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1   package org.eclipse.jetty.websocket;
2   
3   import java.io.IOException;
4   
5   import javax.servlet.ServletException;
6   import javax.servlet.http.HttpServlet;
7   import javax.servlet.http.HttpServletRequest;
8   import javax.servlet.http.HttpServletResponse;
9   
10  
11  /* ------------------------------------------------------------ */
12  /**
13   * Servlet to upgrade connections to WebSocket
14   * <p>
15   * The request must have the correct upgrade headers, else it is
16   * handled as a normal servlet request.
17   * <p>
18   * The initParameter "bufferSize" can be used to set the buffer size,
19   * which is also the max frame byte size (default 8192).
20   * <p>
21   * The initParameter "maxIdleTime" can be used to set the time in ms
22   * that a websocket may be idle before closing (default 300,000).
23   * 
24   */
25  public abstract class WebSocketServlet extends HttpServlet
26  {
27      WebSocketFactory _websocket;
28         
29      /* ------------------------------------------------------------ */
30      /**
31       * @see javax.servlet.GenericServlet#init()
32       */
33      @Override
34      public void init() throws ServletException
35      {
36          String bs=getInitParameter("bufferSize");
37          _websocket = new WebSocketFactory(bs==null?8192:Integer.parseInt(bs));
38          String mit=getInitParameter("maxIdleTime");
39          if (mit!=null)
40              _websocket.setMaxIdleTime(Integer.parseInt(mit));
41      }
42  
43      /* ------------------------------------------------------------ */
44      /**
45       * @see javax.servlet.http.HttpServlet#service(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
46       */
47      @Override
48      protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
49      {
50          if ("WebSocket".equals(request.getHeader("Upgrade")))
51          {
52              String protocol=request.getHeader("WebSocket-Protocol");
53              WebSocket websocket=doWebSocketConnect(request,protocol);
54  
55              String host=request.getHeader("Host");
56              String origin=request.getHeader("Origin");
57              origin=checkOrigin(request,host,origin);
58              
59              if (websocket!=null)
60                  _websocket.upgrade(request,response,websocket,origin,protocol);
61              else
62                  response.sendError(503);
63          }
64          else
65              super.service(request,response);
66      }
67  
68      protected String checkOrigin(HttpServletRequest request, String host, String origin)
69      {
70          if (origin==null)
71              origin=host;
72          return origin;
73      }
74      
75      abstract protected WebSocket doWebSocketConnect(HttpServletRequest request,String protocol);
76      
77      
78  }