(incomplete, see also http://old.gale.org/gag/proto )

Messages are composed of fragments. The order of fragments in a message doesn't matter. Unknown fragments should be ignored; this will allow the format to be extended without sacrificing compatibility.

Fragment Data Types

 ID Type
 0 UCS-2 text.
 1 Arbitrary binary data.
 2 128-bit date/time stamp: 64-bit seconds since epoch, 64-bit second fraction.

 +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
 | sec. high | sec. low  | frac. hi. | frac. low |
 +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+

 3 32-bit signed integer.
 4 Nested fragment list.

Current fragments:

message/sender - real name of person sending puff
message/body - contents of puff
id/class - identifies the type of sending client; should be client name and version number, separated with a slash. Examples:
- gsend/0.99egg
- vtFugu/1.2.1
- yammer.net/1.0pre.2161
id/instance - identifies the particular sending client process; in gsend, follows this form, which should be replicated as closely as possible:
- $GALE_DOMAIN/$HOSTNAME/$USER/$TTY/$PID

Fragments in key requests and responses:

question.key - used in an AKD request; supercedes question/key; the local part of the key name must not be reversed
answer/key - response to old-style or new-style AKD request
answer.key - some key responses use this instead of answer/key
answer/key/error - error result for AKD request (old or new)

Fragments in a return receipt:

question.receipt - supercedes question/receipt; must be set to the location to which receipts should be sent
answer.receipt - supercedes answer/receipt; set to Gale ID of user sending receipt
notice/presence - presence status, such as "in.present"

deprecated/obsolete fragments:

message/recipient - deprecated; used to set a friendly name for the recipient of the message whether a puff is a return receipt or not
question/key - used in an AKD request; obsolete; the local part of the key name must be reversed

custom fragments

_ginsu.timestamp - time message was recieved by ginsu, set on incoming puffs for default sorting method of time recieved
_ginsu.spumbuster - sha1 digest of raw message, useful for busting spum. text fragment consisting of hexadecimal representation of digest.

experimental fragments