[OpenSIPS-Users] [OpenSIPS-Devel] [RFC] OpenSIPS 2.0 - changes on the SIP messages

[Bogdan-Andrei Iancu]

Hi Dan,

what you are saying is similar with the idea I suggested (keeping the 
new message per header - each header has its own buffer ) - see  
http://lists.opensips.org/pipermail/users/2010-April/012401.html

Regards,
Bogdan

Dan Pascu wrote:
> IMO lumps should go. They're a hackish solution that caused enough  
> problems already.
> As I see it, we must have the original message and the current message  
> (original plus all changes applied in realtime) so one can get at any  
> moment the original message and the modified message without any  
> complication (modified message should be per branch of course). Re- 
> parsing can be kept to a minimum or even avoided completely in certain  
> circumstances if the modified message is kept as a dictionary of SIP  
> header name/value pairs, plus some extra info about the first line in  
> the message and the content.
> In other words while the original message is kept both parsed and  
> unparsed, the current modified messages are only kept parsed and are  
> reconstructed in a text buffer only when sent out.
>
> On 28 Apr 2010, at 13:40, Bogdan-Andrei Iancu wrote:
>
>   
>> Hi,
>>
>> sorry for crossposting, but I thing this topic is interesting both for
>> users (as experience) and for developers (as solution).
>>
>> So, right now the code for 2.0 got to a stage were we need to "apply"
>> changes on the received messages (like adding VIA headers, changing
>> headers, etc). And before starting the work on this area, I would like
>> to get some opinions on the available options:
>>
>>    1) keep the current mechanism for changing the SIP messages by  
>> using
>> lumps that are applied only when the message is sent out :
>>       Advantages: code is there and works; the mechanism is very  
>> fast ;
>> no need to re-parse the message after the parsing
>>       Disadvantages : from script or code, you are not able to see the
>> previous changes you did on the message, like:
>>                 if you remove a hdr, it will be marked to be removed,
>> but you will still see it there after the removed
>>                 if you add a new hdr, you will not be able to see it
>> (it will be actually added only when the message will be sent out)
>>                 if you replace the contact hdr (like after
>> fix_nated_contact() ) will not see the new contact, but the old one
>>                 trying to apply 2 changes in the same area (like
>> changing twice the contact) will result in bogus result.
>>
>>    2) find a new approach that will allow to push in realtime the
>> changes on messages
>>       Advantages: the change will take affect instantly, so all the
>> disadvantages from 1) (as user experience in operating opensips) will
>> disappear .
>>       Disadvantages : the code will probably be slower (the changes
>> part), but will speed up other parts of the code (where you need to
>> manually identify the prev changes);
>>             changed parts of the SIP message will require re-parsing
>> (so the code will have to check the state of a header (if parsed or  
>> not)
>> before each usage)
>>             you will not be able to undo changes on the SIP messages  
>> in
>> an easy way (for example during the parallel and serial forking on
>> per-branch changes)
>>
>> So this is the dilemma: if the current mechanism (with applying  
>> changes
>> at the end) such a bad user experience (scripting) in order to try for
>> 2.0 a different approach ?
>>
>> I would like to hear some opinions from both people writing scripts  
>> and
>> people writing code.
>>
>> Thanks and regards,
>> Bogdan
>>
>> -- 
>> Bogdan-Andrei Iancu
>> www.voice-system.ro
>>
>>
>> _______________________________________________
>> Devel mailing list
>> Devel at lists.opensips.org
>> http://lists.opensips.org/cgi-bin/mailman/listinfo/devel
>>
>>     
>
>
> --
> Dan
>
>
>
>
>
>
>
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>   


-- 
Bogdan-Andrei Iancu
www.voice-system.ro