org.springframework.web.servlet.mvc.method.annotation.StreamingResponseBodyReturnValueHandler Maven / Gradle / Ivy
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* Copyright 2002-2019 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
*
* https://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.web.servlet.mvc.method.annotation;
import java.io.OutputStream;
import java.util.concurrent.Callable;
import jakarta.servlet.ServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import org.springframework.core.MethodParameter;
import org.springframework.core.ResolvableType;
import org.springframework.http.ResponseEntity;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.http.server.ServletServerHttpResponse;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.context.request.async.WebAsyncUtils;
import org.springframework.web.filter.ShallowEtagHeaderFilter;
import org.springframework.web.method.support.HandlerMethodReturnValueHandler;
import org.springframework.web.method.support.ModelAndViewContainer;
/**
* Supports return values of type
* {@link org.springframework.web.servlet.mvc.method.annotation.StreamingResponseBody}
* and also {@code ResponseEntity}.
*
* @author Rossen Stoyanchev
* @since 4.2
*/
public class StreamingResponseBodyReturnValueHandler implements HandlerMethodReturnValueHandler {
@Override
public boolean supportsReturnType(MethodParameter returnType) {
if (StreamingResponseBody.class.isAssignableFrom(returnType.getParameterType())) {
return true;
}
else if (ResponseEntity.class.isAssignableFrom(returnType.getParameterType())) {
Class bodyType = ResolvableType.forMethodParameter(returnType).getGeneric().resolve();
return (bodyType != null && StreamingResponseBody.class.isAssignableFrom(bodyType));
}
return false;
}
@Override
@SuppressWarnings("resource")
public void handleReturnValue(@Nullable Object returnValue, MethodParameter returnType,
ModelAndViewContainer mavContainer, NativeWebRequest webRequest) throws Exception {
if (returnValue == null) {
mavContainer.setRequestHandled(true);
return;
}
HttpServletResponse response = webRequest.getNativeResponse(HttpServletResponse.class);
Assert.state(response != null, "No HttpServletResponse");
ServerHttpResponse outputMessage = new ServletServerHttpResponse(response);
if (returnValue instanceof ResponseEntity responseEntity) {
response.setStatus(responseEntity.getStatusCode().value());
outputMessage.getHeaders().putAll(responseEntity.getHeaders());
returnValue = responseEntity.getBody();
if (returnValue == null) {
mavContainer.setRequestHandled(true);
outputMessage.flush();
return;
}
}
ServletRequest request = webRequest.getNativeRequest(ServletRequest.class);
Assert.state(request != null, "No ServletRequest");
ShallowEtagHeaderFilter.disableContentCaching(request);
Assert.isInstanceOf(StreamingResponseBody.class, returnValue, "StreamingResponseBody expected");
StreamingResponseBody streamingBody = (StreamingResponseBody) returnValue;
Callable callable = new StreamingResponseBodyTask(outputMessage.getBody(), streamingBody);
WebAsyncUtils.getAsyncManager(webRequest).startCallableProcessing(callable, mavContainer);
}
private static class StreamingResponseBodyTask implements Callable {
private final OutputStream outputStream;
private final StreamingResponseBody streamingBody;
public StreamingResponseBodyTask(OutputStream outputStream, StreamingResponseBody streamingBody) {
this.outputStream = outputStream;
this.streamingBody = streamingBody;
}
@Override
public Void call() throws Exception {
this.streamingBody.writeTo(this.outputStream);
this.outputStream.flush();
return null;
}
}
}