[Freeswitch-users] Dropping the Subject: header

Thu Dec 23 19:27:39 MSK 2010

Thanks Steve.

Mike

-----Original Message-----
From: freeswitch-users-bounces at lists.freeswitch.org [mailto:freeswitch-users-bounces at lists.freeswitch.org] On Behalf Of Steven Ayre
Sent: Thursday, December 23, 2010 10:46 AM
To: FreeSWITCH Users Help
Subject: Re: [Freeswitch-users] Dropping the Subject: header

http://www.rfc-editor.org/rfc/rfc3427.txt
The RFC recognises X- has been used in other protocols (eg SMTP) and
says prefix P- should be used for SIP. In practice both P- and X- are
used.

The reason is that if you are setting a custom header, it avoids
conflicts if they revise the SIP specification in future (eg for
SIPv3) and add a header with the same name as yours but a different
purpose.

See also:
http://blogs.voxeo.com/speakingofstandards/2008/05/06/what-is-a-p-header-in-sip-and-whyhow-would-you-use-one/
http://www.the-asterisk-book.com/unstable/applikationen-sipaddheader.html

Note that the X-header functionality is specifically coded within the
Sofia-SIP library:
http://sofia-sip.sourceforge.net/refdocs/sip/group__sip__header__x.html
To handle custom headers not prefixed with X- or P- would involve
considerable rewriting of the library to expose the ability. Since the
library is written by Nokia that would result in a large difference
between the FS and upstream versions, making it hard to maintain.

Regards,
Steve

On 23 December 2010 13:46, Kane, Michael (mkane02) <mkane02 at harris.com> wrote:
> Hey Steve/David, I'm a bit confused about having to add the X- prefix to the Subject header.  Can you please point me in the direction of which RFC talks to experimental headers?
>
> Thanks Mike
>
> Ps...thanks for looking into this for me.
>
> -----Original Message-----
> From: freeswitch-users-bounces at lists.freeswitch.org [mailto:freeswitch-users-bounces at lists.freeswitch.org] On Behalf Of Steven Ayre
> Sent: Wednesday, December 22, 2010 5:04 PM
> To: FreeSWITCH Users Help
> Subject: Re: [Freeswitch-users] Dropping the Subject: header
>
> David,
>
> Change your custom app to use X-Subject not Subject (AFAIK the RFC
> says any custom headers should be prefixed X-). My previous example
> will then work if you export sip_h_X-Subject.
>
> -Steve
>
>
> On 22 December 2010 19:40, Kane, Michael (mkane02) <mkane02 at harris.com> wrote:
>> Thanks David, I really appreciate your clarification.
>>
>>
>>
>>
>>
>> Brian, please contact me regarding how we can get a patch incorporated into
>> FS to pass the Subject header.
>>
>>
>>
>> Thanks Mike
>>
>>
>>
>>
>>
>>
>>
>> From: freeswitch-users-bounces at lists.freeswitch.org
>> [mailto:freeswitch-users-bounces at lists.freeswitch.org] On Behalf Of David
>> Ponzone
>> Sent: Wednesday, December 22, 2010 2:31 PM
>>
>> To: FreeSWITCH Users Help
>> Subject: Re: [Freeswitch-users] Dropping the Subject: header
>>
>>
>>
>> Michael,
>>
>>
>>
>> what Brian meant is that FreeSWICH can only passes the X-something and
>> P-something headers, which are the only allowed ones.
>>
>> Any system requiring custom headers should implement:
>>
>> X-Subject
>>
>> and not
>>
>> Subject
>>
>>
>>
>>
>>
>> David Ponzone  Direction Technique
>>
>> email: david.ponzone at ipeva.fr
>>
>> tel:      01 74 03 18 97
>>
>> gsm:   06 66 98 76 34
>>
>>
>>
>> Service Client IPeva
>>
>> tel:      0811 46 26 26
>>
>> www.ipeva.fr  -   www.ipeva-studio.com
>>
>>
>>
>> Ce message et toutes les pièces jointes sont confidentiels et établis à
>> l'intention exclusive de ses destinataires. Toute utilisation ou diffusion
>> non autorisée est interdite. Tout message électronique est susceptible
>> d'altération. IPeva décline toute responsabilité au titre de ce message s'il
>> a été altéré, déformé ou falsifié. Si vous n'êtes pas destinataire de ce
>> message, merci de le détruire immédiatement et d'avertir l'expéditeur.
>>
>>
>>
>>
>>
>> Le 22/12/2010 à 20:09, Kane, Michael (mkane02) a écrit :
>>
>> We have a custom app that requires the Subject header with values so our
>> endpoints can route the audio accordingly.  I'm ok with using sip_h_X
>> and or sip_h_P, but can't seem to get FS to pass the Subject header.
>> Any direction would be greatly appreciated.
>>
>> Mike
>>
>> -----Original Message-----
>> From: freeswitch-users-bounces at lists.freeswitch.org
>> [mailto:freeswitch-users-bounces at lists.freeswitch.org] On Behalf Of
>> Brian West
>> Sent: Wednesday, December 22, 2010 1:58 PM
>> To: FreeSWITCH Users Help
>> Subject: Re: [Freeswitch-users] Dropping the Subject: header
>>
>> What is the sudden obsession with the subject header?  Looking thru the
>> code it appears as if sip_h_X and sip_h_P are the only two things that
>> you can do... a patch will have to be made if you wish to set the
>> subject on an outbound invite... see sofia_glue.c  in do_invite.
>>
>> /b
>>
>> On Dec 22, 2010, at 12:50 PM, Kane, Michael (mkane02) wrote:
>>
>>
>> Hey Steve, the Subject is still not regenerated through the switch.  I
>>
>> posted a new pastbin.
>>
>>
>>
>> 14858
>>
>>
>>
>> Mike
>>
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>
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