Improve this AngularJS factory to use with socket.io

Question

I want to use socket.io in AngularJS. I found the following factory:

app.factory(\'socket\', function ($rootScope) {
    var socket = io.connect();
    retur         


        

Answer 1

I tried different ways but nothing worked as expected. In my app I'm using a socket factory in both the MainController and a GameController. When the user switches to a different view I only want to remove the duplicates events generated by the GameController and leave the MainController running so I cannot use a removeAllListeners function. Instead I discovered a better way to just avoid creating duplicates inside my socket factory:

app.factory('socket', function ($rootScope) {
  var socket = io.connect();

  function on(eventName, callback) {
    socket.on(eventName, function () {
      var args = arguments;

      $rootScope.$apply(function () {
        callback.apply(socket, args);
      });
    });

    // Remove duplicate listeners
    socket.removeListener(eventName, callback);
  }

  function emit(eventName, data, callback) {
    socket.emit(eventName, data, function () {
      var args = arguments;

      $rootScope.$apply(function () {
        if (callback) {
          callback.apply(socket, args);
        }
      });
    });

    // Remove duplicate listeners
    socket.removeListener(eventName, callback);
  }

  return {
    on: on,
    emit: emit
  };
}

Answer 2

I tried with the above code in my AngularApp and found the events duplicating. With the same Example from @pootzko using the SocketIoFactory

I have added a unSubscribe(even_name) inside the $destroy of the Controller, that will remove/clear the socketEventListner

var app = angular.module("app", []);
..
..
..
//Create a SocketIoFactory
app.service('SocketIoFactory', function($rootScope){

    console.log("SocketIoFactory....");
    //Creating connection with server
    var protocol = 'ws:',//window.location.protocol,
        host = window.location.host,
        port = 80,
        socket = null;
    var nodePath = protocol+'//'+host+':'+port+'/';

    function listenerExists(eventName) {
        return socket.hasOwnProperty("$events") && socket.$events.hasOwnProperty(eventName);
    }

    return {
        connect: function () {
            socket = io.connect(nodePath);
            console.log('SOCKET CONNECTION ... ',nodePath);
        },
        connected: function () {
            return socket != null;
        },
        on: function (eventName, callback) {
            if (!listenerExists(eventName)) {
                socket.on(eventName, function () {
                    var args = arguments;
                    $rootScope.$apply(function () {
                        callback.apply(socket, args);
                    });
                });
            }
        },
        emit: function (eventName, data, callback) {
            socket.emit(eventName, data, function () {
                var args = arguments;
                $rootScope.$apply(function () {
                    if (callback) {
                        callback.apply(socket, args);
                    }
                });
            })
        },
        unSubscribe: function(listener) {
            socket.removeAllListeners(listener);
        }
    };
});

..
..
..

//Use in a controller
app.controller("homeControl", ['$scope', 'SocketIoFactory', function ($scope, SocketIoFactory) {

  //Bind the events
  SocketIoFactory.on('<event_name>', function (data) {

  });

  //On destroy remove the eventListner on socketConnection
   $scope.$on('$destroy', function (event) {
        console.log('[homeControl] destroy...');
        SocketIoFactory.unSubscribe('<event_name>');
    });
}]);

Answer 3

I use something like the code below. socketsService is only instantiated once and I believe Angular takes care of GC the $on's

If you don't like $broadcast/$on, there are some slightly more solid Message Bus implementations for Angular available...

app.service('socketsService', ['$rootScope', function ($rootScope) {
    var socket = window.io.connect();

    socket.on('info', function(data) {
        $rootScope.$broadcast("info_received", data);
    });

    socket.emit('ready', "Hello");
}]);

app.controller("infoController",['$scope',
    function ($scope) {
        $scope.$root.$on("info_received", function(e,data){
            console.log(data);
        });
        //...
    }]);

app.run(
    ['socketsService',
        function (socketsService) {
        //...
    }]);

Answer 4

Instead of doing app.factory, create a service (singleton) like so:

var service = angular.module('socketService', []);
service.factory('$socket', function() {
    // Your factory logic
});

You can then simply inject the service to your app and use it in controllers as you would $rootScope.

Here is a more complete example of how I have this set up:

// App module
var app = angular.module('app', ['app.services']);

// services
var services = angular.module('app.services', []);

// Socket service
services.factory('$socket', ['$rootScope', function(rootScope) {

    // Factory logic here

}]);

// Controller
app.controller('someController', ['$scope', '$socket', function(scope, socket) {

    // Controller logic here

}]);

Answer 5

I was having the exact same problem of duplicate events after a browser refresh. I was using a 'factory', but switched to use a 'service'. Here's my socket.io wrapper:

myApp.service('mysocketio',['$rootScope', function($rootScope)
{
    var socket = io.connect();

    return {

        on: function(eventName, callback )
        {
            socket.on(eventName, function()
            {
                var args=arguments;
                $rootScope.$apply(function()
                {
                    callback.apply(socket,args);
                });
            });
        },

        emit: function(eventName,data,callback)
        {
            socket.emit(eventName,data,function()
            {
                var args=arguments;
                $rootScope.$apply(function()
                {
                    if(callback)
                    {
                        callback.apply(socket,args);
                    }
                });
            });
        }
    }

}]);

I use this service inside my controller and listen for events:

myApp.controller('myController', ['mysocketio', function(mysocketio)
{
    mysocketio.on( 'myevent', function(msg)
    {
        console.log('received event: ' + msg );
    }
}]);

Once I switched from using a factory to using a service, I don't receive duplicates after a browser refresh.

Answer 6

create function in your service or factory like below.

unSubscribe: function(listener) {
    socket.removeAllListeners(listener);
}

and then call in your controller under the "$destroy" event like below.

$scope.$on('$destroy', function() {
    yourServiceName.unSubscribe('eventName');
});

that's solve