Welcome!

Apache Authors: Liz McMillan, Pat Romanski, Elizabeth White, Christopher Harrold, Janakiram MSV

Related Topics: Machine Learning , Java IoT, PowerBuilder, Microsoft Cloud, Agile Computing, Apache

Machine Learning : Blog Feed Post

Building a Simple Peer-to-Peer WebSocket App – Part 2

A Step-by-Step Tutorial

<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
        <title>Kaazing WebSocket Tutorial - JMS</title>
        <script src="http://demo.kaazing.com/lib/client/javascript/StompJms.js" type="text/javascript" language="javascript"></script>
    </head>
    <body onload="doConnect()">
        <div id="logMsgs"></div>
    </body>
</html>

 

Line 05: References the Kaazing WebSocket client libraries that ensure that communication between any Web browser and the WebSocket server is seamless, even if the browser doesn’t natively support the WebSocket API and protocol.
Line 07: Invokes the doConnect() function after the contents of the page is loaded.
Line 08: Defines a div tag that will contain the log messages. At the moment, we just have a completely empty HTML page, so there’s nothing exciting to see yet.

Let’s move on to the JavaScript code. While walking through the JavaScript code, we’ll see the power of messaging. One of the key differentiators that sets the Kaazing WebSocket Gateway apart from other WebSocket servers is its extensive support for rich business protocols and messaging APIs on top of the WebSocket standard, including XMPP, JMS, and AMQP. This tutorial focuses on the most widely used messaging API: Java Message Service (JMS).

JMS is a messaging standard that allows the loose coupling of applications by creating, sending, receiving, and reading messages. The Kaazing JMS offering extends the reach of enterprise messaging applications to the Web by providing JMS APIs in various client technologies, including Java, JavaScript, Microsoft .NET/Silverlight, as well as Flash/Flex. In this tutorial, we focus on the JavaScript JMS APIs and how you can use JMS in modern HTML5 applications.

The following code shows a simple example of a JavaScript application that uses Kaazing’s JMS APIs. Take a look at the code, then the explanations below the code snippet.

 

// Variables you can change
//
var MY_WEBSOCKET_URL = "ws://tutorial.kaazing.com/jms";
var TOPIC_NAME = "/topic/myTopic";
var IN_DEBUG_MODE = true;
var DEBUG_TO_SCREEN = true;

// WebSocket and JMS variables
//
var connection;
var session;
var wsUrl;

// JSFiddle-specific variables
//
var runningOnJSFiddle = (window.location.hostname === "fiddle.jshell.net");
var WEBSOCKET_URL = (runningOnJSFiddle ? MY_WEBSOCKET_URL : "ws://" + window.location.hostname + ":" + window.location.port + "/jms");

// Variable for log messages
//
var screenMsg = "";

// Used for development and debugging. All logging can be turned
// off by modifying this function.
//
var consoleLog = function(text) {
    if (IN_DEBUG_MODE) {
        if (runningOnJSFiddle || DEBUG_TO_SCREEN) {
            // Logging to the screen
            screenMsg = screenMsg + text + "
";
            $("#logMsgs").html(screenMsg);
        } else {
            // Logging to the browser console
            console.log(text);
        }
    }
};

var handleException = function (e) {
    consoleLog("EXCEPTION: " + e);
};

// Connecting...
//
var doConnect = function() {
    // Connect to JMS, create a session and start it.
    //
    var stompConnectionFactory = new StompConnectionFactory(WEBSOCKET_URL);
    try {
        var connectionFuture = stompConnectionFactory.createConnection(function() {
            if (!connectionFuture.exception) {
                try {
                    connection = connectionFuture.getValue();
                    connection.setExceptionListener(handleException);

                    consoleLog("Connected to " + WEBSOCKET_URL);
                    session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
                    connection.start(function() {
                        // Put any callback logic here.
                        //
                        consoleLog("JMS session created");
                    });
                } catch (e) {
                    handleException(e);
                }
            } else {
                handleException(connectionFuture.exception);
            }
        });
    } catch (e) {
        handleException(e);
    }
};
​

 

At the top of this code snippet, you can see variables that you can change.

Line 03: MY_WEBSOCKET_URL points to the WebSocket server, which in our case runs on tutorial.kaazing.com. JMS, being a messaging API, follows the publish/subscribe pattern.

Line 04: A topic in JMS is a distribution mechanism for publishing messages that are delivered to multiple subscribers. Our topic is called /topic/myTopic. You can, and probably should change the name of the topic to your liking to ensure nobody else is interfering with your experimentation. For example:

 

var TOPIC_NAME = "/topic/PeterTopic";

 

Lines 05-06: The IN_DEBUG_MODE and DEBUG_TO_SCREEN variables give you simple ways to control debugging. By default, debugging is enabled and is directed to the screen.

Lines 16-17: If the app is running outside of the context of JSFiddle, the WebSocket URL is constructed dynamically, pointing back to the same server where the HTML page was downloaded from.

Line 21: The screenMsg variable holds the log messages.
Note: When this variable grows big, the performance of the application may degrade significantly. If you’re seeing increased latency, disabling logging of the application often helps.

Line 26: The consoleLog() function is used for logging. It honors the preferences set through the logging variables, specified in lines 05-06.

Line 45: The doConnect() function is in charge of establishing the WebSocket connection.

Line 48: Next, we create a StompConnectionFactory, allowing us to create a connection with a JMS provider via a WebSocket connection.

Line 50: Then, we create a connection, where ConnectionFuture handles the returned result.

Line 57: Finally, we create a session. Optionally, you can use sessions to handle transactions. This tutorial doesn’t use transactions.

When you run this code, the Result pane in the bottom right displays the following log messages:

 

Connected to ws://tutorial.kaazing.com/jms
JMS session created

 

In Part 3 (coming soon), we will evolve our application.


Read the original blog entry...

More Stories By Kaazing Blog

Kaazing is helping define the future of the event-driven enterprise by accelerating the Web for the Internet of Things.

@ThingsExpo Stories
SYS-CON Events announced today that HTBase will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. HTBase (Gartner 2016 Cool Vendor) delivers a Composable IT infrastructure solution architected for agility and increased efficiency. It turns compute, storage, and fabric into fluid pools of resources that are easily composed and re-composed to meet each application’s needs. With HTBase, companies can quickly prov...
SYS-CON Events announced today that Linux Academy, the foremost online Linux and cloud training platform and community, will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Linux Academy was founded on the belief that providing high-quality, in-depth training should be available at an affordable price. Industry leaders in quality training, provided services, and student certification passes, its goal is to c...
SYS-CON Events announced today that SoftLayer, an IBM Company, has been named “Gold Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2016, at the Javits Center in New York, New York. SoftLayer, an IBM Company, provides cloud infrastructure as a service from a growing number of data centers and network points of presence around the world. SoftLayer’s customers range from Web startups to global enterprises.
In his session at @ThingsExpo, Eric Lachapelle, CEO of the Professional Evaluation and Certification Board (PECB), will provide an overview of various initiatives to certifiy the security of connected devices and future trends in ensuring public trust of IoT. Eric Lachapelle is the Chief Executive Officer of the Professional Evaluation and Certification Board (PECB), an international certification body. His role is to help companies and individuals to achieve professional, accredited and worldw...
SYS-CON Events announced today that Technologic Systems Inc., an embedded systems solutions company, will exhibit at SYS-CON's @ThingsExpo, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Technologic Systems is an embedded systems company with headquarters in Fountain Hills, Arizona. They have been in business for 32 years, helping more than 8,000 OEM customers and building over a hundred COTS products that have never been discontinued. Technologic Systems’ pr...
SYS-CON Events announced today that Auditwerx will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Auditwerx specializes in SOC 1, SOC 2, and SOC 3 attestation services throughout the U.S. and Canada. As a division of Carr, Riggs & Ingram (CRI), one of the top 20 largest CPA firms nationally, you can expect the resources, skills, and experience of a much larger firm combined with the accessibility and attent...
SYS-CON Events announced today that CA Technologies has been named “Platinum Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY, and the 21st International Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. CA Technologies helps customers succeed in a future where every business – from apparel to energy – is being rewritten by software. From ...
With major technology companies and startups seriously embracing Cloud strategies, now is the perfect time to attend @CloudExpo | @ThingsExpo, June 6-8, 2017, at the Javits Center in New York City, NY and October 31 - November 2, 2017, Santa Clara Convention Center, CA. Learn what is going on, contribute to the discussions, and ensure that your enterprise is on the right path to Digital Transformation.
SYS-CON Events announced today that Loom Systems will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Founded in 2015, Loom Systems delivers an advanced AI solution to predict and prevent problems in the digital business. Loom stands alone in the industry as an AI analysis platform requiring no prior math knowledge from operators, leveraging the existing staff to succeed in the digital era. With offices in S...
SYS-CON Events announced today that T-Mobile will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. As America's Un-carrier, T-Mobile US, Inc., is redefining the way consumers and businesses buy wireless services through leading product and service innovation. The Company's advanced nationwide 4G LTE network delivers outstanding wireless experiences to 67.4 million customers who are unwilling to compromise on ...
SYS-CON Events announced today that Infranics will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Since 2000, Infranics has developed SysMaster Suite, which is required for the stable and efficient management of ICT infrastructure. The ICT management solution developed and provided by Infranics continues to add intelligence to the ICT infrastructure through the IMC (Infra Management Cycle) based on mathemat...
SYS-CON Events announced today that Interoute, owner-operator of one of Europe's largest networks and a global cloud services platform, has been named “Bronze Sponsor” of SYS-CON's 20th Cloud Expo, which will take place on June 6-8, 2017 at the Javits Center in New York, New York. Interoute is the owner-operator of one of Europe's largest networks and a global cloud services platform which encompasses 12 data centers, 14 virtual data centers and 31 colocation centers, with connections to 195 add...
SYS-CON Events announced today that Cloudistics, an on-premises cloud computing company, has been named “Bronze Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Cloudistics delivers a complete public cloud experience with composable on-premises infrastructures to medium and large enterprises. Its software-defined technology natively converges network, storage, compute, virtualization, and management into a ...
SYS-CON Events announced today that SD Times | BZ Media has been named “Media Sponsor” of SYS-CON's 20th International Cloud Expo, which will take place on June 6–8, 2017, at the Javits Center in New York City, NY. BZ Media LLC is a high-tech media company that produces technical conferences and expositions, and publishes a magazine, newsletters and websites in the software development, SharePoint, mobile development and commercial UAV markets.
"I think that everyone recognizes that for IoT to really realize its full potential and value that it is about creating ecosystems and marketplaces and that no single vendor is able to support what is required," explained Esmeralda Swartz, VP, Marketing Enterprise and Cloud at Ericsson, in this SYS-CON.tv interview at @ThingsExpo, held June 7-9, 2016, at the Javits Center in New York City, NY.
Why do your mobile transformations need to happen today? Mobile is the strategy that enterprise transformation centers on to drive customer engagement. In his general session at @ThingsExpo, Roger Woods, Director, Mobile Product & Strategy – Adobe Marketing Cloud, covered key IoT and mobile trends that are forcing mobile transformation, key components of a solid mobile strategy and explored how brands are effectively driving mobile change throughout the enterprise.
My team embarked on building a data lake for our sales and marketing data to better understand customer journeys. This required building a hybrid data pipeline to connect our cloud CRM with the new Hadoop Data Lake. One challenge is that IT was not in a position to provide support until we proved value and marketing did not have the experience, so we embarked on the journey ourselves within the product marketing team for our line of business within Progress. In his session at @BigDataExpo, Sum...
Keeping pace with advancements in software delivery processes and tooling is taxing even for the most proficient organizations. Point tools, platforms, open source and the increasing adoption of private and public cloud services requires strong engineering rigor - all in the face of developer demands to use the tools of choice. As Agile has settled in as a mainstream practice, now DevOps has emerged as the next wave to improve software delivery speed and output. To make DevOps work, organization...
SYS-CON Events announced today that MobiDev, a client-oriented software development company, will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place June 6-8, 2017, at the Javits Center in New York City, NY, and the 21st International Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. MobiDev is a software company that develops and delivers turn-key mobile apps, websites, web services, and complex softw...
DevOps is often described as a combination of technology and culture. Without both, DevOps isn't complete. However, applying the culture to outdated technology is a recipe for disaster; as response times grow and connections between teams are delayed by technology, the culture will die. A Nutanix Enterprise Cloud has many benefits that provide the needed base for a true DevOps paradigm.