Node:The User Area, Next:Membership visibility, Previous:LysKOM Content Types, Up:Top
The user area is a regular text that is used to store client-specific information in the server. Most clients use this to store settings a user has made that are specific to a particular server. There are also provisions to store settings that are shared between clients.
The user-area is divided into several sub-blocks. The
common block is
shared by all clients, and its formats and contents are dictated by this
protocol specification. Clients may also create one or more other blocks.
In normal texts, everything up to the first linefeed is considered to be the subject line. The user area is an exception: it does not contain any subject line.
Each block is encoded as a
HOLLERITH string. A table of
contents is also encoded as a
HOLLERITH string and added first
in the user area. There must be at last one space between each
string, and there might be spaces at the beginning and/or end of the
user-area. Thus, a user-area made up of three blocks will contain
HOLLERITH-encoded strings, each separated by at least one
space, and maybe with extra spaces at the beginning or end of the
The table of contents consists of one
for each block in the user-area. Each string contains the name of the
corresponding block. There is at least one space between each string,
and there may be spaces before the first string and after the last
string. Clients must never create two or more blocks with the same
This format ensures that clients can copy or read past other clients' blocks without knowing their structure.
13H7Hblock-a 1Hb 4Hasdf 5H hjkl
In the above example, there are two blocks:
block-a contains four bytes,
b contains five bytes:
hjkl (note the leading
space). Below are a few other ways to encode the same user-area:
14H 7Hblock-a 1Hb 4Hasdf 5H hjkl 16H 7Hblock-a 1Hb 4Hasdf 5H hjkl 13H1Hb 7Hblock-a 5H hjkl 4Hasdf
The first two examples embed extra (redundant) spaces, and the last swaps the order of the two blocks.
The following block names have been defined:
If you're writing a client that uses the user-area, please let us know what you name your client's block.
This defines the structure of the common block. The common block contains a list of variable settings. Each variable setting consists of a name, some whitespace, and a value. Settings are separated by a linefeed character. The values can be of several different types (such as integers, strings, booleans, lists of stuff) but they are all encoded as HOLLERITHs. The reason for this is to simplify for clients that need to ignore the value, and so it is possible to add new value types without confusing old clients.
The grammar below defines the syntax of the common block.
common-block : settings settings : settings setting | /* empty */ setting : variable ' ' value '\n' variable : [A-Za-z-_0-9]+ value : HOLLERITH
The values contain structure within the HOLLERITH. The following
grammar defines the data types that are currently used. Clients must
be prepared to ignore values that have other data types.
boolean : 1 | 0 integer : -?[0-9]+ string-list : string-list ' ' HOLLERITH | HOLLERITH
Currently the following variables are used, but more may be added, and clients must cope with variables they know nothing of in the common block. (Doing so is easy, as all values are encoded as HOLLERITHs.)
This contains a list of ISO 639 language codes. ISO 639-2 should be used for languages that have a 2-character language code. For other languages, ISO 639-1 should be used. http://lcweb.loc.gov/standards/iso639-2/langcodes.html contains a list of the current language codes.
The client should configure its user interface to use the first language in the list that it supports. Example: a client that supports English and Swedish would use:
2Hfr 2Hsv 2Hen
2Hen 2Hsv 2Hfr