AngularJS : how to call service function from controller

Question

AngularJS : a web socket defines several functions inside a service. Do you know how to call these functions (onCLose, send, ...) from a controller ?? The controller is called when i click on a button. A error says "is not a function" about these 2 lines : $scope.websocket.send and $scope.websocket.onClose

<!DOCTYPE html><html>
<head>
<meta charset="UTF-8">
<script type="text/javascript" src="lib/angular.min.js"></script>
<script type="text/javascript" src="lib/angular-websocket.js"></script>
<script type="text/javascript">

var app = angular.module('myApp', ['ngWebSocket']);

app.service('WebSocketWrapper', ['$log', '$websocket', '$rootScope', function($log, $websocket, $rootScope){
    var ws = null;
    this.state = 'initializing';
    this.message = 'websocket initializing';
    var self = this;
    this.init = function(){
        if(!ws){
            ws = $websocket('ws://127.0.0.1:8080/WebSocketHome/echo', null, {reconnectIfNorNormalClose: true});

            ws.onClose(function(){
                console.info('close');
                $rootScope.$apply(function(){
                    self.state = 'disconnected';
                    self.message = 'Websocket disconnected';
                });
            });

            ws.onOpen(function(){
                console.info('connected');
                $rootScope.$apply(function(){
                    self.state = 'connected';
                    self.message = 'websocket connected';
                });
            });

            ws.onMessage(function(message){
                console.log("RECEIVED : " + message);
            });
        }
    };
}]);

app.controller('WebSocketStateCtrl', ['$scope', 'WebSocketWrapper', function($scope, WebSocketWrapper){
    $scope.websocket = WebSocketWrapper;
    $scope.websocket.init();
    $scope.sendMessage = function(){
        $scope.websocket.send($scope.name);
        $scope.websocket.onClose();
    }

}]);

</script>

</head>
<body>

    <div ng-app="myApp" ng-controller="WebSocketStateCtrl">
        <form action="">
            <input type="text" ng-model="name">
            <button ng-click="sendMessage()">SEND</button>
        </form>
    </div>

</body>
</html>

Vandesh · Accepted Answer · 2017-10-31 12:53:54Z

1

To get rid of the "is not a function" errors, you need to bind the ws object to the service object by using this.ws instead of var ws With this, you need not return any object from the service.
So, your service code would look like -

app.service('WebSocketWrapper', ['$log', '$websocket', '$rootScope', function($log, $websocket, $rootScope){
    this.ws = null; // Attach ws to service object
    this.state = 'initializing';
    this.message = 'websocket initializing';
    var self = this;
    this.init = function(){
        if(!this.ws){
            this.ws = $websocket('ws://127.0.0.1:8080/WebSocketHome/echo', null, {reconnectIfNorNormalClose: true});

            this.ws.onClose(function(){
                console.info('close');
                $rootScope.$apply(function(){
                    self.state = 'disconnected';
                    self.message = 'Websocket disconnected';
                });
            });

            this.ws.onOpen(function(){
                console.info('connected');
                $rootScope.$apply(function(){
                    self.state = 'connected';
                    self.message = 'websocket connected';
                });
            });

            this.ws.onMessage(function(message){
                console.log("RECEIVED : " + message);
            });
        }
    };
}]);

edited Oct 31, 2017 at 12:53

answered Oct 31, 2017 at 10:52

Vandesh

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10 Comments

Erixx Over a year ago

i added "return ws", but from inside the controller i get : "$scope.websocket.ws is undefined" and "$scope.websocket.onClose is not a function". Maybe there is another way to call onClose() from the controller ???

Vandesh Over a year ago

Intsead of var ws = null; try this.ws = null;

Vandesh Over a year ago

You need to use it everywhere in your service. Please check my updated answer.

Erixx Over a year ago

i made what you say, then i call the function onClose from the controller with : "$scope.websocket.ws.onClose()" => i have no more error message, but the onClose() method is not executed ! My original issue is this one : stackoverflow.com/questions/46979076/websocket-angularjs-client

Vandesh Over a year ago

Can you edit the original post with the updated code?

|

Erixx · Accepted Answer · 2017-10-31 15:33:46Z

I finally found the solution, thanks to Vandesh :

app.service('WebSocketWrapper', ['$log', '$websocket', '$rootScope', function($log, $websocket, $rootScope){
    this.ws = null; // Attach ws to service object
    this.state = 'initializing';
    this.message = 'websocket initializing';
    var self = this;
    this.init = function(){
        if(!this.ws){
            this.ws = $websocket('ws://127.0.0.1:8080/WebSocketHome/echo', null, {reconnectIfNorNormalClose: true});

            this.ws.onClose(function(){
                console.info('close');
                $rootScope.$apply(function(){
                    self.state = 'disconnected';
                    self.message = 'Websocket disconnected';
                });
            });

            this.ws.onOpen(function(){
                console.info('connected');
                $rootScope.$apply(function(){
                    self.state = 'connected';
                    self.message = 'websocket connected';
                });
            });

            this.ws.onMessage(function(message){
                console.log("RECEIVED : " + message);
            });
        }
    };
return this.ws;
}]);

app.controller('WebSocketStateCtrl', ['$scope', 'WebSocketWrapper', function($scope, WebSocketWrapper){
    $scope.websocket = WebSocketWrapper;
    $scope.websocket.init();
    $scope.sendMsg = function sendMsg() {
        $scope.websocket.ws.send($scope.name);
    }
}]);

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