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.protocol; 029 030import java.io.IOException; 031 032import org.apache.http.HttpEntity; 033import org.apache.http.HttpException; 034import org.apache.http.HttpResponse; 035import org.apache.http.HttpResponseInterceptor; 036import org.apache.http.HttpStatus; 037import org.apache.http.HttpVersion; 038import org.apache.http.ProtocolException; 039import org.apache.http.ProtocolVersion; 040import org.apache.http.annotation.ThreadingBehavior; 041import org.apache.http.annotation.Contract; 042import org.apache.http.util.Args; 043 044/** 045 * ResponseContent is the most important interceptor for outgoing responses. 046 * It is responsible for delimiting content length by adding 047 * {@code Content-Length} or {@code Transfer-Content} headers based 048 * on the properties of the enclosed entity and the protocol version. 049 * This interceptor is required for correct functioning of server side protocol 050 * processors. 051 * 052 * @since 4.0 053 */ 054@Contract(threading = ThreadingBehavior.IMMUTABLE) 055public class ResponseContent implements HttpResponseInterceptor { 056 057 private final boolean overwrite; 058 059 /** 060 * Default constructor. The {@code Content-Length} or {@code Transfer-Encoding} 061 * will cause the interceptor to throw {@link ProtocolException} if already present in the 062 * response message. 063 */ 064 public ResponseContent() { 065 this(false); 066 } 067 068 /** 069 * Constructor that can be used to fine-tune behavior of this interceptor. 070 * 071 * @param overwrite If set to {@code true} the {@code Content-Length} and 072 * {@code Transfer-Encoding} headers will be created or updated if already present. 073 * If set to {@code false} the {@code Content-Length} and 074 * {@code Transfer-Encoding} headers will cause the interceptor to throw 075 * {@link ProtocolException} if already present in the response message. 076 * 077 * @since 4.2 078 */ 079 public ResponseContent(final boolean overwrite) { 080 super(); 081 this.overwrite = overwrite; 082 } 083 084 /** 085 * Processes the response (possibly updating or inserting) Content-Length and Transfer-Encoding headers. 086 * @param response The HttpResponse to modify. 087 * @param context Unused. 088 * @throws ProtocolException If either the Content-Length or Transfer-Encoding headers are found. 089 * @throws IllegalArgumentException If the response is null. 090 */ 091 @Override 092 public void process(final HttpResponse response, final HttpContext context) 093 throws HttpException, IOException { 094 Args.notNull(response, "HTTP response"); 095 if (this.overwrite) { 096 response.removeHeaders(HTTP.TRANSFER_ENCODING); 097 response.removeHeaders(HTTP.CONTENT_LEN); 098 } else { 099 if (response.containsHeader(HTTP.TRANSFER_ENCODING)) { 100 throw new ProtocolException("Transfer-encoding header already present"); 101 } 102 if (response.containsHeader(HTTP.CONTENT_LEN)) { 103 throw new ProtocolException("Content-Length header already present"); 104 } 105 } 106 final ProtocolVersion ver = response.getStatusLine().getProtocolVersion(); 107 final HttpEntity entity = response.getEntity(); 108 if (entity != null) { 109 final long len = entity.getContentLength(); 110 if (entity.isChunked() && !ver.lessEquals(HttpVersion.HTTP_1_0)) { 111 response.addHeader(HTTP.TRANSFER_ENCODING, HTTP.CHUNK_CODING); 112 } else if (len >= 0) { 113 response.addHeader(HTTP.CONTENT_LEN, Long.toString(entity.getContentLength())); 114 } 115 // Specify a content type if known 116 if (entity.getContentType() != null && !response.containsHeader( 117 HTTP.CONTENT_TYPE )) { 118 response.addHeader(entity.getContentType()); 119 } 120 // Specify a content encoding if known 121 if (entity.getContentEncoding() != null && !response.containsHeader( 122 HTTP.CONTENT_ENCODING)) { 123 response.addHeader(entity.getContentEncoding()); 124 } 125 } else { 126 final int status = response.getStatusLine().getStatusCode(); 127 if (status != HttpStatus.SC_NO_CONTENT 128 && status != HttpStatus.SC_NOT_MODIFIED 129 && status != HttpStatus.SC_RESET_CONTENT) { 130 response.addHeader(HTTP.CONTENT_LEN, "0"); 131 } 132 } 133 } 134 135}