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ProxyFilter xref 

1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   * http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.apache.chemistry.opencmis.server.filter;
20  
21  import java.io.IOException;
22  import java.util.regex.Pattern;
23  
24  import javax.servlet.Filter;
25  import javax.servlet.FilterChain;
26  import javax.servlet.FilterConfig;
27  import javax.servlet.ServletException;
28  import javax.servlet.ServletRequest;
29  import javax.servlet.ServletResponse;
30  import javax.servlet.http.HttpServletRequest;
31  
32  /**
33   * A filter that corrects server name, server port and scheme if OpenCMIS is
34   * running behind a proxy or load balancer.
35   */
36  public class ProxyFilter implements Filter {
37  
38      public static final String PARAM_TRUSTED_PROXIES = "trustedProxies";
39  
40      private Pattern trustedProxies;
41  
42      public void init(FilterConfig filterConfig) throws ServletException {
43          trustedProxies = null;
44          String trustedProxiesString = filterConfig.getInitParameter(PARAM_TRUSTED_PROXIES);
45          if (trustedProxiesString != null) {
46              try {
47                  trustedProxies = Pattern.compile(trustedProxiesString);
48              } catch (Exception e) {
49                  throw new ServletException("Could not compile trustedProxies parameter: " + e, e);
50              }
51          }
52      }
53  
54      public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException,
55              ServletException {
56  
57          // check for trusted proxy
58          if (trustedProxies != null && (request instanceof HttpServletRequest)
59                  && trustedProxies.matcher(request.getRemoteAddr()).matches()) {
60              request = new ProxyHttpServletRequestWrapper((HttpServletRequest) request);
61          }
62  
63          // call next
64          chain.doFilter(request, response);
65      }
66  
67      public void destroy() {
68      }
69  }