1 APPLICATION LAYER PROTOCOL FOR THE CITADEL SYSTEM
2 (c) 1995-2005 by Art Cancro et. al. All Rights Reserved
8 This is an attempt to document the application layer protocol used by the
9 Citadel system, beginning with version 4.00, which is the first version
10 to implement a client/server paradigm. It is intended as a resource for
11 programmers who intend to develop their own Citadel clients, but it may have
15 IMPORTANT NOTE TO DEVELOPERS!
16 -----------------------------
18 Anyone who wants to add commands or other functionality to this protocol,
19 *please* get in touch so that these efforts can be coordinated. New
20 commands added by other developers can be added to this document, so we
21 don't end up with new server commands from multiple developers which have
22 the same name but perform different functions. If you don't coordinate new
23 developments ahead of time, please at least send in an e-mail documenting
24 what you did, so that your new commands can be added to this document.
26 The coordinator of the Citadel project is Art Cancro
27 <ajc@uncensored.citadel.org>.
30 CONNECTING TO A SERVER
31 ----------------------
33 The protocols used below the application layer are beyond the scope of this
34 document, but we will briefly cover the methodology employed by Citadel.
36 Citadel offers its client protocol using TCP/IP. It does so via a
37 multithreaded server listening on a TCP port. Local connections may also
38 be made using the same protocol using Unix domain sockets.
40 The port number officially assigned to Citadel by the IANA is 504/tcp. Since
41 our application layer assumes a clean, reliable, sequenced connection, the use
42 of UDP would render the server unstable and unusable, so we stick with TCP.
48 The native character set for the Citadel system is UTF-8. Unless otherwise
49 specified, all data elements are expected to be in the UTF-8 character set.
50 Specifically, all non-MIME messages should be assumed to be in UTF-8. MIME
51 messages may be in whatever character set is specified by the MIME header, of
52 course; however, some clients (such as WebCit) will automatically convert
53 messages from other character sets before displaying them.
56 GENERAL INFORMATION ABOUT THE SERVER
57 ------------------------------------
59 The server is connection-oriented and stateful: each client requires its own
60 connection to a server process, and when a command is sent, the client must
61 read the response, and then transfer data or change modes if necessary.
63 The application layer is very much like other Internet protocols such as SMTP
64 or NNTP. A client program sends one-line commands to the server, and the
65 server responds with a three-digit numeric result code followed by a message
66 describing what happened. This cycle continues until the end of the
69 Unlike protocols such as FTP, all data transfers occur in-band. This means
70 that the same connection that is used for exchange of client/server
71 messages, will also be used to transfer data back and forth. (FTP opens a
72 separate connection for data transfers.) This keeps protocol administration
73 straightforward, as it can traverse firewalls without any special protocol
74 support on the firewall except for opening the port number.
80 The server will respond to all commands with a 3-digit result code, which
81 will be the first three characters on the line. The rest of the line may
82 contain a human-readable string explaining what happened. (Some client
83 software will display some of these strings to the user.)
85 The first digit is the most important. The following codes are defined for
86 this position: ERROR, OK, MORE_DATA, LISTING_FOLLOWS, and SEND_LISTING.
88 The second and third digits may provide a reason as to why a command
89 succeeded or failed. See ipcdef.h for the available codes.
91 ERROR means the command did not complete.
92 OK means the command executed successfully.
93 MORE_DATA means the command executed partially. Usually this means that
94 another command needs to be executed to complete the operation. For example,
95 sending the USER command to log in a user usually results in a MORE_DATA
96 result code, because the client needs to execute a PASS command to send the
97 password and complete the login.
98 LISTING_FOLLOWS means that after the server response, the server will
99 output a listing of some sort. The client *must* read the listing, whether
100 it wants to or not. The end of the listing is signified by the string
101 "000" on a line by itself.
102 SEND_LISTING is the opposite of LISTING_FOLLOWS. It means that the client
103 should begin sending a listing of some sort. The client *must* send something,
104 even if it is an empty listing. Again, the listing ends with "000" on a line
106 BINARY_FOLLOWS and SEND_BINARY mean that the client must immediately send
107 or receive a block of binary data. The first parameter will always be the
109 ASYNC_MESSAGE_FOLLOWS means that an asynchronous, or unsolicited, message
110 follows. The next line will be one of the above codes, and if a data transfer
111 is involved it must be handled immediately. Note that the client will not
112 receive this type of response unless it indicates to the server that it is
113 capable of handling them; see the writeup of the ASYN command later in this
119 Zero or more parameters may be passed to a command. When more than one
120 parameter is passed to a command, they should be separated by the "|"
123 In this example, we're using the "SETU" command and passing three
124 parameters: 80, 24, and 260.
126 When the server spits out data that has parameters, if more than one
127 parameter is returned, they will be separated by the "|" symbol like
130 In this example, we just executed the "GETU" command, and it returned us
131 an OK result code (the '2' in the 200) and three parameters: 80, 24, and
138 This is a listing of all the commands that a Citadel server can execute.
143 This command does nothing. It takes no arguments and always returns
144 OK. It is intended primarily for testing and development, but it might also
145 be used as a "keep alive" command to prevent the server from timing out, if
146 it's running over a transport that needs this type of thing.
149 ECHO (ECHO something)
151 This command also does nothing. It simply returns OK followed by whatever
157 Terminate the server connection. This command takes no arguments. It
158 returns OK and closes the connection immediately.
163 Log out the user without closing the server connection. It always returns
164 OK even if no user is logged in.
167 USER (send USER name)
169 The first step in logging in a user. This command takes one argument: the
170 name of the user to be logged in. If the user exists, a MORE_DATA return
171 code will be sent, which means the client should execute PASS as the next
172 command. If the user does not exist, ERROR + NO_SUCH_USER is returned.
177 The second step in logging in a user. This command takes one argument: the
178 password for the user we are attempting to log in. If the password doesn't
179 match the correct password for the user we specified for the USER command,
180 ERROR + PASSWORD_REQUIRED is returned. If a USER command has not been
181 executed yet, ERROR + USERNAME_REQUIRED is returned. If a user is already
182 logged in, ERROR + ALREADY_LOGGED_IN is returned. If the password is
183 correct, OK is returned and the user is now logged in... and most of the
184 other server commands can now be executed. Along with OK, the following
185 parameters are returned:
187 0 - The user's name (in case the client wants the right upper/lower casing)
188 1 - The user's current access level
191 4 - Various flags (see citadel.h)
193 6 - Time of last call (UNIX timestamp)
196 NEWU (create NEW User account)
198 This command creates a new user account AND LOGS IT IN. The argument to
199 this command will be the name of the account. No case conversion is done
200 on the name. Note that the new account is installed with a default
201 configuration, and no password, so the client should immediately prompt the
202 user for a password and install it with the SETP command as soon as this
203 command completes. This command returns OK if the account was created and
204 logged in, ERROR + ALREADY_EXISTS if another user already exists with this
205 name, ERROR + NOT_HERE if self-service account creation is disabled,
206 ERROR + MAX_SESSIONS_EXCEEDED if too many users are logged in, ERROR +
207 USERNAME_REQUIRED if a username was not provided, or ERROR + ILELGAL_VALUE
208 if the username provided is invalid. If OK, it will also return the same
209 parameters that PASS returns.
211 Please note that the NEWU command should only be used for self-service
212 user account creation. For administratively creating user accounts, please
213 use the CREU command.
216 SETP (SET new Password)
218 This command sets a new password for the currently logged in user. The
219 argument to this command will be the new password. The command always
220 returns OK, unless the client is not logged in, in which case it will return
221 ERROR + NOT_LOGGED_IN, or if the user is an auto-login user, in which case
222 it will return ERROR + NOT_HERE.
225 CREU (CREate new User account)
227 This command creates a new user account AND DOES NOT LOG IT IN. The first
228 argument to this command will be the name of the account. No case conversion
229 is done on the name. Note that the new account is installed with a default
230 configuration, and no password. The second argument is optional, and will be
231 an initial password for the user. This command returns OK if the account was
232 created, ERROR + HIGHER_ACCESS_REQUIRED if the user is not an Aide, ERROR +
233 USERNAME_REQUIRED if no username was specified, or ERROR + ALREADY_EXISTS if
234 another user already exists with this name.
236 Please note that CREU is intended to be used for activities in which a
237 system administrator is creating user accounts. For self-service user
238 account creation, use the NEWU command.
241 LKRN (List Known Rooms with New messages)
243 List known rooms with new messages. If the client is not logged in, ERROR +
244 NOT_LOGGED_IN is returned. Otherwise, LISTING_FOLLOWS is returned, followed
245 by the room listing. Each line in the listing contains the full name of a
246 room, followed by the '|' symbol, and then a number that may contain the
249 #define QR_PERMANENT 1 /* Room does not purge */
250 #define QR_PRIVATE 4 /* Set for any type of private room */
251 #define QR_PASSWORDED 8 /* Set if there's a password too */
252 #define QR_GUESSNAME 16 /* Set if it's a guessname room */
253 #define QR_DIRECTORY 32 /* Directory room */
254 #define QR_UPLOAD 64 /* Allowed to upload */
255 #define QR_DOWNLOAD 128 /* Allowed to download */
256 #define QR_VISDIR 256 /* Visible directory */
257 #define QR_ANONONLY 512 /* Anonymous-Only room */
258 #define QR_ANON2 1024 /* Anonymous-Option room */
259 #define QR_NETWORK 2048 /* Shared network room */
260 #define QR_PREFONLY 4096 /* Preferred status needed to enter */
261 #define QR_READONLY 8192 /* Aide status required to post */
263 Then it returns another '|' symbol, followed by a second set of bits comprised
266 #define QR2_SYSTEM 1 /* System room; hide by default */
267 #define QR2_SELFLIST 2 /* Self-service mailing list mgmt */
269 Other bits may be defined in the future. The listing terminates, as with
270 all listings, with "000" on a line by itself.
272 Starting with version 4.01 and above, floors are supported. The first
273 argument to LKRN should be the number of the floor to list rooms from. Only
274 rooms from this floor will be listed. If no arguments are passed to LKRN, or
275 if the floor number requested is (-1), rooms on all floors will be listed.
277 The third field displayed on each line is the number of the floor the room
278 is on. The LFLR command should be used to associate floor numbers with
281 The fourth field displayed on each line is a "room listing order." Unless
282 there is a compelling reason not to, clients should sort any received room
283 listings by this value.
285 The fifth field is a special bit bucket containing fields which pertain to
286 room access controls:
288 #define UA_KNOWN 2 /* Known room */
289 #define UA_GOTOALLOWED 4 /* Access will be granted to this room
290 * if the user calls it up by name */
291 #define UA_HASNEWMSGS 8 /* Unread messages exist in room */
292 #define UA_ZAPPED 16 /* Zapped from known rooms list */
294 The sixth field is the user's current view for the room. (See VIEW command)
297 LKRO (List Known Rooms with Old [no new] messages)
299 This follows the same usage and format as LKRN.
302 LZRM (List Zapped RooMs)
304 This follows the same usage and format as LKRN and LKRO.
307 LKRA (List All Known Rooms)
309 Same format. Lists all known rooms, with or without new messages.
312 LRMS (List all accessible RooMS)
314 Again, same format. This command lists all accessible rooms, known and
315 forgotten, with and without new messages. It does not, however, list
316 inaccessible private rooms.
319 LPRM (List all Public RooMs)
321 Again, same format. This command lists all public rooms, and nothing else.
322 Unlike the other list rooms commands, this one can be executed without logging
326 GETU (GET User configuration)
328 This command retrieves the screen dimensions and user options for the
329 currently logged in account. ERROR + NOT_LOGGED_IN will be returned if no
330 user is logged in, of course. Otherwise, OK will be returned, followed by
331 four parameters. The first parameter is the user's screen width, the second
332 parameter is the user's screen height, and the third parameter is a bag of
333 bits with the following meanings:
335 #define US_LASTOLD 16 /* Print last old message with new */
336 #define US_EXPERT 32 /* Experienced user */
337 #define US_UNLISTED 64 /* Unlisted userlog entry */
338 #define US_NOPROMPT 128 /* Don't prompt after each message */
339 #define US_DISAPPEAR 512 /* Use "disappearing msg prompts" */
340 #define US_PAGINATOR 2048 /* Pause after each screen of text */
342 There are other bits, too, but they can't be changed by the user (see below).
345 SETU (SET User configuration)
347 This command does the opposite of SETU: it takes the screen dimensions and
348 user options (which were probably obtained with a GETU command, and perhaps
349 modified by the user) and writes them to the user account. This command
350 should be passed three parameters: the screen width, the screen height, and
351 the option bits (see above). It returns ERROR + NOT_LOGGED_IN if no user is
352 logged in, and ERROR + ILLEGAL_VALUE if the parameters are incorrect.
354 Note that there exist bits here which are not listed in this document. Some
355 are flags that can only be set by Aides or the system administrator. SETU
356 will ignore attempts to toggle these bits. There also may be more user
357 settable bits added at a later date. To maintain later downward compatibility,
358 the following procedure is suggested:
360 1. Execute GETU to read the current flags
361 2. Toggle the bits that we know we can toggle
362 3. Execute SETU to write the flags
364 If we are passed a bit whose meaning we don't know, it's best to leave it
365 alone, and pass it right back to the server. That way we can use an old
366 client on a server that uses an unknown bit without accidentally clearing
367 it every time we set the user's configuration.
372 This command is used to goto a new room. When the user first logs in (login
373 is completed after execution of the PASS command) this command is
374 automatically and silently executed to take the user to the first room in the
375 system (usually called the Lobby).
377 This command can be passed one or two parameters. The first parameter is,
378 of course, the name of the room. Although it is not case sensitive, the
379 full name of the room must be used. Wildcard matching or unique string
380 matching of room names should be the responsibility of the client.
382 Note that the reserved room name "_BASEROOM_" can be passed to the server
383 to cause the goto command to take the user to the first room in the system,
384 traditionally known as the Lobby>. As long as a user is logged in, a
385 GOTO command to _BASEROOM_ is guaranteed to succeed. This is useful to
386 allow client software to return to the base room when it doesn't know
389 There are also several additional reserved room names:
390 "_MAIL_" goes to the user's inbox (i.e. the Mail> room).
391 "_BITBUCKET_" goes to a room that has been chosen for messages without a home.
392 "_CALENDAR_" goes to the user's primary personal calendar.
393 "_CONTACTS_" goes to the user's primary personal address book.
394 "_NOTES_" goes to the user's primary personal notes room.
395 "_TASKS_" goes to the user's primary personal task list.
398 The second (and optional) parameter is a password, if one is required for
399 access to the room. This allows for all types of rooms to be accessed via
400 this command: for public rooms, invitation-only rooms to which the user
401 has access, and preferred users only rooms to which the user has access, the
402 room will appear in a room listing. For guess-name rooms, this command
403 will work transparently, adding the room to the user's known room list when
404 it completes. For passworded rooms, access will be denied if the password
405 is not supplied or is incorrect, or the command will complete successfully
406 if the password is correct.
408 The third (and also) optional parameter is a "transient" flag. Normally,
409 when a user enters a private and/or zapped room, the room is added to the
410 user's known rooms list. If the transient flag is set to non-zero, this is
411 called a "transient goto" which causes the user to enter the room without
412 adding the room to the known rooms list.
414 The possible result codes are:
416 OK - The command completed successfully. User is now in the room.
417 (See the list of returned parameters below)
419 ERROR - The command did not complete successfully. Check the second and
420 third positions of the result code to find out what happened:
422 NOT_LOGGED_IN - Of course you can't go there. You didn't log in.
423 PASSWORD_REQUIRED - Either a password was not supplied, or the supplied
424 password was incorrect.
425 ROOM_NOT_FOUND - The requested room does not exist.
427 The typical procedure for entering a passworded room would be:
429 1. Execute a GOTO command without supplying any password.
430 2. ERROR + PASSWORD_REQUIRED will be returned. The client now knows that
431 the room is passworded, and prompts the user for a password.
432 3. Execute a GOTO command, supplying both the room name and the password.
433 4. If OK is returned, the command is complete. If, however,
434 ERROR + PASSWORD_REQUIRED is still returned, tell the user that the supplied
435 password was incorrect. The user remains in the room he/she was previously
438 When the command succeeds, these parameters are returned:
439 0. The name of the room
440 1. Number of unread messages in this room
441 2. Total number of messages in this room
442 3. Info flag: set to nonzero if the user needs to read this room's info
443 file (see RINF command below)
444 4. Various flags associated with this room. (See LKRN cmd above)
445 5. The highest message number present in this room
446 6. The highest message number the user has read in this room
447 7. Boolean flag: 1 if this is a Mail> room, 0 otherwise.
448 8. Aide flag: 1 if the user is either the Room Aide for this room, *or* is
449 a regular Aide (this makes access checks easy).
450 9. The number of new Mail messages the user has (useful for alerting the
451 user to the arrival of new mail during a session)
452 10. The floor number this room resides on
453 11. The *current* "view" for this room (see views.txt for more info)
454 12. The *default* "view" for this room
456 The default view gives the client a hint as to what views the user should
457 be allowed to select. For example, it would be confusing to allow messages
458 in a room intended for calendar items. The server does not enforce these
459 restrictions, though.
462 MSGS (get pointers to MeSsaGeS in this room)
464 This command obtains a listing of all the messages in the current room
465 which the client may request. This command may be passed a single parameter:
466 either "all", "old", or "new" to request all messages, only old messages, or
467 new messages. Or it may be passed two parameters: "last" plus a number, in
468 which case that many message pointers will be returned; "first" plus a
469 number, for the corresponding effect; or "gt" plus a number, to list all
470 messages in the current room with a message number greater than the one
471 specified. If no parameters are specified, "all" is assumed.
473 The third argument, may be either 0 or 1. If it is 1, this command behaves
474 differently: before a listing is returned, the client must transmit a list
475 of fields to search for. The field headers are listed below in the writeup
476 for the "MSG0" command.
478 The optional fourth argument may also be either 0 or 1. If it is 1, the
479 output of this command will include not only a list of message numbers, but
480 a simple header summary of each message as well. This is somewhat resource
481 intensive so you shouldn't do this unless you absolutely need all the headers
482 immediately. The fields which are output (in the usual delimited fashion, of
483 course) are: message number, timestamp, display name, node name, Internet
484 email address (if present), subject (if present).
486 This command can return three possible results. ERROR + NOT_LOGGED_IN will
487 be returned if no user is currently logged in. Otherwise, LISTING_FOLLOWS
488 will be returned, and the listing will consist of zero or more message
489 numbers, one per line. The listing ends, as always, with the string "000"
490 alone on a line by itself. The listed message numbers can be used to request
491 messages from the system. If "search mode" is being used, the server will
492 return START_CHAT_MODE, and the client is expected to transmit the search
493 criteria, and then read the message list.
495 Since this is somewhat complex, here are some examples:
497 Example 1: Read all new messages
500 Server: 100 Message list...
506 Example 2: Read the last five messages
509 Server: 100 Message list...
517 Example 3: Read all messages written by "IGnatius T Foobar"
520 Server: 800 Send template then receive message list
521 Client: from|IGnatius T Foobar
535 Note that in "search mode" the client may specify any number of search
536 criteria. These criteria are applied with an AND logic.
539 MSG0 (read MeSsaGe, mode 0)
541 This is a command used to read the text of a message. "Mode 0" implies that
542 other MSG commands (MSG1, MSG2, etc.) will probably be added later on to read
543 messages in more robust formats. This command should be passed two arguments.
544 The first is the message number of the message being requested. The second
545 argument specifies whether the client wants headers and/or message body:
549 3 = Headers only, with MIME information suppressed (this runs faster)
551 If the request is denied, ERROR + NOT_LOGGED_IN or ERROR + MESSAGE_NOT_FOUND
552 will be returned. Otherwise, LISTING_FOLLOWS will be returned, followed by
553 the contents of the message. The following fields may be sent:
555 type= Formatting type. The currently defined types are:
556 0 = "traditional" Citadel formatting. This means that newlines should be
557 treated as spaces UNLESS the first character on the next line is a space. In
558 other words, only indented lines should generate a newline on the user's screen
559 when the message is being displayed. This allows a message to be formatted to
560 the reader's screen width. It also allows the use of proportional fonts.
561 1 = a simple fixed-format message. The message should be displayed to
562 the user's screen as is, preferably in a fixed-width font that will fit 80
564 4 = MIME format message. The message text is expected to contain a header
565 with the "Content-type:" directive (and possibly others).
567 msgn= The message ID of this message on the system it originated on.
568 path= An e-mailable path back to the user who wrote the message.
570 time= The date and time of the message, in Unix format (the number of
571 seconds since midnight on January 1, 1970, GMT).
573 from= The name of the author of the message.
574 rcpt= If the message is a private e-mail, this is the recipient.
575 room= The name of the room the message originated in.
576 node= The short node name of the system this message originated on.
577 hnod= The long node name of the system this message originated on.
578 zaps= The id/node of a message which this one zaps (supersedes).
580 part= Information about a MIME part embedded in this message.
581 pref= Information about a multipart MIME prefix such as "multipart/mixed"
582 or "multipart/alternative". This will be output immediately prior
583 to the various "part=" lines which make up the multipart section.
584 suff= Information about a multipart MIME suffix. This will be output
585 immediately following the various "part=" lines which make up the
588 text Note that there is no "=" after the word "text". This string
589 signifies that the message text begins on the next line.
592 WHOK (WHO Knows room)
594 This command is available only to Aides. ERROR + HIGHER_ACCESS_REQUIRED
595 will be returned if the user is not an Aide. Otherwise, it returns
596 LISTING_FOLLOWS and then lists, one user per line, every user who has
597 access to the current room.
600 INFO (get server INFO)
602 This command will *always* return LISTING_FOLLOWS and then print out a
603 listing of zero or more strings. Client software should be written to expect
604 anywhere from a null listing to an infinite number of lines, to allow later
605 backward compatibility. The current implementation defines the following
606 parts of the listing:
608 Line 1 - Your unique session ID on the server
609 Line 2 - The node name of the Citadel server
610 Line 3 - Human-readable node name of the Citadel server
611 Line 4 - The fully-qualified domain name (FQDN) of the server
612 Line 5 - The name of the server software, i.e. "Citadel 4.00"
613 Line 6 - (The revision level of the server code) * 100
614 Line 7 - The geographical location of the site (city and state if in the US)
615 Line 8 - The name of the system administrator
616 Line 9 - A number identifying the server type (see below)
617 Line 10 - The text of the system's paginator prompt
618 Line 11 - Floor Flag. 1 if the system supports floors, 0 otherwise.
619 Line 12 - Paging level. 0 if the system only supports inline paging,
620 1 if the system supports "extended" paging (check-only and
621 multiline modes). See the SEXP command for further information.
622 Line 13 - The "nonce" for this session, for support of APOP-style
623 authentication. If this field is present, clients may authenticate
625 Line 14 - Set to nonzero if this server supports the QNOP command.
626 Line 15 - Set to nonzero if this server is capable of connecting to a
627 directory service using LDAP.
629 *** NOTE! *** The "server type" code is intended to promote global
630 compatibility in a scenario in which developers have added proprietary
631 features to their servers or clients. We are attempting to avoid a future
632 situation in which users need to keep different client software around for
633 each Citadel they use. *Please*, if you are a developer and plan to add
634 proprietary features:
636 -> Your client programs should still be able to utilize servers other than
638 -> Clients other than your own should still be able to utilize your server,
639 even if your proprietary extensions aren't supported.
640 -> Please contact Art Cancro <ajc@uncensored.citadel.org> and obtain a unique
641 server type code, which can be assigned to your server program.
642 -> If you document what you did in detail, perhaps it can be added to a
643 future release of the Citadel program, so everyone can enjoy it. Better
644 yet, just work with the Citadel development team on the main source tree.
646 If everyone follows this scheme, we can avoid a chaotic situation with lots
647 of confusion about which client program works with which server, etc. Client
648 software can simply check the server type (and perhaps the revision level)
649 to determine ahead of time what commands may be utilized.
651 Please refer to "developers.txt" for information on what codes belong to whom.
655 RDIR (Read room DIRectory)
657 Use this command to read the directory of a directory room. ERROR + NOT_HERE
658 will be returned if the room has no directory, ERROR + HIGHER_ACCESS_REQUIRED
659 will be returned if the room's directory is not visible and the user does not
660 have Aide or Room Aide privileges, ERROR + NOT_LOGGED_IN will be returned if
661 the user is not logged in; otherwise LISTING_FOLLOWS will be returned,
662 followed by the room's directory. Each line of the directory listing will
663 contain three fields: a filename, the length of the file, and a description.
665 The server message contained on the same line with LISTING_FOLLOWS will
666 contain the name of the system and the name of the directory, such as:
668 uncensored.citadel.org|/usr/local/citadel/files/my_room_directory
671 SLRP (Set Last-message-Read Pointer)
673 This command marks all messages in the current room as read (seen) up to and
674 including the specified number. Its sole parameter is the number of the last
675 message that has been read. This allows the pointer to be set at any
676 arbitrary point in the room. Optionally, the parameter "highest" may be used
677 instead of a message number, to set the pointer to the number of the highest
678 message in the room, effectively marking all messages in the room as having
679 been read (ala the Citadel <G>oto command).
681 The command will return OK if the pointer was set, or ERROR + NOT_LOGGED_IN
682 if the user is not logged in. If OK is returned, it will be followed by a
683 single argument containing the message number the last-read-pointer was set to.
686 INVT (INViTe a user to a room)
688 This command may only be executed by Aides, or by the room aide for the
689 current room. It is used primarily to add users to invitation-only rooms,
690 but it may also be used in other types of private rooms as well. Its sole
691 parameter is the name of the user to invite.
693 The command will return OK if the operation succeeded. ERROR + NO_SUCH_USER
694 will be returned if the user does not exist, ERROR + HIGHER_ACCESS_REQUIRED
695 will be returned if the operation would have been possible if the user had
696 higher access, and ERROR + NOT_HERE may be returned if the room is not a
700 KICK (KICK a user out of a room)
702 This is the opposite of INVT: it is used to kick a user out of a private
703 room. It can also be used to kick a user out of a public room, but the
704 effect will only be the same as if the user <Z>apped the room - a non-stupid
705 user can simply un-zap the room to get back in.
708 GETR (GET Room attributes)
710 This command is used for editing the various attributes associated with a
711 room. A typical "edit room" command would work like this:
712 1. Use the GETR command to get the current attributes
713 2. Change some of them around
714 3. Use SETR (see below) to save the changes
715 4. Possibly also change the room aide using the GETA and SETA commands
717 GETR takes no arguments. It will only return OK if the SETR command will
718 also return OK. This allows client software to tell the user that he/she
719 can't edit the room *before* going through the trouble of actually doing the
720 editing. Possible return codes are:
722 ERROR+NOT_LOGGED_IN - No user is logged in.
723 ERROR+HIGHER_ACCESS_REQUIRED - Not enough access. Typically, only aides
724 and the room aide associated with the current room, can access this command.
725 OK - Command succeeded. Parameters are returned.
727 If OK is returned, the following parameters will be returned as well:
729 0. The name of the room
730 1. The room's password (if it's a passworded room)
731 2. The name of the room's directory (if it's a directory room)
732 3. Various flags (bits) associated with the room (see LKRN cmd above)
733 4. The floor number on which the room resides
734 5. The room listing order
735 6. The default view for the room (see views.txt)
736 7. A second set of flags (bits) associated with the room
739 SETR (SET Room attributes)
741 This command sets various attributes associated with the current room. It
742 should be passed the following arguments:
744 0. The name of the room
745 1. The room's password (if it's a passworded room)
746 2. The name of the room's directory (if it's a directory room)
747 3. Various flags (bits) associated with the room (see LKRN cmd above)
748 4. "Bump" flag (see below)
749 5. The floor number on which the room should reside
750 6. The room listing order
751 7. The default view for the room (see views.txt)
752 8. A second set of flags (bits) associated with the room
754 *Important: You should always use GETR to retrieve the current attributes of
755 the room, then change what you want to change, and then use SETR to write it
756 all back. This is particularly important with respect to the flags: if a
757 particular bit is set, and you don't know what it means, LEAVE IT ALONE and
758 only toggle the bits you want to toggle. This will allow for upward
761 The _BASEROOM_, user's Mail> and Aide> rooms can only be partially edited.
762 Any changes which cannot be made will be silently ignored.
764 If the room is a private room, you have the option of causing all users who
765 currently have access, to forget the room. If you want to do this, set the
766 "bump" flag to 1, otherwise set it to 0.
771 This command is used to get the name of the Room Aide for the current room.
772 It will return ERROR + NOT_LOGGED_IN if no user is logged in, or OK if the
773 command succeeded. Along with OK there will be returned one parameter: the
774 name of the Room Aide. A conforming server must guarantee that the user is
780 The opposite of GETA, used to set the Room Aide for the current room. One
781 parameter should be passed, which is the name of the user who is to be the
782 new Room Aide. Under Citadel, this command may only be executed by Aides
783 and by the *current* Room Aide for the room. Return codes possible are:
784 ERROR + NOT_LOGGED_IN (Not logged in.)
785 ERROR + HIGHER_ACCESS_REQUIRED (Higher access required.)
786 ERROR + NOT_HERE (Room cannot be edited.)
787 OK (Command succeeded.)
790 ENT0 (ENTer message, mode 0)
792 This command is used to enter messages into the system. It accepts four
795 0 - Post flag. This should be set to 1 to post a message. If it is
796 set to 0, the server only returns OK or ERROR (plus any flags describing
797 the error) without reading in a message. Client software should, in fact,
798 perform this operation at the beginning of an "enter message" command
799 *before* starting up its editor, so the user does not end up typing a message
800 in vain that will not be permitted to be saved. If it is set to 2, the
801 server will accept an "apparent" post name if the user is privileged enough.
802 This post name is arg 5.
803 1 - Recipient (To: field). This argument is utilized only for private
804 mail. It is ignored for public messages. It contains, of course, the name
805 of the recipient(s) of the message.
806 2 - Anonymous flag. This argument is ignored unless the room allows
807 anonymous messages. In such rooms, this flag may be set to 1 to flag a
808 message as anonymous, otherwise 0 for a normal message.
809 3 - Format type. Any valid Citadel format type may be used (this will
810 typically be 0; see the MSG0 command above).
811 4 - Subject. If present, this argument will be used as the subject of
813 5 - Post name. When postflag is 2, this is the name you are posting as.
814 This is an Aide only command.
815 6 - Do Confirmation. NOTE: this changes the protocol semantics! When
816 you set this to nonzero, ENT0 will reply with a confirmation message after
817 you submit the message text. The reply code for the ENT0 command will be
818 START_CHAT_MODE instead of SEND_LISTING.
819 7 - Recipient (Cc: field). This argument is utilized only for private
820 mail. It is ignored for public messages. It contains, of course, the name
821 of the recipient(s) of the message.
822 8 - Recipient (Bcc: field). This argument is utilized only for private
823 mail. It is ignored for public messages. It contains, of course, the name
824 of the recipient(s) of the message.
826 Possible result codes:
827 OK - The request is valid. (Client did not set the "post" flag, so the
828 server will not read in message text.) If the message is an e-mail with
829 a recipient, the text that follows the OK code will contain the exact name
830 to which mail is being sent. The client can display this to the user. The
831 implication here is that the name that the server returns will contain the
832 correct upper and lower case characters. In addition, if the recipient is
833 having his/her mail forwarded, the forwarding address will be returned.
834 SEND_LISTING - The request is valid. The client should now transmit
835 the text of the message (ending with a 000 on a line by itself, as usual).
836 START_CHAT_MODE - The request is valid. The client should now transmit
837 the text of the message, ending with a 000 on a line by itself. After
838 transmitting the 000 terminator, the client MUST read in the confirmation
839 from the server, which will also end with 000 on a line by itself. The format
840 of the confirmation appears below.
841 ERROR + NOT_LOGGED_IN - Not logged in.
842 ERROR + HIGHER_ACCESS_REQUIRED - Higher access is required. An
843 explanation follows, worded in a form that can be displayed to the user.
844 ERROR + NO_SUCH_USER - The specified recipient does not exist.
846 The format of the confirmation message, if requested, is as follows:
847 Line 1: The new message number on the server for the message. It will be
848 positive for a real message number, or negative to denote
849 that an error occurred. If an error occurred, the message was
851 Line 2: A human-readable confirmation or error message.
852 Line 3: The resulting Exclusive UID of the message, if present.
853 (More may be added to this in the future, so do not assume that there will
854 only be these lines output. Keep reading until 000 is received.)
857 RINF (read Room INFormation file)
859 Each room has associated with it a text file containing a description of
860 the room, perhaps containing its intended purpose or other important
861 information. The info file for the Lobby> (the system's base room) is
862 often used as a repository for system bulletins and the like.
864 This command, which accepts no arguments, is simply used to read the info
865 file for the current room. It will return LISTING_FOLLOWS followed by
866 the text of the message (always in format type 0) if the request can be
867 honored, or ERROR if no info file exists for the current room (which is
868 often the case). Other error description codes may accompany this result.
870 When should this command be used? This is, of course, up to the discretion
871 of client software authors, but in Citadel it is executed in two situations:
872 the first time the user ever enters a room; and whenever the contents of the
873 file change. The latter can be determined from the result of a GOTO command,
874 which will tell the client whether the file needs to be read (see GOTO above).
877 DELE (DELEte a message)
879 Delete a message from the current room. The one argument that should be
880 passed to this command is the message number of the message to be deleted.
881 The return value will be OK if the message was deleted, or an ERROR code.
882 If the delete is successful, the message's reference count is decremented, and
883 if the reference count reaches zero, the message is removed from the message
887 MOVE (MOVE or copy a message to a different room)
889 Move or copy a message to a different room. This command expects to be
890 passed three arguments:
891 0: the message number of the message to be moved or copied.
892 1: the name of the target room.
893 2: flag: 0 to move the message, 1 to copy it without deleting from the
896 This command never creates or deletes copies of a message; it merely moves
897 around links. When a message is moved, its reference count remains the same.
898 When a message is copied, its reference count is incremented.
901 KILL (KILL current room)
903 This command deletes the current room. It accepts a single argument, which
904 should be nonzero to actually delete the room, or zero to merely check
905 whether the room can be deleted.
907 Once the room is deleted, the current room is undefined. It is suggested
908 that client software immediately GOTO another room (usually _BASEROOM_)
909 after this command completes.
911 Possible return codes:
913 OK - room has been deleted (or, if checking only, request is valid).
914 ERROR+NOT_LOGGED_IN - no user is logged in.
915 ERROR+HIGHER_ACCESS_REQUIRED - not enough access to delete rooms.
916 ERROR+NOT_HERE - this room can not be deleted.
919 CRE8 (CRE[ate] a new room)
921 This command is used to create a new room. Like some of the other
922 commands, it provides a mechanism to first check to see if a room can be
923 created before actually executing the command. CRE8 accepts the following
926 0 - Create flag. Set this to 1 to actually create the room. If it is
927 set to 0, the server merely checks that there is a free slot in which to
928 create a new room, and that the user has enough access to create a room. It
929 returns OK if the client should go ahead and prompt the user for more info,
930 or ERROR or ERROR+HIGHER_ACCESS_REQUIRED if the command will not succeed.
931 1 - Name for new room.
932 2 - Access type for new room:
934 1 - Private; can be entered by guessing the room's name
935 2 - Private; can be entered by knowing the name *and* password
936 3 - Private; invitation only (sometimes called "exclusive")
937 4 - Personal (mailbox for this user only)
938 3 - Password for new room (if it is a type 2 room)
939 4 - Floor number on which the room should reside (optional)
940 5 - Set to 1 to avoid automatically gaining access to the created room.
941 6 - The default "view" for the room.
943 If the create flag is set to 1, the room is created (unless something
944 went wrong and an ERROR return is sent), and the server returns OK, but
945 the session is **not** automatically sent to that room. The client still
946 must perform a GOTO command to go to the new room.
949 FORG (FORGet the current room)
951 This command is used to forget (zap) the current room. For those not
952 familiar with Citadel, this terminology refers to removing the room from
953 a user's own known rooms list, *not* removing the room itself. After a
954 room is forgotten, it no longer shows up in the user's known room list,
955 but it will exist in the user's forgotten room list, and will return to the
956 known room list if the user goes to the room (in Citadel, this is
957 accomplished by explicitly typing the room's name in a <.G>oto command).
959 The command takes no arguments. If the command cannot execute for any
960 reason, ERROR will be returned. ERROR+NOT_LOGGED_IN or ERROR+NOT_HERE may
961 be returned as they apply.
963 If the command succeeds, OK will be returned. At this point, the current
964 room is **undefined**, and the client software is responsible for taking
965 the user to another room before executing any other room commands (usually
966 this will be _BASEROOM_ since it is always there).
969 MESG (read system MESsaGe)
971 This command is used to display system messages and/or help files. The
972 single argument it accepts is the name of the file to display. IT IS CASE
973 SENSITIVE. Citadel looks for these files first in the "messages"
974 subdirectory and then in the "help" subdirectory.
976 If the file is found, LISTING_FOLLOWS is returned, followed by a pathname
977 to the file being displayed. Then the message is printed, in format type 0
978 (see MSG0 command for more information on this). If the file is not found,
981 There are some "well known" names of system messages which client software
982 may expect most servers to carry:
984 hello - Welcome message, to be displayed before the user logs in.
985 changepw - To be displayed whenever the user is prompted for a new
986 password. Warns about picking guessable passwords and such.
987 register - Should be displayed prior to the user entering registration.
988 Warnings about not getting access if not registered, etc.
989 help - Main system help file.
990 goodbye - System logoff banner; display when user logs off.
991 roomaccess - Information about how public rooms and different types of
992 private rooms function with regards to access.
993 unlisted - Tells users not to choose to be unlisted unless they're
994 really paranoid, and warns that aides can still see
995 unlisted userlog entries.
997 Citadel provides these for the Citadel Unix text client. They are
998 probably not very useful for other clients:
1000 mainmenu - Main menu (when in idiot mode).
1005 saveopt - Options to save a message, abort, etc.
1006 entermsg - Displayed just before a message is entered, when in
1010 GNUR (Get Next Unvalidated User)
1012 This command shows the name of a user that needs to be validated. If there
1013 are no unvalidated users, OK is returned. Otherwise, MORE_DATA is returned
1014 along with the name of the first unvalidated user the server finds. All of
1015 the usual ERROR codes may be returned as well (for example, if the user is
1016 not an Aide and cannot validate users).
1018 A typical "Validate New Users" command would keep executing this command,
1019 and then validating each user it returns, until it returns OK when all new
1020 users have been validated.
1023 GREG (Get REGistration for user)
1025 This command retrieves the registration info for a user, whose name is the
1026 command's sole argument. All the usual error messages can be returned. If
1027 the command succeeds, LISTING_FOLLOWS is returned, followed by the user's name
1028 (retrieved from the userlog, with the right upper and lower case etc.) The
1029 contents of the listing contains one field per line, followed by the usual
1030 000 on the last line.
1032 The following lines are defined. Others WILL be added in the futre, so all
1033 software should be written to read the lines it knows about and then ignore
1034 all remaining lines:
1039 Line 4: Street address or PO Box
1040 Line 5: City/town/village/etc.
1041 Line 6: State/province/etc.
1043 Line 8: Telephone number
1044 Line 9: Access level
1045 Line 10: Internet e-mail address
1048 Users without Aide privileges may retrieve their own registration using
1049 this command. This can be accomplished either by passing the user's own
1050 name as the argument, or the string "_SELF_". The command will always
1051 succeed when used in this manner, unless no user is logged in.
1054 VALI (VALIdate user)
1056 This command is used to validate users. Obviously, it can only be executed
1057 by users with Aide level access. It should be passed two parameters: the
1058 name of the user to validate, and the desired access level
1060 If the command succeeds, OK is returned. The user's access level is changed
1061 and the "need validation" bit is cleared. If the command fails for any
1062 reason, ERROR, ERROR+NO_SUCH_USER, or ERROR+HIGHER_ACCESS_REQUIRED will be
1066 EINF (Enter INFo file for room)
1068 Transmit the info file for the current room with this command. EINF uses
1069 a boolean flag (1 or 0 as the first and only argument to the command) to
1070 determine whether the client actually wishes to transmit a new info file, or
1071 is merely checking to see if it has permission to do so.
1073 If the command cannot succeed, it returns ERROR.
1074 If the client is only checking for permission, and permission will be
1075 granted, OK is returned.
1076 If the client wishes to transmit the new info file, SEND_LISTING is
1077 returned, and the client should transmit the text of the info file, ended
1078 by the usual 000 on a line by itself.
1083 This is a simple user listing. It always succeeds, returning
1084 LISTING_FOLLOWS followed by zero or more user records, 000 terminated. The
1085 fields on each line are as follows:
1090 4. Date/time of last login (Unix format)
1093 7. Password (listed only if the user requesting the list is an Aide)
1095 Unlisted entries will also be listed to Aides logged into the server, but
1096 not to ordinary users.
1098 The LIST command accepts an optional single argument, which is a simple,
1099 case-insensitive search string. If this argument is present, only usernames
1100 in which the search string is present will be returned. It is a simple
1101 substring search, not a regular expression search. If this string is empty
1102 or not present, all users will be returned.
1105 REGI (send REGIstration)
1107 Clients will use this command to transmit a user's registration info. If
1108 no user is logged in, ERROR+NOT_LOGGED_IN is returned. Otherwise,
1109 SEND_LISTING is returned, and the server will expect the following information
1110 (terminated by 000 on a line by itself):
1113 Line 2: Street address or PO Box
1114 Line 3: City/town/village/etc.
1115 Line 4: State/province/etc.
1117 Line 6: Telephone number
1118 Line 7: e-mail address
1122 CHEK (CHEcK various things)
1124 When logging in, there are various things that need to be checked. This
1125 command will return ERROR+NOT_LOGGED_IN if no user is logged in. Otherwise
1126 it returns OK and the following parameters:
1128 0: Number of new private messages in Mail>
1129 1: Nonzero if the user needs to register
1130 2: (Relevant to Aides only) Nonzero if new users require validation
1131 3: The user's preferred Internet e-mail address
1134 DELF (DELete a File)
1136 This command deletes a file from the room's directory, if there is one. The
1137 name of the file to delete is the only parameter to be supplied. Wildcards
1138 are not acceptable, and any slashes in the filename will be converted to
1139 underscores, to prevent unauthorized access to neighboring directories. The
1140 possible return codes are:
1142 OK - Command succeeded. The file was deleted.
1143 ERROR+NOT_LOGGED_IN - Not logged in.
1144 ERROR+HIGHER_ACCESS_REQUIRED - Not an Aide or Room Aide.
1145 ERROR+NOT_HERE - There is no directory in this room.
1146 ERROR+FILE_NOT_FOUND - Requested file was not found.
1151 This command is similar to DELF, except that it moves a file (and its
1152 associated file description) to another room. It should be passed two
1153 parameters: the name of the file to move, and the name of the room to move
1154 the file to. All of the same return codes as DELF may be returned, and also
1155 one additional one: ERROR+NO_SUCH_ROOM, which means that the target room
1156 does not exist. ERROR+NOT_HERE could also mean that the target room does
1157 not have a directory.
1160 NETF (NETwork send a File)
1162 This command is similar to MOVF, except that it attempts to send a file over
1163 the network to another system. It should be passed two parameters: the name
1164 of the file to send, and the node name of the system to send it to. All of
1165 the same return codes as MOVF may be returned, except for ERROR+NO_SUCH_ROOM.
1166 Instead, ERROR+NO_SUCH_SYSTEM may be returned if the name of the target
1169 The name of the originating room will be sent along with the file. Most
1170 implementations will look for a room with the same name at the receiving end
1171 and attempt to place the file there, otherwise it goes into a bit bucket room
1172 for miscellaneous files. This is, however, beyond the scope of this document;
1173 see elsewhere for more details.
1176 RWHO (Read WHO's online)
1178 Displays a list of all users connected to the server. No error codes are
1179 ever returned. LISTING_FOLLOWS will be returned, followed by zero or more
1180 lines containing the following three fields:
1182 0 - Session ID. Citadel fills this with the pid of a server program.
1184 2 - The name of the room the user is currently in. This field might not
1185 be displayed (for example, if the user is in a private room) or it might
1186 contain other information (such as the name of a file the user is
1188 3 - (server v4.03 and above) The name of the host the client is connecting
1189 from, or "localhost" if the client is local.
1190 4 - (server v4.04 and above) Description of the client software being used
1191 5 - The last time, locally to the server, that a command was received from
1192 this client (Note: NOOP's don't count)
1193 6 - The last command received from a client. (NOOP's don't count)
1194 7 - Session flags. These are: + (spoofed address), - (STEALTH mode), *
1195 (posting) and . (idle).
1196 8 - Actual user name, if user name is masqueraded and viewer is an Aide.
1197 9 - Actual room name, if room name is masqueraded and viewer is an Aide.
1198 10 - Actual host name, if host name is masqueraded and viewer is an Aide.
1199 11 - Nonzero if the session is a logged-in user, zero otherwise.
1201 The listing is terminated, as always, with the string "000" on a line by
1205 OPEN (OPEN a file for download)
1207 This command is used to open a file for downloading. Only one download
1208 file may be open at a time. The only argument to this command is the name
1209 of the file to be opened. The user should already be in the room where the
1210 file resides. Possible return codes are:
1213 ERROR+NOT_HERE (no directory in this room)
1214 ERROR+FILE_NOT_FOUND (could not open the file)
1218 If the file is successfully opened, OK will be returned, along with the
1219 size (in bytes) of the file, the time of last modification (if applicable),
1220 the filename (if known), and the MIME type of the file (if known).
1223 CLOS (CLOSe the download file)
1225 This command is used to close the download file. It returns OK if the
1226 file was successfully closed, or ERROR if there wasn't any file open in the
1230 READ (READ from the download file)
1232 Two arguments are passed to this command. The first is the starting position
1233 in the download file, and the second is the total number of bytes to be
1234 read. If the operation can be performed, BINARY_FOLLOWS will be returned,
1235 along with the number of bytes to follow. Then, immediately following the
1236 newline, will be that many bytes of binary data. The client *must* read
1237 exactly that number of bytes, otherwise the client and server will get out
1240 If the operation cannot be performed, any of the usual error codes will be
1244 UOPN (OPeN a file for Uploading)
1246 This command is similar to OPEN, except that this one is used when the
1247 client wishes to upload a file to the server. The first argument is the name
1248 of the file to create, and the second argument is a one-line comment
1249 describing the contents of the file. Only one upload file may be open at a
1250 time. Possible return codes are:
1253 ERROR+NOT_HERE (no directory in this room)
1254 ERROR+FILE_NOT_FOUND (a name must be specified)
1255 ERROR (miscellaneous errors)
1256 ERROR+ALREADY_EXISTS (a file with the same name already exists)
1259 If OK is returned, the command has succeeded and writes may be performed.
1262 UCLS (CLoSe the Upload file)
1264 Close the file opened with UOPN. An argument of "1" should be passed to
1265 this command to close and save the file; otherwise, the transfer will be
1266 considered aborted and the file will be deleted. This command returns OK
1267 if the operation succeeded or ERROR if it did not.
1270 WRIT (WRITe to the upload file)
1272 If an upload file is open, this command may be used to write to it. The
1273 argument passed to this command is the number of bytes the client wishes to
1274 transmit. An ERROR code will be returned if the operation cannot be
1277 If the operation can be performed, SEND_BINARY will be returned, followed
1278 by the number of bytes the server is expecting. The client must then transmit
1279 exactly that number of bytes. Note that in the current implementation, the
1280 number of bytes the server is expecting will always be the number of bytes
1281 the client requested to transmit, but the client software should never assume
1282 that this will always happen, in case changes are made later.
1285 QUSR (Query for a USeR)
1287 This command is used to check to see if a particular user exists. The only
1288 argument to this command is the name of the user being searched for. If
1289 the user exists, OK is returned, along with the name of the user in the userlog
1290 (so the client software can learn the correct upper/lower casing of the name
1291 if necessary). If the user does not exist, ERROR+NO_SUCH_USER is returned.
1292 No login or current room is required to utilize this command.
1295 OIMG (Open an IMaGe file)
1297 Open an image (graphics) file for downloading. Once opened, the file can be
1298 read as if it were a download file. This implies that an image and a download
1299 cannot be opened at the same time. OIMG returns the same result codes as OPEN.
1301 All images will be in GIF (Graphics Interchange Format). In the case of
1302 Citadel, the server will convert the supplied filename to all lower case,
1303 append the characters ".gif" to the filename, and look for it in the "images"
1304 subdirectory. As with the MESG command, there are several "well known"
1305 images which are likely to exist on most servers:
1307 hello - "Welcome" graphics to be displayed alongside MESG "hello"
1308 goodbye - Logoff banner graphics to be displayed alongside MESG "goodbye"
1309 background - Background image (usually tiled) for graphical clients
1311 The following "special" image names are defined in Citadel server version
1314 _userpic_ - Picture of a user (send the username as the second argument)
1315 _floorpic_ - A graphical floor label (send the floor number as the second
1316 argument). Clients which request a floor picture will display
1317 the picture *instead* of the floor name.
1318 _roompic_ - A graphic associated with the *current* room. Clients which
1319 request a room picture will display the picture in *addition*
1320 to the room name (i.e. it's used for a room banner, as
1321 opposed to the floor picture's use in a floor listing).
1324 NETP (authenticate as network session with connection NET Password)
1326 This command is used by client software to identify itself as a transport
1327 session for Citadel site-to-site networking. It should be called with
1328 two arguments: the node name of the calling system, and the "shared secret"
1329 password for that connection. If the authentication succeeds, NETP will
1330 return OK, otherwise, it returns ERROR.
1333 NSYN (Network SYNchronize room)
1335 This command can be used to synchronize the contents of a room on the
1336 network. It is only usable by Aides. It accepts one argument: the name of
1337 a network node (which must be a valid one).
1339 When NSYN is run, the *entire* contents of the current room will be spooled
1340 to the specified node, without regard to whether any of the messages have
1341 already undergone network processing. It is up to the receiving node to
1342 check for duplicates (the Citadel networker does handle this) and avoid
1345 The command returns OK upon success or ERROR if the user is not an Aide.
1348 NUOP (Network Upload OPen file)
1350 Open a network spool file for uploading. The client must have already
1351 identified itself as a network session using the NETP command. If the command
1352 returns OK, the client may begin transmitting IGnet/Open spool data using
1353 a series of WRIT commands. When a UCLS command is issued, the spooled data
1354 is entered into the server if the argument to UCLS is 1 or discarded if the
1355 argument to UCLS is 0. If the client has not authenticated itself with a
1356 NETP command, ERROR+HIGHER_ACCESS_REQUIRED will be returned.
1359 NDOP (Network Download OPen file)
1361 Open a network spool file for downloading. The client must have already
1362 identified itself as a network session using the NETP command. If the command
1363 returns OK, the client may begin receiving IGnet/Open spool data using
1364 a series of READ commands. When a CLOS command is issued, the spooled data
1365 is deleted from the server and may not be read again. If the client has not
1366 authenticated itself with a NETP command, ERROR+HIGHER_ACCESS_REQUIRED will
1370 LFLR (List all known FLooRs)
1372 On systems supporting floors, this command lists all known floors. The
1373 command accepts no parameters. It will return ERROR+NOT_LOGGED_IN if no
1374 user is logged in. Otherwise it returns LISTING_FOLLOWS and a list of
1375 the available floors, each line consisting of three fields:
1377 1. The floor number associated with the floor
1378 2. The name of the floor
1379 3. Reference count (number of rooms on this floor)
1382 CFLR (Create a new FLooR)
1384 This command is used to create a new floor. It should be passed two
1385 arguments: the name of the new floor to be created, and a 1 or 0 depending
1386 on whether the client is actually creating a floor or merely checking to
1387 see if it has permission to create the floor. The user must be logged in
1388 and have Aide privileges to create a floor.
1390 If the command succeeds, it will return OK followed by the floor number
1391 associated with the new floor. Otherwise, it will return ERROR (plus perhaps
1392 HIGHER_ACCESS_REQUIRED, ALREADY_EXISTS, or INVALID_FLOOR_OPERATION)
1393 followed by a description of why the command failed.
1398 This command is used to delete a floor. It should be passed two
1399 argument: the *number* of the floor to be deleted, and a 1 or 0 depending
1400 on whether the client is actually deleting the floor or merely checking to
1401 see if it has permission to delete the floor. The user must be logged in
1402 and have Aide privileges to delete a floor.
1404 Floors that contain rooms may not be deleted. If there are rooms on a floor,
1405 they must be either deleted or moved to different floors first. This implies
1406 that the Main Floor (floor 0) can never be deleted, since Lobby>, Mail>, and
1407 Aide> all reside on the Main Floor and cannot be deleted.
1409 If the command succeeds, it will return OK. Otherwise it will return
1410 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1411 followed by a description of why the command failed.
1416 Edit the parameters of a floor. The client may pass one or more parameters
1419 1. The number of the floor to be edited
1420 2. The desired new name
1422 More parameters may be added in the future. Any parameters not passed to
1423 the server will remain unchanged. A minimal command would be EFLR and a
1424 floor number -- which would do nothing. EFLR plus the floor number plus a
1425 floor name would change the floor's name.
1427 If the command succeeds, it will return OK. Otherwise it will return
1428 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1431 IDEN (IDENtify the client software)
1433 The client software has the option to identify itself to the server.
1434 Currently, the server does nothing with this information except to write
1435 it to the syslog to satisfy the system administrator's curiosity. Other
1436 uses might become apparent in the future.
1438 The IDEN command should contain five fields: a developer ID number (same as
1439 the server developer ID numbers in the INFO command -- please obtain one if
1440 you are a new developer), a client ID number (which does not have to be
1441 globally unique - only unique within the domain of the developer number),
1442 a version number, a free-form text string describing the client, and the name
1443 of the host the user is located at.
1445 It is up to the server to determine whether to accept the host name or to
1446 use the host name it has detected itself. Generally, if the client is
1447 running on a trusted host (either localhost or a well-known publically
1448 accessible client) it should use the host name transmitted by IDEN,
1449 otherwise it should use the host name it has detected itself.
1451 IDEN always returns OK, but since that's the only way it ever returns
1452 there's no point in checking the result code.
1455 IPGM (identify as an Internal ProGraM)
1457 IPGM is a low-level command that should not be used by normal user clients.
1458 It is used for various utilities to communicate with the server on the same
1459 host. For example, the "sendcommand" utility logs onto the server as an
1460 internal program in order to run arbitrary server commands. Since user clients
1461 do not utilize this command (or any of its companion commands), developers
1462 writing Citadel-compatible servers need not implement it.
1464 The sole argument to IPGM is the system's internal program password. This
1465 password is generated by the setup program and stored in the config file.
1466 Since internal programs have access to the config file, they know the correct
1469 IPGM returns OK for a correct authentication or ERROR otherwise.
1472 CHAT (enter CHAT mode)
1474 This command functions differently from every other command in the system. It
1475 is used to implement multi-user chat. For this to function, a new transfer
1476 mode, called START_CHAT_MODE, is implemented. If a client does not support
1477 chat mode, it should never send a CHAT command!
1479 In chat mode, messages may arrive asynchronously from the server at any
1480 time. The client may send messages at any time. This allows the arrival of
1481 messages without the client having to poll for them. Arriving messages will
1482 be of the form "user|message", where the "user" portion is, of course, the
1483 name of the user sending the message, and "message" is the message text.
1485 Chat mode ends when the server says it ends. The server will signal the end
1486 of chat mode by transmitting "000" on a line by itself. When the client reads
1487 this line, it must immediately exit from chat mode without sending any
1488 further traffic to the server. The next transmission sent to the server
1489 will be a regular server command.
1491 The Citadel server understands the following commands:
1492 /quit - Exit from chat mode (causes the server to do an 000 end)
1493 /who - List users currently in chat
1494 /whobbs - List users currently in chat and elsewhere
1495 /me - Do an irc-style action.
1496 /join - Join a new "room" in which all messages are only heard by
1497 people in that room.
1498 /msg - /msg <user> <msg> will send the msg to <user> only.
1499 /help - Print help information
1500 NOOP - Do nothing (silently)
1502 Any other non-empty string is treated as message text and will be broadcast
1503 to other users currently in chat.
1506 SEXP (Send instant message)
1508 This is one of two commands which implement instant messages (also known
1509 as "paging"). Commands ending in "...EXP" are so-named because we called
1510 them "express messages" before the industry standardized on the term
1511 "instant messages." When an instant message is sent, it will be
1512 logged in user to another. When an instant message is sent, it will be
1513 displayed the next time the target user executes a PEXP or GEXP command.
1515 The SEXP command accepts two arguments: the name of the user to send the
1516 message to, and the text of the message. If the message is successfully
1517 transmitted, OK is returned. If the target user is not logged in or if
1518 anything else goes wrong, ERROR is returned.
1520 If the server supports extended paging, sending a zero-length message
1521 merely checks for the presence of the requested user without actually sending
1522 a message. Sending a message consisting solely of a "-" (hyphen) will cause
1523 the server to return SEND_LISTING if the requested user is logged in, and the
1524 client can then transmit a multi-line page.
1526 The reserved name "broadcast" may be used instead of a user name, to
1527 broadcast an instant message to all users currently connected to the server.
1529 Do be aware that if an instant message is transmitted to a user who is logged
1530 in using a client that does not check for instant messages, the message will
1531 never be received. Also, instant messages are NOT sent via the following
1532 transports: SMTP, POP3.
1535 PEXP (Print instant messages) ***DEPRECATED***
1537 This command is deprecated; it will eventually disappear from the protocol and
1538 its use is not recommended. Please use the GEXP command instead.
1540 Called without any arguments, PEXP simply dumps out the contents
1541 of any waiting instant messages. It returns ERROR if there is a problem,
1542 otherwise it returns LISTING_FOLLOWS followed by all messages.
1544 So how does the client know there are instant messages waiting? It could
1545 execute a random PEXP every now and then. Or, it can check the byte in
1546 server return code messages, between the return code and the parameters. In
1547 much the same way as FTP uses "-" to signify a continuation, Citadel uses
1548 an "*" in this position to signify the presence of waiting instant messages.
1551 EBIO (Enter BIOgraphy)
1553 Transmit to the server a free-form text file containing a little bit of
1554 information about the user for other users to browse. This is typically
1555 referred to as a 'bio' online. EBIO returns SEND_LISTING if it succeeds,
1556 after which the client is expected to transmit the file, or any of the usual
1557 ERROR codes if it fails.
1560 RBIO (Read BIOgraphy)
1562 Receive from the server a named user's bio. This command should be passed
1563 a single argument - the name of the user whose bio is requested. RBIO returns
1564 LISTING_FOLLOWS plus the bio file if the user exists and has a bio on file.
1565 The return has the following parameters: the user name, user number, access
1566 level, date of last call, times called, and messages posted. This command
1567 returns ERROR+NO_SUCH_USER if the named user does not exist.
1569 RBIO no longer considers a user with no bio on file to be an error condition.
1570 It now returns a message saying the user has no bio on file as the text of the
1571 bio. This allows newer servers to operate with older clients.
1574 STEL (enter STEaLth mode)
1576 When in "stealth mode," a user will not show up in the "Who is online"
1577 listing (the RWHO server command). Only Aides may use stealth mode. The
1578 STEL command accepts one argument: a 1 indicating that the user wishes to
1579 enter stealth mode, or a 0 indicating that the user wishes to exit stealth
1580 mode. STEL returns OK if the command succeeded, ERROR+NOT_LOGGED_IN if no
1581 user is logged in, or ERROR+HIGHER_ACCESS_REQUIRED if the user is not an Aide;
1582 followed by a 1 or 0 indicating the new state.
1584 If any value other than 1 or 0 is sent by the client, the server simply
1585 replies with 1 or 0 to indicate the current state without changing it.
1587 The STEL command also makes it so a user does not show up in the chat room
1591 LBIO (List users who have BIOs on file)
1593 This command is self-explanatory. Any user who has used EBIO to place a bio
1594 on file is listed. LBIO almost always returns LISTING_FOLLOWS followed by
1595 this listing, unless it experiences an internal error in which case ERROR
1599 MSG2 (read MeSsaGe, mode 2)
1601 MSG2 follows the same calling convention as MSG0. The difference between
1602 the two commands is that MSG2 outputs messages in standard RFC822 format
1603 rather than in Citadel proprietary format.
1605 This command was implemented in order to make various gateway programs
1606 easier to implement, and to provide some sort of multimedia support in the
1607 future. Keep in mind that when this command is used, all messages will be
1608 output in fixed 80-column format.
1611 MSG3 (read MeSsaGe, mode 3 -- internal command)
1613 MSG3 is for use by internal programs only and should not be utilized by
1614 user-mode clients. It does require IPGM authentication. MSG3 follows the
1615 same calling convention as the other MSG commands, but upon success returns
1616 BINARY_FOLLOWS followed by a data block containing the _raw_ message format
1620 TERM (TERMinate another session)
1622 In a multithreaded environment, it sometimes becomes necessary to terminate
1623 a session that is unusable for whatever reason. The TERM command performs
1624 this task. Naturally, only Aides can execute TERM. The command should be
1625 called with a single argument: the session ID (obtained from an RWHO command)
1626 of the session to be terminated.
1628 TERM returns OK if the session was terminated, or ERROR otherwise. Note that
1629 a client program is prohibited from terminating the session it is currently
1635 DOWN (shut DOWN the server)
1637 This command, which may only be executed by an Aide, immediately shuts down
1638 the server. It is only implemented on servers on which such an operation is
1639 possible, such as a multithreaded Citadel engine. The server does not restart.
1640 DOWN returns OK if the user is allowed to shut down the server, in which case
1641 the client program should expect the connection to be immediately broken.
1644 SCDN (Schedule or Cancel a shutDowN)
1646 SCDN sets or clears the "scheduled shutdown" flag. Pass this command a 1 or
1647 0 to respectively set or clear the flag. When the "scheduled shutdown" flag is
1648 set, the server will be shut down when there are no longer any users logged in.
1649 Any value other than 0 or 1 will not change the flag, only report its state.
1650 No users will be kicked off the system, and in fact the server is still
1651 available for new connections. The command returns ERROR if it fails;
1652 otherwise, it returns OK followed by a number representing the current state
1656 EMSG (Enter a system MeSsaGe)
1658 This is the opposite of the MESG command - it allows the creation and editing
1659 of system messages. The only argument passed to EMSG is the name of the
1660 file being transmitted. If the file exists in any system message directory
1661 on the server it will be overwritten, otherwise a new file is created. EMSG
1662 returns SEND_LISTING on success or ERROR+HIGHER_ACCESS_REQUIRED if the user
1665 Typical client software would use MESG to retrieve any existing message into
1666 an edit buffer, then present an editor to the user and run EMSG if the changes
1670 UIMG (Upload an IMaGe file)
1672 UIMG is complemenary to OIMG; it is used to upload an image to the server.
1673 The first parameter supplied to UIMG should be 0 if the client is only checking
1674 for permission to upload, or 1 if the client is actually attempting to begin
1675 the upload operation. The second argument is the name of the file to be
1676 transmitted. In Citadel, the filename is converted to all lower case,
1677 appended with the characters ".gif", and stored in the "images" directory.
1679 UIMG returns OK if the client has permission to perform the requested upload,
1680 or ERROR+HIGHER_ACCESS_REQUIRED otherwise. If the client requested to begin
1681 the operation (first parameter set to 1), an upload file is opened, and the
1682 client should begin writing to it with WRIT commands, then close it with a
1685 The supplied filename should be one of:
1687 -> _userpic_ (Server will attempt to write to the user's online photo)
1688 -> Any of the "well known" filenames described in the writeup for the
1692 HCHG (Hostname CHanGe)
1694 HCHG is a command, usable by any user, that allows a user to change their RWHO
1695 host value. This will mask a client's originating hostname from normal
1696 users; access level 6 and higher can see, in an extended wholist, the actual
1697 hostname the user originates from.
1699 The format of an HCHG command is:
1703 If a HCHG command is successful, the value OK (200) is returned.
1706 RCHG (Roomname CHanGe)
1708 RCHG is a command, usable by any user, that allows a user to change their RWHO
1709 room value. This will mask a client's roomname from normal users; access
1710 level 6 and higher can see, in an extended wholist, the actual room the user
1713 The format of an RCHG command is:
1717 If a RCHG command is successful, the value OK (200) is returned.
1720 UCHG (Username CHanGe)
1722 UCHG is an aide-level command which allows an aide to effectively change their
1723 username. If this value is blank, the user goes into stealth mode (see
1725 will show up as being from the real username in this mode, however. In
1726 addition, the RWHO listing will include both the spoofed and real usernames.
1728 The format of an UCHG command is:
1732 If a UCHG command is successful, the value OK (200) is returned.
1735 TIME (get server local TIME)
1737 TIME returns OK followed by the current time measured in seconds since
1738 00:00:00 GMT, Jan 1, 1970 (standard Unix format).
1740 This is used in allowing a client to calculate idle times.
1743 AGUP (Administrative Get User Parameters)
1744 ASUP (Administrative Set User Parameters)
1746 These commands are only executable by Aides and by server extensions running
1747 at system-level. They are used to get/set any and all parameters relating to
1748 a user account. AGUP requires only one argument: the name of the user in
1749 question. SGUP requires all of the parameters to be set. The parameters are
1750 as follows, and are common to both commands:
1754 2 - Flags (see citadel.h)
1759 7 - Timestamp of last call
1760 8 - Purge time (in days) for this user (or 0 to use system default)
1762 Upon success, AGUP returns OK followed by all these parameters, and ASUP
1763 simply returns OK. If the client has insufficient access to perform the
1764 requested operation, ERROR+HIGHER_ACCESS_REQUIRED is returned. If the
1765 requested user does not exist, ERROR+NO_SUCH_USER is returned.
1769 GPEX (Get Policy for message EXpiration)
1771 Returns the policy of the current room, floor, or site regarding the automatic
1772 purging (expiration) of messages. The following policies are available:
1773 0 - Fall back to the policy of the next higher level. If this is a room,
1774 use the floor's default policy. If this is a floor, use the system
1775 default policy. This is an invalid value for the system policy.
1776 1 - Do not purge messages automatically.
1777 2 - Purge by message count. (Requires a value: number of messages)
1778 3 - Purge by message age. (Requires a value: number of days)
1780 The format of this command is: GPEX <which>
1781 The value of <which> must be one of: "room" "floor" "site" "mailboxes"
1783 If successful, GPEX returns OK followed by <policy>|<value>.
1787 SPEX (Set Policy for message EXpiration)
1789 Sets the policy of the current room, floor, or site regarding the automatic
1790 purging (expiration) of messages. See the writeup for the GPEX command for
1791 the list of available policies.
1793 The format of this command is: SPEX <which>|<policy>|<value>
1794 The value of <which> must be one of: "room" "floor" "site" "mailboxes"
1796 If successful, GPEX returns OK; otherwise, an ERROR code is returned.
1800 CONF (get or set global CONFiguration options)
1802 Retrieves or sets various system-wide configuration and policy options. This
1803 command is only available to Aides. The sole parameter accepted is a command,
1804 which should be either GET or SET. If the GET command succeeds, CONF will
1805 return LISTING_FOLLOWS followed by the fields described below, one line at a
1806 time. If the SET command succeeds, CONF will return SEND_LISTING and expect
1807 the fields described below, one line at a time (don't worry about other fields
1808 being added in the future; if a 'short' configuration list is sent, the missing
1809 values at the end will be left unchanged on the system). If either command
1810 fails for any reason, ERROR is returned.
1812 The configuration lines are as follows:
1815 2. Fully qualified domain name
1816 3. Human-readable node name
1817 4. Landline telephone number of this system
1818 5. Flag (0 or 1) - creator of private room automatically becomes room aide
1819 6. Server connection idle timeout (in seconds)
1820 7. Initial access level for new users
1821 8. Flag (0 or 1) - require registration for new users
1822 9. Flag (0 or 1) - automatically move Problem User messages to twit room
1823 10. Name of twit room
1824 11. Text of <more> prompt
1825 12. Flag (0 or 1) - restrict access to Internet mail
1826 13. Geographic location of this system
1827 14. Name of the system administrator
1828 15. Number of maximum concurrent sessions allowed on the server
1829 16. (placeholder -- this field is no longer in use)
1830 17. Default purge time (in days) for users
1831 18. Default purge time (in days) for rooms
1832 19. Name of room to log instant messages to (or a zero-length name for none)
1833 20. Access level required to create rooms
1834 21. Maximum message length which may be entered into the system
1835 22. Minimum number of worker threads
1836 23. Maximum number of worker threads
1837 24. Port number for POP3 service
1838 25. Port number for SMTP service
1839 26. Flag (0 or 1) - strict RFC822 adherence - don't correct From: forgeries
1840 27. Flag (0 or 1) - allow Aides to zap (forget) rooms
1841 28. Port number for IMAP service
1842 29. How often (in seconds) to run the networker
1843 30. Flag (0 or 1) - disable self-service new user registration
1844 31. (placeholder -- this field is no longer in use)
1845 32. Hour (0 through 23) during which database auto-purge jobs are run
1846 33. Name of host where an LDAP service may be found
1847 34. Port number of LDAP service on above host
1850 37. Password for LDAP Bind DN
1851 38. Server IP address to listen on (or "0.0.0.0" for all addresses)
1852 39. Port number for SMTP MSA service
1853 40. Port number for IMAPS (SSL-encrypted IMAP)
1854 41. Port number for POP3S (SSL-encrypted POP3)
1855 42. Port number for SMTPS (SSL-encrypted SMTP)
1856 43. Flag (0 or 1) - enable full text search index
1857 44. Flag (0 or 1) - automatically cull database log files
1858 45. Flag (0 or 1) - enable IMAP "instant expunge" of deleted messages
1859 46. Flag (0 or 1) - allow unauthenticated SMTP clients to spoof my domains
1861 CONF also accepts two additional commands: GETSYS and PUTSYS followed by an
1862 arbitrary MIME type (such as application/x-citadel-internet-config) which
1863 provides a means of storing generic configuration data in the Global System
1864 Configuration room without the need to add extra get/set commands to the
1867 Please note that the LDAP-specific configs have no effect on Citadel servers
1868 in which LDAP support is not enabled.
1872 MSG4 (read MeSsaGe, mode 4 -- output in preferred MIME format)
1874 This is the equivalent of MSG0, except it's a bit smarter about messages in
1875 rich text formats. Immediately following the "text" directive, the server
1876 will output RFC822-like MIME part headers such as "Content-type:" and
1877 "Content-length:". MIME formats are chosen and/or converted based on the
1878 client's preferred format settings, which are set using the MSGP command,
1883 MSGP (set MeSsaGe Preferred MIME format)
1885 Client tells the server what MIME content types it knows how to handle, and
1886 the order in which it prefers them. This is similar to an HTTP "Accept:"
1889 The parameters to a MSGP command are the client's acceptable MIME content
1890 types, in the order it prefers them (from most preferred to least preferred).
1891 For example: MSGP text/html|text/plain
1893 The MSGP command always returns OK.
1897 OPNA (OPeN Attachment)
1899 Opens, as a download file, a component of a MIME-encoded message. The two
1900 parameters which must be passed to this command are the message number and the
1901 name of the desired section. If the message or section does not exist, an
1902 appropriate ERROR code will be returned; otherwise, if the open is successful,
1903 this command will succeed returning the same information as an OPEN command.
1906 GEXP (Get instant messages)
1908 This is a more sophisticated way of retrieving instant messages than the old
1909 PEXP method. If there are no instant messages waiting, PEXP returns ERROR;
1910 otherwise, it returns LISTING_FOLLOWS and the following arguments:
1912 0 - a boolean value telling the client whether there are any additional
1913 instant messages waiting following this one
1914 1 - a Unix-style timestamp
1915 2 - flags (see server.h for more info)
1916 3 - the name of the sender
1917 4 - the node this message originated on (for future support of PIP, ICQ, etc.)
1919 The text sent to the client will be the body of the instant message.
1921 So how does the client know there are instant messages waiting? It could
1922 execute a random GEXP every now and then. Or, it can check the byte in
1923 server return code messages, between the return code and the parameters. In
1924 much the same way as FTP uses "-" to signify a continuation, Citadel uses
1925 an "*" in this position to signify the presence of waiting instant messages.
1928 FSCK (check message base reference counts)
1930 Verify, via the long way, that all message referenmce counts are correct. If
1931 the user has permission to do this then LISTING_FOLLOWS is returned, followed
1932 by a transcript of the run. Otherwise ERROR is returned.
1935 DEXP (Disable receiving instant messages)
1937 DEXP sets or clears the "disable instant messages" flag. Pass this command a
1938 1 or 0 to respectively set or clear the flag. When the "disable instant
1939 messages" flag is set, no one except Aides may send the user instant messages.
1940 Any value other than 0 or 1 will not change the flag, only report its state.
1941 The command returns ERROR if it fails; otherwise, it returns OK followed by a
1942 number representing the current state of the flag.
1945 REQT (REQuest client Termination)
1947 Request that the specified client (or all clients) log off. Aide level
1948 access is required to run this command, otherwise ERROR+HIGHER_ACCESS_REQUIRED
1951 The REQT command accepts one parameter: the session ID of the client which
1952 should be terminated, or 0 for all clients. When successful, the REQT command
1955 It should be noted that REQT simply transmits an instant message to the
1956 specified client(s) with the EM_GO_AWAY flag set. Older clients do not honor
1957 this flag, and it is certainly possible for users to re-program their client
1958 software to ignore it. Therefore the effects of the REQT command should be
1959 considered advisory only. The recommended implementation practice is to first
1960 issue a REQT command, then wait a little while (from 30 seconds up to a few
1961 minutes) for well-behaved clients to voluntarily terminate, and then issue a
1962 TERM command to forcibly disconnect the client (or perhaps a DOWN command, if
1963 you are logging off users for the purpose of shutting down the server).
1966 SEEN (set or clear the SEEN flag for a message)
1968 Beginning with version 5.80, Citadel supports the concept of setting or
1969 clearing the "seen" flag for each individual message, instead of only allowing
1970 a "last seen" pointer. In fact, the old semantics are implemented in terms
1971 of the new semantics. This command requires two arguments: the number of the
1972 message to be set, and a 1 or 0 to set or clear the "seen" bit.
1974 This command returns OK, unless the user is not logged in or a usage error
1975 occurred, in which case it returns ERROR. Please note that no checking is
1976 done on the supplied data; if the requested message does not exist, the SEEN
1977 command simply returns OK without doing anything.
1980 GTSN (GeT the list of SeeN messages)
1982 This command retrieves the list of "seen" (as opposed to unread) messages for
1983 the current room. It returns OK followed by an IMAP-format message list.
1986 SMTP (utility commands for the SMTP gateway)
1988 This command, accessible only by Aides, supports several utility operations
1989 which examine or manipulate Citadel's SMTP support. The first command argument
1990 is a subcommand telling the server what to do. The following subcommands are
1993 SMTP mx|hostname (display all MX hosts for 'hostname')
1994 SMTP runqueue (attempt immediate delivery of all messages
1995 in the outbound SMTP queue, ignoring any
1996 retry times stored there)
1999 STLS (Start Transport Layer Security)
2001 This command starts TLS on the current connection. The current
2002 implementation uses OpenSSL on both the client and server end. For future
2003 compatibility all clients must support at least TLSv1, and servers are
2004 guaranteed to support TLSv1. During TLS negotiation (see below) the server
2005 and client may agree to use a different protocol.
2007 The server returns ERROR if it does not support SSL or SSL initialization
2008 failed on the server; otherwise it returns OK. Once the server returns OK and
2009 the client has read the response, the server and client immediately negotiate
2010 TLS (in OpenSSL, using SSL_connect() on the client and SSL_accept() on the
2011 server). If negotiation fails, the server and client should attempt to resume
2012 the session unencrypted. If either end is unable to resume the session, the
2013 connection should be closed.
2015 This command may be run at any time.
2018 GTLS (Get Transport Layer Security Status)
2020 This command returns information about the current connection. The server
2021 returns OK plus several parameters if the connection is encrypted, and ERROR
2022 if the connection is not encrypted. It is primarily used for debugging. The
2023 command may be run at any time.
2025 0 - Protocol name, e.g. "SSLv3"
2026 1 - Cipher suite name, e.g. "ADH-RC4-MD5"
2027 2 - Cipher strength bits, e.g. 128
2028 3 - Cipher strength bits actually in use, e.g. 128
2031 IGAB (Initialize Global Address Book)
2033 This command creates, or re-creates, a database of Internet e-mail addresses
2034 using the vCard information in the Global Address Book room. This procedure
2035 is normally run internally when the server determines it necessary, but is
2036 also provided as a server command to be used as a troubleshooting/maintenenance
2037 tool. Only a system Aide can run the command. It returns OK on success or
2041 QDIR (Query global DIRectory)
2043 Look up an internet address in the global directory. Any logged-in user may
2044 call QDIR with one parameter, the Internet e-mail address to look up. QDIR
2045 returns OK followed by a Citadel address if there is a match, otherwise it
2046 returns ERROR+NOT_LOGGED_IN.
2049 ISME (find out if an e-mail address IS ME)
2051 This is a quickie shortcut command to find out if a given e-mail address
2052 belongs to the user currently logged in. Its sole argument is an address to
2053 parse. The supplied address may be in any format (local, IGnet, or Internet).
2054 The command returns OK if the address belongs to the user, ERROR otherwise.
2057 VIEW (set the VIEW for a room)
2059 Set the preferred view for the current user in the current room. Please see
2060 views.txt for more information on views. The sole parameter for this command
2061 is the type of view requested. VIEW returns OK on success or ERROR on failure.
2064 QNOP (Quiet No OPeration)
2066 This command does nothing, similar to the NOOP command. However, unlike the
2067 NOOP command, it returns *absolutely no response* at all. The client has no
2068 way of knowing that the command executed. It is intended for sending
2069 "keepalives" in situations where a full NOOP would cause the client protocol
2072 Naturally, sending this command to a server that doesn't support it is an
2073 easy way to mess things up. Therefore, client software should first check
2074 the output of an INFO command to ensure that the server supports quiet noops.
2078 ICAL (Internet CALendaring commands)
2080 This command supports a number of subcommands which are used to process the
2081 calendaring/scheduling support in Citadel. Here are the subcommands which
2085 Test server for calendaring support. Always returns OK unless the server
2086 does not have the calendar module enabled.
2088 ICAL respond|msgnum|partnum|action
2089 Respond to a meeting request. 'msgnum' and 'partnum' refer to a MIME-encoded
2090 meeting invitation in the current room. 'action' must be set to either
2091 "accept" or "decline" to determine the action to take. This subcommand will
2092 return either OK or ERROR.
2094 ICAL conflicts|msgnum|partnum
2095 Determine whether an incoming VEVENT will fit in the user's calendar by
2096 checking it against the existing VEVENTs. 'msgnum' and 'partnum' refer to
2097 a MIME-encoded meeting invitation in the current room (usually the inbox).
2098 This command may return ERROR if something went wrong, but usually it will
2099 return LISTING_FOLLOWS followed by a list of zero or more conflicting
2100 events. A zero-length list means that there were no conflicts.
2102 ICAL handle_rsvp|msgnum|partnum
2103 Handle an incoming "reply" (or RSVP) to a meeting request you sent out.
2104 'msgnum' and 'partnum' refer to a MIME-encoded reply in the current room.
2105 'action' must be set to either "update" or "ignore" to determine the action
2106 to take. If the action is "update" then the server will hunt for the meeting
2107 in the user's Calendar> room, and update the status for this attendee. Either
2108 way, the reply message is deleted from the current room. This subcommand will
2109 return either OK or ERROR.
2111 ICAL freebusy|username
2112 Output the free/busy times for the requested user. If the user specified
2113 has a calendar available, this command will return LISTING_FOLLOWS and a
2114 compound VCALENDAR object. That object, in turn, will contain VEVENT
2115 objects that have been stripped of all properties except for the bare
2116 minimum needed to learn free/busy times (such as DTSTART, DTEND, and
2117 TRANSP). If there is no such user, or no calendar available, the usual
2118 ERROR codes will be returned.
2122 Readers who are paying attention will notice that there is no subcommand to
2123 send out meeting invitations. This is because that task can be handled
2124 automatically by the Citadel server. Issue this command with <bool> set to 1
2125 to enable Server Generated Invitations. In this mode, when an event is saved
2126 to the user's Calendar> room and it contains attendees, Citadel will
2127 automatically turn the event into vCalendar REQUEST messages and mail them
2128 out to all listed attendees. If for some reason the client needs to disable
2129 Server Generated Invitations, the command may be sent again with <bool> = 0.
2133 MRTG (Multi Router Traffic Grapher)
2135 Multi Router Traffic Grapher (please see http://www.mrtg.org for more info) is
2136 a tool which creates pretty graphs of network activity, usually collected from
2137 routers using SNMP. However, its ability to call external scripts has spawned
2138 a small community of people using it to graph anything which can be graphed.
2139 The MRTG command can output Citadel server activity in the format MRTG expects.
2141 This format is as follows:
2146 Line 3: uptime of system
2147 Line 4: name of system
2150 MRTG accepts two different keywords. "MRTG users" will return two variables,
2151 the number of connected users and the number of active users. "MRTG messages"
2152 will return one variable (and a zero in the second field), showing the current
2153 highest message number on the system. Any other keyword, or a missing keyword,
2154 will cause the MRTG command to return an ERROR code.
2156 Please get in touch with the Citadel developers if you wish to experiment with
2161 GNET (Get NETwork configuration for this room)
2162 SNET (Set NETwork configuration for this room)
2164 These commands get/set the network configuration for the current room. Aide
2165 or Room Aide privileges are required, otherwise an ERROR code is returned.
2166 If the command succeeds, LISTING_FOLLOWS or SEND_LISTING is returned. The
2167 network configuration for a specific room includes neighbor nodes with whom
2168 the room is shared, and mailing list recipients. The format of the network
2169 configuration is described in the file "netconfigs.txt".
2173 ASYN (ASYNchronous message support)
2175 Negotiate the use of asynchronous, or unsolicited, protocol messages. The
2176 only parameter specified should be 1 or 0 to indicate that the client can or
2177 cannot handle this type of messages. The server will reply OK followed by a
2178 1 or 0 to tell the client which mode it is now operating in.
2180 If the command is not available on the server (i.e. it returns ERROR), or
2181 if the command has not been executed by the client, it should be assumed that
2182 this mode of operation is NOT in effect.
2184 The client may also send any value other than 0 or 1 to simply cause the
2185 server to output its current state without changing it.
2187 When asynchronous protocol mode is in effect, the client MUST handle any
2188 asynchronous messages as they arrive, before doing anything else.
2192 AUTO (AUTOcompletion of email addresses)
2194 The AUTO command is used by clients which want to request a list of email
2195 recipients whose names or email addresses match a partial string supplied by
2196 the client. This string is the only parameter passed to this command. The
2197 command will return ERROR if no user is logged in or if no address book could
2198 be found; otherwise, it returns LISTING_FOLLOWS followed by zero or more
2199 candidate recipients.
2203 SRCH (SeaRCH the message base)
2205 This command's implementation is incomplete and will be documented when it
2206 is finished. The current implementation accepts a search string as its sole
2207 argument, and will respond with LISTING_FOLLOWS followed by a list of
2208 messages (globally, not just in the current room) which contain ALL of the
2209 words in the search string. If the client desires an "exact phrase" match,
2210 it must then slow-search the text of each returned message for the exact
2211 string. The client should also compare the returned message numbers against
2212 those which actually exist in the room or rooms being searched. In
2213 particular, clients should avoid telling the user about messages which exist
2214 only in rooms to which the user does not have access.
2216 Again, keep in mind that this is a temporary implementation and is not
2217 guaranteed to continue to exist in this form.
2220 EUID (get message number using an EUID)}
2222 Returns the message number, if present, of the message in the current room
2223 which is indexed using the supplied EUID (exclusive message ID). There can be
2224 only one message in a room with any given EUID; if another message arrives
2225 with the same EUID, the existing one is replaced. This makes it possible to
2226 reference things like calendar items using an immutable URL that does not
2227 change even when the message number changes due to an update.
2229 The format of this command is: EUID <euid>
2231 If successful, EUID returns OK followed by a message number. The message is
2232 *not* guaranteed to exist, because EUID indices are not immediately removed
2233 when a message is deleted.
2234 If no message exists in the current room with the supplied EUID, the command
2235 returns ERROR+MESSAGE_NOT_FOUND.
2241 ASYNCHRONOUS MESSAGES
2242 ---------------------
2244 When the client protocol is operating in asynchronous mode (please refer to
2245 the writeup of the ASYN command above), the following messages may arrive at
2249 902 (instant message arriving)
2251 One or more instant messages have arrived for this client.