org.springframework.http.server.reactive.HttpHeadResponseDecorator Maven / Gradle / Ivy
/*
* 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.http.server.reactive;
import java.util.function.BiFunction;
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);
}
/**
* Apply {@link Flux#reduce(Object, BiFunction) reduce} on the body, count
* the number of bytes produced, release data buffers without writing, and
* set the {@literal Content-Length} header.
*/
@Override
public final Mono writeWith(Publisher body) {
return Flux.from(body)
.reduce(0, (current, buffer) -> {
int next = current + buffer.readableByteCount();
DataBufferUtils.release(buffer);
return next;
})
.doOnNext(length -> {
if (length > 0 || getHeaders().getFirst(HttpHeaders.CONTENT_LENGTH) == null) {
getHeaders().setContentLength(length);
}
})
.then();
}
/**
* 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();
}
}