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Added support for streaming response modification #3477

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33 changes: 33 additions & 0 deletions ...in/java/org/springframework/cloud/gateway/filter/factory/rewrite/FluxRewriteFunction.java
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Original file line number Diff line number Diff line change
@@ -0,0 +1,33 @@
/*
* Copyright 2013-2020 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.cloud.gateway.filter.factory.rewrite;

import java.util.function.BiFunction;

import reactor.core.publisher.Flux;

import org.springframework.web.server.ServerWebExchange;

/**
* This interface is BETA and may be subject to change in a future release.
*
* @param <T> the type of the first argument to the function
* @param <R> the type of element signaled by the {@link Flux}
*/
public interface FluxRewriteFunction<T, R> extends BiFunction<ServerWebExchange, Flux<T>, Flux<R>> {

}
161 changes: 131 additions & 30 deletions ...ramework/cloud/gateway/filter/factory/rewrite/ModifyResponseBodyGatewayFilterFactory.java
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Expand Up @@ -91,8 +91,19 @@ public static class Config {

private String newContentType;

/**
* Deprecated in favour of {@link FluxRewriteFunction} &
* {@link MonoRewriteFunction} Use {@link MonoRewriteFunction} for modifying
* non-streaming response body Use {@link FluxRewriteFunction} for modifying
* streaming response body
*/
@Deprecated
private RewriteFunction rewriteFunction;

private FluxRewriteFunction fluxRewriteFunction;

private MonoRewriteFunction monoRewriteFunction;

public Class getInClass() {
return inClass;
}
Expand Down Expand Up @@ -138,15 +149,42 @@ public Config setNewContentType(String newContentType) {
return this;
}

@Deprecated
public RewriteFunction getRewriteFunction() {
return rewriteFunction;
}

public <T, R> MonoRewriteFunction<Mono<T>, Mono<R>> getMonoRewriteFunction() {
return monoRewriteFunction;
}

public <T, R> FluxRewriteFunction<Flux<T>, Flux<R>> getFluxRewriteFunction() {
return fluxRewriteFunction;
}

/**
* Deprecated in favour of {@link Config#setMonoRewriteFunction} &
* {@link Config#setFluxRewriteFunction} Use {@link Config#setMonoRewriteFunction}
* for modifying non-streaming response body Use
* {@link Config#setFluxRewriteFunction} for modifying streaming response body
*/
@Deprecated
public Config setRewriteFunction(RewriteFunction rewriteFunction) {
this.rewriteFunction = rewriteFunction;
return this;
}

public Config setMonoRewriteFunction(MonoRewriteFunction monoRewriteFunction) {
this.monoRewriteFunction = monoRewriteFunction;
return this;
}

public Config setFluxRewriteFunction(FluxRewriteFunction fluxRewriteFunction) {
this.fluxRewriteFunction = fluxRewriteFunction;
return this;
}

@Deprecated
public <T, R> Config setRewriteFunction(Class<T> inClass, Class<R> outClass,
RewriteFunction<T, R> rewriteFunction) {
setInClass(inClass);
Expand All @@ -155,6 +193,21 @@ public <T, R> Config setRewriteFunction(Class<T> inClass, Class<R> outClass,
return this;
}

public <T, R> Config setFluxRewriteFunction(Class<T> inClass, Class<R> outClass,
FluxRewriteFunction<T, R> fluxRewriteFunction) {
setInClass(inClass);
setOutClass(outClass);
setFluxRewriteFunction(fluxRewriteFunction);
return this;
}

public <T, R> Config setMonoRewriteFunction(Class<T> inClass, Class<R> outClass,
MonoRewriteFunction<T, R> monoRewriteFunction) {
setInClass(inClass);
setOutClass(outClass);
setMonoRewriteFunction(monoRewriteFunction);
return this;
}
}

public class ModifyResponseGatewayFilter implements GatewayFilter, Ordered {
Expand Down Expand Up @@ -204,51 +257,99 @@ public ModifiedServerHttpResponse(ServerWebExchange exchange, Config config) {
this.config = config;
}

@SuppressWarnings("unchecked")
@Override
@SuppressWarnings({ "unchecked", "rawtypes" })
public Mono<Void> writeWith(Publisher<? extends DataBuffer> body) {

Class inClass = config.getInClass();
Class outClass = config.getOutClass();

String originalResponseContentType = exchange.getAttribute(ORIGINAL_RESPONSE_CONTENT_TYPE_ATTR);
HttpHeaders httpHeaders = new HttpHeaders();
// explicitly add it in this way instead of
// 'httpHeaders.setContentType(originalResponseContentType)'
// this will prevent exception in case of using non-standard media
// types like "Content-Type: image"
httpHeaders.add(HttpHeaders.CONTENT_TYPE, originalResponseContentType);

HttpHeaders httpHeaders = prepareHttpHeaders();
ClientResponse clientResponse = prepareClientResponse(body, httpHeaders);

// TODO: flux or mono
Mono modifiedBody = extractBody(exchange, clientResponse, inClass)
.flatMap(originalBody -> config.getRewriteFunction().apply(exchange, originalBody))
.switchIfEmpty(Mono.defer(() -> (Mono) config.getRewriteFunction().apply(exchange, null)));
var modifiedBody = extractBody(exchange, clientResponse, inClass);
if (config.getRewriteFunction() != null) {
// TODO: to be removed with removal of rewriteFunction
modifiedBody = modifiedBody
.flatMap(originalBody -> config.getRewriteFunction()
.apply(exchange, originalBody))
.switchIfEmpty(Mono.defer(() -> (Mono) config.getRewriteFunction()
.apply(exchange, null)));
}
if (config.getMonoRewriteFunction() != null) {
modifiedBody = config.getMonoRewriteFunction().apply(exchange,
modifiedBody);
}

BodyInserter bodyInserter = BodyInserters.fromPublisher(modifiedBody, outClass);
BodyInserter bodyInserter = BodyInserters.fromPublisher(modifiedBody,
outClass);
CachedBodyOutputMessage outputMessage = new CachedBodyOutputMessage(exchange,
exchange.getResponse().getHeaders());
return bodyInserter.insert(outputMessage, new BodyInserterContext()).then(Mono.defer(() -> {
Mono<DataBuffer> messageBody = writeBody(getDelegate(), outputMessage, outClass);
HttpHeaders headers = getDelegate().getHeaders();
if (!headers.containsKey(HttpHeaders.TRANSFER_ENCODING)
|| headers.containsKey(HttpHeaders.CONTENT_LENGTH)) {
messageBody = messageBody.doOnNext(data -> headers.setContentLength(data.readableByteCount()));
}
return bodyInserter.insert(outputMessage, new BodyInserterContext())
.then(Mono.defer(() -> {
Mono<DataBuffer> messageBody = writeBody(getDelegate(), outputMessage, outClass);
HttpHeaders headers = getDelegate().getHeaders();
if (!headers.containsKey(HttpHeaders.TRANSFER_ENCODING)
|| headers.containsKey(HttpHeaders.CONTENT_LENGTH)) {
messageBody = messageBody.doOnNext(data -> headers.setContentLength(data.readableByteCount()));
}

if (StringUtils.hasText(config.newContentType)) {
headers.set(HttpHeaders.CONTENT_TYPE, config.newContentType);
}

// TODO: fail if isStreamingMediaType?
return getDelegate().writeWith(messageBody);
}));
}

if (StringUtils.hasText(config.newContentType)) {
headers.set(HttpHeaders.CONTENT_TYPE, config.newContentType);
}
@Override
@SuppressWarnings({ "unchecked", "rawtypes" })
public Mono<Void> writeAndFlushWith(
Publisher<? extends Publisher<? extends DataBuffer>> body) {
final var httpHeaders = prepareHttpHeaders();
final var fluxRewriteConfig = config.getFluxRewriteFunction();
final var publisher = Flux.from(body).flatMapSequential(r -> r);
final var clientResponse = prepareClientResponse(publisher, httpHeaders);
var modifiedBody = clientResponse.bodyToFlux(config.inClass);
if (config.getRewriteFunction() != null) {
// TODO: to be removed with removal of rewriteFunction
modifiedBody = modifiedBody
.flatMap(originalBody -> config.getRewriteFunction()
.apply(exchange, originalBody))
.switchIfEmpty(Flux.defer(() -> (Flux) config.getRewriteFunction()
.apply(exchange, null)));
}
if (config.getFluxRewriteFunction() != null) {
modifiedBody = fluxRewriteConfig.apply(exchange, modifiedBody);
}
final var bodyInserter = BodyInserters.fromPublisher(modifiedBody,
config.outClass);
final var outputMessage = new CachedBodyOutputMessage(exchange,
exchange.getResponse().getHeaders());

// TODO: fail if isStreamingMediaType?
return getDelegate().writeWith(messageBody);
}));
return bodyInserter.insert(outputMessage, new BodyInserterContext())
.then(Mono.defer(() -> {
final var messageBody = outputMessage.getBody();
HttpHeaders headers = getDelegate().getHeaders();
if (StringUtils.hasText(config.newContentType)) {
headers.set(HttpHeaders.CONTENT_TYPE, config.newContentType);
}
return getDelegate()
.writeAndFlushWith(messageBody.map(Flux::just));
}));
}

@Override
public Mono<Void> writeAndFlushWith(Publisher<? extends Publisher<? extends DataBuffer>> body) {
return writeWith(Flux.from(body).flatMapSequential(p -> p));
private HttpHeaders prepareHttpHeaders() {
String originalResponseContentType = exchange
.getAttribute(ORIGINAL_RESPONSE_CONTENT_TYPE_ATTR);
HttpHeaders httpHeaders = new HttpHeaders();
// explicitly add it in this way instead of
// 'httpHeaders.setContentType(originalResponseContentType)'
// this will prevent exception in case of using non-standard media
// types like "Content-Type: image"
httpHeaders.add(HttpHeaders.CONTENT_TYPE, originalResponseContentType);
return httpHeaders;
}

private ClientResponse prepareClientResponse(Publisher<? extends DataBuffer> body, HttpHeaders httpHeaders) {
Expand Down
34 changes: 34 additions & 0 deletions ...in/java/org/springframework/cloud/gateway/filter/factory/rewrite/MonoRewriteFunction.java
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/*
* Copyright 2013-2020 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.cloud.gateway.filter.factory.rewrite;

import java.util.function.BiFunction;

import reactor.core.publisher.Mono;

import org.springframework.web.server.ServerWebExchange;


/**
* This interface is BETA and may be subject to change in a future release.
*
* @param <T> the type of the first argument to the function
* @param <R> the type of element signaled by the {@link Mono}
*/
public interface MonoRewriteFunction<T, R> extends BiFunction<ServerWebExchange, Mono<T>, Mono<R>> {

}