001/* 002 * ==================================================================== 003 * Licensed to the Apache Software Foundation (ASF) under one 004 * or more contributor license agreements. See the NOTICE file 005 * distributed with this work for additional information 006 * regarding copyright ownership. The ASF licenses this file 007 * to you under the Apache License, Version 2.0 (the 008 * "License"); you may not use this file except in compliance 009 * with the License. You may obtain a copy of the License at 010 * 011 * http://www.apache.org/licenses/LICENSE-2.0 012 * 013 * Unless required by applicable law or agreed to in writing, 014 * software distributed under the License is distributed on an 015 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 016 * KIND, either express or implied. See the License for the 017 * specific language governing permissions and limitations 018 * under the License. 019 * ==================================================================== 020 * 021 * This software consists of voluntary contributions made by many 022 * individuals on behalf of the Apache Software Foundation. For more 023 * information on the Apache Software Foundation, please see 024 * <http://www.apache.org/>. 025 * 026 */ 027 028package org.apache.http.client.protocol; 029 030import java.io.IOException; 031 032import org.apache.http.HttpEntity; 033import org.apache.http.HttpEntityEnclosingRequest; 034import org.apache.http.HttpException; 035import org.apache.http.HttpRequest; 036import org.apache.http.HttpRequestInterceptor; 037import org.apache.http.HttpVersion; 038import org.apache.http.ProtocolVersion; 039import org.apache.http.annotation.Contract; 040import org.apache.http.annotation.ThreadingBehavior; 041import org.apache.http.client.config.RequestConfig; 042import org.apache.http.protocol.HTTP; 043import org.apache.http.protocol.HttpContext; 044import org.apache.http.util.Args; 045 046/** 047 * RequestExpectContinue is responsible for enabling the 'expect-continue' 048 * handshake by adding {@code Expect} header. 049 * <p> 050 * This interceptor takes into account {@link RequestConfig#isExpectContinueEnabled()} 051 * setting. 052 * </p> 053 * 054 * @since 4.3 055 */ 056@Contract(threading = ThreadingBehavior.IMMUTABLE) 057public class RequestExpectContinue implements HttpRequestInterceptor { 058 059 public RequestExpectContinue() { 060 super(); 061 } 062 063 @Override 064 public void process(final HttpRequest request, final HttpContext context) 065 throws HttpException, IOException { 066 Args.notNull(request, "HTTP request"); 067 068 if (!request.containsHeader(HTTP.EXPECT_DIRECTIVE)) { 069 if (request instanceof HttpEntityEnclosingRequest) { 070 final ProtocolVersion ver = request.getRequestLine().getProtocolVersion(); 071 final HttpEntity entity = ((HttpEntityEnclosingRequest)request).getEntity(); 072 // Do not send the expect header if request body is known to be empty 073 if (entity != null 074 && entity.getContentLength() != 0 && !ver.lessEquals(HttpVersion.HTTP_1_0)) { 075 final HttpClientContext clientContext = HttpClientContext.adapt(context); 076 final RequestConfig config = clientContext.getRequestConfig(); 077 if (config.isExpectContinueEnabled()) { 078 request.addHeader(HTTP.EXPECT_DIRECTIVE, HTTP.EXPECT_CONTINUE); 079 } 080 } 081 } 082 } 083 } 084 085}