When to disconnect bosh connection establish from

This question is Extension of my previous question on this SO question "How to connect XMPP bosh server using java smack library?"

I am using Java as server side language. I have successfully implement xmpp BOSH connection using smach-jbosh thanks to @Deuteu for helping me to achieve this, so far I have modify jbosh's BOSHClient.java file and added two getter method for extracting RID and SID.

Now I have RID and SID on my app server (I am using Apache Tomcat). I need to pass this credential to Strophe (web client) so that it can attach to connection.

Here I have some doubt.

When to disconnect bosh Connection establish from the app server? before passing sid, rid and jid to strophe or after passing sid, rid and jid to strophe?
As per my observation during implementation for the same, I have observed that once bosh connection from the app server has been disconnected, session is expired and SID and RID is no longer useful!!!
I have implemented this logic (Establishing bosh connection and Extracting sid and rid) on a Servlet, here once response has been send from Servlet, Thread will get expired and end BOSH connection will get terminated, so I am not able perform `Attach()` on strophe as session is expired.

Can somebody help me with that problem?

回答1:

After you have created a BOSH session with smack and have extracted the SID+RID values, you need to pass them to Strophe's attach() and from here on out you need to let strophe deal with this connection. Once Strophe has attached, you do not want your server to be doing anything to the connection at all.

If your server side code sends any messages at all to the connection manager after strophe has attached, it's likely that it will send a invalid RID which will cause your session to terminate.

Again, once the session has been established and is usable by strophe, do not attempt to continue using it from the server side. After your server side bosh client completes authentication and you've passed the SID+RID to the page, just destroy the server side connection object, don't attempt to disconnect or anything as this will end your session.

The thing you need to remember is, unlike traditional XMPP connections over TCP, BOSH clients do NOT maintain a persistent connection to the server (this is why we use BOSH in web applications). So there is nothing to disconnect. The persistent connection is actually between the XMPP server and the BOSH connection manager, it's not something you need to deal with. So when you call disconnect from your server side BOSH client, you're telling the connection manager to end the session and close it's connection to the XMPP server, which completely defeats the purpose of creating the session in the first place.

回答2:

I believe @fpsColton's answer is correct - I'm just added extra info for clarity. As requested on linked thread here is the code changes I made on this - note: I only added the parts where I've labelled "DH"

In BOSHConnection:

 // DH: function to preserve current api
public void login(String username, String password, String resource)
        throws XMPPException {
    login(username, password, resource, false);         

}

// DH: Most of this is existing login function, but added prebind parameter 
//     to allow leaving function after all required pre-bind steps done and before 
//     presence stanza gets sent (sent from attach in XMPP client)
public void login(String username, String password, String resource, boolean preBind)         
        throws XMPPException {
    if (!isConnected()) {
        throw new IllegalStateException("Not connected to server.");
    }
    if (authenticated) {
        throw new IllegalStateException("Already logged in to server.");
    }
    // Do partial version of nameprep on the username.
    username = username.toLowerCase().trim();

    String response;
    if (config.isSASLAuthenticationEnabled()
            && saslAuthentication.hasNonAnonymousAuthentication()) {
        // Authenticate using SASL
        if (password != null) {
            response = saslAuthentication.authenticate(username, password, resource);
        } else {
            response = saslAuthentication.authenticate(username, resource, config.getCallbackHandler());
        }
    } else {
        // Authenticate using Non-SASL
        response = new NonSASLAuthentication(this).authenticate(username, password, resource);
    }

    // Indicate that we're now authenticated.
    authenticated = true;
    anonymous = false;

    // DH: Prebind only requires connect and authenticate
    if (preBind) {
        return;
    }

    // Set the user.
    if (response != null) {
        this.user = response;
        // Update the serviceName with the one returned by the server
        config.setServiceName(StringUtils.parseServer(response));
    } else {
        this.user = username + "@" + getServiceName();
        if (resource != null) {
            this.user += "/" + resource;
        }
    }

    // Create the roster if it is not a reconnection.
    if (this.roster == null) {
        this.roster = new Roster(this);
    }
    if (config.isRosterLoadedAtLogin()) {
        this.roster.reload();
    }

    // Set presence to online.
    if (config.isSendPresence()) {
        sendPacket(new Presence(Presence.Type.available));
    }

    // Stores the autentication for future reconnection
    config.setLoginInfo(username, password, resource);

    // If debugging is enabled, change the the debug window title to include
    // the
    // name we are now logged-in as.l
    if (config.isDebuggerEnabled() && debugger != null) {
        debugger.userHasLogged(user);
    }
}

and

 // DH
@Override
public void disconnect() {
    client.close();
}

then my Client-side (Web Server) wrapper class - for connecting from within JSP is:

Note: This is proving code rather than production - so there's some stuff in here you may not want.

public class SmackBoshConnector {

private String sessionID = null;
private String authID = null;
private Long requestID = 0L;
private String packetID = null;
private boolean connected = false;

public boolean connect(String userName, String password, String host, int port, final String xmppService) {

    boolean success = false;

    try {

        Enumeration<SaslClientFactory> saslFacts = Sasl.getSaslClientFactories();
        if (!saslFacts.hasMoreElements()) {
            System.out.println("Sasl Provider not pre-loaded"); 
            int added = Security.addProvider(new com.sun.security.sasl.Provider()); 
            if (added == -1) {
                System.out.println("Sasl Provider could not be loaded");
                System.exit(added);
            }
            else {
                System.out.println("Sasl Provider added"); 
            }                                                      
        }

        BOSHConfiguration config = new BOSHConfiguration(false, host, port, "/http-bind/", xmppService);
        BOSHConnection connection = new BOSHConnection(config);      

        PacketListener sndListener = new PacketListener() {

            @Override
            public void processPacket(Packet packet) {
                SmackBoshConnector.this.packetID = packet.getPacketID();
                System.out.println("Send PacketId["+packetID+"] to["+packet.toXML()+"]");
            }

        };

        PacketListener rcvListener = new PacketListener() {

            @Override
            public void processPacket(Packet packet) {
                SmackBoshConnector.this.packetID = packet.getPacketID();
                System.out.println("Rcvd PacketId["+packetID+"] to["+packet.toXML()+"]");
            }

        };

        PacketFilter packetFilter = new PacketFilter() {

            @Override
            public boolean accept(Packet packet) {
                return true;
            }
        };

        connection.addPacketSendingListener(sndListener, packetFilter);
        connection.addPacketListener(rcvListener, packetFilter);
        connection.connect();

        // login with pre-bind only
        connection.login(userName, password, "", true);                  

        authID = connection.getConnectionID();

        BOSHClient client = connection.getClient();

        sessionID = client.getSid();
        requestID = client.getRid();

        System.out.println("Connected ["+authID+"] sid["+sessionID+"] rid["+requestID+"]");
        success = true;
        connected = true;

        try {
            Thread.yield();
            Thread.sleep(500);
        }
        catch (InterruptedException e) {
            // Ignore
        }
        finally {
            connection.disconnect();
        }

    } catch (XMPPException ex) {
        Logger.getLogger(SmackBoshConnector.class.getName()).log(Level.SEVERE, null, ex);
    }

    return success;
}

public boolean isConnected() {
    return connected;
}

public String getSessionID() {
    return sessionID;
}

public String getAuthID() {
    return authID;
}

public String getRequestIDAsString() {
    return Long.toString(requestID);
}

public String getNextRequestIDAsString() {
    return Long.toString(requestID+1);
}
public static void main(String[] args)  {        
    SmackBoshConnector bc = new SmackBoshConnector();        
    bc.connect("dazed", "i3ji44mj7k2qt14djct0t5o709", "192.168.2.15", 5280, "my.xmppservice.com");
 }

}

I confess that I'm don't fully remember why I put the Thread.yield and Thread.sleep(1/2 sec) in here - I think - as you can see with added PacketListener - the lower level functions return after sending data and before getting a response back from the server - and if you disconnect before the server has sent it's response then it (also) causes it to clean up the session and things won't work. However it may be that, as @fpsColton says, this dicsonnect() isn't actually required.

Edit: I now remember a bit more about whay I included sleep() and yield(). I noticed that Smack library includes sleep() in several places, including XMPPConnection.shutdown() as per source. Plus in terms of yield() I had problems in my environment (Java in Oracle Database - probably untypical) when it wasn't included - as per Smack Forum Thread.

Good luck.