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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 org.jboss.netty.handler.codec.http.websocketx;
17  
18  import org.jboss.netty.channel.Channel;
19  import org.jboss.netty.channel.ChannelFuture;
20  import org.jboss.netty.channel.ChannelFutureListener;
21  import org.jboss.netty.channel.ChannelHandlerContext;
22  import org.jboss.netty.channel.Channels;
23  import org.jboss.netty.handler.codec.http.HttpRequest;
24  import org.jboss.netty.util.internal.StringUtil;
25  
26  import java.util.Collections;
27  import java.util.LinkedHashSet;
28  import java.util.Set;
29  
30  /**
31   * Base class for server side web socket opening and closing handshakes
32   */
33  public abstract class WebSocketServerHandshaker {
34  
35      private final String webSocketUrl;
36  
37      private final String[] subprotocols;
38  
39      private final WebSocketVersion version;
40  
41      private final long maxFramePayloadLength;
42  
43      private String selectedSubprotocol;
44  
45      /**
46       * {@link ChannelFutureListener} which will call
47       * {@link Channels#fireExceptionCaught(ChannelHandlerContext, Throwable)}
48       * if the {@link ChannelFuture} was not successful.
49       */
50      public static final ChannelFutureListener HANDSHAKE_LISTENER = new ChannelFutureListener() {
51          public void operationComplete(ChannelFuture future) throws Exception {
52              if (!future.isSuccess()) {
53                  Channels.fireExceptionCaught(future.getChannel(), future.getCause());
54              }
55          }
56      };
57  
58      /**
59       * Constructor using default values
60       *
61       * @param version
62       *            the protocol version
63       * @param webSocketUrl
64       *            URL for web socket communications. e.g
65       *            "ws://myhost.com/mypath". Subsequent web socket frames will be
66       *            sent to this URL.
67       * @param subprotocols
68       *            CSV of supported protocols. Null if sub protocols not
69       *            supported.
70       */
71      protected WebSocketServerHandshaker(WebSocketVersion version, String webSocketUrl, String subprotocols) {
72          this(version, webSocketUrl, subprotocols, Long.MAX_VALUE);
73      }
74  
75      /**
76       * Constructor specifying the destination web socket location
77       *
78       * @param version
79       *            the protocol version
80       * @param webSocketUrl
81       *            URL for web socket communications. e.g
82       *            "ws://myhost.com/mypath". Subsequent web socket frames will be
83       *            sent to this URL.
84       * @param subprotocols
85       *            CSV of supported protocols. Null if sub protocols not
86       *            supported.
87       * @param maxFramePayloadLength
88       *            Maximum length of a frame's payload
89       */
90      protected WebSocketServerHandshaker(WebSocketVersion version, String webSocketUrl, String subprotocols,
91              long maxFramePayloadLength) {
92          this.version = version;
93          this.webSocketUrl = webSocketUrl;
94          if (subprotocols != null) {
95              String[] subprotocolArray = StringUtil.split(subprotocols, ',');
96              for (int i = 0; i < subprotocolArray.length; i++) {
97                  subprotocolArray[i] = subprotocolArray[i].trim();
98              }
99              this.subprotocols = subprotocolArray;
100         } else {
101             this.subprotocols = new String[0];
102         }
103         this.maxFramePayloadLength = maxFramePayloadLength;
104     }
105 
106     /**
107      * Returns the URL of the web socket
108      */
109     public String getWebSocketUrl() {
110         return webSocketUrl;
111     }
112 
113     /**
114      * Returns the CSV of supported sub protocols
115      */
116     public Set<String> getSubprotocols() {
117         Set<String> ret = new LinkedHashSet<String>();
118         Collections.addAll(ret, subprotocols);
119         return ret;
120     }
121 
122     /**
123      * Returns the version of the specification being supported
124      */
125     public WebSocketVersion getVersion() {
126         return version;
127     }
128 
129     /**
130      * Returns the max length for any frame's payload
131      */
132     public long getMaxFramePayloadLength() {
133         return maxFramePayloadLength;
134     }
135 
136     /**
137      * Performs the opening handshake
138      *
139      * @param channel
140      *            Channel
141      * @param req
142      *            HTTP Request
143      */
144     public abstract ChannelFuture handshake(Channel channel, HttpRequest req);
145 
146     /**
147      * Performs the closing handshake
148      *
149      * @param channel
150      *            Channel
151      * @param frame
152      *            Closing Frame that was received
153      */
154     public abstract ChannelFuture close(Channel channel, CloseWebSocketFrame frame);
155 
156     /**
157      * Selects the first matching supported sub protocol
158      *
159      * @param requestedSubprotocols
160      *            CSV of protocols to be supported. e.g. "chat, superchat"
161      * @return First matching supported sub protocol. Null if not found.
162      */
163     protected String selectSubprotocol(String requestedSubprotocols) {
164         if (requestedSubprotocols == null || subprotocols.length == 0) {
165             return null;
166         }
167 
168         String[] requestedSubprotocolArray = StringUtil.split(requestedSubprotocols, ',');
169         for (String p : requestedSubprotocolArray) {
170             String requestedSubprotocol = p.trim();
171 
172             for (String supportedSubprotocol : subprotocols) {
173                 if (requestedSubprotocol.equals(supportedSubprotocol)) {
174                     return requestedSubprotocol;
175                 }
176             }
177         }
178 
179         // No match found
180         return null;
181     }
182 
183     /**
184      * Returns the selected subprotocol. Null if no subprotocol has been selected.
185      * <p>
186      * This is only available AFTER <tt>handshake()</tt> has been called.
187      * </p>
188      */
189     public String getSelectedSubprotocol() {
190         return selectedSubprotocol;
191     }
192 
193     protected void setSelectedSubprotocol(String value) {
194         selectedSubprotocol = value;
195     }
196 
197 }