[SR-Dev] AVPs

Hello, I think we need to decide about AVPs. Although not deeply investigated, ser seems to have couple of AVPs lists. In kamailio/openser it is one list. Can a ser developer describe a bit the AVP implementation as it is now there? In openser/kamailio we have more or less same architecture as for ser 0.9.6 with couple extensions, but I will detail here so we can have full picture: - avps are kept in shared memory - they are bound to each sip message and moved to transaction if that message create a transaction - avp can have two types of names - integer id, referred as $avp(i:number) - string id, referred as $avp(s:string) - there can be aliases for avp names, defined as "alias=[is]:id", so the script writer can use $avp(alias) - a value of an avp can be either integer or string - not related to avp core part, but important to mention here -- tm, controlled by a parameter, can make the avps from transaction (request) available to onreply_route. Also, just to have in mind, for the future we got into discussion: - moving from linked list to a structure that allows faster search (e.g., hash table) as number of used avps can be big some times - adding support for structure-like values (the value to be another list of (name,value) pairs). A typical use case is serial forking, where one needs to store data in avps. If for one destination an avp is missing, things get screwed. Example: $avp(uri) = {A, B, C} $avp(RPID) = {X, not needed, Y} Internally will look like: $avp(uri) = {A, B, C} $avp(RPID) = {X, Y} So actually, Y will be used for destination B. Workarounds are possible, or course, but maybe we can do it nicer. so it will be like: $avp(dst) = {{u=A,r=Y}, {u=B},{u=C,r=Y}} A possibility to specify the access is $avp(d:dst=>u) Finally, as pointed in another email, it is about making possible to hold "value null" (a mark/flag) and differentiate that from "undefined" (not existing). Cheers, Daniel -- Daniel-Constantin Mierla http://www.asipto.com