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1   /*
2    * Copyright 2012 The Netty Project
3    *
4    * The Netty Project licenses this file to you under the Apache License,
5    * version 2.0 (the "License"); you may not use this file except in compliance
6    * with the License. You may obtain a copy of the License at:
7    *
8    *   http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13   * License for the specific language governing permissions and limitations
14   * under the License.
15   */
16  package io.netty.handler.codec.http.websocketx;
17  
18  import io.netty.handler.codec.http.DefaultFullHttpResponse;
19  import io.netty.handler.codec.http.FullHttpRequest;
20  import io.netty.handler.codec.http.FullHttpResponse;
21  import io.netty.handler.codec.http.HttpHeaders;
22  import io.netty.handler.codec.http.HttpHeaders.Names;
23  import io.netty.handler.codec.http.HttpResponseStatus;
24  import io.netty.util.CharsetUtil;
25  
26  import static io.netty.handler.codec.http.HttpHeaders.Values.*;
27  import static io.netty.handler.codec.http.HttpVersion.*;
28  
29  /**
30   * <p>
31   * Performs server side opening and closing handshakes for <a href="http://netty.io/s/rfc6455">RFC 6455</a>
32   * (originally web socket specification <a href="http://netty.io/s/ws-17">draft-ietf-hybi-thewebsocketprotocol-17</a>).
33   * </p>
34   */
35  public class WebSocketServerHandshaker13 extends WebSocketServerHandshaker {
36  
37      public static final String WEBSOCKET_13_ACCEPT_GUID = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
38  
39      private final boolean allowExtensions;
40  
41      /**
42       * Constructor specifying the destination web socket location
43       *
44       * @param webSocketURL
45       *        URL for web socket communications. e.g "ws://myhost.com/mypath". Subsequent web
46       *        socket frames will be sent to this URL.
47       * @param subprotocols
48       *        CSV of supported protocols
49       * @param allowExtensions
50       *        Allow extensions to be used in the reserved bits of the web socket frame
51       * @param maxFramePayloadLength
52       *        Maximum allowable frame payload length. Setting this value to your application's
53       *        requirement may reduce denial of service attacks using long data frames.
54       */
55      public WebSocketServerHandshaker13(
56              String webSocketURL, String subprotocols, boolean allowExtensions, int maxFramePayloadLength) {
57          super(WebSocketVersion.V13, webSocketURL, subprotocols, maxFramePayloadLength);
58          this.allowExtensions = allowExtensions;
59      }
60  
61      /**
62       * <p>
63       * Handle the web socket handshake for the web socket specification <a href=
64       * "http://tools.ietf.org/html/draft-ietf-hybi-thewebsocketprotocol-17">HyBi versions 13-17</a>. Versions 13-17
65       * share the same wire protocol.
66       * </p>
67       *
68       * <p>
69       * Browser request to the server:
70       * </p>
71       *
72       * <pre>
73       * GET /chat HTTP/1.1
74       * Host: server.example.com
75       * Upgrade: websocket
76       * Connection: Upgrade
77       * Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
78       * Sec-WebSocket-Origin: http://example.com
79       * Sec-WebSocket-Protocol: chat, superchat
80       * Sec-WebSocket-Version: 13
81       * </pre>
82       *
83       * <p>
84       * Server response:
85       * </p>
86       *
87       * <pre>
88       * HTTP/1.1 101 Switching Protocols
89       * Upgrade: websocket
90       * Connection: Upgrade
91       * Sec-WebSocket-Accept: s3pPLMBiTxaQ9kYGzzhZRbK+xOo=
92       * Sec-WebSocket-Protocol: chat
93       * </pre>
94       */
95      @Override
96      protected FullHttpResponse newHandshakeResponse(FullHttpRequest req, HttpHeaders headers) {
97          FullHttpResponse res = new DefaultFullHttpResponse(HTTP_1_1, HttpResponseStatus.SWITCHING_PROTOCOLS);
98          if (headers != null) {
99              res.headers().add(headers);
100         }
101 
102         String key = req.headers().get(Names.SEC_WEBSOCKET_KEY);
103         if (key == null) {
104             throw new WebSocketHandshakeException("not a WebSocket request: missing key");
105         }
106         String acceptSeed = key + WEBSOCKET_13_ACCEPT_GUID;
107         byte[] sha1 = WebSocketUtil.sha1(acceptSeed.getBytes(CharsetUtil.US_ASCII));
108         String accept = WebSocketUtil.base64(sha1);
109 
110         if (logger.isDebugEnabled()) {
111             logger.debug("WebSocket version 13 server handshake key: {}, response: {}", key, accept);
112         }
113 
114         res.headers().add(Names.UPGRADE, WEBSOCKET.toLowerCase());
115         res.headers().add(Names.CONNECTION, Names.UPGRADE);
116         res.headers().add(Names.SEC_WEBSOCKET_ACCEPT, accept);
117         String subprotocols = req.headers().get(Names.SEC_WEBSOCKET_PROTOCOL);
118         if (subprotocols != null) {
119             String selectedSubprotocol = selectSubprotocol(subprotocols);
120             if (selectedSubprotocol == null) {
121                 if (logger.isDebugEnabled()) {
122                     logger.debug("Requested subprotocol(s) not supported: {}", subprotocols);
123                 }
124             } else {
125                 res.headers().add(Names.SEC_WEBSOCKET_PROTOCOL, selectedSubprotocol);
126             }
127         }
128         return res;
129     }
130 
131     @Override
132     protected WebSocketFrameDecoder newWebsocketDecoder() {
133         return new WebSocket13FrameDecoder(true, allowExtensions, maxFramePayloadLength());
134     }
135 
136     @Override
137     protected WebSocketFrameEncoder newWebSocketEncoder() {
138         return new WebSocket13FrameEncoder(false);
139     }
140 }