1 //
2 // ========================================================================
3 // Copyright (c) 1995-2013 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
23 import javax.servlet.RequestDispatcher;
24 import javax.servlet.ServletContext;
25 import javax.servlet.ServletException;
26 import javax.servlet.http.HttpServlet;
27 import javax.servlet.http.HttpServletRequest;
28 import javax.servlet.http.HttpServletResponse;
29
30 /* ------------------------------------------------------------ */
31 /** Concatenation Servlet
32 * This servlet may be used to concatenate multiple resources into
33 * a single response. It is intended to be used to load multiple
34 * javascript or css files, but may be used for any content of the
35 * same mime type that can be meaningfully concatenated.
36 * <p>
37 * The servlet uses {@link RequestDispatcher#include(javax.servlet.ServletRequest, javax.servlet.ServletResponse)}
38 * to combine the requested content, so dynamically generated content
39 * may be combined (Eg engine.js for DWR).
40 * <p>
41 * The servlet uses parameter names of the query string as resource names
42 * relative to the context root. So these script tags:
43 * <pre>
44 * <script type="text/javascript" src="../js/behaviour.js"></script>
45 * <script type="text/javascript" src="../js/ajax.js&/chat/chat.js"></script>
46 * <script type="text/javascript" src="../chat/chat.js"></script>
47 * </pre> can be replaced with the single tag (with the ConcatServlet mapped to /concat):
48 * <pre>
49 * <script type="text/javascript" src="../concat?/js/behaviour.js&/js/ajax.js&/chat/chat.js"></script>
50 * </pre>
51 * The {@link ServletContext#getMimeType(String)} method is used to determine the
52 * mime type of each resource. If the types of all resources do not match, then a 415
53 * UNSUPPORTED_MEDIA_TYPE error is returned.
54 * <p>
55 * If the init parameter "development" is set to "true" then the servlet will run in
56 * development mode and the content will be concatenated on every request. Otherwise
57 * the init time of the servlet is used as the lastModifiedTime of the combined content
58 * and If-Modified-Since requests are handled with 206 NOT Modified responses if
59 * appropriate. This means that when not in development mode, the servlet must be
60 * restarted before changed content will be served.
61 *
62 *
63 *
64 */
65 public class ConcatServlet extends HttpServlet
66 {
67 boolean _development;
68 long _lastModified;
69 ServletContext _context;
70
71 /* ------------------------------------------------------------ */
72 public void init() throws ServletException
73 {
74 _lastModified=System.currentTimeMillis();
75 _context=getServletContext();
76 _development="true".equals(getInitParameter("development"));
77 }
78
79 /* ------------------------------------------------------------ */
80 /*
81 * @return The start time of the servlet unless in development mode, in which case -1 is returned.
82 */
83 protected long getLastModified(HttpServletRequest req)
84 {
85 return _development?-1:_lastModified;
86 }
87
88 /* ------------------------------------------------------------ */
89 protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException
90 {
91 String q=req.getQueryString();
92 if (q==null)
93 {
94 resp.sendError(HttpServletResponse.SC_NO_CONTENT);
95 return;
96 }
97
98 String[] parts = q.split("\\&");
99 String type=null;
100 for (int i=0;i<parts.length;i++)
101 {
102 String t = _context.getMimeType(parts[i]);
103 if (t!=null)
104 {
105 if (type==null)
106 type=t;
107 else if (!type.equals(t))
108 {
109 resp.sendError(HttpServletResponse.SC_UNSUPPORTED_MEDIA_TYPE);
110 return;
111 }
112 }
113 }
114
115 if (type!=null)
116 resp.setContentType(type);
117
118 for (int i=0;i<parts.length;i++)
119 {
120 RequestDispatcher dispatcher=_context.getRequestDispatcher(parts[i]);
121 if (dispatcher!=null)
122 dispatcher.include(req,resp);
123 }
124 }
125 }