[Freeswitch-dev] Conference CDRs via http

Mariusz Czulada manieq at wp.eu
Tue Jun 12 05:38:53 MSD 2012

Hi all,

I was thinking about sending CDRs via HTTP in a same or similar way mod_xml_cdr does. I consider implementing this (unless someone else is working on it) but first wanted to discuss with you the best approach.

A. All in mod_conference

This would require to copy many fragments of code from mod_xml_cdr into mod_conference. Also same configuration parameters used in xml_cdr must be processed and used for sending data. The advantage for this solution is that everything related to this mechanism is included in this module. Drawback: if something in mod_xml_cdr requires fixing or extending, probably the same changes should by applied in related parts of mod_conference.

B. mod_conference builds, mod_xml_cdr sends data

For this solution I'll give more details.
1. New event type should be added (like SWITCH_EVENT_CDR)
2. When a module (in this case: mod_conference) wants to store CDR via HTTP it must fire an event of that type and:
- "Event-Subclass" set (like "conference")
- Only common headers are needed, plus...
- "Content-Type" and "Content-Length" must be set
- CDR data must be build as XML in a module and added as an event content.
3. mod_xml_cdr will listen to this event type.
4. For each event subclass which mod_xml_cdr must must react, configuration file will contain a set of params same as for generic channel CDRs.
5. If subclass matches configuration, mod_xml_cdr reads data from event content and sends them according to configuration.

Changes in mod_conference:
- one new parameter for each profile (like "cdr-via-event=yes|no")
- if "yes" then xml must be build even if "cdr-log-dir" is unset
- if "yes", then an event must be fired as described above

Changes in mod_xml_cdr:
- extra parameters from configuration to be parsed (like '<settings subclass="conference">....</settings>')
- if 'Event-Subclass' matches configuration, a content of the event will be sent via HTTP (probably most of 'my_on_report' routine bellow 'try to post it to the web server' comment will be reused)

A [small] drawback is that it makes an indirect module dependency, but we already have such situations (like mod_shout needed to record a conference in mp3).

Advantages are:
- one can create an external tool for handling this type of event (to store it directly in db or send it with other protocols)
- this mechanism can be easily reused in other modules if needed; maybe in mod_callcenter, maybe in other components. No further changes in mod_xml_cdr should be needed.

What is unknown to me is a maximum size of event content. Conference CDR XMLs can be quite big - will it be a problem to send it this way?

I think the second solution is better and more universal but I'd like to hear your opinions about this case. 



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