How to Make FreeSWITCH Set a Variable after the Bridge

So one of my customers is creating a calling card service to call abroad. Without entering in many details, the big challenge here is setting a variable after leg B has been answered. It took me a while to figure out how; I can tell you now that exporting variables locally or non-locally (nolocal:) doesn't work. But then, I found the right way.

LUA is FreeSWITH's Best Friend

I have found no way to do it directly in the dialplans. The tricky part here is that you need to assign the post-bridge variable when leg B is answered, but before it is destroyed. Then, LUA is the right way to do it.

I did the following:

• add this direction in your dialplan before the bridge statement: export nolocal:execute_on_answer=lua script.lua ${uuid}
• create a Lua script like this:
  if ( session:ready() ) then
         local uuid = argv[1]
         api = freeswitch.API();
         reply = api:executeString("uuid_setvar "..uuid.." post_bridge_variable 000");
  end

This little script will create a variable named "post_bridge_variable" and it will be assigned "000" as its value. You can verify it when you review your CDR variables.

Use Case

When you are doing a DISA, you may want to log in the CDR when leg B is answered. This is the way to do it.

Good luck!