Introduction:

If you’re a developer looking for a robust and secure way to integrate Xmpp communication into your applications, look no further than Smack. Smack is a popular XMPP client library that provides an easy-to-use API for sending and receiving messages via XMPP protocols. In this article, we’ll walk you through how to connect to ABN XMPP server using Smack, so you can start building your own XMPP-enabled applications. Whether you’re building a chat application, integrating real-time messaging into your existing application, or just exploring the world of XMPP, this article will help you get started with Smack.

In this tutorial, we’ll build a small app able to communicate with an xmpp server, and that could be perhaps be expanded, in time, into a full messaging app.

Set-up:

For this tutorial we’ll be using android studio and java, with gradle, as well as the latest version of the smack library(4.4.5). You can download the library at the link below:

https://www.igniterealtime.org/projects/smack/

Importing the library:

After creating our project in android studio, we import the smack library with gradle, by appending the following lines to the dependencies in the build gradle:

implementation ('org.igniterealtime.smack:smack-android:4.4.5')
{
exclude module: 'xpp3'
}
implementation ('org.igniterealtime.smack:smack-core:4.4.5'){
exclude module: 'xpp3'
}
implementation ('org.igniterealtime.smack:smack-im:4.4.5'){
exclude module: 'xpp3'
}
implementation ('org.igniterealtime.smack:smack-resolver-minidns:4.4.5')
{
exclude module: 'xpp3'
}
implementation ('org.igniterealtime.smack:smack-sasl-provided:4.4.5'){
exclude module: 'xpp3'
}
implementation('org.igniterealtime.smack:smack-tcp:4.4.5') {
exclude module: 'xpp3'
}

The exclude xpp3 is necessary to avoid running into the following error at build:

Duplicate class org.xmlpull.mxp1.MXParser found in modules xpp3-1.1.4c (xpp3:xpp3:1.1.4c) and xpp3_min-1.1.4c (xpp3:xpp3_min:1.1.4c)
Duplicate class org.xmlpull.v1.XmlPullParser found in modules xpp3-1.1.4c (xpp3:xpp3:1.1.4c) and xpp3_min-1.1.4c (xpp3:xpp3_min:1.1.4c)
Duplicate class org.xmlpull.v1.XmlPullParserException found in modules xpp3-1.1.4c (xpp3:xpp3:1.1.4c) and xpp3_min-1.1.4c (xpp3:xpp3_min:1.1.4c)

After this, build and you should be able to use smack in your app.

Working with smack, and XMPP basics:

Now that smack is installed, we’ll go over the basics of XMPP and how smack can be used to send and receive back and forth messages from an to a server.

XMPP, or Extensible Messaging and Presence Protocol, is an open-standard protocol for real-time messaging, presence, and chat. XMPP is built on XML, which means that messages are sent as XML stanzas. A stanza is the basic unit of communication in XMPP and can be used for a variety of purposes, including sending messages, updating presence status, and exchanging data.
Smack provides an easy-to-use API for sending and receiving these stanzas, which allows developers to build powerful and flexible XMPP-enabled applications. With Smack, developers can easily create chat applications, real-time messaging systems, and much more.

Connecting to XMPP with smack:

We will begin by defining the methods we will use to initiate a secure connection with smack. For this tutorial , we are using a server hosted on a local network:

public void intiateConnection(String id, String password, String ipXmppAdress, int xmppPort, String xmppDomain){
        AbstractXMPPConnection connection = null;
        XMPPTCPConnectionConfiguration config = null;

        try {
            config = XMPPTCPConnectionConfiguration.builder()
                    .setUsernameAndPassword(id, password)
                    .setHost(ipXmppAdress)
           .setSecurityMode(ConnectionConfiguration.SecurityMode.ifpossible)
                    .setPort(xmppPort)
                    .setXmppDomain(xmppDomain)
                    .build();
            } catch (XmppStringprepException e) {
                e.printStackTrace();
            }
        connection= new XMPPTCPConnection(config);
        try {
            connection.connect().login();
            } catch (XMPPException e) {
                e.printStackTrace();
            } catch (SmackException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
       

To initiate a connection, you’ll have to specify a domain, a port (usually 5222 but check with your XMPP server provider), and provide the username and password of the user you wanna login with. You can also use smack to create an account, but we’ll go over the more advanced functionalities of the library in a later post.

To function, this method will have to be run outside of the main thread, on a separate thread.

If all goes well, you should be able to connect to the server, and appear in the list of connected users.

Receiving stanzas:

The next step in handling stanzas would be to register a listener on the connection for incoming stanzas.

 connection.addAsyncStanzaListener(new StanzaListener() {
            public void processStanza(Stanza stanza)
                    throws SmackException.NotConnectedException,InterruptedException,
                        SmackException.NotLoggedInException {
                            Message message=(Message) stanza;
                }
            }, StanzaTypeFilter.MESSAGE);

Sending stanzas:

You can then implement the logic to send stanzas as well:

Message message = null;
message = connection.getStanzaFactory()
                                .buildMessageStanza()
                                .to(receiver_address)
                                .setBody(msgBody)
                                .setLanguage("en")
                                .build();
connection.sendStanza(message);

Conclusion:

You can use this tutorial as a starting point to implementing a chat application or just a simple XMPP client. Stay tuned for a more advanced XMPP tutorial coming up…

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