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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.core5.http.protocol;
29  
30  import java.io.IOException;
31  
32  import org.apache.hc.core5.annotation.Contract;
33  import org.apache.hc.core5.annotation.ThreadingBehavior;
34  import org.apache.hc.core5.http.EntityDetails;
35  import org.apache.hc.core5.http.HeaderElements;
36  import org.apache.hc.core5.http.HttpException;
37  import org.apache.hc.core5.http.HttpHeaders;
38  import org.apache.hc.core5.http.HttpRequest;
39  import org.apache.hc.core5.http.HttpRequestInterceptor;
40  import org.apache.hc.core5.util.Args;
41  
42  /**
43   * RequestConnControl is responsible for adding {@code Connection} header
44   * to the outgoing requests, which is essential for managing persistence of
45   * {@code HTTP/1.0} connections. This interceptor is recommended for
46   * client side protocol processors.
47   *
48   * @since 4.0
49   */
50  @Contract(threading = ThreadingBehavior.IMMUTABLE)
51  public class RequestConnControl implements HttpRequestInterceptor {
52  
53      public RequestConnControl() {
54          super();
55      }
56  
57      @Override
58      public void process(final HttpRequest request, final EntityDetails entity, final HttpContext context)
59              throws HttpException, IOException {
60          Args.notNull(request, "HTTP request");
61  
62          final String method = request.getMethod();
63          if (method.equalsIgnoreCase("CONNECT")) {
64              return;
65          }
66  
67          if (!request.containsHeader(HttpHeaders.CONNECTION)) {
68              // Default policy is to keep connection alive
69              // whenever possible
70              if (request.containsHeader(HttpHeaders.UPGRADE)) {
71                  request.addHeader(HttpHeaders.CONNECTION, HeaderElements.UPGRADE);
72              } else {
73                  request.addHeader(HttpHeaders.CONNECTION, HeaderElements.KEEP_ALIVE);
74              }
75          }
76      }
77  
78  }