netty5/codec-http/src/main/java/io/netty/handler/codec/http/websocketx/WebSocketServerHandshaker13.java

/*
 * Copyright 2011 The Netty Project
 *
 * The Netty Project 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 io.netty.handler.codec.http.websocketx;

import static io.netty.handler.codec.http.HttpHeaders.Values.WEBSOCKET;
import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;

import java.security.NoSuchAlgorithmException;

import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelPipeline;
import io.netty.handler.codec.http.HttpChunkAggregator;
import io.netty.handler.codec.http.DefaultHttpResponse;
import io.netty.handler.codec.http.HttpRequest;
import io.netty.handler.codec.http.HttpRequestDecoder;
import io.netty.handler.codec.http.HttpResponse;
import io.netty.handler.codec.http.HttpResponseEncoder;
import io.netty.handler.codec.http.HttpResponseStatus;
import io.netty.handler.codec.http.HttpHeaders.Names;
import io.netty.logging.InternalLogger;
import io.netty.logging.InternalLoggerFactory;
import io.netty.util.CharsetUtil;

/**
 * <p>
 * Performs server side opening and closing handshakes for <a href="http://tools.ietf.org/html/rfc6455 ">RFC 6455</a>
 * (originally web socket specification version <a
 * href="http://tools.ietf.org/html/draft-ietf-hybi-thewebsocketprotocol-17" >draft-ietf-hybi-thewebsocketprotocol-
 * 17</a>).
 * </p>
 */
public class WebSocketServerHandshaker13 extends WebSocketServerHandshaker {

    private static final InternalLogger logger = InternalLoggerFactory.getInstance(WebSocketServerHandshaker13.class);

    public static final String WEBSOCKET_13_ACCEPT_GUID = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";

    private boolean allowExtensions;

    /**
     * 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
     * @param allowExtensions
     *            Allow extensions to be used in the reserved bits of the web socket frame
     */
    public WebSocketServerHandshaker13(String webSocketURL, String subProtocols, boolean allowExtensions) {
        super(webSocketURL, subProtocols);
        this.allowExtensions = allowExtensions;
    }

    /**
     * <p>
     * Handle the web socket handshake for the web socket specification <a href=
     * "http://tools.ietf.org/html/draft-ietf-hybi-thewebsocketprotocol-17">HyBi versions 13-17</a>. Versions 13-17
     * share the same wire protocol.
     * </p>
     * 
     * <p>
     * Browser request to the server:
     * </p>
     * 
     * <pre>
     * GET /chat HTTP/1.1
     * Host: server.example.com
     * Upgrade: websocket
     * Connection: Upgrade
     * Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
     * Sec-WebSocket-Origin: http://example.com
     * Sec-WebSocket-Protocol: chat, superchat
     * Sec-WebSocket-Version: 13
     * </pre>
     * 
     * <p>
     * Server response:
     * </p>
     * 
     * <pre>
     * HTTP/1.1 101 Switching Protocols
     * Upgrade: websocket
     * Connection: Upgrade
     * Sec-WebSocket-Accept: s3pPLMBiTxaQ9kYGzzhZRbK+xOo=
     * Sec-WebSocket-Protocol: chat
     * </pre>
     * 
     * @param channel
     *            Channel
     * @param req
     *            HTTP request
     * @throws NoSuchAlgorithmException
     */
    @Override
    public void performOpeningHandshake(Channel channel, HttpRequest req) {

        if (logger.isDebugEnabled()) {
            logger.debug(String.format("Channel %s WS Version 13 server handshake", channel.getId()));
        }

        HttpResponse res = new DefaultHttpResponse(HTTP_1_1, new HttpResponseStatus(101, "Switching Protocols"));
        this.setVersion(WebSocketVersion.V13);

        String key = req.getHeader(Names.SEC_WEBSOCKET_KEY);
        if (key == null) {
            res.setStatus(HttpResponseStatus.BAD_REQUEST);
            return;
        }
        String acceptSeed = key + WEBSOCKET_13_ACCEPT_GUID;
        byte[] sha1 = sha1(acceptSeed.getBytes(CharsetUtil.US_ASCII));
        String accept = base64Encode(sha1);

        if (logger.isDebugEnabled()) {
            logger.debug(String.format("WS Version 13 Server Handshake key: %s. Response: %s.", key, accept));
        }

        res.setStatus(new HttpResponseStatus(101, "Switching Protocols"));
        res.addHeader(Names.UPGRADE, WEBSOCKET.toLowerCase());
        res.addHeader(Names.CONNECTION, Names.UPGRADE);
        res.addHeader(Names.SEC_WEBSOCKET_ACCEPT, accept);
        String protocol = req.getHeader(Names.SEC_WEBSOCKET_PROTOCOL);
        if (protocol != null) {
            res.addHeader(Names.SEC_WEBSOCKET_PROTOCOL, this.selectSubProtocol(protocol));
        }

        channel.write(res);

        // Upgrade the connection and send the handshake response.
        ChannelPipeline p = channel.getPipeline();
        p.remove(HttpChunkAggregator.class);
        p.replace(HttpRequestDecoder.class, "wsdecoder", new WebSocket13FrameDecoder(true, this.allowExtensions));
        p.replace(HttpResponseEncoder.class, "wsencoder", new WebSocket13FrameEncoder(false));

    }

    /**
     * Echo back the closing frame and close the connection
     * 
     * @param channel
     *            Channel
     * @param frame
     *            Web Socket frame that was received
     */
    @Override
    public void performClosingHandshake(Channel channel, CloseWebSocketFrame frame) {
        ChannelFuture f = channel.write(frame);
        f.addListener(ChannelFutureListener.CLOSE);
    }

}