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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.channel.Channel;
19  import io.netty.channel.ChannelFuture;
20  import io.netty.channel.ChannelPromise;
21  import io.netty.handler.codec.http.HttpHeaders;
22  import io.netty.handler.codec.http.HttpHeaders.Names;
23  import io.netty.handler.codec.http.DefaultFullHttpResponse;
24  import io.netty.handler.codec.http.HttpRequest;
25  import io.netty.handler.codec.http.HttpResponse;
26  import io.netty.handler.codec.http.HttpResponseStatus;
27  import io.netty.handler.codec.http.HttpVersion;
28  
29  /**
30   * Auto-detects the version of the Web Socket protocol in use and creates a new proper
31   * {@link WebSocketServerHandshaker}.
32   */
33  public class WebSocketServerHandshakerFactory {
34  
35      private final String webSocketURL;
36  
37      private final String subprotocols;
38  
39      private final boolean allowExtensions;
40  
41      private final int maxFramePayloadLength;
42  
43      /**
44       * Constructor specifying the destination web socket location
45       *
46       * @param webSocketURL
47       *            URL for web socket communications. e.g "ws://myhost.com/mypath".
48       *            Subsequent web socket frames will be sent to this URL.
49       * @param subprotocols
50       *            CSV of supported protocols. Null if sub protocols not supported.
51       * @param allowExtensions
52       *            Allow extensions to be used in the reserved bits of the web socket frame
53       */
54      public WebSocketServerHandshakerFactory(
55              String webSocketURL, String subprotocols, boolean allowExtensions) {
56          this(webSocketURL, subprotocols, allowExtensions, 65536);
57      }
58  
59      /**
60       * Constructor specifying the destination web socket location
61       *
62       * @param webSocketURL
63       *            URL for web socket communications. e.g "ws://myhost.com/mypath".
64       *            Subsequent web socket frames will be sent to this URL.
65       * @param subprotocols
66       *            CSV of supported protocols. Null if sub protocols not supported.
67       * @param allowExtensions
68       *            Allow extensions to be used in the reserved bits of the web socket frame
69       * @param maxFramePayloadLength
70       *            Maximum allowable frame payload length. Setting this value to your application's
71       *            requirement may reduce denial of service attacks using long data frames.
72       */
73      public WebSocketServerHandshakerFactory(
74              String webSocketURL, String subprotocols, boolean allowExtensions,
75              int maxFramePayloadLength) {
76          this.webSocketURL = webSocketURL;
77          this.subprotocols = subprotocols;
78          this.allowExtensions = allowExtensions;
79          this.maxFramePayloadLength = maxFramePayloadLength;
80      }
81  
82      /**
83       * Instances a new handshaker
84       *
85       * @return A new WebSocketServerHandshaker for the requested web socket version. Null if web
86       *         socket version is not supported.
87       */
88      public WebSocketServerHandshaker newHandshaker(HttpRequest req) {
89  
90          String version = req.headers().get(Names.SEC_WEBSOCKET_VERSION);
91          if (version != null) {
92              if (version.equals(WebSocketVersion.V13.toHttpHeaderValue())) {
93                  // Version 13 of the wire protocol - RFC 6455 (version 17 of the draft hybi specification).
94                  return new WebSocketServerHandshaker13(
95                          webSocketURL, subprotocols, allowExtensions, maxFramePayloadLength);
96              } else if (version.equals(WebSocketVersion.V08.toHttpHeaderValue())) {
97                  // Version 8 of the wire protocol - version 10 of the draft hybi specification.
98                  return new WebSocketServerHandshaker08(
99                          webSocketURL, subprotocols, allowExtensions, maxFramePayloadLength);
100             } else if (version.equals(WebSocketVersion.V07.toHttpHeaderValue())) {
101                 // Version 8 of the wire protocol - version 07 of the draft hybi specification.
102                 return new WebSocketServerHandshaker07(
103                         webSocketURL, subprotocols, allowExtensions, maxFramePayloadLength);
104             } else {
105                 return null;
106             }
107         } else {
108             // Assume version 00 where version header was not specified
109             return new WebSocketServerHandshaker00(webSocketURL, subprotocols, maxFramePayloadLength);
110         }
111     }
112 
113     /**
114      * @deprecated use {@link #sendUnsupportedVersionResponse(Channel)}
115      */
116     @Deprecated
117     public static void sendUnsupportedWebSocketVersionResponse(Channel channel) {
118         sendUnsupportedVersionResponse(channel);
119     }
120 
121     /**
122      * Return that we need cannot not support the web socket version
123      */
124     public static ChannelFuture sendUnsupportedVersionResponse(Channel channel) {
125         return sendUnsupportedVersionResponse(channel, channel.newPromise());
126     }
127 
128     /**
129      * Return that we need cannot not support the web socket version
130      */
131     public static ChannelFuture sendUnsupportedVersionResponse(Channel channel, ChannelPromise promise) {
132         HttpResponse res = new DefaultFullHttpResponse(
133                 HttpVersion.HTTP_1_1,
134                 HttpResponseStatus.UPGRADE_REQUIRED);
135         res.headers().set(Names.SEC_WEBSOCKET_VERSION, WebSocketVersion.V13.toHttpHeaderValue());
136         HttpHeaders.setContentLength(res, 0);
137         return channel.writeAndFlush(res, promise);
138     }
139 }