Documentation -> Tutorials -> Presence -> Presence Server -> Presence Module - Parameters and Functions

Exported Functions

• handle_publish()
• handle_subscribe()

handle_publish()

• function which handles PUBLISH requests. It stores and updates presence information in database and calls functions to send NOTIFY messages when changes in presence information occur;
• it takes one optional parameter - the URI of the sender, used by the BLA feature( event dialog;sla ).

Actions:

• verifies if the PUBLISH message is correct:
  • check its structure - calls an event specific function defined in a presence_ev module (presence_xml or presence_mwi);
  • if it has a SIP-if-Match header, checks is there is a previous record for the same presentity;
  • if not present checks if a body is present
• if the conditions are not complied with it sends an adequate error message
• if a correct message:
  • sends a 200Ok message with 2 extra header fields : Expires and SIP-if-Match
• if a new PUBLISH without a Sip-if-Match header field
  • it generates one
  • inserts a new row in database
  • calls a function which sends Notify with presence to all the watchers which have subscribed to the presentity
• if the PUBLISH message is a sequential one
  • updates the expires value
  • generates a new E-Tag and sends it in the Sip-Etag header of the 200OK reply
• if body present
  • updates body (replace with the new one)
  • calls a function which sends Notify with presence to all watchers

handle_subscribe()

• function which handles SUBSCRIBE requests. It stores or updates dialog information in and calls functions to send Notify messages to teh watcher and to the presentity (if a subscription for event presence.winfo exists for the presentity and the event)
• it does not take any parameter.

Actions

• checks if the SUBSCRIBE message is correct:
  • check its structure;
  • if inside a dialog tries to match the dialogs with the records stored
• if the conditions are not complied with it sends an adequate error message
• if a correct message sends 2XX reply
  • the reply contains an Expires header
  • for SUBSCRIBE messages for event "presence.winfo" the status of the reply is 202OK and for all the other 200OK
• if a new SUBSCRIBE, saves the dialog information in cache
• if a Subscribe inside a dialog
  • if the Expires header field value is 0
    • deletes the registration from cache and database
    • if event is a PUBLISH event - sends a Notify for winfo to the presentity with full state
  • if update
    • updates the expires value
    • sends Notifies
• if a SUBSCRIBE for a PUBLISH event( 'presence', 'dialog.sla', 'message-summary'):
  • sends Notify with presence.winfo to the presentity(if a winfo subscription from the presentity exists) with a partial state informing only about the subscription status of the new watcher
  • sends Notify with the presence information
• if a SUBSCRIBE for a winfo(watcher info) event
  • sends Notify with presence.winfo to the subscriber with full state informing about all the watchers

Exported Parameters

Please refer to the module's documentation for the full list of parameters and a comprehensive description.