org.springframework.http.server.reactive.HttpHeadResponseDecorator Maven / Gradle / Ivy
/*
* Copyright 2002-2020 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.http.server.reactive;
import org.reactivestreams.Publisher;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.DataBufferUtils;
import org.springframework.http.HttpHeaders;
/**
* {@link ServerHttpResponse} decorator for HTTP HEAD requests.
*
* @author Rossen Stoyanchev
* @since 5.0
*/
public class HttpHeadResponseDecorator extends ServerHttpResponseDecorator {
public HttpHeadResponseDecorator(ServerHttpResponse delegate) {
super(delegate);
}
/**
* Consume and release the body without writing.
* If the headers contain neither Content-Length nor Transfer-Encoding,
* and the body is a {@link Mono}, count the bytes and set Content-Length.
*/
@Override
@SuppressWarnings("unchecked")
public final Mono writeWith(Publisher body) {
if (shouldSetContentLength() && body instanceof Mono) {
return ((Mono) body)
.doOnSuccess(buffer -> {
if (buffer != null) {
getHeaders().setContentLength(buffer.readableByteCount());
DataBufferUtils.release(buffer);
}
else {
getHeaders().setContentLength(0);
}
})
.then();
}
else {
return Flux.from(body)
.doOnNext(DataBufferUtils::release)
.then();
}
}
private boolean shouldSetContentLength() {
return (getHeaders().getFirst(HttpHeaders.CONTENT_LENGTH) == null &&
getHeaders().getFirst(HttpHeaders.TRANSFER_ENCODING) == null);
}
/**
* Invoke {@link #setComplete()} without writing.
* RFC 7302 allows HTTP HEAD response without content-length and it's not
* something that can be computed on a streaming response.
*/
@Override
public final Mono writeAndFlushWith(Publisher> body) {
// Not feasible to count bytes on potentially streaming response.
// RFC 7302 allows HEAD without content-length.
return setComplete();
}
}