From: sr-dev [sr-dev-bounces@lists.sip-router.org] on behalf of Daniel-Constantin Mierla [miconda@gmail.com]
Sent: Wednesday, February 18, 2015 3:51 AM
To: Kamailio (SER) - Development Mailing List
Subject: Re: [sr-dev] registrar - additional features

Hello,

some comments inline.

Hi,

please consider the addition of these features to master branch.

you can view the full PR in https://github.com/kamailio/kamailio/pull/91

the purpose of these additional features is to provide better information to configuration script to help in complex routing decisions and adding custom headers based on rich information. 

registrar - add user xavp on successful registered call

this commit adds the contact xavp when we call registered()

it acts like lookup without rewriting uri or appending branches

it acts like lookup_to_dest without appending branches

benefits, used in conjuction with usrloc param xavp_contact

prior to this commit, we would have to use sqlops to make a select directly into location_attrs, but not all sb engines support raw query or we would need to call lookup causing the unnecessary and unwanted set of the ruri.

modparam("usrloc", "xavp_contact", "ulattrs")

..

if(registered("location", "$fu") ) {

   $xavp(ulattrs=>my extended information about the contact)

}

before

if( registered("location", "$fu") ) {

##    lookup_to_dset("location", "$fu") ## not available

    lookup("location", "$fu")

   $xavp(ulattrs=>my extended information about the contact)

will this add the xavp only for first valid contact found in location table? Or for all contacts (e.g., when a user is registered with many phones)?

A : it will add the xavp for the first contact found since registered function exits on first match.

registrar - add optional avp params for usrloc comparison

reg_received_avp - match with received field
reg_contact_avp - match with contact field

this commit adds 2 optional params to be used on the registered function

prior to this commit, the only restriction available when calling registered was by using a call-id.

the 2 params added allow the match to be more restrictive

. by received column

. by contact column

I see that the match on call-id was added by Henning back in 2008, haven't used it.

My concern here is about adding too many avps parameters which can endup in loops across the list of avps to see if they are defined or not.

I am thinking of having a different implementation that is better in terms of performances and flexibility, like:
- extend the registered parameters to take one more as flags - here will be a bitmask of what matching rules to be applied (e.g., 1 - callid matching, 2 - received matching, 4 - contact matching)
- add the values for matching as part of xavp_cfg avp (e.g., say xavp_cfg is set to 'reg', then will be $xavp(reg=>match_callid) = "..."; $xavp(reg=>match_received) = "..." ...)

Practically the search for the values to be match will be done only if the appropriate flag is set.

The avp for matching call id should be removed.

In the future, adding another matching rule will be adding a new flag and an inner attribute/value for xavp_cfg.

What do you think?

A : i like this approach. trying that.

registrar - add xavp to reg_fetch_contacts

modparams("usrloc", "xavp_contact", "ulattrs");

this commit adds the usrloc xavp_contact to the returned structure.

reg_fetch_contacts("location", "$fu", "caller");
xlog("L_INFO", "$fu xavp = $ulc(caller=>received)");
xlog("L_INFO", "$fu xavp = $ulc(caller=>ulattrs=>MyExtendedInfoOnUser)");

I think this can be done also conditionally -- I would add a new parameter to reg_fetch_contacts where we can specify this behaviour as a flag.

A : instead of a parameter, we could add a parameter "return_xavp_on_match" (or better naming) that would control the addition of the xavp in registered and reg_fetch_contacts.

      in reg_fetch_contacts the xavp is returned for each contact (not like in registered). 

      i added it since we are already doing it in the lookup and lookup_to_dset.

Thanks for these contributions and let's see if others have other ideas or commends on my proposal to get to a solution that is fair from performance/feature ratio point of view.

Cheers,
Daniel

-- 
Daniel-Constantin Mierla
http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda
Kamailio World Conference, May 27-29, 2015
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