How to play a complete prompt and do a CURL request at the backend?

Question

The callflow I want to build:

1. Play Welcome Prompt (5 seconds)
2. Do a CURL request to an API based on the callerId number
3. Based on the response of step 2, play another prompt or hangup the call

Problem

The Curl request may take upto 3 seconds of delay, I want to play the prompt and want to do a CURL request simultaneously, I have tried MOH, but the problem with MOH is that it stops playing the prompt when the CURL response is recieved. Actual callflow is:

exten => 1002,1,Progress()
exten => 1002,n,StartMusicOnHold(T1)
exten => 1002,n,Set(CURL_RESULT=${CURL(http://192.168.0.38/test.php?aparty=${CALLERID(num)})})
exten => 1002,n,NoOp(isSubscriber:${CURL_RESULT})
exten => 1002,n,GotoIf($["${CURL_RESULT}"!="0"]?lbl_call_hangup:)
exten => 1002,n,StopMusicOnHold(T1)
exten => 1002,n,Playback(welcome)
exten => 1002,n,Read(DTMF,,0,n,1,10)
exten => 1002,n,Hangup

What I want is to playing complete prompt and while playing the prompt, do the curl request at the backend. There is another solution we have tried which is to write a wrapper for this API call which returns immediately and another API call to get the result.

Here is what we built:

1. Do CURL request to wrapper which returns immediately
2. Play Welcome Prompt
3. Do CURL request to get the response of the initial request done in step 1
4. -do the rest of the things-

But the problem in this callflow is that the wrapper has to keep the request/response pair in memory, have to do alot of house keeping in case the call drops during step 2 etc.

Question

So is there a way in the dialplan to achieve playing of prompt and doing a curl request in the meanwhile.

PS: Using astersik 13.18.3

Answer 1

Can recommend you read book, for example ORelly's "Asterisk the future of telephony"

Possible solutions:

1) use dial and Local channel with 'm' param for hold music. In local context where you dial do curl

2) use AGI and "SET MUSIC ON/OFF"

3) use curl in background thread.

4) use Background app.

BTW, if call drop while dooing curl request anyway you get unpredictable result. You have care about that yourself(transaction,confirmation etc)