[OpenSIPS-Devel] RFC: adding new callback mechanism into core API

[Maxim Sobolev]

Here is the pre-final patch along those lines:

http://sobomax.sippysoft.com/opensips_rtpproxy_multihome.diff

Any comments or suggestions are welcome.

Maxim Sobolev wrote:
> Gang,
> 
> We have some new functionality for the nathelper planned that would need 
> to know final destination URI for the message to work properly. 
> Currently this means that we have to require script writer to invoke 
> this function only after all URI transformations have been applied, 
> which might quite significantly complicate script logic. Moreover it 
> might be even impossible in some cases to do so, for example when using 
> t_relay() function, which uses transaction state to determine message 
> destination.
> 
> Therefore, I see the need for a callback mechanism in core, allowing 
> callback functions to be registered on per-message basis and then to be 
> executed in some well-defined points of message processing. The 
> mechanism could be sufficiently generic to allow different uses. One of 
> the other use that I have in mind is destructor callback, which is to be 
> called when the message structure is being freed, so that modules would 
> be able to release any resources allocated (memory, connections, 
> descriptors, etc).
> 
> Any comments and suggestions are welcome.

Regards,
-- 
Maksym Sobolyev
Sippy Software, Inc.
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