1 //
2 // ========================================================================
3 // Copyright (c) 1995-2012 Mort Bay Consulting Pty. Ltd.
4 // ------------------------------------------------------------------------
5 // All rights reserved. This program and the accompanying materials
6 // are made available under the terms of the Eclipse Public License v1.0
7 // and Apache License v2.0 which accompanies this distribution.
8 //
9 // The Eclipse Public License is available at
10 // http://www.eclipse.org/legal/epl-v10.html
11 //
12 // The Apache License v2.0 is available at
13 // http://www.opensource.org/licenses/apache2.0.php
14 //
15 // You may elect to redistribute this code under either of these licenses.
16 // ========================================================================
17 //
18
19 package org.eclipse.jetty.servlets;
20
21 import java.io.IOException;
22 import javax.servlet.RequestDispatcher;
23 import javax.servlet.ServletContext;
24 import javax.servlet.ServletException;
25 import javax.servlet.http.HttpServlet;
26 import javax.servlet.http.HttpServletRequest;
27 import javax.servlet.http.HttpServletResponse;
28
29 /* ------------------------------------------------------------ */
30 /** Concatenation Servlet
31 * This servlet may be used to concatenate multiple resources into
32 * a single response. It is intended to be used to load multiple
33 * javascript or css files, but may be used for any content of the
34 * same mime type that can be meaningfully concatenated.
35 * <p>
36 * The servlet uses {@link RequestDispatcher#include(javax.servlet.ServletRequest, javax.servlet.ServletResponse)}
37 * to combine the requested content, so dynamically generated content
38 * may be combined (Eg engine.js for DWR).
39 * <p>
40 * The servlet uses parameter names of the query string as resource names
41 * relative to the context root. So these script tags:
42 * <pre>
43 * <script type="text/javascript" src="../js/behaviour.js"></script>
44 * <script type="text/javascript" src="../js/ajax.js&/chat/chat.js"></script>
45 * <script type="text/javascript" src="../chat/chat.js"></script>
46 * </pre> can be replaced with the single tag (with the ConcatServlet mapped to /concat):
47 * <pre>
48 * <script type="text/javascript" src="../concat?/js/behaviour.js&/js/ajax.js&/chat/chat.js"></script>
49 * </pre>
50 * The {@link ServletContext#getMimeType(String)} method is used to determine the
51 * mime type of each resource. If the types of all resources do not match, then a 415
52 * UNSUPPORTED_MEDIA_TYPE error is returned.
53 * <p>
54 * If the init parameter "development" is set to "true" then the servlet will run in
55 * development mode and the content will be concatenated on every request. Otherwise
56 * the init time of the servlet is used as the lastModifiedTime of the combined content
57 * and If-Modified-Since requests are handled with 206 NOT Modified responses if
58 * appropriate. This means that when not in development mode, the servlet must be
59 * restarted before changed content will be served.
60 *
61 *
62 *
63 */
64 public class ConcatServlet extends HttpServlet
65 {
66 boolean _development;
67 long _lastModified;
68 ServletContext _context;
69
70 /* ------------------------------------------------------------ */
71 public void init() throws ServletException
72 {
73 _lastModified=System.currentTimeMillis();
74 _context=getServletContext();
75 _development="true".equals(getInitParameter("development"));
76 }
77
78 /* ------------------------------------------------------------ */
79 /*
80 * @return The start time of the servlet unless in development mode, in which case -1 is returned.
81 */
82 protected long getLastModified(HttpServletRequest req)
83 {
84 return _development?-1:_lastModified;
85 }
86
87 /* ------------------------------------------------------------ */
88 protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException
89 {
90 String q=req.getQueryString();
91 if (q==null)
92 {
93 resp.sendError(HttpServletResponse.SC_NO_CONTENT);
94 return;
95 }
96
97 String[] parts = q.split("\\&");
98 String type=null;
99 for (int i=0;i<parts.length;i++)
100 {
101 String t = _context.getMimeType(parts[i]);
102 if (t!=null)
103 {
104 if (type==null)
105 type=t;
106 else if (!type.equals(t))
107 {
108 resp.sendError(HttpServletResponse.SC_UNSUPPORTED_MEDIA_TYPE);
109 return;
110 }
111 }
112 }
113
114 if (type!=null)
115 resp.setContentType(type);
116
117 for (int i=0;i<parts.length;i++)
118 {
119 RequestDispatcher dispatcher=_context.getRequestDispatcher(parts[i]);
120 if (dispatcher!=null)
121 dispatcher.include(req,resp);
122 }
123 }
124 }