Welcome!

Java Authors: Pat Romanski, Elizabeth White, Liz McMillan, Jason Bloomberg, Trevor Parsons

Related Topics: Java

Java: Article

Building an Instant Messaging Application Using Jabber/XMPP

An adventure with Smack and Wildfire

This article will describe our experiences with developing a Java-based instant messenger application using Jabber/XMPP (Extensible Messaging and Presence Protocol) - a free, open and public protocol and technology for instant messaging. According to the Jabber Software Foundation, "Under the hood, Jabber is a set of streaming XML protocols and technologies that enable any two entities on the Internet to exchange messages, presence, and other structured information in close to real-time."

Google Talk uses the standard Jabber/XMPP protocol for authenticating, presence, and messaging. But using Jabber goes beyond instant messaging to almost real-time server-to-server communication.

This article will describe the Jabber/XMPP protocol for messaging, the Jabber/XMPP client program based on JFace and Eclipse, and the Jabber/XMPP Java server. These will be illustrated through Open Source Smack and the Wildfire Server 2.4.4. It will offer examples of a login-class plug-in for custom authentication, a plug-in and server extension for custom messages, and a server-side extension for database interactions. Each example will contain the XML messages, client-side code, and server-side code.

What's Different About Jabber?
Compared to traditional IM programs, Jabber:

  1. Is an XML-based messaging protocol that is open and extensible
  2. It lets you build custom client IM applications. We'll talk about Smack, a project based on JFace and Eclipse that provides tools for building custom client applications
  3. It lets you extend the functionality of the server to process custom messages by writing server-side plug-ins. We'll describe the plug-in architecture of the Wildfire Server
What Are the Basic Features of Instant Messaging?
Any instant messaging system will have these basic features: It connects to server, registers new users, logs in, gets presence information, exchanges messages, and does custom interactions (VoIP, Web conferencing, etc.). Below each of these IM features are described using XMPP:

  • Connect to Server - This is done through a XML stream header exchange. The client sends:

    <stream to='192.168.0.12:5222' xmlns='jabber:client'/>

    The client receives:

    <stream id='xxxx' from:'192.168.0.12:5222' xmlns='jabber:
    client'/>

  • Register - The client sends a message to discover the server's requirements for registration:

    <iq type='get' id='reg1' to='192.168.0.12:5222'><query xmlns='jabber:iq:register'/></iq>

    The server responds with a message that lists the fields required for registration:

    <iq type='result' id='reg1'> <query xmlns='jabber:iq:register'>
          <instructions>

    Choose a username and password for use with this service.
    Please also provide your email address.        </instructions>
         <username/>
         <password/>
         <email/>
       </query></iq>

    The client responds by sending the requested information:

    <iq type='set' id='reg2'>
       <query xmlns='jabber:iq:register'>
         <username>a3</username>
         <password>password</password>
         <email>[email protected]</email>
       </query>
    </iq>

    On successful registration, the server responds:

    <iq type='result' id='reg2'/>

    Declare Presence and Get Presence Information
    To declare presence information, the client sends:

    <presence xmlns="" id="d6vNV-3" from="mahaveerj@sow/1139352545625"/>

    Note the "to" attribute isn't required in the above message because the client knows which server it's talking to.

    To get presence information, client sends:

    <iq xmlns="" id="d6vNV-2" type="get" from="mahaveerj@sow/1139352545625">
    <query xmlns="jabber:iq:roster"/>
    </iq>

    The server responds with presence data about two people in the roster:

    <iq xmlns="" type="result" id="d6vNV-2" to="mahaveerj@sow/1139352545625">
       <query xmlns="jabber:iq:roster">
          <item jid="jorge@sow" name="Jorge" subscription="both"></item>
          <item jid="bruce@sow" name="Dr. Bruce" subscription="both"></item>
       </query></iq>

    Exchange Messages
    User a1 sends message to user a2:

    <message xmlns="" id="H49LH-12" to="a1@sow" type="chat" from="a2 @sow/1139385809707">
         <body>Good Morning, I am testing chat in Jabber Client.</body>
    </message>

    The elements above form the core of XMPP (Extensible Messaging and Presence Protocol) XML syntax. It also gives you a sense of the flow of XML messages between the client and server to accomplish a task.

    Jabber/XMPP Client and Server
    Since Jabber/XMPP is an open protocol scores of implementations have been created for the client and server, some Open Source and others commercial. There are literally hundreds of Jabber clients available. (See References.)

    In this article we'll use the Smack library (www.jivesoftware.org/smack/) to illustrate client-side functionality. Smack provides an API for implementing the GUI and managing XML data. Managing XML data involves creating XML messages, sending the messages, receiving messages from the server, and processing the incoming messages.

    We'll use the Wildfire Server (www.jivesoftware.org/wildfire/) for illustrating creating server-side plug-ins. For basic IM needs, no server-side programming is required. For other needs Wildfire provides a plug-in architecture for extending the server's functionality. We'll look next at a use case to illustrate how custom messages can be created and processed at both the client and server.

    Use Case 1: Custom Authentication and Custom Queries
    Consider a case in which an IM client and a Web portal are part of a suite of collaboration applications. The Web portal has database-driven MD5-based authentication and the requirement is that IM client use the portal's authentication service. This will allow users to log in to IM and then launch applications on the portal from the IM client without logging into the portal.

    Part A: Custom Authentication
    The Wildfire Server uses the DefaultAuthProvider class to authenticate users and DefaultUserProvider to get user information. These use the database tables Wildfire provides.

    If you want to use a custom authentication method you'll have to change the user and authentication provider in wildfire.xml.

    <provider>
    <user> <className>org.indent.wildfire.user.SOWUserProvider</className> </user>
    <auth><className>org.indent.wildfire.auth.SOWAuthProvider</className> </auth>
    </provider>

    The simple extension defined in Listing 1 uses custom tables and custom encryption methods. The SOWUserProvider class is for user info and SOWAuthProvider is for authentication.

    The two static variables shown define the database authentication strings. And if custom encryption is used then the encryptPassword() method provides the encryption logic.

    Part B: Retrieving a Token from the Database
    In this use case, after authenticating, the client is going to ask the database for an encrypted token that uniquely identifies the client. This token is later used to launch applications in the Web portal without explicitly logging into the portal. The steps are:
    a)  The client generates a custom message to request a token
    b)  The server gets the message and processes the request by getting a token from the database. The server generates a reply message that contains the token and sends it to the requesting client
    c)  The client gets the message and extracts the token

    This process is illustrated in Figure 1.

    Client to Server
    The client generates a <iq> packet that looks like:

    <iq to="serverName" type="get"><query xmlns="jabber:iq:token"/></iq>

    jabber:iq:token is a namespace for our custom query. This message is generated at the client using the following code:

           XMPPConnection connection = session.getConnection();
           ClientID packet = new ClientID();
           connection.sendPacket(packet);

    The Class ClientID is defined in the section "Client-side Processing of Reply Packets" below.

    The Server-Side Plug-In
    The first step is to create a plug-in that will process the custom message with xmlns="jabber:iq:token." The plug-in is called ClientTokenPlugin. It first creates an IQTokenHandler; the handler is then added to the iq router that routes all the incoming iq messages:

    public class ClientTokenPlugin implements Plugin {
        public ClientTokenPlugin() {
           IQHandler iqRDHandler = new IQTokenHandler();
           IQRouter iqRouter = XMPPServer.getInstance().getIQRouter();
           iqRouter.addHandler(iqRDHandler);
        }
        public void initializePlugin(PluginManager manager, File pluginDirectory) { }
        public void destroyPlugin() { }
    }

    For more on how to create a plug-in, see www.jivesoftware.org/builds/wildfire/docs/ latest/documentation/plugin-dev-guide.html.

    IQTokenHandler has two key methods:

    a)  getInfo() which returns the type of queries in the iq messages that the token handler is going to process
    b)  handleIQ() which processes the incoming message/packet and creates a reply message/packet

    public class IQTokenHandler extends IQHandler {
       public IQTokenHandler() { super("Client Token Handler"); }
       public IQHandlerInfo getInfo() {
         return new IQHandlerInfo("query","jabber:iq:token"); }

       public IQ handleIQ(IQ packet) {
       IQ replyPacket = IQ.createResultIQ(packet);
       Element m = replyPacket.setChildElement("query", "jabber:iq:token");
    // 2 lines below are specific to our needs; change them to get data according to your needs
       ClientSession session = sessionManager.getSession(packet.getFrom());
       String token = (String)UserTokenList.get(JID.unescapeNode(session.getAddress().getNode().toLowerCase()));
       m.addElement("tokenNum").addText(token);
       return replyPacket;
       }
    }

    The reply message will look like:

    <iq to="clientName">
       <query xmlns="jabber:iq:token">
         <tokenNum>abcdefgh</tokenNum>
       </query></iq>


  • More Stories By Pramod Jain

    Pramod Jain is president of Innovative Decision Technologies, Inc. (INDENT, www.indent.org), in Jacksonville, FL. Their clients include Recruitmax, NASA, and NIH. Pramod has a PhD from the University of California, Berkeley.

    More Stories By Mahaveer Jain

    Mahaveer Jain is a lead programmer at INDENT. His expertise is in developing collaboration applications with Java technologies.

    Comments (2) View Comments

    Share your thoughts on this story.

    Add your comment
    You must be signed in to add a comment. Sign-in | Register

    In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


    Most Recent Comments
    SYS-CON Australia News Desk 06/23/06 09:05:30 AM EDT

    This article will describe our experiences with developing a Java-based instant messenger application using Jabber/XMPP (Extensible Messaging and Presence Protocol) - a free, open and public protocol and technology for instant messaging. According to the Jabber Software Foundation, 'Under the hood, Jabber is a set of streaming XML protocols and technologies that enable any two entities on the Internet to exchange messages, presence, and other structured information in close to real-time.'

    SYS-CON Australia News Desk 06/22/06 03:52:45 PM EDT

    This article will describe our experiences with developing a Java-based instant messenger application using Jabber/XMPP (Extensible Messaging and Presence Protocol) - a free, open and public protocol and technology for instant messaging. According to the Jabber Software Foundation, 'Under the hood, Jabber is a set of streaming XML protocols and technologies that enable any two entities on the Internet to exchange messages, presence, and other structured information in close to real-time.'

    @ThingsExpo Stories
    Scott Jenson leads a project called The Physical Web within the Chrome team at Google. Project members are working to take the scalability and openness of the web and use it to talk to the exponentially exploding range of smart devices. Nearly every company today working on the IoT comes up with the same basic solution: use my server and you'll be fine. But if we really believe there will be trillions of these devices, that just can't scale. We need a system that is open a scalable and by using the URL as a basic building block, we open this up and get the same resilience that the web enjoys.
    The Internet of Things is tied together with a thin strand that is known as time. Coincidentally, at the core of nearly all data analytics is a timestamp. When working with time series data there are a few core principles that everyone should consider, especially across datasets where time is the common boundary. In his session at Internet of @ThingsExpo, Jim Scott, Director of Enterprise Strategy & Architecture at MapR Technologies, discussed single-value, geo-spatial, and log time series data. By focusing on enterprise applications and the data center, he will use OpenTSDB as an example t...
    P2P RTC will impact the landscape of communications, shifting from traditional telephony style communications models to OTT (Over-The-Top) cloud assisted & PaaS (Platform as a Service) communication services. The P2P shift will impact many areas of our lives, from mobile communication, human interactive web services, RTC and telephony infrastructure, user federation, security and privacy implications, business costs, and scalability. In his session at @ThingsExpo, Robin Raymond, Chief Architect at Hookflash, will walk through the shifting landscape of traditional telephone and voice services ...
    The Domain Name Service (DNS) is one of the most important components in networking infrastructure, enabling users and services to access applications by translating URLs (names) into IP addresses (numbers). Because every icon and URL and all embedded content on a website requires a DNS lookup loading complex sites necessitates hundreds of DNS queries. In addition, as more internet-enabled ‘Things' get connected, people will rely on DNS to name and find their fridges, toasters and toilets. According to a recent IDG Research Services Survey this rate of traffic will only grow. What's driving t...
    Enthusiasm for the Internet of Things has reached an all-time high. In 2013 alone, venture capitalists spent more than $1 billion dollars investing in the IoT space. With "smart" appliances and devices, IoT covers wearable smart devices, cloud services to hardware companies. Nest, a Google company, detects temperatures inside homes and automatically adjusts it by tracking its user's habit. These technologies are quickly developing and with it come challenges such as bridging infrastructure gaps, abiding by privacy concerns and making the concept a reality. These challenges can't be addressed w...
    Explosive growth in connected devices. Enormous amounts of data for collection and analysis. Critical use of data for split-second decision making and actionable information. All three are factors in making the Internet of Things a reality. Yet, any one factor would have an IT organization pondering its infrastructure strategy. How should your organization enhance its IT framework to enable an Internet of Things implementation? In his session at Internet of @ThingsExpo, James Kirkland, Chief Architect for the Internet of Things and Intelligent Systems at Red Hat, described how to revolutioniz...
    Bit6 today issued a challenge to the technology community implementing Web Real Time Communication (WebRTC). To leap beyond WebRTC’s significant limitations and fully leverage its underlying value to accelerate innovation, application developers need to consider the entire communications ecosystem.
    The definition of IoT is not new, in fact it’s been around for over a decade. What has changed is the public's awareness that the technology we use on a daily basis has caught up on the vision of an always on, always connected world. If you look into the details of what comprises the IoT, you’ll see that it includes everything from cloud computing, Big Data analytics, “Things,” Web communication, applications, network, storage, etc. It is essentially including everything connected online from hardware to software, or as we like to say, it’s an Internet of many different things. The difference ...
    Cloud Expo 2014 TV commercials will feature @ThingsExpo, which was launched in June, 2014 at New York City's Javits Center as the largest 'Internet of Things' event in the world.
    SYS-CON Events announced today that Windstream, a leading provider of advanced network and cloud communications, has been named “Silver Sponsor” of SYS-CON's 16th International Cloud Expo®, which will take place on June 9–11, 2015, at the Javits Center in New York, NY. Windstream (Nasdaq: WIN), a FORTUNE 500 and S&P 500 company, is a leading provider of advanced network communications, including cloud computing and managed services, to businesses nationwide. The company also offers broadband, phone and digital TV services to consumers primarily in rural areas.
    "There is a natural synchronization between the business models, the IoT is there to support ,” explained Brendan O'Brien, Co-founder and Chief Architect of Aria Systems, in this SYS-CON.tv interview at the 15th International Cloud Expo®, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
    The major cloud platforms defy a simple, side-by-side analysis. Each of the major IaaS public-cloud platforms offers their own unique strengths and functionality. Options for on-site private cloud are diverse as well, and must be designed and deployed while taking existing legacy architecture and infrastructure into account. Then the reality is that most enterprises are embarking on a hybrid cloud strategy and programs. In this Power Panel at 15th Cloud Expo (http://www.CloudComputingExpo.com), moderated by Ashar Baig, Research Director, Cloud, at Gigaom Research, Nate Gordon, Director of T...
    An entirely new security model is needed for the Internet of Things, or is it? Can we save some old and tested controls for this new and different environment? In his session at @ThingsExpo, New York's at the Javits Center, Davi Ottenheimer, EMC Senior Director of Trust, reviewed hands-on lessons with IoT devices and reveal a new risk balance you might not expect. Davi Ottenheimer, EMC Senior Director of Trust, has more than nineteen years' experience managing global security operations and assessments, including a decade of leading incident response and digital forensics. He is co-author of t...

    ARMONK, N.Y., Nov. 20, 2014 /PRNewswire/ --  IBM (NYSE: IBM) today announced that it is bringing a greater level of control, security and flexibility to cloud-based application development and delivery with a single-tenant version of Bluemix, IBM's platform-as-a-service. The new platform enables developers to build ap...

    Technology is enabling a new approach to collecting and using data. This approach, commonly referred to as the "Internet of Things" (IoT), enables businesses to use real-time data from all sorts of things including machines, devices and sensors to make better decisions, improve customer service, and lower the risk in the creation of new revenue opportunities. In his General Session at Internet of @ThingsExpo, Dave Wagstaff, Vice President and Chief Architect at BSQUARE Corporation, discuss the real benefits to focus on, how to understand the requirements of a successful solution, the flow of ...
    The security devil is always in the details of the attack: the ones you've endured, the ones you prepare yourself to fend off, and the ones that, you fear, will catch you completely unaware and defenseless. The Internet of Things (IoT) is nothing if not an endless proliferation of details. It's the vision of a world in which continuous Internet connectivity and addressability is embedded into a growing range of human artifacts, into the natural world, and even into our smartphones, appliances, and physical persons. In the IoT vision, every new "thing" - sensor, actuator, data source, data con...
    "BSQUARE is in the business of selling software solutions for smart connected devices. It's obvious that IoT has moved from being a technology to being a fundamental part of business, and in the last 18 months people have said let's figure out how to do it and let's put some focus on it, " explained Dave Wagstaff, VP & Chief Architect, at BSQUARE Corporation, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4-6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
    Focused on this fast-growing market’s needs, Vitesse Semiconductor Corporation (Nasdaq: VTSS), a leading provider of IC solutions to advance "Ethernet Everywhere" in Carrier, Enterprise and Internet of Things (IoT) networks, introduced its IStaX™ software (VSC6815SDK), a robust protocol stack to simplify deployment and management of Industrial-IoT network applications such as Industrial Ethernet switching, surveillance, video distribution, LCD signage, intelligent sensors, and metering equipment. Leveraging technologies proven in the Carrier and Enterprise markets, IStaX is designed to work ac...
    C-Labs LLC, a leading provider of remote and mobile access for the Internet of Things (IoT), announced the appointment of John Traynor to the position of chief operating officer. Previously a strategic advisor to the firm, Mr. Traynor will now oversee sales, marketing, finance, and operations. Mr. Traynor is based out of the C-Labs office in Redmond, Washington. He reports to Chris Muench, Chief Executive Officer. Mr. Traynor brings valuable business leadership and technology industry expertise to C-Labs. With over 30 years' experience in the high-tech sector, John Traynor has held numerous...
    The 3rd International @ThingsExpo, co-located with the 16th International Cloud Expo - to be held June 9-11, 2015, at the Javits Center in New York City, NY - announces that it is now accepting Keynote Proposals. The Internet of Things (IoT) is the most profound change in personal and enterprise IT since the creation of the Worldwide Web more than 20 years ago. All major researchers estimate there will be tens of billions devices - computers, smartphones, tablets, and sensors - connected to the Internet by 2020. This number will continue to grow at a rapid pace for the next several decades.