[OpenSIPS-Users] TEXTOPS module

[Denis Putyato]

Thank you Bogdan for your answer. Now I understood that apply changes is a bad idea.
But during process a call I have to make some changes to INVITE message. 
For example,
I need to add Remote-Party-ID (RPI) and/or P-Asserted-ID (PAI) and make uac_replace_from(). If I make it for the first time everything fine. 
But if I need then change these fields (via subst or uac_replace_from() again)(for example, some gateways fails and cannot accepts call, I use use_next_gw() of d_routing module and MUST change callerid information) then my tests show that during, for example, second time call of uac_replace_from() there are two uri in From: header field (as you understand that is wrong), or if I make subst() of RPI or PAI then second header RPI and PAI appear in addition of first headers which I added (or subst) before. 

And to avoid this I make signaling loop. New INVITE process as a new message with modified early headers, so I can change it again.   

-----Original Message-----
From: users-bounces at lists.opensips.org [mailto:users-bounces at lists.opensips.org] On Behalf Of Bogdan-Andrei Iancu
Sent: Monday, December 20, 2010 4:07 PM
To: OpenSIPS users mailling list
Subject: Re: [OpenSIPS-Users] TEXTOPS module

Hello Denis,

So far there is no good arguments for such a function, but there are a 
lot of performance penalties while using such a function.

Basically, to apply the change to a message, opensips/kamilio has to 1) 
take the received buffer and the changes and to generate a new buffer 
with the whole message (including the changes) and to 2) take the newly 
generate buffer and to parse it as a SIP content in order to be able to 
use internally it.
Bottom line, each time you use such a function you double the processing 
effort for parsing and generating SIP messages. And if you check the 
code profiling we did (see 
http://www.opensips.org/Resources/TestsProfiling), these operations are 
~50% from the total CPU usage (cumulate the PARSE and BUILD times).

Now, in most of the cases (99% of the case) you do not really need to 
apply changes in realtime - there are a lot of simple tricks to avoid 
it. If you describe the problem you have, I can help you in putting some 
extra logic in the script to avoid the need to apply changes.

Using a smart approach is more efficient than a brute force approach - 
the idea is that you are aware of the changes you do in script and you 
remember (in script) these changes, so you can take them into account in 
your later processing even if they are not actually applied on the SIPS 
message.

Regards,
Bogdan

Denis Putyato wrote:
>
> Hello!
>
> In kamailio project there is a function |msg_apply_changes() ||in 
> textops module for applying changes (for example add or subst some 
> header field) in SIP messages. Is there some way on opensips for doing 
> such operation? Now I need make signaling “loop” for change header 
> fields which I, for example, add during call process.|
>
> | |
>
> |Opensips 1.6.3|
>
> | |
>
> |Thank you || |
>
> ------------------------------------------------------------------------
>
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-- 
Bogdan-Andrei Iancu
OpenSIPS Event - expo, conf, social, bootcamp
2 - 4 February 2011, ITExpo, Miami,  USA
www.voice-system.ro


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