/*
*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
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*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common Development
* and Distribution License("CDDL") (collectively, the "License"). You
* may not use this file except in compliance with the License. You can obtain
* a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
* or glassfish/bootstrap/legal/LICENSE.txt. See the License for the specific
* language governing permissions and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
* Sun designates this particular file as subject to the "Classpath" exception
* as provided by Sun in the GPL Version 2 section of the License file that
* accompanied this code. If applicable, add the following below the License
* Header, with the fields enclosed by brackets [] replaced by your own
* identifying information: "Portions Copyrighted [year]
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* only the GPL Version 2, indicate your decision by adding "[Contributor]
* elects to include this software in this distribution under the [CDDL or GPL
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* recipient has the option to distribute your version of this file under
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/*
* Copyright 2009 Richard Zschech.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package org.atmosphere.gwt.client.impl;
import com.google.gwt.core.client.JavaScriptException;
import com.google.gwt.dom.client.NativeEvent;
import com.google.gwt.event.dom.client.KeyCodes;
import com.google.gwt.event.dom.client.KeyDownEvent;
import com.google.gwt.http.client.RequestException;
import com.google.gwt.user.client.Event;
import com.google.gwt.user.client.Event.NativePreviewEvent;
import com.google.gwt.user.client.Event.NativePreviewHandler;
import com.google.gwt.user.client.Timer;
import com.google.gwt.xhr.client.ReadyStateChangeHandler;
import com.google.gwt.xhr.client.XMLHttpRequest;
/**
* This class uses a XmlHttpRequest and onreadystatechange events to process stream events.
*
* The main issue with this implementation is that GWT does not generate RECEIVING events from its XMLHTTPRequest. The
* implementation of XMLHTTPRequest included in this package overrides that behaviour.
*
* Another issues is that the memory required for the XMLHTTPRequest's responseText constantly grows so the server
* occasionally disconnects the client who then reestablishes the connection.
*
* The protocol for this transport is a '\n' separated transport messages. The different types of transport message are
* identified by the first character in the line as follows:
*
* ! A connection message followed by the heartbeat duration as an integer
*
* ? A clean server disconnection message
*
* # A heartbeat message
*
* * A padding message to cause the browser to start processing the stream
*
* ] A string message that needs unescaping
*
* | A string message that does not need unescaping
*
* [ A GWT serialized object
*
* R, r or f A GWT deRPC object
*
* string messages are escaped for '\\' and '\n' characters as '\n' is the message separator.
*
* GWT serialized object messages are escaped by GWT so do not need to be escaped by the transport
*
* @author Richard Zschech
*/
public class HTTPRequestCometTransport extends StreamingProtocolTransport {
/**
* Fix dropping RPC request when hitting ESC in firefox
* @see http://is.gd/dDeGQ
*/
static {
Event.addNativePreviewHandler(new NativePreviewHandler() {
@Override
public void onPreviewNativeEvent(NativePreviewEvent e) {
if (e.getTypeInt() == Event.getTypeInt(KeyDownEvent.getType().getName())) {
NativeEvent nativeEvent = e.getNativeEvent();
if (nativeEvent.getKeyCode() == KeyCodes.KEY_ESCAPE) {
nativeEvent.preventDefault();
}
}
}
});
}
private final static int POLLING_INTERVAL = 250;
private XMLHttpRequest xmlHttpRequest;
private Timer pollingTimer = new Timer() {
@Override
public void run() {
if (xmlHttpRequest != null && read < xmlHttpRequest.getResponseText().length()) {
onReceiving(xmlHttpRequest.getStatus(), xmlHttpRequest.getResponseText());
}
}
};
@Override
public void connect(int connectionCount) {
init();
xmlHttpRequest = XMLHttpRequest.create();
try {
xmlHttpRequest.open("GET", getUrl(connectionCount));
xmlHttpRequest.setRequestHeader("Accept", "application/comet");
xmlHttpRequest.setOnReadyStateChange(new ReadyStateChangeHandler() {
@Override
public void onReadyStateChange(XMLHttpRequest request) {
if (!aborted) {
switch (request.getReadyState()) {
case XMLHttpRequest.LOADING:
onReceiving(request.getStatus(), request.getResponseText());
if (needPolling()) {
pollingTimer.scheduleRepeating(POLLING_INTERVAL);
}
break;
case XMLHttpRequest.DONE:
onLoaded(request.getStatus(), request.getResponseText());
pollingTimer.cancel();
break;
}
} else {
request.clearOnReadyStateChange();
if (request.getReadyState() != XMLHttpRequest.DONE) {
request.abort();
}
}
}
});
xmlHttpRequest.send();
}
catch (JavaScriptException e) {
if (xmlHttpRequest != null) {
xmlHttpRequest.abort();
xmlHttpRequest = null;
}
listener.onError(new RequestException(e.getMessage()), false);
}
}
@Override
public void disconnect() {
aborted = true;
expectingDisconnection = true;
super.disconnect();
if (xmlHttpRequest != null) {
if (xmlHttpRequest.getReadyState() >= XMLHttpRequest.HEADERS_RECEIVED) {
// if readystate >= HEADERS_RECEIVED we can abort otherwise wait for this in onReadyStateChange
xmlHttpRequest.clearOnReadyStateChange();
if (xmlHttpRequest.getReadyState() != XMLHttpRequest.DONE) {
listener.onDisconnected();
xmlHttpRequest.abort();
}
xmlHttpRequest = null;
} else {
new Timer() {
XMLHttpRequest r = xmlHttpRequest;
@Override
public void run() {
r.clearOnReadyStateChange();
if (r.getReadyState() != XMLHttpRequest.DONE
&& r.getReadyState() != XMLHttpRequest.UNSENT) {
listener.onDisconnected();
r.abort();
}
r = null;
}
}.schedule(5000);
xmlHttpRequest = null;
}
}
}
protected boolean needPolling() {
String ua = getUserAgent();
return ua.contains("opera");
}
/**
* Returns the browser's user agent.
*
* @return the user agent
*/
public native static String getUserAgent() /*-{
return $wnd.navigator.userAgent.toLowerCase();
}-*/;
private void onLoaded(int statusCode, String responseText) {
xmlHttpRequest.clearOnReadyStateChange();
xmlHttpRequest = null;
onReceiving(statusCode, responseText, false);
}
private void onReceiving(int statusCode, String responseText) {
onReceiving(statusCode, responseText, true);
}
}