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1   /*
2    * ====================================================================
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *   http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing,
14   * software distributed under the License is distributed on an
15   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16   * KIND, either express or implied.  See the License for the
17   * specific language governing permissions and limitations
18   * under the License.
19   * ====================================================================
20   *
21   * This software consists of voluntary contributions made by many
22   * individuals on behalf of the Apache Software Foundation.  For more
23   * information on the Apache Software Foundation, please see
24   * <http://www.apache.org/>.
25   *
26   */
27  
28  package org.apache.http.client.protocol;
29  
30  import java.io.IOException;
31  
32  import org.apache.commons.logging.Log;
33  import org.apache.commons.logging.LogFactory;
34  import org.apache.http.HttpException;
35  import org.apache.http.HttpRequest;
36  import org.apache.http.HttpRequestInterceptor;
37  import org.apache.http.annotation.Contract;
38  import org.apache.http.annotation.ThreadingBehavior;
39  import org.apache.http.conn.routing.RouteInfo;
40  import org.apache.http.protocol.HTTP;
41  import org.apache.http.protocol.HttpContext;
42  import org.apache.http.util.Args;
43  
44  /**
45   * This protocol interceptor is responsible for adding {@code Connection}
46   * or {@code Proxy-Connection} headers to the outgoing requests, which
47   * is essential for managing persistence of {@code HTTP/1.0} connections.
48   *
49   * @since 4.0
50   */
51  @Contract(threading = ThreadingBehavior.IMMUTABLE)
52  public class RequestClientConnControl implements HttpRequestInterceptor {
53  
54      private final Log log = LogFactory.getLog(getClass());
55  
56      private static final String PROXY_CONN_DIRECTIVE = "Proxy-Connection";
57  
58      public RequestClientConnControl() {
59          super();
60      }
61  
62      @Override
63      public void process(final HttpRequest request, final HttpContext context)
64              throws HttpException, IOException {
65          Args.notNull(request, "HTTP request");
66  
67          final String method = request.getRequestLine().getMethod();
68          if (method.equalsIgnoreCase("CONNECT")) {
69              request.setHeader(PROXY_CONN_DIRECTIVE, HTTP.CONN_KEEP_ALIVE);
70              return;
71          }
72  
73          final HttpClientContext clientContext = HttpClientContext.adapt(context);
74  
75          // Obtain the client connection (required)
76          final RouteInfo route = clientContext.getHttpRoute();
77          if (route == null) {
78              this.log.debug("Connection route not set in the context");
79              return;
80          }
81  
82          if (route.getHopCount() == 1 || route.isTunnelled()) {
83              if (!request.containsHeader(HTTP.CONN_DIRECTIVE)) {
84                  request.addHeader(HTTP.CONN_DIRECTIVE, HTTP.CONN_KEEP_ALIVE);
85              }
86          }
87          if (route.getHopCount() == 2 && !route.isTunnelled()) {
88              if (!request.containsHeader(PROXY_CONN_DIRECTIVE)) {
89                  request.addHeader(PROXY_CONN_DIRECTIVE, HTTP.CONN_KEEP_ALIVE);
90              }
91          }
92      }
93  
94  }