[asterisk-users] Asterisk Tips and Tricks: Dynamic Subroutines in AGI

[Darren Sessions]

When I set out to develop a basic service provider Perl AGI framework  
for Asterisk three or four years ago, I wanted to design something  
that would make developing additional Perl AGI apps under this  
framework scalable and easy to do. One of the features I wanted to  
have in this framework was the ability to do a database dip on a  
particular incoming called number to see which service I needed to  
execute and then to dynamically execute that subroutine from the  
database servers results. I could switch services or point the number  
to a canceled operator message by simply doing an update to that  
telephone number’s record in the database - instantly re-provisioning  
the telephone number.

The hurdle in doing something like this was how to dynamically execute  
a subroutine from the results of the database query which were dumped  
into a variable. The method I used with the subroutine reference  
doesn’t allow for arguments to be passed (if anyone finds / knows a  
way to do this, let me know), so I use global variables.

This is a simple example of dynamic subroutine execution (without the  
database query):

use strict;
use warnings;

our $called_number;
our $calling_number;

sub run_me {
   $AGI->verbose(”Called Number = “.$called_number, 1);
   $AGI->verbose(”Calling Number = “.$calling_number, 1);
}

sub set_variables {
   $called_number = “8005551212″;
   $calling_number = “3002221111″;
}

sub dynamic_execute {
   my ($sub) = @_;
   if (!$sub) {
     $AGI->verbose(”No subroutine name passed!!”, 1);
     return(-1);
   }
   my $exec = \&{$sub};
   return($exec->());
}

set_variables();
dynamic_execute(”run_me”);


_____________________________

Darren Sessions
dmsessions at gmail.com
http://www.darrensessions.com
_____________________________


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