Smack/documentation/extensions/hoxt.html

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<title>HTTP over XMPP transport</title>
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<div class="header">HTTP over XMPP transport</div><p>
Allows to transport HTTP communication over XMPP peer-to-peer networks.<p>
<ul>
<li><a href="#disco">Discover HOXT support</a></li>
<li><a href="#iqexchange">IQ exchange</a></li>
</ul>
<hr>
<div class="subheader"><a name="disco">Discover HOXT support</a></div><p>
<b>Description</b><p>
Before using this extension you must ensure that your counterpart supports it also.</p>
<b>Usage</b><p>
<p>Once you have your <i><b>ServiceDiscoveryManager</b></i> you will be able to discover information associated with
an XMPP entity. To discover the information of a given XMPP entity send <b>discoverInfo(entityID)</b>
to your <i><b>ServiceDiscoveryManager</b></i> where entityID is the ID of the entity. The message
<b>discoverInfo(entityID)</b> will answer an instance of <i><b>DiscoverInfo</b></i> that contains
the discovered information.</p>
<b>Examples</b><p>
In this example we can see how to check if the counterpart supports HOXT: <br>
<blockquote>
<pre> <font color="#3f7f5f">// Obtain the ServiceDiscoveryManager associated with my XMPPConnection</font>
ServiceDiscoveryManager discoManager = ServiceDiscoveryManager.getInstanceFor(connection);
<font color="#3f7f5f">// Get the information of a given XMPP entity</font>
DiscoverInfo discoInfo = discoManager.discoverInfo("juliet@capulet.com");
<font color="#3f7f5f">// Check if room is HOXT is supported</font>
discoInfo.containsFeature("urn:xmpp:http");
</pre>
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<hr>
<div class="subheader"><a name="iqexchange">IQ exchange</a></div><p>
<b>Description</b><p>
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).</p>
<b>Usage</b><p>
<p>First you need to register a <i><b>PacketListener</b></i> to be able to handle intended IQs.<p>
For the HTTP client you:
<ul>
<li>You create and send <i><b>HttpOverXmppReq</b></i> request.</li>
<li>Then you handle the <i><b>HttpOverXmppResp</b></i> response in your <i><b>PacketListener</b></i>.</li>
</ul>
For the HTTP server you:
<ul>
<li>You handle the <i><b>HttpOverXmppReq</b></i> requests in your <i><b>PacketListener</b></i>.</li>
<li>And create and send <i><b>HttpOverXmppResp</b></i> responses.</li>
</ul>
</p>
<b>Examples</b><p>
In this example we are HTTP client, so we send request (POST) and handle the response: <br>
<blockquote>
<pre> <font color="#3f7f5f">// register listener for IQ packets</font>
connection.addPacketListener(new IqPacketListener(), new PacketTypeFilter(IQ.class));
<font color="#3f7f5f">// create a request body</font>
String urlEncodedMessage = "I_love_you";
<font color="#3f7f5f">// create request</font>
HttpOverXmppReq.Req req = new HttpOverXmppReq.Req(HttpMethod.POST, "/mailbox");
req.setVersion("1.1");
<font color="#3f7f5f">// prepare headers</font>
Set&lt;Header&gt; set = new HashSet&lt;Header&gt;();
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));
<font color="#3f7f5f">// provide body or request (not mandatory, - empty body is used for GET)</font>
AbstractHttpOverXmpp.Text child = new AbstractHttpOverXmpp.Text(urlEncodedMessage);
AbstractHttpOverXmpp.Data data = new AbstractHttpOverXmpp.Data(child);
req.setData(data);
<font color="#3f7f5f">// create IQ packet</font>
HttpOverXmppReq packet = new HttpOverXmppReq();
packet.setReq(req);
packet.setTo("juliet@capulet.com/balcony");
packet.setType(IQ.Type.SET);
packet.setPacketID("42");
<font color="#3f7f5f">// send it</font>
connection.sendPacket(packet);
<font color="#3f7f5f">// then in your PacketListener</font>
private class IqPacketListener implements PacketListener {
@Override
public void processPacket(Packet packet) {
IQ iq = (IQ) packet;
<font color="#3f7f5f">// verify from and packed ID</font>
if (iq.getFrom().equals("juliet@capulet.com/balcony") && (iq.getPacketID().equals("42"))) {
<font color="#3f7f5f">// ensure it's not ERROR</font>
if (iq.getType().equals(IQ.Type.RESULT)) {
<font color="#3f7f5f">// check if correct IQ implementation arrived</font>
if (iq instanceof HttpOverXmppResp) {
HttpOverXmppResp resp = (HttpOverXmppResp) iq;
<font color="#3f7f5f">// check HTTP response code</font>
if (resp.getResp().getStatusCode() == 200) {
<font color="#3f7f5f">// get content of the response</font>
AbstractHttpOverXmpp.DataChild child = resp.getResp().getData().getChild();
<font color="#3f7f5f">// check which type of content of the response arrived</font>
if (child instanceof AbstractHttpOverXmpp.Xml) {
<font color="#3f7f5f">// print the message and anxiously read if from console ;)</font>
System.out.println(((AbstractHttpOverXmpp.Xml) child).getText());
} else {
<font color="#3f7f5f">// process other AbstractHttpOverXmpp.DataChild subtypes</font>
}
}
}
}
}
}
}
</pre>
</blockquote>
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