Asterisk tips callback

How to create callback voicemail

by Jpiterak

Here are a couple of scripts I use to do callback voicemail to my users. This was a request from a customer who was looking at a similar feature on an Avaya system.

How it works:

- Instead of calling Voicemail() directly, I set up a macro ‘macro-leave_voicemail’ that makes the Voicemail() call, then checks to see if you want to send a call to the user.
- If callback is set, the macro calls a bash script that creates the call file. This script:
  - Checks the voicemail.conf file for a specially formatted comment line after the mailbox definition with the telephone numbers to call for this user.
  - Creates a call file for each of these phone numbers. Note that the call file:
    - Puts the callee into a context in extensions.conf that tells them that they have a call waiting, and allows them to press 1 to go directly to voicemail.
    - Sets a variable ‘${mailbox}’, which is used to enter the correct voicemailbox if the user chooses to listen to the voicemail.

/var/lib/asterisk/scripts:

Usage:
voicemail_callback.sh <voicemailbox>

Requires that you add a line after each entry in Asterisk config voicemail.conf where you want the mailbox to get a callback, in the format
315 => 4513,Jim Doh,[email protected],[email protected]
callme = 5555555555,6666666666

TODO:

Allow for different contexts, as the config file does.
Right now, anyone with the same mailbox # will get called 🙂

get_phone_numbers()
{
if [ “x$1” != “x” ];then voicemailbox=”$1″; else return 1; fi
cfg_line=$(grep -A 1 “^$voicemailbox” “$VOICEMAIL_CFG”)
if ( echo “$cfg_line”|grep -E ‘callme\W*=\W*[[:digit:]]+’>/dev/null);then
phnum_list=$(echo “$cfg_line”|grep -E ‘callme = ‘|cut -d’=’ -f 2|sed -e ‘s/,/ /g’)
echo “$phnum_list”
else
return 1
fi
}

make_callfile()
{
if [ “x$1” != “x” ];then mailbox=”$1″; else return 1; fi
if [ “x$2” != “x” ];then phone_number=”$2″; else return 1; fi

note use of ‘-‘ in ‘-EOF1’ – Escapes tab at beginning of lines

CALLFILE=$(cat <<-EOF1
Channel: Zap/g1/$phone_number
MaxRetries: 2

Retry in 5 min

RetryTime: 300
WaitTime: 45

Context: feature-voicemail_callback
Extension: s
Priority: 1
SetVar: mailbox=$mailbox

EOF1)

echo “$CALLFILE” >> “$CALL_SPOOL_DIR”/$(date +%Y%m%d-%I%M%S)-$phone_number

}

CONSTANTS

ASTERISK_CFG=”/etc/asterisk”
VOICEMAIL_CFG=”$ASTERISK_CFG/voicemail.conf”
CALL_SPOOL_DIR=”/var/spool/asterisk/outgoing”

CALL_SPOOL_DIR=tst/
VOICEMAIL_CFG=”./asterisk/voicemail.conf”

*********MAIN*******************************************************

if [ “x$1” != “x” ];then voicemailbox=”$1″; else exit 1; fi

if ph_numbers=$(get_phone_numbers $voicemailbox) ;then
for ph_num in $ph_numbers; do
make_callfile “$voicemailbox” “$ph_num”
done
fi

In extensions.conf:

A macro that is used to call app_voicemail, and which calls the bash script to initiate the call out.


  [macro-leave_voicemail]
  ; Leave a voicemail message, then do post-processing.
  ;   o Call configured phones, with an announcement that a message
  ;      is waiting, and the option to listen to the voicemail(s)
  ;        ${ARG1} = u or b for 'unavailable' or 'busy' message
  ;        ${ARG2} = mailbox
  ;	 ${ARG3} = Call user flag
  ; USAGE:
  ;	exten => s,15,Macro(leave_voicemail,u,310,1)

  exten => s,1,ResponseTimeout(30)
  exten => s,2,Voicemail2(${ARG1}${ARG2})
  exten => s,3,GoToIf($[${ARG3} = 0]?s|5)
  exten => s,4,system(${SCRIPTS_DIR}/voicemail_callback.sh ${ARG2})
  exten => s,5,NoOp

  exten => h,1,GoToIf($[${ARG3} = 0]?h|3)
  exten => h,2,system(${SCRIPTS_DIR}/voicemail_callback.sh ${ARG2})
  exten => h,3,NoOp
  exten => t,1,GoToIf($[${ARG3} = 0]?t|3)
  exten => t,2,system(${SCRIPTS_DIR}/voicemail_callback.sh ${ARG2})
  exten => t,3,NoOp

Note that the h and t extensions may not be necessary… I used them for troubleshooting problems with call progress detection on FXO cards (More on that later… Down in ‘Please Note!’)

and…

The context that is connected to by the call file:

[feature-voicemail_callback]
exten => s,1,ResponseTimeout(2)
exten => s,2,Background(vm_callback-announcement)
exten => s,3,Background(vm_callback-options)
exten => t,1,Goto(s|2)

exten => 1,1,VoicemailMain2(s${mailbox})