Allow ExchangeStrategies customizations in WebClient

Backport of d420939 and acfeb77

Closes gh-23961

spring-test/src/main/java/org/springframework/test/web/reactive/server/DefaultWebTestClientBuilder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * 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.
@@ -142,6 +142,12 @@ public WebTestClient.Builder exchangeStrategies(ExchangeStrategies strategies) {
 		return this;
 	}
 
+	@Override
+	public WebTestClient.Builder exchangeStrategies(Consumer<ExchangeStrategies.Builder> configurer) {
+		this.webClientBuilder.exchangeStrategies(configurer);
+		return this;
+	}
+
 	@Override
 	public WebTestClient.Builder responseTimeout(Duration timeout) {
 		this.responseTimeout = timeout;

spring-test/src/main/java/org/springframework/test/web/reactive/server/WebTestClient.java

@@ -77,6 +77,7 @@
  * and Spring Kotlin extensions to perform integration tests on an embedded WebFlux server.
  *
  * @author Rossen Stoyanchev
+ * @author Brian Clozel
  * @since 5.0
  * @see StatusAssertions
  * @see HeaderAssertions
@@ -436,11 +437,25 @@ interface Builder {
 
 		/**
 		 * Configure the {@link ExchangeStrategies} to use.
-		 * <p>By default {@link ExchangeStrategies#withDefaults()} is used.
+		 * <p>Note that in a scenario where the builder is configured by
+		 * multiple parties, it is preferable to use
+		 * {@link #exchangeStrategies(Consumer)} in order to customize the same
+		 * {@code ExchangeStrategies}. This method here sets the strategies that
+		 * everyone else then can customize.
+		 * <p>By default this is {@link ExchangeStrategies#withDefaults()}.
 		 * @param strategies the strategies to use
 		 */
 		Builder exchangeStrategies(ExchangeStrategies strategies);
 
+		/**
+		 * Customize the strategies configured via
+		 * {@link #exchangeStrategies(ExchangeStrategies)}. This method is
+		 * designed for use in scenarios where multiple parties wish to update
+		 * the {@code ExchangeStrategies}.
+		 * @since 5.1.12
+		 */
+		Builder exchangeStrategies(Consumer<ExchangeStrategies.Builder> configurer);
+
 		/**
 		 * Max amount of time to wait for responses.
 		 * <p>By default 5 seconds.
@@ -877,7 +892,7 @@ interface BodyContentSpec {
 		 * @since 5.1
 		 * @see #xpath(String, Map, Object...)
 		 */
-		default XpathAssertions xpath(String expression, Object... args){
+		default XpathAssertions xpath(String expression, Object... args) {
 			return xpath(expression, null, args);
 		}
 
@@ -891,7 +906,7 @@ default XpathAssertions xpath(String expression, Object... args){
 		 * @param args arguments to parameterize the expression
 		 * @since 5.1
 		 */
-		XpathAssertions xpath(String expression, @Nullable  Map<String, String> namespaces, Object... args);
+		XpathAssertions xpath(String expression, @Nullable Map<String, String> namespaces, Object... args);
 
 		/**
 		 * Assert the response body content with the given {@link Consumer}.

spring-web/src/main/java/org/springframework/http/codec/ClientCodecConfigurer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * 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.
@@ -63,6 +63,12 @@ public interface ClientCodecConfigurer extends CodecConfigurer {
 	@Override
 	ClientDefaultCodecs defaultCodecs();
 
+	/**
+	 * {@inheritDoc}.
+	 */
+	@Override
+	ClientCodecConfigurer clone();
+
 
 	/**
 	 * Static factory method for a {@code ClientCodecConfigurer}.

spring-web/src/main/java/org/springframework/http/codec/CodecConfigurer.java

@@ -87,6 +87,15 @@ public interface CodecConfigurer {
 	 */
 	List<HttpMessageWriter<?>> getWriters();
 
+	/**
+	 * Create a copy of this {@link CodecConfigurer}. The returned clone has its
+	 * own lists of default and custom codecs and generally can be configured
+	 * independently. Keep in mind however that codec instances (if any are
+	 * configured) are themselves not cloned.
+	 * @since 5.1.12
+	 */
+	CodecConfigurer clone();
+
 
 	/**
 	 * Customize or replace the HTTP message readers and writers registered by

spring-web/src/main/java/org/springframework/http/codec/ServerCodecConfigurer.java

@@ -62,6 +62,12 @@ public interface ServerCodecConfigurer extends CodecConfigurer {
 	@Override
 	ServerDefaultCodecs defaultCodecs();
 
+	/**
+	 * {@inheritDoc}.
+	 */
+	@Override
+	ServerCodecConfigurer clone();
+
 
 	/**
 	 * Static factory method for a {@code ServerCodecConfigurer}.

spring-web/src/main/java/org/springframework/http/codec/support/BaseCodecConfigurer.java

@@ -34,13 +34,14 @@
  * client and server specific variants.
  *
  * @author Rossen Stoyanchev
+ * @author Brian Clozel
  * @since 5.0
  */
-class BaseCodecConfigurer implements CodecConfigurer {
+abstract class BaseCodecConfigurer implements CodecConfigurer {
 
-	private final BaseDefaultCodecs defaultCodecs;
+	protected final BaseDefaultCodecs defaultCodecs;
 
-	private final DefaultCustomCodecs customCodecs = new DefaultCustomCodecs();
+	protected final DefaultCustomCodecs customCodecs;
 
 
 	/**
@@ -50,8 +51,25 @@ class BaseCodecConfigurer implements CodecConfigurer {
 	BaseCodecConfigurer(BaseDefaultCodecs defaultCodecs) {
 		Assert.notNull(defaultCodecs, "'defaultCodecs' is required");
 		this.defaultCodecs = defaultCodecs;
+		this.customCodecs = new DefaultCustomCodecs();
 	}
 
+	/**
+	 * Create a deep copy of the given {@link BaseCodecConfigurer}.
+	 * @since 5.1.12
+	 */
+	protected BaseCodecConfigurer(BaseCodecConfigurer other) {
+		this.defaultCodecs = other.cloneDefaultCodecs();
+		this.customCodecs = new DefaultCustomCodecs(other.customCodecs);
+	}
+
+	/**
+	 * Sub-classes should override this to create  deep copy of
+	 * {@link BaseDefaultCodecs} which can can be client or server specific.
+	 * @since 5.1.12
+	 */
+	protected abstract BaseDefaultCodecs cloneDefaultCodecs();
+
 
 	@Override
 	public DefaultCodecs defaultCodecs() {
@@ -87,6 +105,7 @@ public List<HttpMessageWriter<?>> getWriters() {
 		return getWritersInternal(false);
 	}
 
+
 	/**
 	 * Internal method that returns the configured writers.
 	 * @param forMultipart whether to returns writers for general use ("false"),
@@ -106,11 +125,14 @@ protected List<HttpMessageWriter<?>> getWritersInternal(boolean forMultipart) {
 		return result;
 	}
 
+	@Override
+	public abstract CodecConfigurer clone();
+
 
 	/**
 	 * Default implementation of {@code CustomCodecs}.
 	 */
-	private static final class DefaultCustomCodecs implements CustomCodecs {
+	protected static final class DefaultCustomCodecs implements CustomCodecs {
 
 		private final List<HttpMessageReader<?>> typedReaders = new ArrayList<>();
 
@@ -121,6 +143,20 @@ private static final class DefaultCustomCodecs implements CustomCodecs {
 		private final List<HttpMessageWriter<?>> objectWriters = new ArrayList<>();
 
 
+		DefaultCustomCodecs() {
+		}
+
+		/**
+		 * Create a deep copy of the given {@link DefaultCustomCodecs}.
+		 * @since 5.1.12
+		 */
+		DefaultCustomCodecs(DefaultCustomCodecs other) {
+			other.typedReaders.addAll(this.typedReaders);
+			other.typedWriters.addAll(this.typedWriters);
+			other.objectReaders.addAll(this.objectReaders);
+			other.objectWriters.addAll(this.objectWriters);
+		}
+
 		@Override
 		public void decoder(Decoder<?> decoder) {
 			reader(new DecoderHttpMessageReader<>(decoder));

spring-web/src/main/java/org/springframework/http/codec/support/BaseDefaultCodecs.java

@@ -105,6 +105,24 @@ class BaseDefaultCodecs implements CodecConfigurer.DefaultCodecs {
 	private boolean registerDefaults = true;
 
 
+	BaseDefaultCodecs() {
+	}
+
+	/**
+	 * Create a deep copy of the given {@link BaseDefaultCodecs}.
+	 */
+	protected BaseDefaultCodecs(BaseDefaultCodecs other) {
+		this.jackson2JsonDecoder = other.jackson2JsonDecoder;
+		this.jackson2JsonEncoder = other.jackson2JsonEncoder;
+		this.protobufDecoder = other.protobufDecoder;
+		this.protobufEncoder = other.protobufEncoder;
+		this.jaxb2Decoder = other.jaxb2Decoder;
+		this.jaxb2Encoder = other.jaxb2Encoder;
+		this.maxInMemorySize = other.maxInMemorySize;
+		this.enableLoggingRequestDetails = other.enableLoggingRequestDetails;
+		this.registerDefaults = other.registerDefaults;
+	}
+
 	@Override
 	public void jackson2JsonDecoder(Decoder<?> decoder) {
 		this.jackson2JsonDecoder = decoder;

spring-web/src/main/java/org/springframework/http/codec/support/ClientDefaultCodecsImpl.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * 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.
@@ -49,6 +49,17 @@ class ClientDefaultCodecsImpl extends BaseDefaultCodecs implements ClientCodecCo
 	private Supplier<List<HttpMessageWriter<?>>> partWritersSupplier;
 
 
+	ClientDefaultCodecsImpl() {
+	}
+
+	ClientDefaultCodecsImpl(ClientDefaultCodecsImpl other) {
+		super(other);
+		this.multipartCodecs = new DefaultMultipartCodecs(other.multipartCodecs);
+		this.sseDecoder = other.sseDecoder;
+		this.partWritersSupplier = other.partWritersSupplier;
+	}
+
+
 	/**
 	 * Set a supplier for part writers to use when
 	 * {@link #multipartCodecs()} are not explicitly configured.
@@ -73,6 +84,14 @@ public void serverSentEventDecoder(Decoder<?> decoder) {
 		this.sseDecoder = decoder;
 	}
 
+	@Override
+	public ClientDefaultCodecsImpl clone() {
+		ClientDefaultCodecsImpl codecs = new ClientDefaultCodecsImpl();
+		codecs.multipartCodecs = this.multipartCodecs;
+		codecs.sseDecoder = this.sseDecoder;
+		codecs.partWritersSupplier = this.partWritersSupplier;
+		return codecs;
+	}
 
 	@Override
 	protected void extendObjectReaders(List<HttpMessageReader<?>> objectReaders) {
@@ -116,6 +135,17 @@ private static class DefaultMultipartCodecs implements ClientCodecConfigurer.Mul
 
 		private final List<HttpMessageWriter<?>> writers = new ArrayList<>();
 
+
+		DefaultMultipartCodecs() {
+		}
+
+		DefaultMultipartCodecs(@Nullable DefaultMultipartCodecs other) {
+			if (other != null) {
+				this.writers.addAll(other.writers);
+			}
+		}
+
+
 		@Override
 		public ClientCodecConfigurer.MultipartCodecs encoder(Encoder<?> encoder) {
 			writer(new EncoderHttpMessageWriter<>(encoder));

spring-web/src/main/java/org/springframework/http/codec/support/DefaultClientCodecConfigurer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * 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.
@@ -26,14 +26,30 @@
  */
 public class DefaultClientCodecConfigurer extends BaseCodecConfigurer implements ClientCodecConfigurer {
 
+
 	public DefaultClientCodecConfigurer() {
 		super(new ClientDefaultCodecsImpl());
 		((ClientDefaultCodecsImpl) defaultCodecs()).setPartWritersSupplier(() -> getWritersInternal(true));
 	}
 
+	private DefaultClientCodecConfigurer(DefaultClientCodecConfigurer other) {
+		super(other);
+	}
+
+
 	@Override
 	public ClientDefaultCodecs defaultCodecs() {
 		return (ClientDefaultCodecs) super.defaultCodecs();
 	}
 
+	@Override
+	public DefaultClientCodecConfigurer clone() {
+		return new DefaultClientCodecConfigurer(this);
+	}
+
+	@Override
+	protected BaseDefaultCodecs cloneDefaultCodecs() {
+		return new ClientDefaultCodecsImpl((ClientDefaultCodecsImpl) defaultCodecs());
+	}
+
 }

spring-web/src/main/java/org/springframework/http/codec/support/DefaultServerCodecConfigurer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * 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.
@@ -26,13 +26,28 @@
  */
 public class DefaultServerCodecConfigurer extends BaseCodecConfigurer implements ServerCodecConfigurer {
 
+
 	public DefaultServerCodecConfigurer() {
 		super(new ServerDefaultCodecsImpl());
 	}
 
+	private DefaultServerCodecConfigurer(BaseCodecConfigurer other) {
+		super(other);
+	}
+
+
 	@Override
 	public ServerDefaultCodecs defaultCodecs() {
 		return (ServerDefaultCodecs) super.defaultCodecs();
 	}
 
+	@Override
+	public DefaultServerCodecConfigurer clone() {
+		return new DefaultServerCodecConfigurer(this);
+	}
+
+	@Override
+	protected BaseDefaultCodecs cloneDefaultCodecs() {
+		return new ServerDefaultCodecsImpl((ServerDefaultCodecsImpl) defaultCodecs());
+	}
 }

spring-web/src/main/java/org/springframework/http/codec/support/ServerDefaultCodecsImpl.java

@@ -46,6 +46,16 @@ class ServerDefaultCodecsImpl extends BaseDefaultCodecs implements ServerCodecCo
 	private Encoder<?> sseEncoder;
 
 
+	ServerDefaultCodecsImpl() {
+	}
+
+	ServerDefaultCodecsImpl(ServerDefaultCodecsImpl other) {
+		super(other);
+		this.multipartReader = other.multipartReader;
+		this.sseEncoder = other.sseEncoder;
+	}
+
+
 	@Override
 	public void multipartReader(HttpMessageReader<?> reader) {
 		this.multipartReader = reader;