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; 29 30 import java.io.IOException; 31 32 import org.apache.http.protocol.HttpContext; 33 34 /** 35 * HTTP protocol interceptor is a routine that implements a specific aspect of 36 * the HTTP protocol. Usually protocol interceptors are expected to act upon 37 * one specific header or a group of related headers of the incoming message 38 * or populate the outgoing message with one specific header or a group of 39 * related headers. 40 * <p> 41 * Protocol Interceptors can also manipulate content entities enclosed with messages. 42 * Usually this is accomplished by using the 'Decorator' pattern where a wrapper 43 * entity class is used to decorate the original entity. 44 * <p> 45 * Protocol interceptors must be implemented as thread-safe. Similarly to 46 * servlets, protocol interceptors should not use instance variables unless 47 * access to those variables is synchronized. 48 * 49 * @since 4.0 50 */ 51 public interface HttpRequestInterceptor { 52 53 /** 54 * Processes a request. 55 * On the client side, this step is performed before the request is 56 * sent to the server. On the server side, this step is performed 57 * on incoming messages before the message body is evaluated. 58 * 59 * @param request the request to preprocess 60 * @param context the context for the request 61 * 62 * @throws HttpException in case of an HTTP protocol violation 63 * @throws IOException in case of an I/O error 64 */ 65 void process(HttpRequest request, HttpContext context) 66 throws HttpException, IOException; 67 68 }