/*
* 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.http.server.reactive;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.Function;
import java.util.function.Supplier;
import java.util.stream.Collectors;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
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.DataBufferFactory;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseCookie;
import org.springframework.util.Assert;
import org.springframework.util.CollectionUtils;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
/**
* Base class for {@link ServerHttpResponse} implementations.
*
* @author Rossen Stoyanchev
* @author Sebastien Deleuze
* @since 5.0
*/
public abstract class AbstractServerHttpResponse implements ServerHttpResponse {
/**
* COMMITTING -> COMMITTED is the period after doCommit is called but before
* the response status and headers have been applied to the underlying
* response during which time pre-commit actions can still make changes to
* the response status and headers.
*/
private enum State {NEW, COMMITTING, COMMITTED}
private final Log logger = LogFactory.getLog(getClass());
private final DataBufferFactory dataBufferFactory;
private HttpStatus statusCode;
private final HttpHeaders headers;
private final MultiValueMap<String, ResponseCookie> cookies;
private Function<String, String> urlEncoder = url -> url;
private final AtomicReference<State> state = new AtomicReference<>(State.NEW);
private final List<Supplier<? extends Mono<Void>>> commitActions = new ArrayList<>(4);
public AbstractServerHttpResponse(DataBufferFactory dataBufferFactory) {
Assert.notNull(dataBufferFactory, "'dataBufferFactory' must not be null");
this.dataBufferFactory = dataBufferFactory;
this.headers = new HttpHeaders();
this.cookies = new LinkedMultiValueMap<>();
}
@Override
public final DataBufferFactory bufferFactory() {
return this.dataBufferFactory;
}
@Override
public boolean setStatusCode(HttpStatus statusCode) {
Assert.notNull(statusCode, "Status code must not be null");
if (this.state.get() == State.COMMITTED) {
if (logger.isDebugEnabled()) {
logger.debug("Can't set the status " + statusCode.toString() +
" because the HTTP response has already been committed");
}
return false;
}
else {
this.statusCode = statusCode;
return true;
}
}
@Override
public HttpStatus getStatusCode() {
return this.statusCode;
}
@Override
public HttpHeaders getHeaders() {
return (this.state.get() == State.COMMITTED ?
HttpHeaders.readOnlyHttpHeaders(this.headers) : this.headers);
}
@Override
public MultiValueMap<String, ResponseCookie> getCookies() {
return (this.state.get() == State.COMMITTED ?
CollectionUtils.unmodifiableMultiValueMap(this.cookies) : this.cookies);
}
@Override
public void addCookie(ResponseCookie cookie) {
Assert.notNull(cookie, "'cookie' must not be null");
if (this.state.get() == State.COMMITTED) {
throw new IllegalStateException("Can't add the cookie " + cookie +
"because the HTTP response has already been committed");
}
else {
getCookies().add(cookie.getName(), cookie);
}
}
@Override
public String encodeUrl(String url) {
return (this.urlEncoder != null ? this.urlEncoder.apply(url) : url);
}
@Override
public void registerUrlEncoder(Function<String, String> encoder) {
this.urlEncoder = (this.urlEncoder != null ? this.urlEncoder.andThen(encoder) : encoder);
}
@Override
public void beforeCommit(Supplier<? extends Mono<Void>> action) {
if (action != null) {
this.commitActions.add(action);
}
}
@Override
public boolean isCommitted() {
return this.state.get() != State.NEW;
}
@Override
public final Mono<Void> writeWith(Publisher<? extends DataBuffer> body) {
return new ChannelSendOperator<>(body,
writePublisher -> doCommit(() -> writeWithInternal(writePublisher)));
}
@Override
public final Mono<Void> writeAndFlushWith(Publisher<? extends Publisher<? extends DataBuffer>> body) {
return new ChannelSendOperator<>(body,
writePublisher -> doCommit(() -> writeAndFlushWithInternal(writePublisher)));
}
@Override
public Mono<Void> setComplete() {
return doCommit(null);
}
/**
* A variant of {@link #doCommit(Supplier)} for a response without no body.
* @return a completion publisher
*/
protected Mono<Void> doCommit() {
return doCommit(null);
}
/**
* Apply {@link #beforeCommit(Supplier) beforeCommit} actions, apply the
* response status and headers/cookies, and write the response body.
* @param writeAction the action to write the response body (may be {@code null})
* @return a completion publisher
*/
protected Mono<Void> doCommit(Supplier<? extends Mono<Void>> writeAction) {
if (!this.state.compareAndSet(State.NEW, State.COMMITTING)) {
if (logger.isDebugEnabled()) {
logger.debug("Skipping doCommit (response already committed).");
}
return Mono.empty();
}
this.commitActions.add(() -> {
applyStatusCode();
applyHeaders();
applyCookies();
this.state.set(State.COMMITTED);
return Mono.empty();
});
if (writeAction != null) {
this.commitActions.add(writeAction);
}
List<? extends Mono<Void>> actions = this.commitActions.stream()
.map(Supplier::get).collect(Collectors.toList());
return Flux.concat(actions).next();
}
/**
* Write to the underlying the response.
* @param body the publisher to write with
*/
protected abstract Mono<Void> writeWithInternal(Publisher<? extends DataBuffer> body);
/**
* Write to the underlying the response, and flush after each {@code Publisher<DataBuffer>}.
* @param body the publisher to write and flush with
*/
protected abstract Mono<Void> writeAndFlushWithInternal(Publisher<? extends Publisher<? extends DataBuffer>> body);
/**
* Write the status code to the underlying response.
* This method is called once only.
*/
protected abstract void applyStatusCode();
/**
* Apply header changes from {@link #getHeaders()} to the underlying response.
* This method is called once only.
*/
protected abstract void applyHeaders();
/**
* Add cookies from {@link #getHeaders()} to the underlying response.
* This method is called once only.
*/
protected abstract void applyCookies();
}