Variable interpolation in xavp identifiers - sr-users

1 Apr 2015

Hello,

There seems to be an implementational difference in interpolation of PVs 
in AVP and XAVP identifiers and/or field names.

The pseudovariables documentation[1] on classical AVPs says:

    The 'id' can be:

       ...

       pseudo variable - if value of pv is integer, id is integer,
       if string, id is string

So, for example, this composition of variables works:

    $var(f) = 'donkey';
    $avp($var(f) = 'eehaw';

    xlog("L_INFO", "Donkey says: $avp(donkey)\n");

It correctly prints:

    Donkey says: eehaw

Making some assumptions, I tried this, and it did not work similarly as 
expected:

    $var(f) = 'donkey';
    $xavp(r=>$var(f)) = 'eehaw';

    xlog("L_INFO", "Donkey says: $xavp(r=>donkey)\n");

This prints:

    Donkey says: <null>

And a PV dump confirms that the PV value is not interpolated:

Mar 31 18:26:15 localhost /usr/local/sbin/kamailio[2399]: INFO: debugger 
[debugger_api.c:1799]: dbg_dump_json():
{"$xavp(r)":[{"$var(f)":["eehaw"]}]}

Interpolation of variables does not work for either field or stem names.

Is this a design principle of XAVPs, or an oversight?

Thanks,

-- Alex

[1] 
http://www.kamailio.org/wiki/cookbooks/4.2.x/pseudovariables#avp_id_-_avps

-- 
Alex Balashov | Principal | Evariste Systems LLC
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