1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
|
//
// ========================================================================
// Copyright (c) 1995-2016 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
//
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
//
// You may elect to redistribute this code under either of these licenses.
// ========================================================================
//
package org.eclipse.jetty.fcgi.server.proxy;
import java.io.IOException;
import java.net.URISyntaxException;
import java.net.URL;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Inspired by nginx's try_files functionality.
* <p>
* This filter accepts the <code>files</code> init-param as a list of space-separated
* file URIs. The special token <code>$path</code> represents the current request URL's
* path (the portion after the context path).
* <p>
* Typical example of how this filter can be configured is the following:
* <pre>
* <filter>
* <filter-name>try_files</filter-name>
* <filter-class>org.eclipse.jetty.fcgi.server.proxy.TryFilesFilter</filter-class>
* <init-param>
* <param-name>files</param-name>
* <param-value>maintenance.html $path index.php?p=$path</param-value>
* </init-param>
* </filter>
* </pre>
* For a request such as <code>/context/path/to/resource.ext</code>, this filter will
* try to serve the <code>/maintenance.html</code> file if it finds it; failing that,
* it will try to serve the <code>/path/to/resource.ext</code> file if it finds it;
* failing that it will forward the request to <code>index.php?p=/path/to/resource.ext</code>.
* The last file URI specified in the list is therefore the "fallback" to which the request
* is forwarded to in case no previous files can be found.
* <p>
* The files are resolved using {@link ServletContext#getResource(String)} to make sure
* that only files visible to the application are served.
*
* @see FastCGIProxyServlet
*/
public class TryFilesFilter implements Filter
{
public static final String FILES_INIT_PARAM = "files";
private String[] files;
@Override
public void init(FilterConfig config) throws ServletException
{
String param = config.getInitParameter(FILES_INIT_PARAM);
if (param == null)
throw new ServletException(String.format("Missing mandatory parameter '%s'", FILES_INIT_PARAM));
files = param.split(" ");
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException
{
HttpServletRequest httpRequest = (HttpServletRequest)request;
HttpServletResponse httpResponse = (HttpServletResponse)response;
for (int i = 0; i < files.length - 1; ++i)
{
String file = files[i];
String resolved = resolve(httpRequest, file);
URL url = request.getServletContext().getResource(resolved);
if (url == null)
continue;
if (Files.isReadable(toPath(url)))
{
chain.doFilter(httpRequest, httpResponse);
return;
}
}
// The last one is the fallback
fallback(httpRequest, httpResponse, chain, files[files.length - 1]);
}
private Path toPath(URL url) throws IOException
{
try
{
return Paths.get(url.toURI());
}
catch (URISyntaxException x)
{
throw new IOException(x);
}
}
protected void fallback(HttpServletRequest request, HttpServletResponse response, FilterChain chain, String fallback) throws IOException, ServletException
{
String resolved = resolve(request, fallback);
request.getServletContext().getRequestDispatcher(resolved).forward(request, response);
}
private String resolve(HttpServletRequest request, String value)
{
String path = request.getServletPath();
String info = request.getPathInfo();
if (info != null)
path += info;
if (!path.startsWith("/"))
path = "/" + path;
return value.replaceAll("\\$path", path);
}
@Override
public void destroy()
{
}
}
|
