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/* * Copyright 2002-2018 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; /** * {@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<Void> writeWith(Publisher<? extends DataBuffer> body) { return Flux.from(body).reduce(0, (current, buffer) -> { int next = current + buffer.readableByteCount(); DataBufferUtils.release(buffer); return next; }).doOnNext(count -> getHeaders().setContentLength(count)).then(); } /** * Invoke {@link #setComplete()} without writing. * <p>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<Void> writeAndFlushWith(Publisher<? extends Publisher<? extends DataBuffer>> body) { // Not feasible to count bytes on potentially streaming response. // RFC 7302 allows HEAD without content-length. return setComplete(); } }