/*
* Copyright 2002-2016 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.http.client;
import java.io.IOException;
import org.springframework.http.HttpRequest;
/**
* Intercepts client-side HTTP requests. Implementations of this interface can be {@linkplain
* org.springframework.web.client.RestTemplate#setInterceptors(java.util.List) registered} with the
* {@link org.springframework.web.client.RestTemplate RestTemplate}, as to modify the outgoing {@link ClientHttpRequest}
* and/or the incoming {@link ClientHttpResponse}.
*
* <p>The main entry point for interceptors is {@link #intercept(HttpRequest, byte[], ClientHttpRequestExecution)}.
*
* @author Arjen Poutsma
* @since 3.1
*/
@FunctionalInterface
public interface ClientHttpRequestInterceptor {
/**
* Intercept the given request, and return a response. The given {@link ClientHttpRequestExecution} allows
* the interceptor to pass on the request and response to the next entity in the chain.
*
* <p>A typical implementation of this method would follow the following pattern:
* <ol>
* <li>Examine the {@linkplain HttpRequest request} and body</li>
* <li>Optionally {@linkplain org.springframework.http.client.support.HttpRequestWrapper wrap} the request to filter HTTP attributes.</li>
* <li>Optionally modify the body of the request.</li>
* <li><strong>Either</strong>
* <ul>
* <li>execute the request using {@link ClientHttpRequestExecution#execute(org.springframework.http.HttpRequest, byte[])},</li>
* <strong>or</strong>
* <li>do not execute the request to block the execution altogether.</li>
* </ul>
* <li>Optionally wrap the response to filter HTTP attributes.</li>
* </ol>
*
* @param request the request, containing method, URI, and headers
* @param body the body of the request
* @param execution the request execution
* @return the response
* @throws IOException in case of I/O errors
*/
ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution)
throws IOException;
}