How to use Asterisk Dialplan Functions on Debian 12

To Use Functions On Asterisk Dialplan Context

Introduction:

Asterisk functions are very similar to functions in many programming languages. Functions are: Sophisticated subroutines that help you manipulate data in a variety of ways. Callable from within Dialplan and Asterisk's various interfaces.

Procedure:

Step 1: Check the OS version by using following command.

root@linuxhelp:~# lsb_release -a
No LSB modules are available.
Distributor ID:	Debian
Description:	Debian GNU/Linux 12 (bookworm)
Release:	12
Codename:	bookworm

Step 2: Goto the following location by using following command.

root@linuxhelp:~# cd /etc/asterisk/

Step 3: Edit the extensions.conf file for use dialplan functions by using following command.

root@linuxhelp:/etc/asterisk# vim extensions.conf
[internal]
exten => 110,1,NoOp(Result for my function: ${CALLERID(all)})
same => n,Dial(PJSIP/110, 20)
same => n,Playback(sorry_didnt_get)
same => n,Hangup()

exten => 111,1,NoOp(Print the context)
same => n,Dial(PJSIP/111, 20)
same => n,Playback(sorry_didnt_get)
same => n,Hangup()

exten => 112,1,NoOp()
same => n,Dial(PJSIP/112, 20)
same => n,Playback(sorry_didnt_get)
same => n,Hangup()

Step 4: Login to the asterisk console by using following command.

root@linuxhelp:/etc/asterisk# sudo asterisk -rvvvvvvvvvvvvvvv
Asterisk 20.4.0, Copyright (C) 1999 - 2022, Sangoma Technologies Corporation and others.
Created by Mark Spencer <markster@digium.com>
Asterisk comes with ABSOLUTELY NO WARRANTY; type 'core show warranty' for details.
This is free software, with components licensed under the GNU General Public
License version 2 and other licenses; you are welcome to redistribute it under
certain conditions. Type 'core show license' for details.
=========================================================================
Connected to Asterisk 20.4.0 currently running on linuxhelp (pid = 953)

linuxhelp*CLI>

Step 5: Reload the dialplan by using following command.

linuxhelp*CLI> dialplan reload
Dialplan reloaded.
    -- Time to scan old dialplan and merge leftovers back into the new: 0.000006 sec
    -- Time to restore hints and swap in new dialplan: 0.000006 sec
    -- Time to delete the old dialplan: 0.000006 sec
    -- Total time merge_contexts_delete: 0.000018 sec
    -- pbx_config successfully loaded 1 contexts (enable debug for details).

Step 6: Make a Call to Check Dialplan Functions by using Softphone Softwares.

linuxhelp*CLI> 
    -- Executing [110@internal:1] NoOp("PJSIP/112-00000010", "Result for my function: "linuxhelp3" <112>") in new stack
    -- Executing [110@internal:2] Dial("PJSIP/112-00000010", "PJSIP/110, 20") in new stack
    -- Called PJSIP/110
    -- PJSIP/110-00000011 is ringing
    -- Nobody picked up in 20000 ms
    -- Executing [110@internal:3] Playback("PJSIP/112-00000010", "sorry_didnt_get") in new stack
       > 0x7f5708012710 -- Strict RTP learning after remote address set to: 192.168.6.102:8000
       > 0x7f5708012710 -- Strict RTP switching to RTP target address 192.168.6.102:8000 as source
    -- <PJSIP/112-00000010> Playing 'sorry_didnt_get.ulaw' (language 'en')
    -- Executing [110@internal:4] Hangup("PJSIP/112-00000010", "") in new stack
  == Spawn extension (internal, 110, 4) exited non-zero on 'PJSIP/112-00000010'

Step 7: Check all the functions of asterisk by using following command.

linuxhelp*CLI> core show functions
Installed Custom Functions:
--------------------------------------------------------------------------------
AMI_CLIENT            AMI_CLIENT(loginname,field)          Checks attributes of manager accounts 
ARRAY                 ARRAY(var1[,var2[,...][,varN]])      Allows setting multiple variables at once. 


AST_SORCERY           AST_SORCERY(module_name,object_type  Get a field from a sorcery object 
CALLERID              CALLERID(datatype[,CID])             Gets or sets Caller*ID data on the channel. 
CDR                   CDR(name[,options])                  Gets or sets a CDR variable. 
CDR_PROP              CDR_PROP(name)                       Set a property on a channel's CDR. 
CONFBRIDGE            CONFBRIDGE(type,option)              Set a custom dynamic bridge, user, or menu profile on a channel for the ConfBridge application using the same options available in confbridge.conf. 
CONFBRIDGE_CHANNELS   CONFBRIDGE_CHANNELS(type,conf)       Get a list of channels in a ConfBridge conference. 
CONFBRIDGE_INFO       CONFBRIDGE_INFO(type,conf)           Get information about a ConfBridge conference. 
CONNECTEDLINE         CONNECTEDLINE(datatype[,i])          Gets or sets Connected Line data on the channel. 
CSV_QUOTE             CSV_QUOTE(string)                    Quotes a given string for use in a CSV file, escaping embedded quotes as necessary 
DEVICE_STATE          DEVICE_STATE(device)                 Get or Set a device state. 
EVAL                  EVAL(variable)                       Evaluate stored variables 
EXCEPTION             EXCEPTION(field)                     Retrieve the details of the current dialplan exception. 
FEATURE               FEATURE(option_name)                 Get or set a feature option on a channel. 
FEATUREMAP            FEATUREMAP(feature_name)             Get or set a feature map to a given value on a specific channel. 
FIELDNUM              FIELDNUM(varname,delim,value)        Return the 1-based offset of a field in a list 
FIELDQTY              FIELDQTY(varname,delim)              Count the fields with an arbitrary delimiter 
FILTER                FILTER(allowed-chars,string)         Filter the string to include only the allowed characters 
HASH                  HASH(hashname[,hashkey])             Implementation of a dialplan associative array 
HASHKEYS              HASHKEYS(hashname)                   Retrieve the keys of the HASH() function. 
HINT                  HINT(extension[@context][,options])  Get the devices set for a dialplan hint. 

Conclusion:

We have reached the end of this article. In this guide, we have walked you through the steps required to use Asterisk Dialplan Functions on Debian 12. Your feedback is much welcome.