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.http.Method;
41 import org.apache.hc.core5.util.Args;
42
43 /**
44 * This request interceptor is responsible for adding {@code Connection} header
45 * to outgoing requests, which is essential for managing persistence of
46 * {@code HTTP/1.0} connections.
47 * <p>
48 * This interceptor is recommended for the HTTP protocol conformance and
49 * the correct operation of the client-side message processing pipeline.
50 * </p>
51 *
52 * @since 4.0
53 */
54 @Contract(threading = ThreadingBehavior.IMMUTABLE)
55 public class RequestConnControl implements HttpRequestInterceptor {
56
57 /**
58 * Singleton instance.
59 * @since 5.2
60 */
61 public static final HttpRequestInterceptor INSTANCE = new RequestConnControl();
62
63 public RequestConnControl() {
64 super();
65 }
66
67 @Override
68 public void process(final HttpRequest request, final EntityDetails entity, final HttpContext context)
69 throws HttpException, IOException {
70 Args.notNull(request, "HTTP request");
71
72 final String method = request.getMethod();
73 if (Method.CONNECT.isSame(method)) {
74 return;
75 }
76 if (!request.containsHeader(HttpHeaders.CONNECTION)) {
77 // Default policy is to keep connection alive
78 // whenever possible
79 if (request.containsHeader(HttpHeaders.UPGRADE)) {
80 request.addHeader(HttpHeaders.CONNECTION, HeaderElements.UPGRADE);
81 } else {
82 request.addHeader(HttpHeaders.CONNECTION, HeaderElements.KEEP_ALIVE);
83 }
84 }
85 }
86
87 }