Facebook Chat XMPP Services

Since 2 months ago, I’ve got my second remote job as Java EE Developer for Telco Company in Singapore named Hub9. So, currently now I’m working for two Telco’s Company in Singapore (i.e. CoreSDP and Hub9) as Java EE Developer. Both of them are remote jobs (which means working from home :-D), and I’ve got monthly payment for these jobs. This is what i’ve been dreaming for a long time :-).
Start from here I’ll write some notes about anything what i’ve been doing for over the last 2 months with Hub9.
As my first assignment, they’ve asked me to develop facebook chat (IM/Instant Messaging) application via SMS (known as Facebook SMS Chat). As you’ve already known, there are many chat (IM) application now, such as Yahoo Messenger, GoogleTalk, eBuddy, Jabber, etc. Even Facebook has provided it’s application with IM service, so every user on facebook could have a conversation via this chat (IM) service.
Every IM service need communication protocol in order to be working correctly. There are many protocols around can be used for this purpose. Some of them are under commercial (propietary) license, and some of them are not (means ‘free’, and this is what i’m going to use :-D).
One of the protocol that is free to be used is XMPP.
XMPP (stands for eXtensible Messaging and Presence Protocol) is an open-standard communication protocol for message oriented middleware based on XML (eXtensible Markup Language). This protocol was originally named Jabber, and was developed by the Jabber open source community in 1999 for near real-time, extensible instant messaging (IM), presence information, and contact list maintenance. The software implementation and client application based on this protocol are distributed as free and open source software (looks nice to me ^_^).
I think, you should read by your self later about XMPP, so I won’t give you the detail explanation about XMPP here (b’cause I’m not the kind of person who’s enjoy to talking to much about the ‘philosophy’ behind the ‘theory’ #:-s). So please googling or read the “RTFM” :-).
One thing that I think is important for us to know before we jump into the XMPP implementation is: basically, there are 2 implementations of XMPP. i.e. XMPP Server and XMPP Client.

In order to work, we should have those 2 implementation in our software.

Luckily, Facebook has implemented XMPP Server for us, so we just need to make the implementation for client.
After googled, i’ve found one Java XMPP Client API called SMACK that I think is suitable for this case. So, I’m going to use this API.
First, you have to download the API from here (last stable version was 3.2.1 when I wrote this note).
After downloaded the API (whether in zip or tar.gz), extract that compressed file to your local directory in your machine.
The file has already came with several documentation, examples, and Doc API. So, it will be easy for us to learn.
For basic use, there are 3 required jar files for this API as follows:

1. smack.jar
2. smackx.jar
3. smackx-debug.jar (used for debug mode, i.e. if you turn on the debug mode).

Before going into the Facebook SMS Chat, here I’ll show you the basic use of this API first by giving you a simple console application that provides Facebook Chat Services.
First i’ll just write down the creation steps and the code of the application (including short explanation about the code), then give you the detail explanation afterwards.
The creation of this console application could be described as the following:

1. Create new directory for the application called FBConsoleChat
2. Create 3 directories as follows:
   • src (used for source code)
   • bin (used for binary/bytecode, i.e. compiled class)
   • lib (used for library/API, i.e. smack)
3. Copy jars needed into lib directory.
   The picture below shows us about the 3 steps above.

   

4. Create package com.fb.xmppchat.app and com.fb.xmppchat.helper in the source (src) directory.
   e.g.:

   yauritux@yauritux:~/Works/FBConsoleChat$ mkdir -p src/com/fb/xmppchat/app 
   yauritux@yauritux:~/Works/FBConsoleChat$ mkdir -p src/com/fb/xmppchat/helper 
   

5. Create new JAVA class called CustomSASLDigestMD5Mechanism (CustomSASLDigestMD5Mechanism.java) using your favourite editor (e.g. VI/VIM) under directory “src/com/fb/xmppchat/helper” then write the following code:

   package com.fb.xmppchat.helper;
   
   import java.io.IOException;
   import java.util.HashMap;
   import java.util.Map;
   
   import javax.security.auth.callback.CallbackHandler;
   import javax.security.sasl.Sasl;
   
   import org.jivesoftware.smack.SASLAuthentication;
   import org.jivesoftware.smack.XMPPException;
   import org.jivesoftware.smack.sasl.SASLMechanism;
   
   public class CustomSASLDigestMD5Mechanism extends SASLMechanism {
      
      public CustomSASLDigestMD5Mechanism(SASLAuthentication saslAuthentication) {
         super(saslAuthentication);
      }
   
      @Override
      public void authenticate(String username, String host, String password)
        throws IOException, XMPPException {
         this.authenticationId = username;
         this.password = password;
         this.hostname = host;
   
         String[] mechanisms = { getName() };
         Map<String, String> props = new HashMap<String, String>();
         sc = Sasl.createSaslClient(mechanisms, null, "xmpp", host, props, this);
         super.authenticate();
      }
   
      @Override
      public void authenticate(String username, String host, CallbackHandler cbh)
        throws IOException, XMPPException {
         String[] mechanisms = { getName() };
         Map<String, String> props = new HashMap<String, String>();
         sc = Sasl.createSaslClient(mechanisms, null, "xmpp", host, props, cbh);
         super.authenticate();
      }
   
      protected String getName() {
        return "DIGEST-MD5";
      }
   }
   

6. Compile CustomSASLDigestMD5Mechanism.java by using javac (don’t forget to include the 3 required libraries into the classpath), place the bytecode result into “bin” directory. Example command as follows (from FBConsoleChat directory) :

   yauritux@yauritux:~/Works/FBConsoleChat$javac -verbose -d ./bin/ -cp ".:./lib/smack.jar:./lib/smackx.jar:./lib/smackx-debug.jar" src/com/fb/xmppchat/helper/CustomSASLDigestMD5Mechanism.java
   

   See the picture below:

   

7. Create new JAVA class called FBMessageListener (FBMessageListener.java) using your favourite editor (e.g. VI/VIM) under directory “src/com/fb/xmppchat/helper”.
   We’ll use this class as the message listener (i.e. listening for incoming/outgoing message). Please note that we create this class with it’s own thread rather than using the same thread with the application. So, our application later will have 2 thread running simultaneously. This is important in order to make our application can send and receive message (chat between user) at the same time.
   You can see the code as follows:

   package com.fb.xmppchat.helper;
   
   import org.apache.commons.collections.BidiMap;
   import org.apache.commons.collections.MapIterator;
   
   import org.jivesoftware.smack.Chat;
   import org.jivesoftware.smack.ChatManagerListener;
   import org.jivesoftware.smack.MessageListener;
   import org.jivesoftware.smack.RosterEntry;
   import org.jivesoftware.smack.XMPPConnection;
   import org.jivesoftware.smack.packet.Message;
   
   public class FBMessageListener implements MessageListener, Runnable {
   
      private FBMessageListener fbml = this;
      private XMPPConnection conn;
      private BidiMap friends;
   
      public FBMessageListener(XMPPConnection conn) {
         this.conn = conn;
         new Thread(this).start();
      }
   
      public void setFriends(BidiMap friends) {
         this.friends = friends;
      }
   
      public void processMessage(Chat chat, Message message) {
         System.out.println();
         MapIterator it = friends.mapIterator();
         String key = null;
         RosterEntry entry = null;
         while (it.hasNext()) {
            key = (String) it.next();
            entry = (RosterEntry) it.getValue();
            if (entry.getUser().equalsIgnoreCase(chat.getParticipant())) {
               break;
            }
         }
         if ((message != null) && (message.getBody() != null)) {
            System.out.println("You've got new message from " + entry.getName() 
               + "(" + key + ") :");
            System.out.println(message.getBody());
            System.out.print("Your choice [1-3]: ");
         }
      }
   
      public void run() {
         conn.getChatManager().addChatListener(
            new ChatManagerListener() {
               public void chatCreated(Chat chat, boolean createdLocally) {
                  if (!createdLocally) {
                     chat.addMessageListener(fbml);
                  }
               }
            }
         );
      }
   }
   

8. You can see from the above source code that i prefer to use BidiMap collection class from Apache commons-collections instead of collection classes from java.util package, because all collection classes from Apache commons-collections more flexible and powerfull in my opinion. So, before compiling this class into bytecode, you have to copy the commons-collections.jar into lib directory. You can download the jar from here (last stable version is 3.2 when I wrote this note).
9. Compile the FBMessageListener class (don’t forget to add all required jars into the classpath), and set the output to bin directory (see picture below for example):

   

10. Create new JAVA class called FBConsoleChatApp (FBConsoleChatApp.java) using your favourite editor (e.g. VI/VIM) under directory “src/com/fb/xmppchat/app”.
    This class is the main class, so the application will be running use this class as the starting point.
    The code as follows:

    package com.fb.xmppchat.app;
    
    import com.fb.xmppchat.helper.CustomSASLDigestMD5Mechanism;
    import com.fb.xmppchat.helper.FBMessageListener;
    
    import java.io.BufferedReader;
    import java.io.InputStreamReader;
    import java.io.IOException;
    
    import org.apache.commons.collections.BidiMap;
    import org.apache.commons.collections.bidimap.DualHashBidiMap;
    
    import org.jivesoftware.smack.ConnectionConfiguration;
    import org.jivesoftware.smack.Chat;
    import org.jivesoftware.smack.ChatManager;
    import org.jivesoftware.smack.MessageListener;
    import org.jivesoftware.smack.Roster;
    import org.jivesoftware.smack.RosterEntry;
    import org.jivesoftware.smack.SASLAuthentication;
    import org.jivesoftware.smack.XMPPConnection;
    import org.jivesoftware.smack.XMPPException;
    import org.jivesoftware.smack.packet.Message;
    import org.jivesoftware.smack.packet.Presence;
    
    public class FBConsoleChatApp {
    
       public static final String FB_XMPP_HOST = "chat.facebook.com";
       public static final int FB_XMPP_PORT = 5222;
    
       private ConnectionConfiguration config;
       private XMPPConnection connection;
       private BidiMap friends = new DualHashBidiMap();
       private FBMessageListener fbml;
    
       public String connect() throws XMPPException {
          config = new ConnectionConfiguration(FB_XMPP_HOST, FB_XMPP_PORT);
          SASLAuthentication.registerSASLMechanism("DIGEST-MD5"
            , CustomSASLDigestMD5Mechanism.class);
          config.setSASLAuthenticationEnabled(true);
          config.setDebuggerEnabled(false);
          connection = new XMPPConnection(config);
          connection.connect();
          fbml = new FBMessageListener(connection);
          return connection.getConnectionID();
       }
    
       public void disconnect() {
          if ((connection != null) && (connection.isConnected())) {
             Presence presence = new Presence(Presence.Type.unavailable);
             presence.setStatus("offline");
             connection.disconnect(presence);
          }
       }
    
       public boolean login(String userName, String password) 
         throws XMPPException {
          if ((connection != null) && (connection.isConnected())) {
             connection.login(userName, password);
             return true;
          }
          return false;
       }
    
       public String readInput() throws IOException {
          BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
          return br.readLine();
       }
    
       public void showMenu() {
          System.out.println("Please select one of the following menu.");
          System.out.println("1. List of Friends online");
          System.out.println("2. Send Message");
          System.out.println("3. EXIT");
          System.out.print("Your choice [1-3]: ");
       }
    
       public void getFriends() {
          if ((connection != null) && (connection.isConnected())) {
             Roster roster = connection.getRoster();
             int i = 1;
             for (RosterEntry entry : roster.getEntries()) {
                Presence presence = roster.getPresence(entry.getUser());
                if ((presence != null) 
                   && (presence.getType() != Presence.Type.unavailable)) {
                   friends.put("#" + i, entry);
                   System.out.println(entry.getName() + "(#" + i + ")");
                   i++;
                }
             }
             fbml.setFriends(friends);
          }
       }
    
       public void sendMessage() throws XMPPException
         , IOException {
          System.out.println("Type the key number of your friend (e.g. #1) and the text that you wish to send !");
          String friendKey = null;
          String text = null;
          System.out.print("Your friend's Key Number: ");
          friendKey = readInput();
          System.out.print("Your Text message: ");
          text = readInput();
          sendMessage((RosterEntry) friends.get(friendKey), text);
       }
    
       public void sendMessage(final RosterEntry friend, String text) 
         throws XMPPException {
          if ((connection != null) && (connection.isConnected())) {
             ChatManager chatManager = connection.getChatManager();
             Chat chat = chatManager.createChat(friend.getUser(), fbml);
             chat.sendMessage(text);
             System.out.println("Your message has been sent to " 
                + friend.getName());
          }
       }
      
       public static void main(String[] args) {
          if (args.length == 0) {
            System.err.println("Usage: java FBConsoleChatApp [username_facebook] [password]");
            System.exit(-1);
          }
    
          String username = args[0];
          String password = args[1];
    
          FBConsoleChatApp app = new FBConsoleChatApp();
    
          try {
             app.connect();
             if (!app.login(username, password)) {
                System.err.println("Access Denied...");
                System.exit(-2);
             }
             app.showMenu();
             String data = null;
             menu:
             while((data = app.readInput().trim()) != null) {
                if (!Character.isDigit(data.charAt(0))) {
                   System.out.println("Invalid input.Only 1-3 is allowed !");
                   app.showMenu();
                   continue;
                }
                int choice = Integer.parseInt(data);
                if ((choice != 1) && (choice != 2) && (choice != 3)) {
                   System.out.println("Invalid input.Only 1-3 is allowed !");
                   app.showMenu();
                   continue;
                }
                switch (choice) {
                   case 1: app.getFriends();
                           app.showMenu();
                           continue menu;
                   case 2: app.sendMessage();
                           app.showMenu();
                           continue menu;
                   default: break menu;
                }
             }
             app.disconnect();
          } catch (XMPPException e) {
            if (e.getXMPPError() != null) {
               System.err.println("ERROR-CODE : " + e.getXMPPError().getCode());
               System.err.println("ERROR-CONDITION : " + e.getXMPPError().getCondition());
               System.err.println("ERROR-MESSAGE : " + e.getXMPPError().getMessage());
               System.err.println("ERROR-TYPE : " + e.getXMPPError().getType());
            }
            app.disconnect();
          } catch (IOException e) {
            System.err.println(e.getMessage());
            app.disconnect();
          }
      }
    }
    

11. Compile the class (as usual, see the picture below which shows some output from mine :-)).

    

Now, I’ll show you the usage of this application by testing it using my 2 facebook accounts :-).
I’ll log into the Facebook with my account yauritux from the console application that I’ve just created, and using account Solusi Java to login from Facebook Web, and start conversation from there :-D.
See the 2 pictures below:

(Click the picture above to enlarge)

See…, it works #:-s.