WebSocketServerHandshakerFactory.java

/*
 * Copyright 2010 Red Hat, Inc.
 *
 * Red Hat licenses this file to you 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.chililog.server.pubsub.websocket;

import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.handler.codec.http.DefaultHttpResponse;
import org.jboss.netty.handler.codec.http.HttpRequest;
import org.jboss.netty.handler.codec.http.HttpResponse;
import org.jboss.netty.handler.codec.http.HttpResponseStatus;
import org.jboss.netty.handler.codec.http.HttpVersion;

/**
 * Instances the appropriate handshake class to use for clients
 * 
 * @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
 */
public class WebSocketServerHandshakerFactory {

	private String webSocketURL;

	private String subProtocols;

	private boolean allowExtensions = false;

    public static final String SEC_WEBSOCKET_VERSION = "Sec-WebSocket-Version";
    public static final String SEC_WEBSOCKET_KEY = "Sec-WebSocket-Key";
    public static final String SEC_WEBSOCKET_ACCEPT = "Sec-WebSocket-Accept";

	/**
	 * Constructor specifying the destination web socket location
	 * 
	 * @param webSocketURL
	 *            URL for web socket communications. e.g
	 *            "ws://myhost.com/mypath". Subsequent web socket frames will be
	 *            sent to this URL.
	 * @param subProtocols
	 *            CSV of supported protocols. Null if sub protocols not
	 *            supported.
	 * @param allowExtensions
	 *            Allow extensions to be used in the reserved bits of the web
	 *            socket frame
	 */
	public WebSocketServerHandshakerFactory(String webSocketURL, String subProtocols, boolean allowExtensions) {
		this.webSocketURL = webSocketURL;
		this.subProtocols = subProtocols;
		this.allowExtensions = allowExtensions;
		return;
	}

	/**
	 * Instances a new handshaker
	 * 
	 * @param webSocketURL
	 *            URL for web socket communications. e.g
	 *            "ws://myhost.com/mypath". Subsequent web socket frames will be
	 *            sent to this URL.
	 * @param version
	 *            Version of web socket specification to use to connect to the
	 *            server
	 * @param subProtocol
	 *            Sub protocol request sent to the server. Null if no
	 *            sub-protocol support is required.
	 * @return A new WebSocketServerHandshaker for the requested web socket
	 *         version. Null if web socket version is not supported.
	 */
	public WebSocketServerHandshaker newHandshaker(ChannelHandlerContext ctx, HttpRequest req) {

		String version = req.getHeader(SEC_WEBSOCKET_VERSION);
		if (version != null) {
			if (version.equals("8")) {
				// Version 8 of the wire protocol - assume version 10 of the
				// specification.
				return new WebSocketServerHandshaker10(webSocketURL, subProtocols, this.allowExtensions);
			} else {
				return null;
			}
		} else {
			// Assume version 00 where version header was not specified
			return new WebSocketServerHandshaker00(webSocketURL, subProtocols);
		}
	}

	/**
	 * Return that we need cannot not support the web socket version
	 * 
	 * @param ctx
	 *            Context
	 */
	public void sendUnsupportedWebSocketVersionResponse(ChannelHandlerContext ctx) {
		HttpResponse res = new DefaultHttpResponse(HttpVersion.HTTP_1_1, new HttpResponseStatus(101,
				"Switching Protocols"));
		res.setStatus(HttpResponseStatus.UPGRADE_REQUIRED);
		res.setHeader(SEC_WEBSOCKET_VERSION, "8");
		ctx.getChannel().write(res);
		return;
	}

}