1 /*
2 * Copyright (C) 2010, Google Inc.
3 * and other copyright owners as documented in the project's IP log.
4 *
5 * This program and the accompanying materials are made available
6 * under the terms of the Eclipse Distribution License v1.0 which
7 * accompanies this distribution, is reproduced below, and is
8 * available at http://www.eclipse.org/org/documents/edl-v10.php
9 *
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or
13 * without modification, are permitted provided that the following
14 * conditions are met:
15 *
16 * - Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 *
19 * - Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials provided
22 * with the distribution.
23 *
24 * - Neither the name of the Eclipse Foundation, Inc. nor the
25 * names of its contributors may be used to endorse or promote
26 * products derived from this software without specific prior
27 * written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
30 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
31 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
34 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
35 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
37 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
38 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
41 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 */
43
44 package org.eclipse.jgit.http.server;
45
46 import static org.eclipse.jgit.util.HttpSupport.HDR_CACHE_CONTROL;
47 import static org.eclipse.jgit.util.HttpSupport.HDR_EXPIRES;
48 import static org.eclipse.jgit.util.HttpSupport.HDR_PRAGMA;
49
50 import java.io.IOException;
51
52 import javax.servlet.Filter;
53 import javax.servlet.FilterChain;
54 import javax.servlet.FilterConfig;
55 import javax.servlet.ServletException;
56 import javax.servlet.ServletRequest;
57 import javax.servlet.ServletResponse;
58 import javax.servlet.http.HttpServletResponse;
59
60 /** Add HTTP response headers to prevent caching by proxies/browsers. */
61 class NoCacheFilter implements Filter {
62 /** {@inheritDoc} */
63 @Override
64 public void init(FilterConfig config) throws ServletException {
65 // Do nothing.
66 }
67
68 /** {@inheritDoc} */
69 @Override
70 public void destroy() {
71 // Do nothing.
72 }
73
74 /** {@inheritDoc} */
75 @Override
76 public void doFilter(ServletRequest request, ServletResponse response,
77 FilterChain chain) throws IOException, ServletException {
78 HttpServletResponse rsp = (HttpServletResponse) response;
79
80 rsp.setHeader(HDR_EXPIRES, "Fri, 01 Jan 1980 00:00:00 GMT");
81 rsp.setHeader(HDR_PRAGMA, "no-cache");
82
83 final String nocache = "no-cache, max-age=0, must-revalidate";
84 rsp.setHeader(HDR_CACHE_CONTROL, nocache);
85
86 chain.doFilter(request, response);
87 }
88 }