example.html

<!DOCTYPE html>
    <html>
    <head></head>
    <body>
        <h3>Websocket Client</h3>
        <div id='content'></div>

        <script type='text/javascript' src="./src/ws.js"></script>
        <script type='text/javascript'>

        var API_KEY = '<your_api_key_here>';

        // got websocket
        if (!PrintNode.WebSocket.isSupported()) {

            // once a websocket is authenticated you can register
            function authenticated (authData) {
                if (authData.error) {
                    // most likely not authenticated, see authData.error for more detail
                    return;
                }
                // authData will contain information about accountId, permissions, and maxSubscriptions

                // ok, now make some requests to the server to get data you're interested in
                // pass in optional second argument to have this called when server publishes a event
                // but you can also use the event emitter
                this.getScales({}, function (measurement) {
                    // this is only meaningful if the websocket is running on the same machine
                    // as the running PrintNode client
                    console.log("scales data by subscription callback", measurement);
                    console.log("scales latency %dms", measurement.getLatency());
                });

            }

            // error callback fired if anything goes wrong including
            //  - exceptions thrown by subscription callbacks
            //  - network issues which cause socket to fail or any timeouts
            //  - errors in printnode server or client libs
            function errorCallback (err, data) {
                console.log("Error!", err, data);
            }

            // instantiate a new
            var ws = new PrintNode.WebSocket(
                {apiKey: API_KEY},
                authenticated,
                errorCallback
            );

            // subscribe to all computer events
            ws.subscribe("computer", function computerEvent (something, info) {
                // lots of things could come in on this event
                // for now we're only interested in scalesMeasurements
                if (something instanceof PrintNode.ScalesMeasurement) {
                    console.log("scales data by computer subscription", something);
                }
            });

            // subscribe to all scales events
            ws.subscribe("scales", function computerEvent (measurement) {
                console.log("scales data by scales subscription", measurement);
            });

            // debugging
            ws.subscribe('system.state', function stateChange (newState) {
                console.log("newState", newState);
            });

        // TODO fallback to polling
        } else {

            var httpOptions = {
                success: function (responseBody, repsonse) {
                    console.log("success", response);
                },
                error: function (responseBody, repsonse) {
                    console.log(response);
                },
                complete: function (response) {
                    console.log(
                        "%d %s %s returned %db in %dms",
                        response.xhr.status,
                        response.reqMethod,
                        response.reqUrl,
                        response.xhr.responseText.length,
                        response.getDuration()
                    );
                },
                timeout: function (url, duration) {
                    console.log("%s timeout %d", url, duration);
                }
            };

            var http = new PrintNode.HTTP(
                new PrintNode.HTTP.ApiKey(API_KEY),
                httpOptions
            );

            http.scales(
                {success: function (response) {
                    console.log("success from callback", response);
                }},
                {computerId: 0}
            ).then(
                function (response, info ) {
                    console.log("success from promise", response);
                },
                function (err) {
                    throw "simulated exception in a promise callback";
                }
            // If your promise callbacks start throw[ing] you can 'catch' this in the returned
            // promise from .then() but this is getting pretty meta right here.
            // Callbacks really shouldn't throw exceptions in async code like this.
            ).then(null, console.log.bind(console, "promise callbacks threw error;"));

        }

        </script>
    </body>
</html>