001/* 002 * Copyright 2002-2018 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.http.client; 018 019import java.io.IOException; 020 021import org.springframework.http.HttpRequest; 022 023/** 024 * Intercepts client-side HTTP requests. Implementations of this interface can be 025 * {@linkplain org.springframework.web.client.RestTemplate#setInterceptors registered} 026 * with the {@link org.springframework.web.client.RestTemplate RestTemplate}, 027 * as to modify the outgoing {@link ClientHttpRequest} and/or the incoming 028 * {@link ClientHttpResponse}. 029 * 030 * <p>The main entry point for interceptors is 031 * {@link #intercept(HttpRequest, byte[], ClientHttpRequestExecution)}. 032 * 033 * @author Arjen Poutsma 034 * @since 3.1 035 */ 036public interface ClientHttpRequestInterceptor { 037 038 /** 039 * Intercept the given request, and return a response. The given 040 * {@link ClientHttpRequestExecution} allows the interceptor to pass on the 041 * request and response to the next entity in the chain. 042 * <p>A typical implementation of this method would follow the following pattern: 043 * <ol> 044 * <li>Examine the {@linkplain HttpRequest request} and body</li> 045 * <li>Optionally {@linkplain org.springframework.http.client.support.HttpRequestWrapper 046 * wrap} the request to filter HTTP attributes.</li> 047 * <li>Optionally modify the body of the request.</li> 048 * <li><strong>Either</strong> 049 * <ul> 050 * <li>execute the request using 051 * {@link ClientHttpRequestExecution#execute(org.springframework.http.HttpRequest, byte[])},</li> 052 * <strong>or</strong> 053 * <li>do not execute the request to block the execution altogether.</li> 054 * </ul> 055 * <li>Optionally wrap the response to filter HTTP attributes.</li> 056 * </ol> 057 * @param request the request, containing method, URI, and headers 058 * @param body the body of the request 059 * @param execution the request execution 060 * @return the response 061 * @throws IOException in case of I/O errors 062 */ 063 ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution) 064 throws IOException; 065 066}