Align multipart codecs on client and server

This commit ensures that the same multipart codecs are registered on
both client and server. Previously, only the client enabled only sending
 multipart, and the server only receiving.

Closes gh-29630

Author: poutsma

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -17,7 +17,6 @@
 package org.springframework.http.codec;
 
 import org.springframework.core.codec.Decoder;
-import org.springframework.core.codec.Encoder;
 
 /**
  * Extension of {@link CodecConfigurer} for HTTP message reader and writer
@@ -83,13 +82,6 @@ static ClientCodecConfigurer create() {
 	 */
 	interface ClientDefaultCodecs extends DefaultCodecs {
 
-		/**
-		 * Configure encoders or writers for use with
-		 * {@link org.springframework.http.codec.multipart.MultipartHttpMessageWriter
-		 * MultipartHttpMessageWriter}.
-		 */
-		MultipartCodecs multipartCodecs();
-
 		/**
 		 * Configure the {@code Decoder} to use for Server-Sent Events.
 		 * <p>By default if this is not set, and Jackson is available, the
@@ -102,26 +94,4 @@ interface ClientDefaultCodecs extends DefaultCodecs {
 		void serverSentEventDecoder(Decoder<?> decoder);
 	}
 
-
-	/**
-	 * Registry and container for multipart HTTP message writers.
-	 */
-	interface MultipartCodecs {
-
-		/**
-		 * Add a Part {@code Encoder}, internally wrapped with
-		 * {@link EncoderHttpMessageWriter}.
-		 * @param encoder the encoder to add
-		 */
-		MultipartCodecs encoder(Encoder<?> encoder);
-
-		/**
-		 * Add a Part {@link HttpMessageWriter}. For writers of type
-		 * {@link EncoderHttpMessageWriter} consider using the shortcut
-		 * {@link #encoder(Encoder)} instead.
-		 * @param writer the writer to add
-		 */
-		MultipartCodecs writer(HttpMessageWriter<?> writer);
-	}
-
 }

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

@@ -258,6 +258,24 @@ interface DefaultCodecs {
 		 * @since 5.1
 		 */
 		void enableLoggingRequestDetails(boolean enable);
+
+		/**
+		 * Configure encoders or writers for use with
+		 * {@link org.springframework.http.codec.multipart.MultipartHttpMessageWriter
+		 * MultipartHttpMessageWriter}.
+		 * @since 6.0.3
+		 */
+		MultipartCodecs multipartCodecs();
+
+		/**
+		 * Configure the {@code HttpMessageReader} to use for multipart requests.
+		 * <p>Note that {@link #maxInMemorySize(int)} and/or
+		 * {@link #enableLoggingRequestDetails(boolean)}, if configured, will be
+		 * applied to the given reader, if applicable.
+		 * @param reader the message reader to use for multipart requests.
+		 * @since 6.0.3
+		 */
+		void multipartReader(HttpMessageReader<?> reader);
 	}
 
 
@@ -389,4 +407,27 @@ interface DefaultCodecConfig {
 		Boolean isEnableLoggingRequestDetails();
 	}
 
+
+	/**
+	 * Registry and container for multipart HTTP message writers.
+	 * @since 6.0.3
+	 */
+	interface MultipartCodecs {
+
+		/**
+		 * Add a Part {@code Encoder}, internally wrapped with
+		 * {@link EncoderHttpMessageWriter}.
+		 * @param encoder the encoder to add
+		 */
+		MultipartCodecs encoder(Encoder<?> encoder);
+
+		/**
+		 * Add a Part {@link HttpMessageWriter}. For writers of type
+		 * {@link EncoderHttpMessageWriter} consider using the shortcut
+		 * {@link #encoder(Encoder)} instead.
+		 * @param writer the writer to add
+		 */
+		MultipartCodecs writer(HttpMessageWriter<?> writer);
+	}
+
 }

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -82,16 +82,6 @@ static ServerCodecConfigurer create() {
 	 */
 	interface ServerDefaultCodecs extends DefaultCodecs {
 
-		/**
-		 * Configure the {@code HttpMessageReader} to use for multipart requests.
-		 * <p>Note that {@link #maxInMemorySize(int)} and/or
-		 * {@link #enableLoggingRequestDetails(boolean)}, if configured, will be
-		 * applied to the given reader, if applicable.
-		 * @param reader the message reader to use for multipart requests.
-		 * @since 5.1.11
-		 */
-		void multipartReader(HttpMessageReader<?> reader);
-
 		/**
 		 * Configure the {@code Encoder} to use for Server-Sent Events.
 		 * <p>By default if this is not set, and Jackson is available, the

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

@@ -79,7 +79,7 @@ public class MultipartHttpMessageWriter extends MultipartWriterSupport
 	private static final Map<String, Object> DEFAULT_HINTS = Hints.from(Hints.SUPPRESS_LOGGING_HINT, true);
 
 
-	private final List<HttpMessageWriter<?>> partWriters;
+	private final Supplier<List<HttpMessageWriter<?>>> partWritersSupplier;
 
 	@Nullable
 	private final HttpMessageWriter<MultiValueMap<String, String>> formWriter;
@@ -112,8 +112,23 @@ public MultipartHttpMessageWriter(List<HttpMessageWriter<?>> partWriters) {
 	public MultipartHttpMessageWriter(List<HttpMessageWriter<?>> partWriters,
 			@Nullable  HttpMessageWriter<MultiValueMap<String, String>> formWriter) {
 
+		this(() -> partWriters, formWriter);
+	}
+
+	/**
+	 * Constructor with a supplier for an explicit list of writers for
+	 * serializing parts and a writer for plain form data to fall back when
+	 * no media type is specified and the actual map consists of String
+	 * values only.
+	 * @param partWritersSupplier the supplier for writers for serializing parts
+	 * @param formWriter the fallback writer for form data, {@code null} by default
+	 * @since 6.0.3
+	 */
+	public MultipartHttpMessageWriter(Supplier<List<HttpMessageWriter<?>>> partWritersSupplier,
+			@Nullable  HttpMessageWriter<MultiValueMap<String, String>> formWriter) {
+
 		super(initMediaTypes(formWriter));
-		this.partWriters = partWriters;
+		this.partWritersSupplier = partWritersSupplier;
 		this.formWriter = formWriter;
 	}
 
@@ -131,7 +146,7 @@ private static List<MediaType> initMediaTypes(@Nullable HttpMessageWriter<?> for
 	 * @since 5.0.7
 	 */
 	public List<HttpMessageWriter<?>> getPartWriters() {
-		return Collections.unmodifiableList(this.partWriters);
+		return Collections.unmodifiableList(this.partWritersSupplier.get());
 	}
 
 
@@ -264,8 +279,8 @@ else if (resolvableType.resolve() == Resource.class) {
 
 		MediaType contentType = headers.getContentType();
 
-		final ResolvableType finalBodyType = resolvableType;
-		Optional<HttpMessageWriter<?>> writer = this.partWriters.stream()
+		ResolvableType finalBodyType = resolvableType;
+		Optional<HttpMessageWriter<?>> writer = this.partWritersSupplier.get().stream()
 				.filter(partWriter -> partWriter.canWrite(finalBodyType, contentType))
 				.findFirst();
 

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

@@ -55,6 +55,7 @@ abstract class BaseCodecConfigurer implements CodecConfigurer {
 		Assert.notNull(defaultCodecs, "'defaultCodecs' is required");
 		this.defaultCodecs = defaultCodecs;
 		this.customCodecs = new DefaultCustomCodecs();
+		this.defaultCodecs.setPartWritersSupplier(this::getWriters);
 	}
 
 	/**
@@ -64,6 +65,7 @@ abstract class BaseCodecConfigurer implements CodecConfigurer {
 	protected BaseCodecConfigurer(BaseCodecConfigurer other) {
 		this.defaultCodecs = other.cloneDefaultCodecs();
 		this.customCodecs = new DefaultCustomCodecs(other.customCodecs);
+		this.defaultCodecs.setPartWritersSupplier(this::getWriters);
 	}
 
 	/**

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

@@ -21,6 +21,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.function.Consumer;
+import java.util.function.Supplier;
 
 import org.springframework.core.codec.AbstractDataBufferDecoder;
 import org.springframework.core.codec.ByteArrayDecoder;
@@ -62,6 +63,8 @@
 import org.springframework.http.codec.multipart.MultipartHttpMessageReader;
 import org.springframework.http.codec.multipart.MultipartHttpMessageWriter;
 import org.springframework.http.codec.multipart.PartEventHttpMessageReader;
+import org.springframework.http.codec.multipart.PartEventHttpMessageWriter;
+import org.springframework.http.codec.multipart.PartHttpMessageWriter;
 import org.springframework.http.codec.protobuf.KotlinSerializationProtobufDecoder;
 import org.springframework.http.codec.protobuf.KotlinSerializationProtobufEncoder;
 import org.springframework.http.codec.protobuf.ProtobufDecoder;
@@ -160,6 +163,15 @@ class BaseDefaultCodecs implements CodecConfigurer.DefaultCodecs, CodecConfigure
 	@Nullable
 	private Encoder<?> kotlinSerializationProtobufEncoder;
 
+	@Nullable
+	private DefaultMultipartCodecs multipartCodecs;
+
+	@Nullable
+	private Supplier<List<HttpMessageWriter<?>>> partWritersSupplier;
+
+	@Nullable
+	private HttpMessageReader<?> multipartReader;
+
 	@Nullable
 	private Consumer<Object> codecConsumer;
 
@@ -224,6 +236,9 @@ protected BaseDefaultCodecs(BaseDefaultCodecs other) {
 		this.kotlinSerializationJsonEncoder = other.kotlinSerializationJsonEncoder;
 		this.kotlinSerializationProtobufDecoder = other.kotlinSerializationProtobufDecoder;
 		this.kotlinSerializationProtobufEncoder = other.kotlinSerializationProtobufEncoder;
+		this.multipartCodecs = other.multipartCodecs != null ?
+				new DefaultMultipartCodecs(other.multipartCodecs) : null;
+		this.multipartReader = other.multipartReader;
 		this.codecConsumer = other.codecConsumer;
 		this.maxInMemorySize = other.maxInMemorySize;
 		this.enableLoggingRequestDetails = other.enableLoggingRequestDetails;
@@ -351,6 +366,31 @@ public void enableLoggingRequestDetails(boolean enable) {
 		}
 	}
 
+	@Override
+	public CodecConfigurer.MultipartCodecs multipartCodecs() {
+		if (this.multipartCodecs == null) {
+			this.multipartCodecs = new DefaultMultipartCodecs();
+		}
+		return this.multipartCodecs;
+	}
+
+	@Override
+	public void multipartReader(HttpMessageReader<?> multipartReader) {
+		this.multipartReader = multipartReader;
+		initTypedReaders();
+	}
+
+	/**
+	 * Set a supplier for part writers to use when
+	 * {@link #multipartCodecs()} are not explicitly configured.
+	 * That's the same set of writers as for general except for the multipart
+	 * writer itself.
+	 */
+	void setPartWritersSupplier(Supplier<List<HttpMessageWriter<?>>> supplier) {
+		this.partWritersSupplier = supplier;
+		initTypedWriters();
+	}
+
 	@Override
 	@Nullable
 	public Boolean isEnableLoggingRequestDetails() {
@@ -405,6 +445,15 @@ else if (kotlinSerializationProtobufPresent) {
 					(KotlinSerializationProtobufDecoder) this.kotlinSerializationProtobufDecoder : new KotlinSerializationProtobufDecoder()));
 		}
 		addCodec(this.typedReaders, new FormHttpMessageReader());
+		if (this.multipartReader != null) {
+			addCodec(this.typedReaders, this.multipartReader);
+		}
+		else {
+			DefaultPartHttpMessageReader partReader = new DefaultPartHttpMessageReader();
+			addCodec(this.typedReaders, partReader);
+			addCodec(this.typedReaders, new MultipartHttpMessageReader(partReader));
+		}
+		addCodec(this.typedReaders, new PartEventHttpMessageReader());
 
 		// client vs server..
 		extendTypedReaders(this.typedReaders);
@@ -641,9 +690,25 @@ final List<HttpMessageWriter<?>> getBaseTypedWriters() {
 			addCodec(writers, new ProtobufHttpMessageWriter(this.protobufEncoder != null ?
 					(ProtobufEncoder) this.protobufEncoder : new ProtobufEncoder()));
 		}
+		addCodec(writers, new MultipartHttpMessageWriter(this::getPartWriters, new FormHttpMessageWriter()));
+		addCodec(writers, new PartEventHttpMessageWriter());
+		addCodec(writers, new PartHttpMessageWriter());
 		return writers;
 	}
 
+	private List<HttpMessageWriter<?>> getPartWriters() {
+		if (this.multipartCodecs != null) {
+			return this.multipartCodecs.getWriters();
+		}
+		else if (this.partWritersSupplier != null) {
+			return this.partWritersSupplier.get();
+		}
+		else {
+			return Collections.emptyList();
+		}
+	}
+
+
 	/**
 	 * Hook for client or server specific typed writers.
 	 */
@@ -766,4 +831,41 @@ protected Encoder<?> getKotlinSerializationJsonEncoder() {
 		return this.kotlinSerializationJsonEncoder;
 	}
 
+
+	/**
+	 * Default implementation of {@link CodecConfigurer.MultipartCodecs}.
+	 */
+	protected class DefaultMultipartCodecs implements CodecConfigurer.MultipartCodecs {
+
+		private final List<HttpMessageWriter<?>> writers = new ArrayList<>();
+
+
+		DefaultMultipartCodecs() {
+		}
+
+		DefaultMultipartCodecs(DefaultMultipartCodecs other) {
+			this.writers.addAll(other.writers);
+		}
+
+
+		@Override
+		public CodecConfigurer.MultipartCodecs encoder(Encoder<?> encoder) {
+			writer(new EncoderHttpMessageWriter<>(encoder));
+			initTypedWriters();
+			return this;
+		}
+
+		@Override
+		public CodecConfigurer.MultipartCodecs writer(HttpMessageWriter<?> writer) {
+			this.writers.add(writer);
+			initTypedWriters();
+			return this;
+		}
+
+		List<HttpMessageWriter<?>> getWriters() {
+			return this.writers;
+		}
+	}
+
+
 }