Smack/documentation/extensions/hoxt.md

HTTP over XMPP transport

Allows to transport HTTP communication over XMPP peer-to-peer networks.

• Discover HOXT support
• IQ exchange

Discover HOXT support

Description

Before using this extension you must ensure that your counterpart supports it also.

Usage

Once you have your ServiceDiscoveryManager you will be able to discover information associated with an XMPP entity. To discover the information of a given XMPP entity send discoverInfo(entityID) to your ServiceDiscoveryManager where entityID is the ID of the entity. The message discoverInfo(entityID) will answer an instance of DiscoverInfo that contains the discovered information.

Examples

In this example we can see how to check if the counterpart supports HOXT:

// Obtain the ServiceDiscoveryManager associated with my XMPPConnection
ServiceDiscoveryManager discoManager = ServiceDiscoveryManager.getInstanceFor(connection);
// Get the information of a given XMPP entity
DiscoverInfo discoInfo = discoManager.discoverInfo("juliet@capulet.com");
// Check if room is HOXT is supported
discoInfo.containsFeature("urn:xmpp:http");

IQ exchange

Description

You can use IQ's to perform HTTP requests and responses. This is applicable to relatively short requests and responses (due to limitation of XMPP message size).

Usage

First you need to register a PacketListener to be able to handle intended IQs.

For the HTTP client you:

• You create and send HttpOverXmppReq request.

• Then you handle the HttpOverXmppResp response in your PacketListener. For the HTTP server you:

• You handle the HttpOverXmppReq requests in your PacketListener.

• And create and send HttpOverXmppResp responses.

Examples

In this example we are HTTP client, so we send request (POST) and handle the response:

// register listener for IQ packets
connection.addPacketListener(new IqPacketListener(), new PacketTypeFilter(IQ.class));
// create a request body
String urlEncodedMessage = "I_love_you";

// create request
HttpOverXmppReq.Req req = new HttpOverXmppReq.Req(HttpMethod.POST, "/mailbox");
req.setVersion("1.1");

// prepare headers
Set<Header> set = new HashSet<Header>();
set.add(new Header("Host", "juliet.capulet.com"));
set.add(new Header("Content-Type", "application/x-www-form- urlencoded"));
set.add(new Header("Content-Length", Integer.toString(urlEncodedMessage.length())));
req.setHeaders(new HeadersExtension(set));

// provide body or request (not mandatory, - empty body is used for GET)
AbstractHttpOverXmpp.Text child = new AbstractHttpOverXmpp.Text(urlEncodedMessage);
AbstractHttpOverXmpp.Data data = new AbstractHttpOverXmpp.Data(child);
req.setData(data);

// create IQ packet
HttpOverXmppReq packet = new HttpOverXmppReq();
packet.setReq(req);
packet.setTo("juliet@capulet.com/balcony");
packet.setType(IQ.Type.SET);
packet.setPacketID("42");

// send it
connection.sendPacket(packet);


// then in your PacketListener
private class IqPacketListener implements PacketListener {

	@Override
	public void processPacket(Packet packet) {
	IQ iq = (IQ) packet;

	// verify from and packed ID
	if (iq.getFrom().equals("juliet@capulet.com/balcony") && (iq.getPacketID().equals("42"))) {

		// ensure it's not ERROR
		if (iq.getType().equals(IQ.Type.RESULT)) {

			// check if correct IQ implementation arrived
			if (iq instanceof HttpOverXmppResp) {
				HttpOverXmppResp resp = (HttpOverXmppResp) iq;

				// check HTTP response code
				if (resp.getResp().getStatusCode() == 200) {

					// get content of the response
					AbstractHttpOverXmpp.DataChild child = resp.getResp().getData().getChild();

					// check which type of content of the response arrived
					if (child instanceof AbstractHttpOverXmpp.Xml) {

						// print the message and anxiously read if from console ;)
						System.out.println(((AbstractHttpOverXmpp.Xml) child).getText());
					} else {
						// process other AbstractHttpOverXmpp.DataChild subtypes
					}
				}
			}
		}
	}
}
}