Thanks Daniel.

I didn’t know “$null” existed. But I’ll use is_present_hf since I’m not interested in the contain of the header.

From: sr-users-bounces@lists.sip-router.org [mailto:sr-users-bounces@lists.sip-router.org] On Behalf Of Daniel-Constantin Mierla
Sent: Thursday, 26 June 2014 7:57 p.m.
To: Kamailio (SER) - Users Mailing List
Subject: Re: [SR-Users] How to find whether or not certain header exists?

Hello,

you can use:

if(is_present_hf("aaa")) ...

Also, it should work like:

if($hdr("aaa") != $null) ...

The is_present_hf() should be slightly faster as it just walks through the list of headers, not parsing the header body and not returning its value.

Cheers,
Daniel

On 26/06/14 06:35, Allen Zhang wrote:

Hi,

If I normally receive a INVITE that has a header ‘aaa’ with value ‘bbb’, but it’s possible that some INVITEs don’t have this header.

How do I determine in the config file if the header exists?

To check the value of the header I do if($hdr(aaa) == "bbb"). But what if the header doesn’t exist?

Cheer,

Allen

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