[SR-Users] is $td.did avp a normal avp?

[Daniel-Constantin Mierla]

On 4/26/11 9:20 PM, Klaus Darilion wrote:
> Jan Janak wrote:
>> On Tue, Apr 26, 2011 at 8:42 PM, Klaus Darilion
>> <klaus.mailinglists at pernau.at> wrote:
>>> Jan Janak wrote:
>>>> On Tue, Apr 26, 2011 at 7:41 PM, Klaus Darilion
>>>> <klaus.mailinglists at pernau.at> wrote:
>>>>> Not helping with this issue - but having another question: what is
>>>>> $td.did?
>>>>> Is it a pseudo variable (as it starts with $)? Is it somehow
>>>>> related/derived
>>>>> to/from $td or is the '.' just a character like a-z?
>>>> This is the SER syntax for AVP names, see
>>>> http://sip-router.org/wiki/devel/avps-ser
>>> Aha. But how does sip-router decide if $td is a ser AVP or a 
>>> Kamailio pseudo
>>> variable?
>>
>> If it starts with ${fu,tu,fd,td,g}. then it is taken as a SER AVPs,
>> otherwise it is a Kamailio pseudo variable.
>
> Not sure if I got it right. I guess if I use $fu it will be Kamailio's 
> from-URI pseudo variable as there is no ser $fu AVP as $fu is only the 
> prefix and not the full AVP name, a full ser AVP name would be for 
> example $fu.foo.
>
> Is this correct?
actually, to give further clarifications, the script variable lookup for 
$xyz is like:
- search in K-style PV table  for 'xyz' name and if found use it
- if not found, treat it as AVP

So, $xyz (literally) is practically the same as $avp(xyz). When the 
integration happened, it was discovered there was no critical 
overlapping between existing PV names and ser avp lists - as mentioned 
in this thread, ser had lately several avp classes, using a dot to mark 
the end of the class and the start of the avp name.

In the past a non-existing PV name  in K would have thrown error, now is 
considered to be classic K AVP (in ser style it is from uri avp).

Now the $avp(...) PV supports all classes, so you can use for example 
$avp(td.did). If the avp class is missing, then it is the 'f' class, 
afaik based on some emails sent in the past on the lists -- so these 
should be equivalent in the config file:
- $myavp
- $f.myavp
- $avp(myavp)
- $avp(f.myavp)

However, you better test the above equivalency, since I am using only 
K-style avps.

Cheers,
Daniel

-- 
Daniel-Constantin Mierla
http://www.asipto.com