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; 029 030import java.io.IOException; 031 032import org.apache.http.protocol.HttpContext; 033 034/** 035 * HTTP protocol interceptor is a routine that implements a specific aspect of 036 * the HTTP protocol. Usually protocol interceptors are expected to act upon 037 * one specific header or a group of related headers of the incoming message 038 * or populate the outgoing message with one specific header or a group of 039 * related headers. 040 * <p> 041 * Protocol Interceptors can also manipulate content entities enclosed with messages. 042 * Usually this is accomplished by using the 'Decorator' pattern where a wrapper 043 * entity class is used to decorate the original entity. 044 * <p> 045 * Protocol interceptors must be implemented as thread-safe. Similarly to 046 * servlets, protocol interceptors should not use instance variables unless 047 * access to those variables is synchronized. 048 * 049 * @since 4.0 050 */ 051public interface HttpRequestInterceptor { 052 053 /** 054 * Processes a request. 055 * On the client side, this step is performed before the request is 056 * sent to the server. On the server side, this step is performed 057 * on incoming messages before the message body is evaluated. 058 * 059 * @param request the request to preprocess 060 * @param context the context for the request 061 * 062 * @throws HttpException in case of an HTTP protocol violation 063 * @throws IOException in case of an I/O error 064 */ 065 void process(HttpRequest request, HttpContext context) 066 throws HttpException, IOException; 067 068}