View Javadoc

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