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.http.HttpEntity;
33 import org.apache.http.HttpEntityEnclosingRequest;
34 import org.apache.http.HttpException;
35 import org.apache.http.HttpRequest;
36 import org.apache.http.HttpRequestInterceptor;
37 import org.apache.http.HttpVersion;
38 import org.apache.http.ProtocolVersion;
39 import org.apache.http.annotation.Contract;
40 import org.apache.http.annotation.ThreadingBehavior;
41 import org.apache.http.client.config.RequestConfig;
42 import org.apache.http.protocol.HTTP;
43 import org.apache.http.protocol.HttpContext;
44 import org.apache.http.util.Args;
45
46 /**
47 * RequestExpectContinue is responsible for enabling the 'expect-continue'
48 * handshake by adding {@code Expect} header.
49 * <p>
50 * This interceptor takes into account {@link RequestConfig#isExpectContinueEnabled()}
51 * setting.
52 * </p>
53 *
54 * @since 4.3
55 */
56 @Contract(threading = ThreadingBehavior.IMMUTABLE)
57 public class RequestExpectContinue implements HttpRequestInterceptor {
58
59 public RequestExpectContinue() {
60 super();
61 }
62
63 @Override
64 public void process(final HttpRequest request, final HttpContext context)
65 throws HttpException, IOException {
66 Args.notNull(request, "HTTP request");
67
68 if (!request.containsHeader(HTTP.EXPECT_DIRECTIVE)) {
69 if (request instanceof HttpEntityEnclosingRequest) {
70 final ProtocolVersion ver = request.getRequestLine().getProtocolVersion();
71 final HttpEntity entity = ((HttpEntityEnclosingRequest)request).getEntity();
72 // Do not send the expect header if request body is known to be empty
73 if (entity != null
74 && entity.getContentLength() != 0 && !ver.lessEquals(HttpVersion.HTTP_1_0)) {
75 final HttpClientContext clientContext = HttpClientContext.adapt(context);
76 final RequestConfig config = clientContext.getRequestConfig();
77 if (config.isExpectContinueEnabled()) {
78 request.addHeader(HTTP.EXPECT_DIRECTIVE, HTTP.EXPECT_CONTINUE);
79 }
80 }
81 }
82 }
83 }
84
85 }
86