Dealing with EventEmitter events in Meteor? - meteor

Question

I am trying to use an Asterisk Manager NPM module in Meteor, but am having difficulties with processing emitted events.
This NPM module establishes a permanent connection to Asterisk Manager and emits whatever Events it receives from Asterisk. I've managed to patch the code so that it runs in Meteor. It connects to Asterisk, emits events and I can log them to console, but once I try to do something with the data, like insert it into a collection, I receive the following error:
Error: Meteor code must always run within a Fiber. Try wrapping callbacks that you pass to non-Meteor libraries with Meteor.bindEnvironment.
How do I overcome that? Thank you.
server side code:
var ami = new AsteriskManager( { username: 'meteor', password: '123456' } );
ami.on('ami_data', function(data){
console.log(data); // <- this works fine
// the following causes the error
EventsLog.insert({ timestamp: (new Date()).getTime(),
data: data});
});
ami.connect(function(){});//creates a socket connection and sends the login action
the patched npm module code:
var util = Npm.require('util');
var events = Npm.require('events').EventEmitter;
var net = Npm.require('net');
var AsteriskConstructor = function AsteriskManager(params){
params = params || {};
this.net = net;
this.CRLF = "\r\n";
this.END = "\r\n\r\n";
this.buffer = "";
this.port = params.port || 5038;
this.host = params.host || 'localhost';
this.username = params.username || 'username';
this.password = params.password || 'password';
this.enable_debug = params.debug || false;
this.reconnect = params.reconnect || false;
this.reconnect_after = params.reconnect_after || 3000;
this.events = (params.events != undefined ? params.events : true);
this.identifier = params.identifier || false;
this.ami_encoding = params.ami_encoding || 'ascii';
};
AsteriskManager = AsteriskConstructor;
util.inherits(AsteriskManager, events);
AsteriskManager.prototype.connect = function(connect_cb, data_cb){
var self = this;
self.debug('running ami connect');
self.socket = null;
self.socket = this.net.createConnection(this.port, this.host);//reopen it
self.socket.setEncoding(this.ami_encoding);
self.socket.setKeepAlive(true, 500);
self.socket.on('connect', function(){
self.debug('connected to Asterisk AMI');
//login to the manager interface
self.send({Action: 'login', Username : self.username, Secret : self.password, Events: (self.events ? 'on' : 'off')});
if(connect_cb && typeof connect_cb == 'function'){
connect_cb();
}
}).on('data', function(data){
if(data_cb && typeof data_cb == 'function'){
data_cb(data);
}
var all_events = self.processData(data);
for(var i in all_events){
var result = all_events[i];
if(result.response && result.message && /Authentication/gi.exec(result.message) == 'Authentication'){
self.emit('ami_login', ((result.response == 'Success') ? true : false) ,result);
}
self.emit('ami_data', result);
}
}).on('drain', function(){
self.debug('Asterisk Socket connection drained');
self.emit('ami_socket_drain');
}).on('error', function(error){
if(error){
self.debug('Asterisk Socket connection error, error was: ' + error);//prob lost connection to ami due to asterisk restarting so restart the connection
}
self.emit('ami_socket_error', error);
}).on('timeout',function(){
self.debug('Asterisk Socket connection has timed out');
self.emit('ami_socket_timeout');
}).on('end', function() {
self.debug('Asterisk Socket connection ran end event');
self.emit('ami_socket_end');
}).on('close', function(had_error){
self.debug('Asterisk Socket connection closed, error status - ' + had_error);
self.emit('ami_socket_close', had_error);
if(self.reconnect){
self.debug('Reconnecting to AMI in ' + self.reconnect_after);
setTimeout(function() {
self.connect(connect_cb, data_cb);
}, self.reconnect_after);
}
});
}
AsteriskManager.prototype.disconnect = function(){
this.reconnect = false;//just in case we wanted it to reconnect before, we've asked for it to be closed this time so make sure it doesnt reconnect
this.socket.end(this.generateSocketData({Action: 'Logoff'}));
}
AsteriskManager.prototype.destroy = function(){
this.socket.destroy();
}
AsteriskManager.prototype.processData = function(data, cb){
/*
Thanks to mscdex for this bit of code that takes many lots of data and sorts them out into one if needed!
https://github.com/mscdex/node-asterisk/blob/master/asterisk.js
*/
data = data.toString();
if (data.substr(0, 21) == "Asterisk Call Manager"){
data = data.substr(data.indexOf(this.CRLF)+2); // skip the server greeting when first connecting
}
this.buffer += data;
var iDelim, info, headers, kv, type, all_events = [];
while ((iDelim = this.buffer.indexOf(this.END)) > -1) {
info = this.buffer.substring(0, iDelim+2).split(this.CRLF);
this.buffer = this.buffer.substr(iDelim + 4);
result = {}; type = ""; kv = [];
for (var i=0,len=info.length; i<len; i++) {
if (info[i].indexOf(": ") == -1){
continue;
}
kv = info[i].split(": ", 2);
kv[0] = kv[0].toLowerCase().replace("-", "");
if (i==0){
type = kv[0];
}
result[kv[0]] = kv[1];
}
if(this.identifier){
result.identifier = this.identifier;
}
all_events.push(result);
}
return all_events;
}
AsteriskManager.prototype.debug = function(data){
if(this.enable_debug){
console.log(data);
}
}
AsteriskManager.prototype.generateRandom = function(){
return Math.floor(Math.random()*100000000000000000);
}
AsteriskManager.prototype.generateSocketData = function(obj){
var str = '';
for(var i in obj){
str += (i + ': ' + obj[i] + this.CRLF);
}
return str + this.CRLF;
}
AsteriskManager.prototype.send = function(obj, cb) {
//check state of connection here, if not up then bail out
if(!obj.ActionID){
obj.ActionID = this.generateRandom();
}
//maybe i should be checking if this socket is writeable
if(this.socket != null && this.socket.writable){
this.debug(obj);
this.socket.write(this.generateSocketData(obj), this.ami_encoding, cb);
}else{
this.debug('cannot write to Asterisk Socket');
this.emit('ami_socket_unwritable');
}
}

Answer 1

As the error message says "Try wrapping callbacks that you pass to non-Meteor libraries with Meteor.bindEnvironment"
ami.on('ami_data', Meteor.bindEnvironment( function(data){
console.log(data); // <- this works fine
// the following causes the error
EventsLog.insert({ timestamp: (new Date()).getTime(),
data: data});
}, function( error) { console.log( error);})
);
There are a lot of other examples around.
If the server code above is not in a Fiber you might get "Meteor code must always run within a Fiber" error.