/*
* Copyright 2002-2017 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.integration.http.outbound;
import java.net.URI;
import java.util.List;
import java.util.function.Supplier;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.core.ParameterizedTypeReference;
import org.springframework.expression.Expression;
import org.springframework.expression.common.LiteralExpression;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpMethod;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.http.client.ClientHttpRequestFactory;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.integration.expression.ValueExpression;
import org.springframework.integration.mapping.HeaderMapper;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageHandler;
import org.springframework.messaging.MessageHandlingException;
import org.springframework.util.Assert;
import org.springframework.web.client.ResponseErrorHandler;
import org.springframework.web.client.RestClientException;
import org.springframework.web.client.RestTemplate;
/**
* A {@link MessageHandler} implementation that executes HTTP requests by delegating
* to a {@link RestTemplate} instance. If the 'expectReply' flag is set to true (the default)
* then a reply Message will be generated from the HTTP response. If that response contains
* a body, it will be used as the reply Message's payload. Otherwise the reply Message's
* payload will contain the response status as an instance of the {@link HttpStatus} enum.
* When there is a response body, the {@link HttpStatus} enum instance will instead be
* copied to the MessageHeaders of the reply. In both cases, the response headers will
* be mapped to the reply Message's headers by this handler's {@link HeaderMapper} instance.
*
* @author Mark Fisher
* @author Oleg Zhurakousky
* @author Gary Russell
* @author Gunnar Hillert
* @author Artem Bilan
* @author Wallace Wadge
* @author Shiliang Li
*
* @since 2.0
*/
public class HttpRequestExecutingMessageHandler extends AbstractHttpRequestExecutingMessageHandler {
private final RestTemplate restTemplate;
/**
* Create a handler that will send requests to the provided URI.
*
* @param uri The URI.
*/
public HttpRequestExecutingMessageHandler(URI uri) {
this(new ValueExpression<URI>(uri));
}
/**
* Create a handler that will send requests to the provided URI.
*
* @param uri The URI.
*/
public HttpRequestExecutingMessageHandler(String uri) {
this(uri, null);
}
/**
* Create a handler that will send requests to the provided URI Expression.
*
* @param uriExpression The URI expression.
*/
public HttpRequestExecutingMessageHandler(Expression uriExpression) {
this(uriExpression, null);
}
/**
* Create a handler that will send requests to the provided URI using a provided RestTemplate
* @param uri The URI.
* @param restTemplate The rest template.
*/
public HttpRequestExecutingMessageHandler(String uri, RestTemplate restTemplate) {
this(new LiteralExpression(uri), restTemplate);
/*
* We'd prefer to do this assertion first, but the compiler doesn't allow it. However,
* it's safe because the literal expression simply wraps the String variable, even
* when null.
*/
Assert.hasText(uri, "URI is required");
}
/**
* Create a handler that will send requests to the provided URI using a provided RestTemplate
* @param uriExpression A SpEL Expression that can be resolved against the message object and
* {@link BeanFactory}.
* @param restTemplate The rest template.
*/
public HttpRequestExecutingMessageHandler(Expression uriExpression, RestTemplate restTemplate) {
super(uriExpression);
this.restTemplate = (restTemplate == null ? new RestTemplate() : restTemplate);
}
@Override
public String getComponentType() {
return (this.isExpectReply() ? "http:outbound-gateway" : "http:outbound-channel-adapter");
}
/**
* Set the {@link ResponseErrorHandler} for the underlying {@link RestTemplate}.
* @param errorHandler The error handler.
* @see RestTemplate#setErrorHandler(ResponseErrorHandler)
*/
public void setErrorHandler(ResponseErrorHandler errorHandler) {
this.restTemplate.setErrorHandler(errorHandler);
}
/**
* Set a list of {@link HttpMessageConverter}s to be used by the underlying {@link RestTemplate}.
* Converters configured via this method will override the default converters.
* @param messageConverters The message converters.
* @see RestTemplate#setMessageConverters(java.util.List)
*/
public void setMessageConverters(List<HttpMessageConverter<?>> messageConverters) {
this.restTemplate.setMessageConverters(messageConverters);
}
/**
* Set the {@link ClientHttpRequestFactory} for the underlying {@link RestTemplate}.
*
* @param requestFactory The request factory.
*
* @see RestTemplate#setRequestFactory(ClientHttpRequestFactory)
*/
public void setRequestFactory(ClientHttpRequestFactory requestFactory) {
this.restTemplate.setRequestFactory(requestFactory);
}
@Override
protected Object exchange(Supplier<URI> uriSupplier, HttpMethod httpMethod, HttpEntity<?> httpRequest,
Object expectedResponseType, Message<?> requestMessage) {
URI uri = uriSupplier.get();
ResponseEntity<?> httpResponse;
try {
if (expectedResponseType instanceof ParameterizedTypeReference<?>) {
httpResponse = this.restTemplate.exchange(uri, httpMethod, httpRequest,
(ParameterizedTypeReference<?>) expectedResponseType);
}
else {
httpResponse = this.restTemplate.exchange(uri, httpMethod, httpRequest,
(Class<?>) expectedResponseType);
}
return getReply(httpResponse);
}
catch (RestClientException e) {
throw new MessageHandlingException(requestMessage,
"HTTP request execution failed for URI [" + uri + "]", e);
}
}
}