Welcome!

Java Authors: Liz McMillan, Elizabeth White, Pat Romanski, Trevor Parsons, Carmen Gonzalez

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
    Things are being built upon cloud foundations to transform organizations. This CEO Power Panel at 15th Cloud Expo, moderated by Roger Strukhoff, Cloud Expo and @ThingsExpo conference chair, addressed the big issues involving these technologies and, more important, the results they will achieve. Rodney Rogers, chairman and CEO of Virtustream; Brendan O'Brien, co-founder of Aria Systems, Bart Copeland, president and CEO of ActiveState Software; Jim Cowie, chief scientist at Dyn; Dave Wagstaff, VP and chief architect at BSQUARE Corporation; Seth Proctor, CTO of NuoDB, Inc.; and Andris Gailitis, C...
    SYS-CON Media announced that Splunk, a provider of the leading software platform for real-time Operational Intelligence, has launched an ad campaign on Big Data Journal. Splunk software and cloud services enable organizations to search, monitor, analyze and visualize machine-generated big data coming from websites, applications, servers, networks, sensors and mobile devices. The ads focus on delivering ROI - how improved uptime delivered $6M in annual ROI, improving customer operations by mining large volumes of unstructured data, and how data tracking delivers uptime when it matters most.
    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.
    Code Halos - aka "digital fingerprints" - are the key organizing principle to understand a) how dumb things become smart and b) how to monetize this dynamic. In his session at @ThingsExpo, Robert Brown, AVP, Center for the Future of Work at Cognizant Technology Solutions, outlined research, analysis and recommendations from his recently published book on this phenomena on the way leading edge organizations like GE and Disney are unlocking the Internet of Things opportunity and what steps your organization should be taking to position itself for the next platform of digital competition.
    In their session at @ThingsExpo, Shyam Varan Nath, Principal Architect at GE, and Ibrahim Gokcen, who leads GE's advanced IoT analytics, focused on the Internet of Things / Industrial Internet and how to make it operational for business end-users. Learn about the challenges posed by machine and sensor data and how to marry it with enterprise data. They also discussed the tips and tricks to provide the Industrial Internet as an end-user consumable service using Big Data Analytics and Industrial Cloud.
    How do APIs and IoT relate? The answer is not as simple as merely adding an API on top of a dumb device, but rather about understanding the architectural patterns for implementing an IoT fabric. There are typically two or three trends: Exposing the device to a management framework Exposing that management framework to a business centric logic Exposing that business layer and data to end users. This last trend is the IoT stack, which involves a new shift in the separation of what stuff happens, where data lives and where the interface lies. For instance, it's a mix of architectural styles ...
    The Internet of Things (IoT) promises to evolve the way the world does business; however, understanding how to apply it to your company can be a mystery. Most people struggle with understanding the potential business uses or tend to get caught up in the technology, resulting in solutions that fail to meet even minimum business goals. In his session at @ThingsExpo, Jesse Shiah, CEO / President / Co-Founder of AgilePoint Inc., showed what is needed to leverage the IoT to transform your business. He discussed opportunities and challenges ahead for the IoT from a market and technical point of vie...
    IoT is still a vague buzzword for many people. In his session at @ThingsExpo, Mike Kavis, Vice President & Principal Cloud Architect at Cloud Technology Partners, discussed the business value of IoT that goes far beyond the general public's perception that IoT is all about wearables and home consumer services. He also discussed how IoT is perceived by investors and how venture capitalist access this space. Other topics discussed were barriers to success, what is new, what is old, and what the future may hold. Mike Kavis is Vice President & Principal Cloud Architect at Cloud Technology Pa...
    Dale Kim is the Director of Industry Solutions at MapR. His background includes a variety of technical and management roles at information technology companies. While his experience includes work with relational databases, much of his career pertains to non-relational data in the areas of search, content management, and NoSQL, and includes senior roles in technical marketing, sales engineering, and support engineering. Dale holds an MBA from Santa Clara University, and a BA in Computer Science from the University of California, Berkeley.
    The Internet of Things (IoT) is rapidly in the process of breaking from its heretofore relatively obscure enterprise applications (such as plant floor control and supply chain management) and going mainstream into the consumer space. More and more creative folks are interconnecting everyday products such as household items, mobile devices, appliances and cars, and unleashing new and imaginative scenarios. We are seeing a lot of excitement around applications in home automation, personal fitness, and in-car entertainment and this excitement will bleed into other areas. On the commercial side, m...
    The Industrial Internet revolution is now underway, enabled by connected machines and billions of devices that communicate and collaborate. The massive amounts of Big Data requiring real-time analysis is flooding legacy IT systems and giving way to cloud environments that can handle the unpredictable workloads. Yet many barriers remain until we can fully realize the opportunities and benefits from the convergence of machines and devices with Big Data and the cloud, including interoperability, data security and privacy.
    The 3rd International Internet of @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 its Call for Papers is now open. The Internet of Things (IoT) is the biggest idea since the creation of the Worldwide Web more than 20 years ago.
    "People are a lot more knowledgeable about APIs now. There are two types of people who work with APIs - IT people who want to use APIs for something internal and the product managers who want to do something outside APIs for people to connect to them," explained Roberto Medrano, Executive Vice President at SOA Software, in this SYS-CON.tv interview at Cloud Expo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
    Performance is the intersection of power, agility, control, and choice. If you value performance, and more specifically consistent performance, you need to look beyond simple virtualized compute. Many factors need to be considered to create a truly performant environment. In his General Session at 15th Cloud Expo, Harold Hannon, Sr. Software Architect at SoftLayer, discussed how to take advantage of a multitude of compute options and platform features to make cloud the cornerstone of your online presence.
    In this Women in Technology Power Panel at 15th Cloud Expo, moderated by Anne Plese, Senior Consultant, Cloud Product Marketing at Verizon Enterprise, Esmeralda Swartz, CMO at MetraTech; Evelyn de Souza, Data Privacy and Compliance Strategy Leader at Cisco Systems; Seema Jethani, Director of Product Management at Basho Technologies; Victoria Livschitz, CEO of Qubell Inc.; Anne Hungate, Senior Director of Software Quality at DIRECTV, discussed what path they took to find their spot within the technology industry and how do they see opportunities for other women in their area of expertise.
    DevOps Summit 2015 New York, 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 widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long development cycles that produce software that is obsolete at launch. DevOps may be disruptive, but it is essential.
    Almost everyone sees the potential of Internet of Things but how can businesses truly unlock that potential. The key will be in the ability to discover business insight in the midst of an ocean of Big Data generated from billions of embedded devices via Systems of Discover. Businesses will also need to ensure that they can sustain that insight by leveraging the cloud for global reach, scale and elasticity.
    The Internet of Things will greatly expand the opportunities for data collection and new business models driven off of that data. In her session at @ThingsExpo, Esmeralda Swartz, CMO of MetraTech, discussed how for this to be effective you not only need to have infrastructure and operational models capable of utilizing this new phenomenon, but increasingly service providers will need to convince a skeptical public to participate. Get ready to show them the money!
    The 3rd International Internet of @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 its Call for Papers is now open. The Internet of Things (IoT) is the biggest idea since the creation of the Worldwide Web more than 20 years ago.
    Connected devices and the Internet of Things are getting significant momentum in 2014. In his session at Internet of @ThingsExpo, Jim Hunter, Chief Scientist & Technology Evangelist at Greenwave Systems, examined three key elements that together will drive mass adoption of the IoT before the end of 2015. The first element is the recent advent of robust open source protocols (like AllJoyn and WebRTC) that facilitate M2M communication. The second is broad availability of flexible, cost-effective storage designed to handle the massive surge in back-end data in a world where timely analytics is e...