Exiting in node.js after recursive function is done

Question

I try to rewire my brain for async coding and I still I still seem to fail. Unfortunately I can't figure out how to do it properly in this case. Let me give an example:

var nconf = require('nconf');

 nconf.argv()
 .env();

 function runme(callback){
   var nummessages = nconf.get('SMS_MESSAGES');
   decodemessage(0, nummessages);
   callback();
 }

 function decodemessage(i, nummessages) {
  if( i < nummessages ) {
    var message = 'SMS_'+(i+1)+'_TEXT';
    var number = 'SMS_'+(i+1)+'_NUMBER';
    console.log('number: '+number);
    console.log('message: '+message);
    console.log('message text: '+ nconf.get(message));
    console.log('message number: '+ nconf.get(number));
    decodemessage(i+1);
  }
} 

runme(function(){
  process.exit(0);
});

This gets called by gammu-smsd which receives SMS messages and puts them into ENV vars and launches a script. This works fine as long as I run it on my own, return code seems to work as well. When I run it from gammu-smsd it fails and it looks like decodemessage is never executed. Some debug output shows that I do go into runme().

My guess is that the callback in runme() gets executed before the recursive decodemessage() call is done. Am I right and if so can someone explain how I can do that properly?

If you want to test run it like this:

node server.js --SMS_MESSAGES 2 --SMS_1_TEXT blabliblo --SMS_1_NUMBER=47796546546 --SMS_2_TEXT Iammessagetwo --SMS_2_NUMBER 12345678

Thanks

No, not if the recursive decodemessage is synchronous. Actually, where is the async part that requires the use of a callback at all? — Bergi
– Bergi, Commented Nov 7, 2012 at 11:28
I'm not sure if I understand you correctly, all I want to assure with the callback is that when everything is done and the recursion returns my script exists with 0. — Adrian Gschwend
– Adrian Gschwend, Commented Nov 7, 2012 at 13:47
Javascript execution is single-threaded. So if you don't have any asynchronous stuff, you should just use a normal for-loop and place the process.exit(0) statement right after it. If you have async stuff, show it to us (there is none in your example code)! — Bergi
– Bergi, Commented Nov 7, 2012 at 13:56
ok I see what you mean. I now did a for-loop edition and while it works in the test it does not from gammu-sms, again it doesn't enter the loop. So I have some weird problem I have to figure out, will report back. I will post data via request later so this will be async. — Adrian Gschwend
– Adrian Gschwend, Commented Nov 7, 2012 at 15:24

Bergi · Accepted Answer · 2012-11-07 11:26:36Z

2

Seems like you forgot to pass on the nummessages in your recursive call:

decodemessage(i+1, nummessages);

That's why I personally mostly loop backwards (to zero) when using recursion.

answered Nov 7, 2012 at 11:26

Bergi

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2 Comments

Adrian Gschwend Over a year ago

Tnx that's correct, I had a closure before that's why I forgot to add it. However this does not seem to fix the problem, it still doesn't go into decodemessage when I launch it from gammu-smsd.

Adrian Gschwend Over a year ago

I close this one, I'm pretty sure gammu-smsd does something wrong and the code was correct. Thanks for the hints guys.

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