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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.hc.client5.http.protocol;
29  
30  import java.io.IOException;
31  
32  import org.apache.hc.client5.http.RouteInfo;
33  import org.apache.hc.core5.annotation.Contract;
34  import org.apache.hc.core5.annotation.ThreadingBehavior;
35  import org.apache.hc.core5.http.EntityDetails;
36  import org.apache.hc.core5.http.HeaderElements;
37  import org.apache.hc.core5.http.HttpException;
38  import org.apache.hc.core5.http.HttpHeaders;
39  import org.apache.hc.core5.http.HttpRequest;
40  import org.apache.hc.core5.http.HttpRequestInterceptor;
41  import org.apache.hc.core5.http.protocol.HttpContext;
42  import org.apache.hc.core5.util.Args;
43  import org.slf4j.Logger;
44  import org.slf4j.LoggerFactory;
45  
46  /**
47   * This protocol interceptor is responsible for adding the {@code Connection}
48   * header to the outgoing requests, which is essential for managing persistence
49   * of {@code HTTP/1.0} connections.
50   *
51   * @since 4.0
52   */
53  @Contract(threading = ThreadingBehavior.STATELESS)
54  public class RequestClientConnControl implements HttpRequestInterceptor {
55  
56      private static final Logger LOG = LoggerFactory.getLogger(RequestClientConnControl.class);
57  
58      public RequestClientConnControl() {
59          super();
60      }
61  
62      @Override
63      public void process(final HttpRequest request, final EntityDetails entity, final HttpContext context)
64              throws HttpException, IOException {
65          Args.notNull(request, "HTTP request");
66  
67          final String method = request.getMethod();
68          if (method.equalsIgnoreCase("CONNECT")) {
69              return;
70          }
71  
72          final HttpClientContext clientContext = HttpClientContext.adapt(context);
73  
74          // Obtain the client connection (required)
75          final RouteInfo route = clientContext.getHttpRoute();
76          if (route == null) {
77              LOG.debug("Connection route not set in the context");
78              return;
79          }
80  
81          if (route.getHopCount() == 1 || route.isTunnelled()) {
82              if (!request.containsHeader(HttpHeaders.CONNECTION)) {
83                  request.addHeader(HttpHeaders.CONNECTION, HeaderElements.KEEP_ALIVE);
84              }
85          }
86      }
87  
88  }