Protocol-A.texi 403 KB
Newer Older
David Byers's avatar
David Byers committed
1
\input texinfo                         @c -*-texinfo-*-
David Byers's avatar
David Byers committed
2
@c
David Byers's avatar
David Byers committed
3 4 5 6
@c %**start of header
@setfilename protocol-a.info
@settitle LysKOM Protocol A
@setchapternewpage odd
7 8
@c @afourpaper

Per Cederqvist's avatar
Per Cederqvist committed
9
@set PROTOEDITION 11.1
Per Cederqvist's avatar
Per Cederqvist committed
10
@set PROTOVER 11
Per Cederqvist's avatar
Per Cederqvist committed
11
@set VERSION 2.1.2
David Byers's avatar
David Byers committed
12

13 14


15 16 17 18 19 20 21 22
@c @holl{l, s} is used to construct Hollerith strings.  The main
@c reason to use this macro is to help the spell checker.

@macro holl {l, s}
\l\H\s\
@end macro


23
@c
24
@c Define a few strings that contains characters from ISO Latin-1.
25
@c
26 27 28

@iftex

29
@c ispell-ignore
30
@set IAM Inl@"agg @}t mig
31 32
@set Pell P@"ar Emanuelsson
@set Kent Kent Eng@-str@"om@penalty-10000
33 34
@set presconf @holl{27,Presentation (av nya) m@"oten}
@c ispell-end-ignore
35 36 37 38

@end iftex
@ifnottex

39
@c ispell-ignore
40 41 42
@set IAM Inlägg @}t mig
@set Pell Pär Emanuelsson
@set Kent Kent Engström
43 44
@set presconf @holl{27,Presentation (av nya) möten}
@c ispell-end-ignore
45 46 47

@end ifnottex

48 49 50 51
@c
@c Index setup
@c

52 53 54 55 56 57
@c Index for asynchronous messages.
@defcodeindex am

@c Merge all indices.
@syncodeindex am fn
@syncodeindex tp fn
58
@syncodeindex cp fn
59

60 61 62


@c
63
@c Special markup for this document.
64 65
@c

66 67 68 69 70
@c Indicate something that shouldn't be spell-checked
@macro badspell{s}
\s\
@end macro

71
@c @req{login} is used for protocol requests.
72

73 74 75 76
@macro req {n}
@code{\n\}
@end macro

77
@c @reqlink{login} is used for protocol requests, that should be linked.
78 79 80 81 82 83 84 85 86 87 88 89 90 91

@ifhtml
@macro reqlink {n}
@code{@ref{\n\}}
@end macro
@end ifhtml

@ifnothtml
@macro reqlink {n}
@code{\n\} (@pxref{\n\})
@end macro
@end ifnothtml

@c @reqdlink{login}...@linkhere{} is used for protocol requests, that
92
@c should be linked, where the link should occur a few words after the
93 94 95 96 97 98
@c request itself.

@ifhtml

@c HTML version: make the word a link.
@macro reqdlink {n}
99
@code{@ref{\n\}}
100 101 102 103 104 105 106 107 108 109
@unmacro linkhere
@macro linkhere
@end macro
@end macro

@end ifhtml

@ifnothtml
@ifnottex

110
@c Info version: create @linkhere as a macro that contains a reference.
111 112

@macro reqdlink {n}
113
@code{\n\}
114 115 116 117 118 119
@unmacro linkhere
@macro linkhere
(@pxref{\n\})
@end macro
@end macro
@end ifnottex
120

121 122
@iftex

123
@c TeX version: this produces output similar to the Info version.
124

125
@c ispell-ignore
126 127 128 129 130 131
@tex
    \gdef\reqdlink#1{%
        \code{#1}%
        \gdef\linkhere{ (\pxref{#1})}%
    }
@end tex
132
@c ispell-end-ignore
133 134 135
@end iftex
@end ifnothtml

136 137 138 139 140 141 142 143 144 145
@c @aux{mx-allow-filter} is used for aux-item names.
@macro aux {n}
@code{\n\}
@end macro

@c @async{async-login} is used for async names.
@macro async {n}
@code{\n\}
@end macro

146
@c @asynclink{async-login} is used for async names, that should be linked.
147 148 149 150 151 152 153 154 155 156 157 158 159 160

@ifhtml
@macro asynclink {n}
@code{@ref{\n\}}
@end macro
@end ifhtml

@ifnothtml
@macro asynclink {n}
@code{\n\} (@pxref{\n\})
@end macro
@end ifnothtml

@c @asyncdlink{async-login}...@linkhere{} is used for async messages,
161
@c that should be linked, where the link should occur a few words after
162 163 164 165 166 167
@c the async name itself.

@ifhtml

@c HTML version: make the word a link.
@macro asyncdlink {n}
168
@code{@ref{\n\}}
169 170 171 172 173 174 175 176 177 178
@unmacro linkhere
@macro linkhere
@end macro
@end macro

@end ifhtml

@ifnothtml
@ifnottex

179
@c Info version: create @linkhere as a macro that contains a reference.
180 181

@macro asyncdlink {n}
182
@code{\n\}
183 184 185 186 187 188 189 190 191 192 193
@unmacro linkhere
@macro linkhere
(@pxref{\n\})
@end macro
@end macro
@end ifnottex

@iftex

@c TeX version: this produces output similar to the Info version.

194
@c ispell-ignore
195 196 197 198 199 200
@tex
    \gdef\asyncdlink#1{%
        \code{#1}%
        \gdef\linkhere{ (\pxref{#1})}%
    }
@end tex
201
@c ispell-end-ignore
202 203 204
@end iftex
@end ifnothtml

205 206 207 208 209
@c @type{Conference} is used for LysKOM types.
@macro type {n}
@code{\n\}
@end macro

210 211 212 213 214 215
@c @lt{Conference} is used for linked types.  The link is only present
@c when it is unobtrusive.  It should only be used inside
@c @example...@end example.

@ifhtml
@macro lt {n}
216
@ref{\n\}
217 218 219 220 221
@end macro
@end ifhtml

@ifnothtml
@macro lt {n}
222
\n\
223 224 225
@end macro
@end ifnothtml

226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263
@c @priv{wheel} is used for privilege bits.
@macro priv {n}
@code{\n\}
@end macro

@c @conftype{rd-prot} is used for conference type bits.
@macro conftype {n}
@code{\n\}
@end macro

@c @misc{bcc-recpt} is used for misc-info names.
@macro misc {n}
@code{\n\}
@end macro

@c @rarg{passwd} is used to reference arguments of requests.  This is
@c *only* used in the nodes that defines the requests.
@macro rarg {n}
@code{\n\}
@end macro

@c @aarg{text-no} is used to reference arguments of asynchronous
@c messages.  This is *only* used in the nodes that defines the
@c relevant asynchronous message.
@macro aarg {n}
@code{\n\}
@end macro

@c @errorcode{no-such-text} is used to mark error codes.
@macro errorcode {n}
@code{\n\}
@end macro

@c @field{ident-user} is used to mark fields of struct types.
@macro field {n}
@code{\n\}
@end macro

264 265 266 267 268 269 270
@c @reqexample is used immediately before Protocol-A example
@c fragments.
@macro reqexample
@need 2000
@i{Example:}
@end macro

271 272 273 274 275 276 277 278 279
@c
@c Define strings that can be encoded as macros instead of with @set.
@c

@macro daemon
@badspell{d@ae{}mon}
@end macro


280 281
@c %**end of header

282
@copying
283 284
This is the LysKOM Protocol A specification, edition
@value{PROTOEDITION}.  It specifies version @value{PROTOVER} of the
285 286
protocol.  It was first distributed with version @value{VERSION} of
lyskomd.
David Byers's avatar
David Byers committed
287

288
Copyright @copyright{} 1995-2005 Lysator ACS.
David Byers's avatar
David Byers committed
289

290
@quotation
David Byers's avatar
David Byers committed
291 292 293
Permission is granted to make and distribute verbatim copies of this
specification provided the copyright notice and this permission notice
are preserved on all copies.
294

295 296 297 298 299
@c Permission is granted to process this file through TeX
@c and print the results, provided the printed document
@c carries a copying permission notice identical to this
@c one except for the removal of this paragraph (this
@c paragraph not being relevant to the printed manual).
300 301 302 303 304 305 306 307

Modified versions of this document may be redistributed with the added
condition that all modifications not cleared with the LysKOM development group
are clearly marked and that the entire modified work be redistributed under the
same conditions as the original.

Permission is granted to copy and distribute translations of this manual into
another language under the same conditions as for modified versions.
308 309
@end quotation
@end copying
David Byers's avatar
David Byers committed
310

311
@c ispell-ignore
312
@iftex
Per Cederqvist's avatar
Per Cederqvist committed
313 314
@c
@c Don't indent the first line of paragraphs.
315
@parindent 0pt
Per Cederqvist's avatar
Per Cederqvist committed
316 317 318 319 320 321 322 323 324 325 326
@c
@c Define @t{} so that it switches from slanted to regular to slanted
@c typewriter text as usages are nested. For example:
@c
@c     @t{A @t{B @t{C} D} E}
@c
@c will set A, C and E slanted and B and D as regular typewriter text.
@c This makes @t sort of the typewriter equivalent of LaTeX \em
@c (emphasis is italic, emphasized emphasis is roman).
@c
@c Helpers:
327 328 329
@c   \tensltt: switch to the cmsltt10 font (Computer Modern,
@c          Slanted, Typewriter, 10pt). 
@c   \rett: switch to typewriter text and define
Per Cederqvist's avatar
Per Cederqvist committed
330 331 332 333 334 335
@c          \t as an alias for \sltt.
@c   \sltt: switch to slanted typewriter text and defines
@c          \t as an alias for \rett.
@c
@c Finally \t is defined as an alias for \sltt.
@c
336
@tex
337
\global\font\tensltt=cmsltt10
338 339 340 341 342
\global\def\rett#1{{\let\t\sltt\tt #1}}
\global\def\sltt#1{{\fam\ttfam\tensltt\let\t\rett #1}}
\global\let\t\sltt
@end tex
@end iftex
343
@c ispell-end-ignore
344

David Byers's avatar
David Byers committed
345 346
@titlepage
@title{LysKOM Protocol A}
347 348 349
@subtitle{Protocol version @value{PROTOVER}}
@subtitle{Edition @value{PROTOEDITION}}
@subtitle{(lyskomd @value{VERSION})}
David Byers's avatar
David Byers committed
350 351 352
@author by the LysKOM Developers

@page
353
@c ispell-ignore
David Byers's avatar
David Byers committed
354
@vskip 0pt plus 1filll
355
@c ispell-end-ignore
356
@insertcopying
David Byers's avatar
David Byers committed
357 358

@end titlepage
359 360 361
@ifnothtml
@contents
@end ifnothtml
David Byers's avatar
David Byers committed
362

363 364 365 366 367
@dircategory LysKOM
@direntry
* Protocol A: (protocol-a).             The LysKOM Protocol A specification.
@end direntry

368
@c ispell-ignore
369 370 371 372 373 374 375 376 377 378 379 380
@ifhtml
@html
<a href="http://www.lysator.liu.se/" ><img
src="http://www.lysator.liu.se/icons/lyslogo.gif" alt="Lysator"
width=40 border=0 height=40 align=left ></a>

<a href="http://www.lysator.liu.se/lyskom/" ><img
src="http://www.lysator.liu.se/icons/lyskom.gif" alt="LysKOM" width=40
border=0 height=40 align=left ></a>
<br clear=all>
@end html
@end ifhtml
381
@c ispell-end-ignore
382

383
@node Top
384
@top LysKOM Protocol A
385

386
This document specifies version @value{PROTOVER} of LysKOM Protocol A.
387 388
This is edition @value{PROTOEDITION} of the specification.  It was
first distributed with version @value{VERSION} of lyskomd.
389

390
The most up-to-date version if this document can always be found at
391
@uref{http://www.lysator.liu.se/lyskom/protocol/}.
David Byers's avatar
David Byers committed
392 393

@menu
394
* About this document::         Copyright information.
395 396 397 398
* Preface::                     What is LysKOM?  Who wrote this document?
* Concepts::                    Articles, conferences, aux-items, @dots{}
* Fundamentals::                The building blocks of Protocol A.
* LysKOM Data Types::           Domain-specific data types used in Protocol A.
399
* Protocol Requests::           Each request explained in depth.
400 401 402 403 404 405
* Asynchronous Messages::       Unsolicited information from the server.
* Error Codes::                 All error codes with explanations.
* Aux-Item Types::              All predefined aux-item types.
* Name Expansion::              Looking up the name of a conference or person.
* LysKOM Content Types::        Predefined content types for articles.
* The User Area::               Store client-specific settings in the server.
406
* Membership visibility::       How the security features interacts.
Per Cederqvist's avatar
Per Cederqvist committed
407
* Garb::                        Old texts are deleted automatically.
Per Cederqvist's avatar
Per Cederqvist committed
408
* Measured Properties::         Load average, number of processed requests...
409
* Extracted grammar::           If you want to generate code, read this.
410 411
* Writing Clients::             A few tips for client writers.
* Importing and Exporting E-Mail::  A few thoughts on e-mail integration.
412
* Some Client-specific Aux-Item Types::  Informative info about more aux-items.
413 414 415 416
* Future changes::              The protocol is not yet perfect.
* Protocol Version History::    The protocol was even less perfect before.
* Document Edition History::    Changes in this document.
* Index::                       Index of protocol elements.
David Byers's avatar
David Byers committed
417 418
@end menu

419 420 421 422 423 424 425 426
@ifnottex
@node About this document
@chapter About this document

@insertcopying

@end ifnottex

427
@ifnottex
428 429
@node Preface
@chapter Preface
430
@end ifnottex
431

David Byers's avatar
David Byers committed
432
LysKOM is a conferencing system@footnote{Or in modern terms, enabling
433
technology for Computer-Supported Cooperative Work (CSCW).}.  Similar
434
systems were QZ-KOM and PortaCOM@footnote{Also known as ``PottaKOM'' and
435
``BortaKOM.''}.  The LysKOM system is copyrighted by Lysator Academic
436
Computing Society and distributed under conditions of the GNU Public
437
License.  LysKOM and its documentation is provided ``as is'' without
438
warranty of any kind.
David Byers's avatar
David Byers committed
439

440 441
Anything described here as ``unspecified'' is liable to change in
future protocol versions.
David Byers's avatar
David Byers committed
442

443
This specification is the work of several people.  The main contributors have
444
been
445
Per Cederqvist @email{ceder@@lysator.liu.se},
David Byers's avatar
David Byers committed
446
David Byers @email{byers@@lysator.liu.se},
447
@value{Pell} @email{pell@@lysator.liu.se},
448
Thomas Bellman @email{bellman@@lysator.liu.se},
David Byers's avatar
David Byers committed
449 450
Lars Aronsson @email{aronsson@@lysator.liu.se},
Linus Tolke @email{linus@@lysator.liu.se} and
451
@value{Kent} @email{kent@@lysator.liu.se}.
David Byers's avatar
David Byers committed
452

David Byers's avatar
David Byers committed
453
The LysKOM developers can be reached by email to
454 455
@email{lyskom@@lysator.liu.se}.  If you find any errors in this
document, please report them at
Per Cederqvist's avatar
Per Cederqvist committed
456 457
@uref{http://bugzilla.lysator.liu.se/}.  Use @samp{lyskomd} as the
product, and @samp{documentation} as component.
David Byers's avatar
David Byers committed
458

459 460
@node Concepts
@chapter Concepts used in LysKOM
David Byers's avatar
David Byers committed
461 462

This chapter introduces the concepts used in LysKOM, such as articles,
463
conferences and sessions.
David Byers's avatar
David Byers committed
464 465

@menu
466 467 468 469 470 471 472 473 474 475
* Articles::                    Reading and writing articles is what
                                  LysKOM is about.
* Conferences::                 Articles are organized in conferences.
* Persons and Sessions::        Persons log on to the LysKOM system.
* The Misc-Info List::          How articles are organized in comment
                                  chains and in conferences.
* The Aux-Item List::           A generic extension mechanism.
* Security::                    Some persons have more privileges than
                                  others.
* Membership and Reading::      You don't have to read anything twice.
David Byers's avatar
David Byers committed
476 477 478
@end menu


479
@node Articles
David Byers's avatar
David Byers committed
480 481
@section Articles

482
An article is represented as a value of the type @type{Text-Stat} and a
483
string containing the article contents.  An article will usually have one
484 485
or more recipients and may be a comment or footnote to other articles.
Each article is kept in the database until it is older than the
486
@field{nice} value of each of its recipients and it is not marked by any
487
user.
David Byers's avatar
David Byers committed
488

489 490
There is an array of @type{Misc-Info} included in the
@type{Text-Stat}.  This array contains information about recipients,
491
senders, comments and footnotes.
David Byers's avatar
David Byers committed
492

493 494 495 496 497 498 499 500 501 502 503
Each article is identified by a number, the global@footnote{The number
is not truly global; it is local to a specific LysKOM server.}
article number (the @type{Text-No}).  Global numbers are assigned in
ascending order to new articles, and are never reused.  If an article
has recipients it will also have a local number for each recipient
(the @type{Local-Text-No}).  Local numbers are used in some data
structures to provide more compact storage and to provide an ordering
of articles for a particular recipient.  Local numbers are assigned in
ascending order and are never reused for a particular recipient,
though different recipients will have articles with the same local
numbers.
David Byers's avatar
David Byers committed
504

505
Occasionally it is necessary to map between local and global numbers.
506
The server call @reqdlink{local-to-global} does this@linkhere{}.
David Byers's avatar
David Byers committed
507 508 509



510
@node Conferences
David Byers's avatar
David Byers committed
511 512
@section Conferences

513 514
Conferences hold articles.  They are represented in the protocol as a
data type called @type{Conference}.  Each conference has a
515 516
@dfn{creator}, the person who created the conference, and a
@dfn{supervisor}, a conference whose members can modify the conference.
David Byers's avatar
David Byers committed
517
If the supervisor is a person, the members of that person's mailbox
518 519 520 521 522 523 524 525 526 527 528 529
are supervisors, which in most cases is only that person.  Persons are
a special case: in addition to those who are supervisors for a certain
person because of the @field{supervisor} field, the person is always a
supervisor of himself.  There is one exception to this special case:
the person cannot use @reqlink{set-supervisor} to change who is his
supervisor.

We have also introduced a type called @type{UConference} (pronounced
micro-conf-stat) which holds a subset of the information contained in
the full @type{Conference} type.  Use the @type{UConference} type
whenever possible since it places a much smaller load on the LysKOM
server.
David Byers's avatar
David Byers committed
530

531
Each conference has a type, which is essentially a collection of
532
boolean flags.  Currently the flags @conftype{rd-prot},
533 534
@conftype{letterbox}, @conftype{secret}, @conftype{original},
@conftype{allow-anonymous} and @conftype{forbid-secret} are defined.
David Byers's avatar
David Byers committed
535

536
@table @conftype
David Byers's avatar
David Byers committed
537
@item rd-prot
538
The conference is protected from reading by non-members.  Persons become
David Byers's avatar
David Byers committed
539
members by having one of the existing members or supervisors add him or
540
her to the conference.  This restriction is enforced by the server.
David Byers's avatar
David Byers committed
541
@item original
542
Conferences of this type are intended for original articles only.
543 544 545 546
Comments are to be redirected to the @field{super-conf} instead.  This
restriction is not enforced by the server; clients must implement this
functionality.  (@xref{Recipients of comments}, for a summary of how
a client should select the recipients of a comment.)
David Byers's avatar
David Byers committed
547
@item letterbox
548
Conferences of this type are connected to persons.  Letters to a person
David Byers's avatar
David Byers committed
549
are sent to the mailbox and the name of the mailbox is synchronized
550
with the person name.  It is currently not possible to explicitly set or
551
clear this flag on a conference.
David Byers's avatar
David Byers committed
552
@item secret
553
Conferences of this type are secret.  The server will not divulge any
554
information about the existence of the conference to persons who are not
555
members or supervisors of the conference.  If a mailbox is made secret,
David Byers's avatar
David Byers committed
556 557
that person cannot log in using the person name, but must specify a
person number instead.
558
@item allow-anonymous
559
Conferences of this type accept anonymous articles.  Other conferences
560
will reject anonymous articles.
David Byers's avatar
David Byers committed
561
@item forbid-secret
562
Conferences of this type do not allow secret members.  If a conference is
David Byers's avatar
David Byers committed
563
changed to this type, preexisting secret members remain secret.
David Byers's avatar
David Byers committed
564 565 566 567
@end table



568
@node Persons and Sessions
569
@section Persons and Sessions
David Byers's avatar
David Byers committed
570 571

Persons are represented in the protocol by values of the type
572 573
@type{Person}.  Associated with persons are statistics, a set of personal
flags and a set of privileges (@pxref{Security}).  Persons are also
574
associated with a conference that has the same number as the person and
575
the @conftype{letterbox} bit set.
David Byers's avatar
David Byers committed
576 577

Connections to the server are represented as values of the type
578
@type{Static-Session-Info}, @type{Session-Info-Ident} or
579 580 581
@type{Session-Info}.  Sessions have session number that are unique for
each session in the lifetime of the server execution.  A single user can
have several sessions running at once.  The session is not released until
582 583
the network connection is closed; a user can log in and out repeatedly
in a single session.
David Byers's avatar
David Byers committed
584 585


586
@node The Misc-Info List
David Byers's avatar
David Byers committed
587 588
@section The Misc-Info List

589
The @type{Misc-Info} list contains tagged data.  The fields are sent in
590
groups pertaining to a particular type of information: information about
591 592
recipient; carbon copy recipient; blank carbon copy recipient;
comment to; footnote to; comment in
593 594
and footnote in.  The information groups may be sent in any order and
there may be any number of groups.  Within each group the elements are
595
always sent in the order listed below.
David Byers's avatar
David Byers committed
596

597
@subsection Recipient
David Byers's avatar
David Byers committed
598

599
@table @misc
David Byers's avatar
David Byers committed
600
@item recpt
601
Starts a recipient group.  It contains the conference number of a
602
recipient of the article.
David Byers's avatar
David Byers committed
603
@item loc-no
604
Always present within a recipient group.  It contains the local text
605
number of the article in the conference specified by the preceding
606
@misc{recpt} field.
David Byers's avatar
David Byers committed
607
@item rec-time
608
If the recipient is a person, this element is added by the server when
609
the recipient marks the article as read.  It contains the time when the
610
text was read.
David Byers's avatar
David Byers committed
611
@item sent-by
612 613 614
Present when the recipient was added by a person other than the author
(after the article was created.) It contains the person number of the
person who added the recipient.
David Byers's avatar
David Byers committed
615
@item sent-at
616
Present when the recipient was added after the article was created.  It
617
contains the time when the recipient was added.
David Byers's avatar
David Byers committed
618 619 620
@end table


621
@subsection Carbon Copy (CC) Recipient
David Byers's avatar
David Byers committed
622

623
The carbon-copy recipient group is identical to the recipient group
624 625
above.  The difference is how new comments to an article with a recipient
or carbon-copy recipient are treated.  A comment to an article is sent to
626
all recipients, but not to carbon-copy recipients of the original
627
article.  This difference is enforced by the clients.
David Byers's avatar
David Byers committed
628

629
@table @misc
David Byers's avatar
David Byers committed
630
@item cc-recpt
631
Starts a carbon-copy recipient group.  It contains the conference number
632
of a carbon-copy recipient of the article.
David Byers's avatar
David Byers committed
633
@item loc-no
634
Always present in a CC recipient group.  It contains the local text
635
number of the article in the conference specified by the most recent
636
@misc{cc-recpt} field.
David Byers's avatar
David Byers committed
637
@item rec-time
638 639
Present after the CC recipient has read the article.  It contains the
time when the article was read.  Since only persons can read articles
640
this will only be seen if the CC recipient is a person.
David Byers's avatar
David Byers committed
641 642
@item sent-by
Present when a CC recipient was added by a person other than the author
643
after the article had been created.  It contains the person number of the
644
person who added the CC recipient.
David Byers's avatar
David Byers committed
645 646
@item sent-at
Present when a CC recipient was added after the article had been
647
created.  It is the time when the CC recipient was added.
David Byers's avatar
David Byers committed
648 649 650
@end table


651 652 653
@subsection Blank Carbon Copy (BCC) Recipient

The blank carbon-copy recipient group is identical to the carbon-copy
654 655
recipient group above.  The difference is the visibility of the
information.  A carbon-copy recipient group is visible to anyone that is
656
allowed to fetch both the text status of the involved text and the
657
conference status of the involved conference.  (That is, as long as the
658
conference isn't secret everybody is allowed to see the carbon-copy
659 660
recipient group.)

661 662 663 664 665
A BCC recipient group is basically only visible to members and
supervisors of the recipient.  Persons that have the right to become a
member of the recipient can also see it, as can the author of the text
(unless the recipient is secret to him).  This is enforced by the
server.
666 667

This type of group was introduced in protocol version 10.  When
668
old-style calls such as @reqlink{get-text-stat-old}
669
are used this will be converted to a CC recipient group by the server
670 671 672
for the benefit of clients that don't understand this group.  (This
conversion will of course only be performed when the user is allowed
to se the blank carbon copy.)
673

674
@table @misc
675
@item bcc-recpt
676
Starts a blank carbon-copy recipient group.  It contains the conference
677 678
number of a blank carbon-copy recipient of the article.
@item loc-no
679
Always present in a BCC recipient group.  It contains the local text
680
number of the article in the conference specified by the most recent
681
@misc{bcc-recpt} field.
682
@item rec-time
683 684
Present after the BCC recipient has read the article.  It contains the
time when the article was read.  Since only persons can read articles
685 686 687
this will only be seen if the BCC recipient is a person.
@item sent-by
Present when a BCC recipient was added by a person other than the author
688
after the article had been created.  It contains the person number of the
689 690 691
person who added the BCC recipient.
@item sent-at
Present when a BCC recipient was added after the article had been
692
created.  It is the time when the BCC recipient was added.
693 694 695
@end table


696
@subsection Comment To
David Byers's avatar
David Byers committed
697

698
@table @misc
David Byers's avatar
David Byers committed
699 700 701 702
@item comm-to
Always present when the article is a comment to another article.
@item sent-by
Present when the article was added as a comment by a person other than
703
the author, after the article had been created.  It contains the person
David Byers's avatar
David Byers committed
704 705 706
number of the person who added the article as a comment.
@item sent-at
Present when the article was added as a comment after the article had
707
been created.  It contains the time when it was added as a comment.
David Byers's avatar
David Byers committed
708 709 710
@end table


711
@subsection Footnote To
David Byers's avatar
David Byers committed
712

713
@table @misc
714
@item footn-to
David Byers's avatar
David Byers committed
715 716 717
Always present when the article is a footnote to another article.
@item sent-at
Present when the article was added as a footnote after the article had
718
been created.  It contains the time when it was added as a footnote.
David Byers's avatar
David Byers committed
719 720 721
@end table


722
@subsection Comment in
David Byers's avatar
David Byers committed
723

724
@table @misc
David Byers's avatar
David Byers committed
725
@item comm-in
726
Present when there are comments to this article.  It contains the article
David Byers's avatar
David Byers committed
727 728 729 730
number which is a comment to this article.
@end table


731
@subsection Footnote in
David Byers's avatar
David Byers committed
732

733
@table @misc
734
@item footn-in
735
Present when there are footnotes to this article.  It contains the
David Byers's avatar
David Byers committed
736 737 738 739
article number which is a footnote to this article.
@end table


740
@node The Aux-Item List
741
@section The Aux-Item List
742 743

The aux-item list is used as a generic extension mechanism in the LysKOM
744
server and in protocol A.
745 746

@menu
747
* About Aux-Items::             An introduction to aux-items.
748
* Aux-Item Inheritance::        Comments can inherit aux items.
749 750 751 752 753 754
* Predefined Aux-Item Types::   Predefined aux-items are part of the protocol.
* Client-Specific Aux-Item Types::  Clients can allocate aux-items for
                                    their private use.
* Experimental Aux-Item Types::  A block of aux-items are reserved for
                                    experimental use.
* Defining New Aux-Item Types::  Creating new aux-item types is easy.
755 756
@end menu

757
@node About Aux-Items
758
@subsection About Aux-Items
759 760 761

Aux-items were introduced in protocol version 10 as a mechanism for
extending the conference, text and server information structures without
762 763
changing the protocol.  (There is no need for aux-items on persons --
just add an aux-item to the corresponding mailbox.)
764

765
The exact structure of an aux item is specified elsewhere
766
(@pxref{Auxiliary Information}).  The important fields here are the
767
@field{aux-no}, @field{tag} and @field{data} fields.
768

769
The @field{aux-no} field is used to identify an item.  The
770 771
@field{aux-no} together with a text or conference number uniquely
identifies a particular aux item.  Items are numbered from one and up
772 773
within each item list.  Once assigned, the @field{aux-no} for an item
is never changed.  New items are guaranteed to be assigned numbers that
774
have never been used before within a particular list.
775

776
The @field{tag} field identifies the type of aux item.  It is used by
777 778 779
the server and by clients to figure out how to interpret the data
field, and by the server to decide if the item needs special
treatment.
780

781
The @field{data} field is a simple string.  The meaning of the string
782 783 784
is determined by the @field{tag} field, but since it is a string,
clients that have no understanding of the contents can successfully
parse the item anyway (in contrast to items in the misc-info list.)
785 786 787



788 789 790 791 792 793 794 795 796 797 798 799 800 801 802
@node Aux-Item Inheritance
@subsection Aux-Item Inheritance

An aux item that is placed on a text can be inherited.  This means
that if a comment or footnote to the text is created, an almost
identical item will be created on the new text.  The @field{tag},
@field{creator}, @field{flags} and @field{data} field will be
inherited unchanged.  The @field{aux-no} might be given a different
value.  A non-zero @field{inherit-limit} field will be decremented.
The @field{created-at} timestamp will be set to the time when the new
comment or footnote is created.

Inheritance only happens at text creation time.  If a comment or
footnote link is added later with @reqlink{add-comment} or
@reqlink{add-footnote}, no items will be inherited.  Also, if the link
803
is removed (via @reqlink{sub-comment} or @reqlink{sub-footnote}), the
804 805 806 807 808 809 810 811 812 813 814 815 816 817 818
inherited items will still be in place.

Inheritance only happens when the @field{inherit} bit is set, and if
@field{inherit-limit} is 0 or greater than 1.  @xref{Auxiliary
Information}, for more information.

Inheritance has no meaning for items placed on the server or on a
conference.

It is possible for a predefined aux-item to behave in a way that isn't
consistent with the description in this section.  The documentation
for the specific aux-item should document any deviations.



819
@node Predefined Aux-Item Types
820
@subsection Predefined Aux-Item Types
821

David Byers's avatar
David Byers committed
822
Predefined Aux-Item types are part of Protocol A, and clients should
823
support all of them.  As with other parts of the protocol, changes to
David Byers's avatar
David Byers committed
824
these definitions will be made backwards-compatible, if possible.
825

David Byers's avatar
David Byers committed
826
Creation and deletion of items with a predefined type can cause
827
arbitrarily complex and wondrous behavior in the server.  Furthermore,
David Byers's avatar
David Byers committed
828
the server may place constraints on the items with regard to content,
829
flags, who can create them, to what objects they can be attached and
830
so forth.  The server may also silently enforce specific values for any
David Byers's avatar
David Byers committed
831
field of an item, regardless of what the client requests.
832

833
All items with tags in the range 1-9999 and 30000 and up are considered
834
predefined.  If a client attempts to create an item with a tag in this
835
range, but the server has no idea what that tag means, the server will
836
return an error (@errorcode{illegal-aux-item-tag}).
837

838 839 840 841 842 843 844 845
Some items with tags in the range 10000-19999 are also predefined.
They are items that initially were reserved for private use for a
specific client, but where it was later discovered that the tag was
generally useful.  They should ideally have been assigned a number in
the 1-9999 range from the beginning, but if they already have a
widespread use they can be redefined to be predefined.  Such
redefinition will always be made in cooperation with the client
writer.
846

847 848 849
@xref{Aux-Item Types}, for the complete list of predefined Aux-Item
types.

850 851
@node Client-Specific Aux-Item Types
@subsection Client-Specific Aux-Item Types
852

853
Client-specific items do not cause the server to perform any magic.  All
854
the flags (except the delete flag) are left untouched, the data is not
855
validated in any way, and anyone can create any item.  If you need more
856
server support than this, your item should be on the predefined list.
857

858 859
All tags in the range 10000-19999 are reserved for clients.  Blocks of
100 numbers at a time can be assigned to specific clients.  A client
860
should never create items with tags in a range assigned to another
861 862 863
client or in an unassigned range.  Assigned ranges will never change,
except that specific aux-items may be redefined as predefined, as
explained in @ref{Predefined Aux-Item Types}.
864

865 866 867 868
Currently, the following ranges are assigned to clients:
@itemize @bullet
@item 10000-10099: The Elisp Client
@item 10100-10199: komimportmail
869
@item 10200-10299: Private test use (should never be used on a public server)
870 871
@c See bug 1440 for contact information.
@item 10300-10399: Canidius (Pontus Freyhult)
872
@end itemize
873

874
If you want a range of numbers, send e-mail to the LysKOM development
875
group, or request it via Bugzilla.
876

877 878
@node Experimental Aux-Item Types
@subsection Experimental Aux-Item Types
879

880 881
Experimental numbers are free for all.  Use @badspell{'em} any way you
want.  All
882
numbers in the range 20000-29999 are for experimental use.
883 884 885



886 887
@node Defining New Aux-Item Types
@subsection Defining New Aux-Item Types
David Byers's avatar