467 referred to as a 'bio' online. EBIO returns SEND_LISTING if it succeeds,
1468 after which the client is expected to transmit the file, or any of the usual
1469 ERROR codes if it fails.
1472 RBIO (Read BIOgraphy)
1474 Receive from the server a named user's bio. This command should be passed
1475 a single argument - the name of the user whose bio is requested. RBIO returns
1476 LISTING_FOLLOWS plus the bio file if the user exists and has a bio on file.
1477 The return has the following parameters: the user name, user number, access
1478 level, date of last call, times called, and messages posted. This command
1479 returns ERROR+NO_SUCH_USER if the named user does not exist.
1481 RBIO no longer considers a user with no bio on file to be an error condition.
1482 It now returns a message saying the user has no bio on file as the text of the
1483 bio. This allows newer servers to operate with older clients.
1486 STEL (enter STEaLth mode)
1488 When in "stealth mode," a user will not show up in the "Who is online"
1489 listing (the RWHO server command). Only Aides may use stealth mode. The
1490 STEL command accepts one argument: a 1 indicating that the user wishes to
1491 enter stealth mode, or a 0 indicating that the user wishes to exit stealth
1492 mode. STEL returns OK if the command succeeded, ERROR+NOT_LOGGED_IN if no
1493 user is logged in, or ERROR+HIGHER_ACCESS_REQUIRED if the user is not an Aide;
1494 followed by a 1 or 0 indicating the new state.
1496 If any value other than 1 or 0 is sent by the client, the server simply
1497 replies with 1 or 0 to indicate the current state without changing it.
1499 The STEL command also makes it so a user does not show up in the chat room
1503 LBIO (List users who have BIOs on file)
1505 This command is self-explanatory. Any user who has used EBIO to place a bio
1506 on file is listed. LBIO almost always returns LISTING_FOLLOWS followed by
1507 this listing, unless it experiences an internal error in which case ERROR
1511 MSG2 (read MeSsaGe, mode 2)
1513 MSG2 follows the same calling convention as MSG0. The difference between
1514 the two commands is that MSG2 outputs messages in standard RFC822 format
1515 rather than in Citadel/UX proprietary format.
1517 This command was implemented in order to make various gateway programs
1518 easier to implement, and to provide some sort of multimedia support in the
1519 future. Keep in mind that when this command is used, all messages will be
1520 output in fixed 80-column format.
1523 MSG3 (read MeSsaGe, mode 3 -- internal command)
1525 MSG3 is for use by internal programs only and should not be utilized by
1526 user-mode clients. It does require IPGM authentication. MSG3 follows the
1527 same calling convention as the other MSG commands, but upon success returns
1528 BINARY_FOLLOWS followed by a data block containing the _raw_ message format
1532 TERM (TERMinate another session)
1534 In a multithreaded environment, it sometimes becomes necessary to terminate
1535 a session that is unusable for whatever reason. The TERM command performs
1536 this task. Naturally, only Aides can execute TERM. The command should be
1537 called with a single argument: the session ID (obtained from an RWHO command)
1538 of the session to be terminated.
1540 TERM returns OK if the session was terminated, or ERROR otherwise. Note that
1541 a client program is prohibited from terminating the session it is currently
1547 DOWN (shut DOWN the server)
1549 This command, which may only be executed by an Aide, immediately shuts down
1550 the server. It is only implemented on servers on which such an operation is
1551 possible, such as a multithreaded Citadel engine. The server does not restart.
1552 DOWN returns OK if the user is allowed to shut down the server, in which case
1553 the client program should expect the connection to be immediately broken.
1556 SCDN (Schedule or Cancel a shutDowN)
1558 SCDN sets or clears the "scheduled shutdown" flag. Pass this command a 1 or
1559 0 to respectively set or clear the flag. When the "scheduled shutdown" flag is
1560 set, the server will be shut down when there are no longer any users logged in.
1561 Any value other than 0 or 1 will not change the flag, only report its state.
1562 No users will be kicked off the system, and in fact the server is still
1563 available for new connections. The command returns ERROR if it fails;
1564 otherwise, it returns OK followed by a number representing the current state
1568 EMSG (Enter a system MeSsaGe)
1570 This is the opposite of the MESG command - it allows the creation and editing
1571 of system messages. The only argument passed to EMSG is the name of the
1572 file being transmitted. If the file exists in any system message directory
1573 on the server it will be overwritten, otherwise a new file is created. EMSG
1574 returns SEND_LISTING on success or ERROR+HIGHER_ACCESS_REQUIRED if the user
1577 Typical client software would use MESG to retrieve any existing message into
1578 an edit buffer, then present an editor to the user and run EMSG if the changes
1582 UIMG (Upload an IMaGe file)
1584 UIMG is complemenary to OIMG; it is used to upload an image to the server.
1585 The first parameter supplied to UIMG should be 0 if the client is only checking
1586 for permission to upload, or 1 if the client is actually attempting to begin
1587 the upload operation. The second argument is the name of the file to be
1588 transmitted. In Citadel/UX, the filename is converted to all lower case,
1589 appended with the characters ".gif", and stored in the "images" directory.
1591 UIMG returns OK if the client has permission to perform the requested upload,
1592 or ERROR+HIGHER_ACCESS_REQUIRED otherwise. If the client requested to begin
1593 the operation (first parameter set to 1), an upload file is opened, and the
1594 client should begin writing to it with WRIT commands, then close it with a
1597 The supplied filename should be one of:
1599 -> _userpic_ (Server will attempt to write to the user's online photo)
1600 -> Any of the "well known" filenames described in the writeup for the
1604 HCHG (Hostname CHanGe)
1606 HCHG is a command, usable by any user, that allows a user to change their RWHO
1607 host value. This will mask a client's originating hostname from normal
1608 users; access level 6 and higher can see, in an extended wholist, the actual
1609 hostname the user originates from.
1611 The format of an HCHG command is:
1615 If a HCHG command is successful, the value OK (200) is returned.
1618 RCHG (Roomname CHanGe)
1620 RCHG is a command, usable by any user, that allows a user to change their RWHO
1621 room value. This will mask a client's roomname from normal users; access
1622 level 6 and higher can see, in an extended wholist, the actual room the user
1625 The format of an RCHG command is:
1629 If a RCHG command is successful, the value OK (200) is returned.
1632 UCHG (Username CHanGe)
1634 UCHG is an aide-level command which allows an aide to effectively change their
1635 username. If this value is blank, the user goes into stealth mode (see
1637 will show up as being from the real username in this mode, however. In
1638 addition, the RWHO listing will include both the spoofed and real usernames.
1640 The format of an UCHG command is:
1644 If a UCHG command is successful, the value OK (200) is returned.
1647 TIME (get server local TIME)
1649 TIME returns OK followed by the current time measured in seconds since
1650 00:00:00 GMT, Jan 1, 1970 (standard Unix format).
1652 This is used in allowing a client to calculate idle times.
1655 AGUP (Administrative Get User Parameters)
1656 ASUP (Administrative Set User Parameters)
1658 These commands are only executable by Aides and by server extensions running
1659 at system-level. They are used to get/set any and all parameters relating to
1660 a user account. AGUP requires only one argument: the name of the user in
1661 question. SGUP requires all of the parameters to be set. The parameters are
1662 as follows, and are common to both commands:
1666 2 - Flags (see citadel.h)
1671 7 - Timestamp of last call
1672 8 - Purge time (in days) for this user (or 0 to use system default)
1674 Upon success, AGUP returns OK followed by all these parameters, and ASUP
1675 simply returns OK. If the client has insufficient access to perform the
1676 requested operation, ERROR+HIGHER_ACCESS_REQUIRED is returned. If the
1677 requested user does not exist, ERROR+NO_SUCH_USER is returned.
1681 GPEX (Get Policy for message EXpiration)
1683 Returns the policy of the current room, floor, or site regarding the automatic
1684 purging (expiration) of messages. The following policies are available:
1685 0 - Fall back to the policy of the next higher level. If this is a room,
1686 use the floor's default policy. If this is a floor, use the system
1687 default policy. This is an invalid value for the system policy.
1688 1 - Do not purge messages automatically.
1689 2 - Purge by message count. (Requires a value: number of messages)
1690 3 - Purge by message age. (Requires a value: number of days)
1692 The format of this command is: GPEX <which>
1693 The value of <which> must be one of: "room" "floor" "site"
1695 If successful, GPEX returns OK followed by <policy>|<value>.
1699 SPEX (Set Policy for message EXpiration)
1701 Sets the policy of the current room, floor, or site regarding the automatic
1702 purging (expiration) of messages. See the writeup for the GPEX command for
1703 the list of available policies.
1705 The format of this command is: SPEX <which>|<policy>|<value>
1706 The value of <which> must be one of: "room" "floor" "site"
1708 If successful, GPEX returns OK; otherwise, an ERROR code is returned.
1712 CONF (get or set global CONFiguration options)
1714 Retrieves or sets various system-wide configuration and policy options. This
1715 command is only available to Aides. The sole parameter accepted is a command,
1716 which should be either GET or SET. If the GET command succeeds, CONF will
1717 return LISTING_FOLLOWS followed by the fields described below, one line at a
1718 time. If the SET command succeeds, CONF will return SEND_LISTING and expect
1719 the fields described below, one line at a time (don't worry about other fields
1720 being added in the future; if a 'short' configuration list is sent, the missing
1721 values at the end will be left unchanged on the system). If either command
1722 fails for any reason, ERROR is returned.
1724 The configuration lines are as follows:
1727 2. Fully qualified domain name
1728 3. Human-readable node name
1729 4. Landline telephone number of this system
1730 5. Flag (0 or 1) - creator of private room automatically becomes room aide
1731 6. Server connection idle timeout (in seconds)
1732 7. Initial access level for new users
1733 8. Flag (0 or 1) - require registration for new users
1734 9. Flag (0 or 1) - automatically move Problem User messages to twit room
1735 10. Name of twit room
1736 11. Text of <more> prompt
1737 12. Flag (0 or 1) - restrict access to Internet mail
1738 13. Geographic location of this system
1739 14. Name of the system administrator
1740 15. Number of maximum concurrent sessions allowed on the server
1741 16. (placeholder -- this field is no longer in use)
1742 17. Default purge time (in days) for users
1743 18. Default purge time (in days) for rooms
1744 19. Name of room to log express messages to (or a zero-length name for none)
1745 20. Access level required to create rooms
1746 21. Maximum message length which may be entered into the system
1747 22. Minimum number of worker threads
1748 23. Maximum number of worker threads
1749 24. Port number for POP3 service
1750 25. Port number for SMTP service
1751 26. Flag (0 or 1) - strict RFC822 adherence - don't correct From: forgeries
1752 27. Flag (0 or 1) - allow Aides to zap (forget) rooms
1753 28. Port number for IMAP service
1754 29. How often (in seconds) to run the networker
1755 30. Flag (0 or 1) - disable self-service new user registration
1756 31. Flag (0 or 1) - Aides are allowed access to all mailboxes
1757 32. Hour (0 through 23) during which database auto-purge jobs are run
1759 CONF also accepts two additional commands: GETSYS and PUTSYS followed by an
1760 arbitrary MIME type (such as application/x-citadel-internet-config) which
1761 provides a means of storing generic configuration data in the Global System
1762 Configuration room without the need to add extra get/set commands to the
1767 MSG4 (read MeSsaGe, mode 4 -- output in preferred MIME format)
1769 This is the equivalent of MSG0, except it's a bit smarter about messages in
1770 rich text formats. Immediately following the "text" directive, the server
1771 will output RFC822-like MIME part headers such as "Content-type:" and
1772 "Content-length:". MIME formats are chosen and/or converted based on the
1773 client's preferred format settings, which are set using the MSGP command,
1778 MSGP (set MeSsaGe Preferred MIME format)
1780 Client tells the server what MIME content types it knows how to handle, and
1781 the order in which it prefers them. This is similar to an HTTP "Accept:"
1784 The parameters to a MSGP command are the client's acceptable MIME content
1785 types, in the order it prefers them (from most preferred to least preferred).
1786 For example: MSGP text/html|text/plain
1788 The MSGP command always returns OK.
1792 OPNA (OPeN Attachment)
1794 Opens, as a download file, a component of a MIME-encoded message. The two
1795 parameters which must be passed to this command are the message number and the
1796 name of the desired section. If the message or section does not exist, an
1797 appropriate ERROR code will be returned; otherwise, if the open is successful,
1798 this command will succeed returning the same information as an OPEN command.
1801 GEXP (Get EXPress messages)
1803 This is a more sophisticated way of retrieving express messages than the old
1804 PEXP method. If there are no express messages waiting, PEXP returns ERROR;
1805 otherwise, it returns LISTING_FOLLOWS and the following arguments:
1807 0 - a boolean value telling the client whether there are any additional
1808 express messages waiting following this one
1809 1 - a Unix-style timestamp
1810 2 - flags (see server.h for more info)
1811 3 - the name of the sender
1812 4 - the node this message originated on (for future support of PIP, ICQ, etc.)
1814 The text sent to the client will be the body of the express message.
1816 So how does the client know there are express messages waiting? It could
1817 execute a random GEXP every now and then. Or, it can check the byte in
1818 server return code messages, between the return code and the parameters. In
1819 much the same way as FTP uses "-" to signify a continuation, Citadel uses
1820 an "*" in this position to signify the presence of waiting express messages.
1823 FSCK (check message base reference counts)
1825 Verify, via the long way, that all message referenmce counts are correct. If
1826 the user has permission to do this then LISTING_FOLLOWS is returned, followed
1827 by a transcript of the run. Otherwise ERROR is returned.
1830 DEXP (Disable EXPress messages)
1832 DEXP sets or clears the "disable express messages" flag. Pass this command a
1833 1 or 0 to respectively set or clear the flag. When the "disable express
1834 messages" flag is set, no one except Aides may send the user express messages.
1835 Any value other than 0 or 1 will not change the flag, only report its state.
1836 The command returns ERROR if it fails; otherwise, it returns OK followed by a
1837 number representing the current state of the flag.
1840 REQT (REQuest client Termination)
1842 Request that the specified client (or all clients) log off. Aide level
1843 access is required to run this command, otherwise ERROR+HIGHER_ACCESS_REQUIRED
1846 The REQT command accepts one parameter: the session ID of the client which
1847 should be terminated, or 0 for all clients. When successful, the REQT command
1850 It should be noted that REQT simply transmits an express message to the
1851 specified client(s) with the EM_GO_AWAY flag set. Older clients do not honor
1852 this flag, and it is certainly possible for users to re-program their client
1853 software to ignore it. Therefore the effects of the REQT command should be
1854 considered advisory only. The recommended implementation practice is to first
1855 issue a REQT command, then wait a little while (from 30 seconds up to a few
1856 minutes) for well-behaved clients to voluntarily terminate, and then issue a
1857 TERM command to forcibly disconnect the client (or perhaps a DOWN command, if
1858 you are logging off users for the purpose of shutting down the server).
1861 SEEN (set or clear the SEEN flag for a message)
1863 Beginning with version 5.80, Citadel supports the concept of setting or
1864 clearing the "seen" flag for each individual message, instead of only allowing
1865 a "last seen" pointer. In fact, the old semantics are implemented in terms
1866 of the new semantics. This command requires two arguments: the number of the
1867 message to be set, and a 1 or 0 to set or clear the "seen" bit.
1869 This command returns OK, unless the user is not logged in or a usage error
1870 occurred, in which case it returns ERROR. Please note that no checking is
1871 done on the supplied data; if the requested message does not exist, the SEEN
1872 command simply returns OK without doing anything.
1875 GTSN (GeT the list of SeeN messages)
1877 This command retrieves the list of "seen" (as opposed to unread) messages for
1878 the current room. It returns OK followed by an IMAP-format message list.
1881 SMTP (utility commands for the SMTP gateway)
1883 This command, accessible only by Aides, supports several utility operations
1884 which examine or manipulate Citadel's SMTP support. The first command argument
1885 is a subcommand telling the server what to do. The following subcommands are
1888 SMTP mx|hostname (display all MX hosts for 'hostname')
1889 SMTP runqueue (attempt immediate delivery of all messages
1890 in the outbound SMTP queue, ignoring any
1891 retry times stored there)
1894 STLS (Start Transport Layer Security)
1896 This command starts TLS on the current connection. The current
1897 implementation uses OpenSSL on both the client and server end. For future
1898 compatibility all clients must support at least TLSv1, and servers are
1899 guaranteed to support TLSv1. During TLS negotiation (see below) the server
1900 and client may agree to use a different protocol.
1902 The server returns ERROR if it does not support SSL or SSL initialization
1903 failed on the server; otherwise it returns OK. Once the server returns OK and
1904 the client has read the response, the server and client immediately negotiate
1905 TLS (in OpenSSL, using SSL_connect() on the client and SSL_accept() on the
1906 server). If negotiation fails, the server and client should attempt to resume
1907 the session unencrypted. If either end is unable to resume the session, the
1908 connection should be closed.
1910 This command may be run at any time.
1913 GTLS (Get Transport Layer Security Status)
1915 This command returns information about the current connection. The server
1916 returns OK plus several parameters if the connection is encrypted, and ERROR
1917 if the connection is not encrypted. It is primarily used for debugging. The
1918 command may be run at any time.
1920 0 - Protocol name, e.g. "SSLv3"
1921 1 - Cipher suite name, e.g. "ADH-RC4-MD5"
1922 2 - Cipher strength bits, e.g. 128
1923 3 - Cipher strength bits actually in use, e.g. 128
1926 IGAB (Initialize Global Address Book)
1928 This command creates, or re-creates, a database of Internet e-mail addresses
1929 using the vCard information in the Global Address Book room. This procedure
1930 is normally run internally when the server determines it necessary, but is
1931 also provided as a server command to be used as a troubleshooting/maintenenance
1932 tool. Only a system Aide can run the command. It returns OK on success or
1936 QDIR (Query global DIRectory)
1938 Look up an internet address in the global directory. Any logged-in user may
1939 call QDIR with one parameter, the Internet e-mail address to look up. QDIR
1940 returns OK followed by a Citadel address if there is a match, otherwise it
1941 returns ERROR+NOT_LOGGED_IN.
1944 ISME (find out if an e-mail address IS ME)
1946 This is a quickie shortcut command to find out if a given e-mail address
1947 belongs to the user currently logged in. Its sole argument is an address to
1948 parse. The supplied address may be in any format (local, IGnet, or Internet).
1949 The command returns OK if the address belongs to the user, ERROR otherwise.
1952 VIEW (set the VIEW for a room)
1954 Set the preferred view for the current user in the current room. Please see
1955 views.txt for more information on views. The sole parameter for this command
1956 is the type of view requested. VIEW returns OK on success or ERROR on failure.
1959 QNOP (Quiet No OPeration)
1961 This command does nothing, similar to the NOOP command. However, unlike the
1962 NOOP command, it returns *absolutely no response* at all. The client has no
1963 way of knowing that the command executed. It is intended for sending
1964 "keepalives" in situations where a full NOOP would cause the client protocol
1967 Naturally, sending this command to a server that doesn't support it is an
1968 easy way to mess things up. Therefore, client software should first check
1969 the output of an INFO command to ensure that the server supports quiet noops.
1973 ICAL (Internet CALendaring commands)
1975 This command supports a number of subcommands which are used to process the
1976 calendaring/scheduling support in Citadel. Here are the subcommands which
1980 Test server for calendaring support. Always returns OK unless the server
1981 does not have the calendar module enabled.
1983 ICAL respond|msgnum|partnum|action
1984 Respond to a meeting request. 'msgnum' and 'partnum' refer to a MIME-encoded
1985 meeting invitation in the current room. 'action' must be set to either
1986 "accept" or "decline" to determine the action to take. This subcommand will
1987 return either OK or ERROR.
1989 ICAL conflicts|msgnum|partnum
1990 Determine whether an incoming VEVENT will fit in the user's calendar by
1991 checking it against the existing VEVENTs. 'msgnum' and 'partnum' refer to
1992 a MIME-encoded meeting invitation in the current room (usually the inbox).
1993 This command may return ERROR if something went wrong, but usually it will
1994 return LISTING_FOLLOWS followed by a list of zero or more conflicting
1995 events. A zero-length list means that there were no conflicts.
1997 ICAL handle_rsvp|msgnum|partnum
1998 Handle an incoming "reply" (or RSVP) to a meeting request you sent out.
1999 'msgnum' and 'partnum' refer to a MIME-encoded reply in the current room.
2000 'action' must be set to either "update" or "ignore" to determine the action
2001 to take. If the action is "update" then the server will hunt for the meeting
2002 in the user's Calendar> room, and update the status for this attendee. Either
2003 way, the reply message is deleted from the current room. This subcommand will
2004 return either OK or ERROR.
2006 ICAL freebusy|username
2007 Output the free/busy times for the requested user. If the user specified
2008 has a calendar available, this command will return LISTING_FOLLOWS and a
2009 compound VCALENDAR object. That object, in turn, will contain VEVENT
2010 objects that have been stripped of all properties except for the bare
2011 minimum needed to learn free/busy times (such as DTSTART, DTEND, and
2012 TRANSP). If there is no such user, or no calendar available, the usual
2013 ERROR codes will be returned.
2015 Readers who are paying attention will notice that there is no subcommand to
2016 send out meeting invitations. This is because that task is handled
2017 automatically by the Citadel server. When an event is saved to the user's
2018 Calendar> room and it contains attendees, Citadel will automatically turn
2019 the event into vCalendar REQUEST messages and mail them out to all listed
2024 MRTG (Multi Router Traffic Grapher)
2026 Multi Router Traffic Grapher (please see http://www.mrtg.org for more info) is
2027 a tool which creates pretty graphs of network activity, usually collected from
2028 routers using SNMP. However, its ability to call external scripts has spawned
2029 a small community of people using it to graph anything which can be graphed.
2030 The MRTG command can output Citadel server activity in the format MRTG expects.
2032 This format is as follows:
2037 Line 3: uptime of system
2038 Line 4: name of system
2041 MRTG accepts two different keywords. "MRTG users" will return two variables,
2042 the number of connected users and the number of active users. "MRTG messages"
2043 will return one variable (and a zero in the second field), showing the current
2044 highest message number on the system. Any other keyword, or a missing keyword,
2045 will cause the MRTG command to return an ERROR code.
2047 Please get in touch with the Citadel developers if you wish to experiment with
2052 ASYN (ASYNchronous message support)
2054 Negotiate the use of asynchronous, or unsolicited, protocol messages. The
2055 only parameter specified should be 1 or 0 to indicate that the client can or
2056 cannot handle this type of messages. The server will reply OK followed by a
2057 1 or 0 to tell the client which mode it is now operating in.
2059 If the command is not available on the server (i.e. it returns ERROR), or
2060 if the command has not been executed by the client, it should be assumed that
2061 this mode of operation is NOT in effect.
2063 The client may also send any value other than 0 or 1 to simply cause the
2064 server to output its current state without changing it.
2066 When asynchronous protocol mode is in effect, the client MUST handle any
2067 asynchronous messages as they arrive, before doing anything else.
2072 ASYNCHRONOUS MESSAGES
2073 ---------------------
2075 When the client protocol is operating in asynchronous mode (please refer to
2076 the writeup of the ASYN command above), the following messages may arrive at
2080 901 (express message arriving)
2082 There is an express message intended for this client. When the client
2083 receives this message, it MUST act as if it just sent a GEXP command (the data
2084 following the 901 message WILL be a LISTING_FOLLOWS data transfer; in fact,
2085 the current implementation simply executes a GEXP command internally).