Smack/documentation/extensions/hoxt.md

HTTP over XMPP transport

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Allows the transport of 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 with 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, where entityID is a Jid
DiscoverInfo discoInfo = discoManager.discoverInfo(entityID);
// Check if room is HOXT is supported
boolean isSupported = 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 the limitation of XMPP message size).

Usage

First you need to register a StanzaListener 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 StanzaListener.

For the HTTP server you:

• You handle the HttpOverXmppReq requests in your StanzaListener.
• And create and send HttpOverXmppResp responses.

Examples

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

// create a request body
String urlEncodedMessage = "I_love_you";

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

// 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);

// create request
HttpOverXmppReq req = HttpOverXmppReq.buider()
							.setMethod(HttpMethod.POST)
							.setResource("/mailbox")
							.setHeaders(headers)
							.setVersion("1.1")
							.setData(data)
							.build();

// add to, where jid is the Jid of the individual the packet is sent to
req.setTo(jid);

// send it
connection.sendIqWithResponseCallback(req, new StanzaListener() {
   public void processStanza(Stanza iq) {
		HttpOverXmppResp resp = (HttpOverXmppResp) iq;
		// check HTTP response code
		if (resp.getStatusCode() == 200) {
			// get content of the response
			NamedElement child = resp.getData().getChild();
			// check which type of content of the response arrived
			if (child instanceof AbstractHttpOverXmpp.Xml) {
				// print the message and anxiously read if from the console ;)
				System.out.println(((AbstractHttpOverXmpp.Xml) child).getText());
			} else {
				// process other AbstractHttpOverXmpp data child subtypes
			}
		}
	}
});