Added form support to Body[Inserter|Extractor]

- Added BodyInserter for MultiValueMap form data in BodyInserters
 - Added BodyExtractor to MultiValueMap in BodyExtractors

Issue: SPR-15144

spring-web-reactive/src/main/java/org/springframework/web/reactive/function/BodyExtractors.java

@@ -33,7 +33,9 @@ import org.springframework.http.MediaType;
 import org.springframework.http.ReactiveHttpInputMessage;
 import org.springframework.http.codec.HttpMessageReader;
 import org.springframework.http.codec.UnsupportedMediaTypeException;
+import org.springframework.http.server.reactive.ServerHttpRequest;
 import org.springframework.util.Assert;
+import org.springframework.util.MultiValueMap;
 
 /**
  * Implementations of {@link BodyExtractor} that read various bodies, such a reactive streams.
@@ -43,6 +45,10 @@ import org.springframework.util.Assert;
  */
 public abstract class BodyExtractors {
 
+	private static final ResolvableType FORM_TYPE =
+			ResolvableType.forClassWithGenerics(MultiValueMap.class, String.class, String.class);
+
+
 	/**
 	 * Return a {@code BodyExtractor} that reads into a Reactor {@link Mono}.
 	 * @param elementClass the class of element in the {@code Mono}
@@ -93,6 +99,29 @@ public abstract class BodyExtractors {
 				Flux::error);
 	}
 
+	/**
+	 * Return a {@code BodyExtractor} that reads form data into a {@link MultiValueMap}.
+	 * @return a {@code BodyExtractor} that reads form data
+	 */
+	public static BodyExtractor<Mono<MultiValueMap<String, String>>, ServerHttpRequest> toFormData() {
+		return (serverRequest, context) -> {
+					HttpMessageReader<MultiValueMap<String, String>> messageReader = formMessageReader(context);
+					return messageReader.readMono(FORM_TYPE, serverRequest, context.hints());
+				};
+	}
+
+	private static HttpMessageReader<MultiValueMap<String, String>> formMessageReader(BodyExtractor.Context context) {
+		return context.messageReaders().get()
+				.filter(messageReader -> messageReader
+						.canRead(FORM_TYPE, MediaType.APPLICATION_FORM_URLENCODED))
+				.findFirst()
+				.map(BodyExtractors::<MultiValueMap<String, String>>cast)
+				.orElseThrow(() -> new IllegalStateException(
+						"Could not find HttpMessageReader that supports " +
+								MediaType.APPLICATION_FORM_URLENCODED_VALUE));
+	}
+
+
 	/**
 	 * Return a {@code BodyExtractor} that returns the body of the message as a {@link Flux} of
 	 * {@link DataBuffer}s.

spring-web-reactive/src/main/java/org/springframework/web/reactive/function/BodyInserters.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * 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.
@@ -29,11 +29,13 @@ import org.springframework.core.io.Resource;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.http.MediaType;
 import org.springframework.http.ReactiveHttpOutputMessage;
+import org.springframework.http.client.reactive.ClientHttpRequest;
 import org.springframework.http.codec.HttpMessageWriter;
 import org.springframework.http.codec.ServerSentEvent;
 import org.springframework.http.codec.UnsupportedMediaTypeException;
 import org.springframework.http.server.reactive.ServerHttpResponse;
 import org.springframework.util.Assert;
+import org.springframework.util.MultiValueMap;
 
 /**
  * Implementations of {@link BodyInserter} that write various bodies, such a reactive streams,
@@ -49,6 +51,10 @@ public abstract class BodyInserters {
 	private static final ResolvableType SERVER_SIDE_EVENT_TYPE =
 			ResolvableType.forClass(ServerSentEvent.class);
 
+	private static final ResolvableType FORM_TYPE =
+			ResolvableType.forClassWithGenerics(MultiValueMap.class, String.class, String.class);
+
+
 	private static final BodyInserter<Void, ReactiveHttpOutputMessage> EMPTY =
 					(response, context) -> response.setComplete();
 
@@ -109,16 +115,16 @@ public abstract class BodyInserters {
 	 * If the resource can be resolved to a {@linkplain Resource#getFile() file}, it will be copied
 	 * using
 	 * <a href="https://en.wikipedia.org/wiki/Zero-copy">zero-copy</a>
-	 * @param resource the resource to write to the response
+	 * @param resource the resource to write to the output message
 	 * @param <T> the type of the {@code Resource}
 	 * @return a {@code BodyInserter} that writes a {@code Publisher}
 	 */
 	public static <T extends Resource> BodyInserter<T, ReactiveHttpOutputMessage> fromResource(T resource) {
 		Assert.notNull(resource, "'resource' must not be null");
-		return (response, context) -> {
+		return (outputMessage, context) -> {
 					HttpMessageWriter<Resource> messageWriter = resourceHttpMessageWriter(context);
 					return messageWriter.write(Mono.just(resource), RESOURCE_TYPE, null,
-							response, context.hints());
+							outputMessage, context.hints());
 				};
 	}
 
@@ -143,10 +149,11 @@ public abstract class BodyInserters {
 
 		Assert.notNull(eventsPublisher, "'eventsPublisher' must not be null");
 		return (response, context) -> {
-					HttpMessageWriter<ServerSentEvent<T>> messageWriter = sseMessageWriter(context);
-					return messageWriter.write(eventsPublisher, SERVER_SIDE_EVENT_TYPE,
-							MediaType.TEXT_EVENT_STREAM, response, context.hints());
-				};
+			HttpMessageWriter<ServerSentEvent<T>> messageWriter =
+					findMessageWriter(context, SERVER_SIDE_EVENT_TYPE, MediaType.TEXT_EVENT_STREAM);
+			return messageWriter.write(eventsPublisher, SERVER_SIDE_EVENT_TYPE,
+					MediaType.TEXT_EVENT_STREAM, response, context.hints());
+		};
 	}
 
 	/**
@@ -183,13 +190,45 @@ public abstract class BodyInserters {
 		Assert.notNull(eventsPublisher, "'eventsPublisher' must not be null");
 		Assert.notNull(eventType, "'eventType' must not be null");
 		return (outputMessage, context) -> {
-					HttpMessageWriter<T> messageWriter = sseMessageWriter(context);
-					return messageWriter.write(eventsPublisher, eventType,
-							MediaType.TEXT_EVENT_STREAM, outputMessage, context.hints());
+			HttpMessageWriter<T> messageWriter =
+					findMessageWriter(context, SERVER_SIDE_EVENT_TYPE, MediaType.TEXT_EVENT_STREAM);
+			return messageWriter.write(eventsPublisher, eventType,
+					MediaType.TEXT_EVENT_STREAM, outputMessage, context.hints());
 
-				};
+		};
 	}
 
+	/**
+	 * Return a {@code BodyInserter} that writes the given {@code MultiValueMap} as URL-encoded
+	 * form data.
+	 * @param formData the form data to write to the output message
+	 * @return a {@code BodyInserter} that writes form data
+	 */
+	public static BodyInserter<MultiValueMap<String, String>, ClientHttpRequest> fromFormData(MultiValueMap<String, String> formData) {
+		Assert.notNull(formData, "'formData' must not be null");
+
+		return (outputMessage, context) -> {
+			HttpMessageWriter<MultiValueMap<String, String>> messageWriter =
+					findMessageWriter(context, FORM_TYPE, MediaType.APPLICATION_FORM_URLENCODED);
+			return messageWriter.write(Mono.just(formData), FORM_TYPE,
+					MediaType.APPLICATION_FORM_URLENCODED, outputMessage, context.hints());
+		};
+	}
+
+	private static <T> HttpMessageWriter<T> findMessageWriter(BodyInserter.Context context,
+			ResolvableType type,
+			MediaType mediaType) {
+
+		return context.messageWriters().get()
+				.filter(messageWriter -> messageWriter.canWrite(type, mediaType))
+				.findFirst()
+				.map(BodyInserters::<T>cast)
+				.orElseThrow(() -> new IllegalStateException(
+						"Could not find HttpMessageWriter that supports " + mediaType));
+	}
+
+
+
 	/**
 	 * Return a {@code BodyInserter} that writes the given {@code Publisher<DataBuffer>} to the
 	 * body.
@@ -204,16 +243,6 @@ public abstract class BodyInserters {
 		return (outputMessage, context) -> outputMessage.writeWith(publisher);
 	}
 
-	private static <T> HttpMessageWriter<T> sseMessageWriter(BodyInserter.Context context) {
-		return context.messageWriters().get()
-				.filter(messageWriter -> messageWriter
-						.canWrite(SERVER_SIDE_EVENT_TYPE, MediaType.TEXT_EVENT_STREAM))
-				.findFirst()
-				.map(BodyInserters::<T>cast)
-				.orElseThrow(() -> new IllegalStateException(
-						"Could not find HttpMessageWriter that supports " +
-								MediaType.TEXT_EVENT_STREAM_VALUE));
-	}
 
 	private static <T, P extends Publisher<?>, M extends ReactiveHttpOutputMessage> BodyInserter<T, M> bodyInserterFor(P body, ResolvableType bodyType) {
 

spring-web-reactive/src/test/java/org/springframework/web/reactive/function/BodyExtractorsTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * 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.
@@ -41,11 +41,14 @@ import org.springframework.core.io.buffer.DefaultDataBufferFactory;
 import org.springframework.http.MediaType;
 import org.springframework.http.ReactiveHttpInputMessage;
 import org.springframework.http.codec.DecoderHttpMessageReader;
+import org.springframework.http.codec.FormHttpMessageReader;
 import org.springframework.http.codec.HttpMessageReader;
 import org.springframework.http.codec.UnsupportedMediaTypeException;
 import org.springframework.http.codec.json.Jackson2JsonDecoder;
 import org.springframework.http.codec.xml.Jaxb2XmlDecoder;
+import org.springframework.http.server.reactive.ServerHttpRequest;
 import org.springframework.mock.http.server.reactive.test.MockServerHttpRequest;
+import org.springframework.util.MultiValueMap;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNull;
@@ -68,6 +71,7 @@ public class BodyExtractorsTests {
 		messageReaders.add(new DecoderHttpMessageReader<>(new StringDecoder()));
 		messageReaders.add(new DecoderHttpMessageReader<>(new Jaxb2XmlDecoder()));
 		messageReaders.add(new DecoderHttpMessageReader<>(new Jackson2JsonDecoder()));
+		messageReaders.add(new FormHttpMessageReader());
 
 		this.context = new BodyExtractor.Context() {
 			@Override
@@ -79,7 +83,7 @@ public class BodyExtractorsTests {
 				return hints;
 			}
 		};
-		this.hints = new HashMap();
+		this.hints = new HashMap<String, Object>();
 	}
 
 	@Test
@@ -202,6 +206,36 @@ public class BodyExtractorsTests {
 				.verify();
 	}
 
+	@Test
+	public void toFormData() throws Exception {
+		BodyExtractor<Mono<MultiValueMap<String, String>>, ServerHttpRequest> extractor = BodyExtractors.toFormData();
+
+		DefaultDataBufferFactory factory = new DefaultDataBufferFactory();
+		DefaultDataBuffer dataBuffer =
+				factory.wrap(ByteBuffer.wrap("name+1=value+1&name+2=value+2%2B1&name+2=value+2%2B2&name+3".getBytes(StandardCharsets.UTF_8)));
+		Flux<DataBuffer> body = Flux.just(dataBuffer);
+
+		MockServerHttpRequest request = MockServerHttpRequest.post("/")
+				.contentType(MediaType.APPLICATION_FORM_URLENCODED)
+				.body(body);
+
+		Mono<MultiValueMap<String, String>> result = extractor.extract(request, this.context);
+
+		StepVerifier.create(result)
+				.consumeNextWith(form -> {
+					assertEquals("Invalid result", 3, form.size());
+					assertEquals("Invalid result", "value 1", form.getFirst("name 1"));
+					List<String> values = form.get("name 2");
+					assertEquals("Invalid result", 2, values.size());
+					assertEquals("Invalid result", "value 2+1", values.get(0));
+					assertEquals("Invalid result", "value 2+2", values.get(1));
+					assertNull("Invalid result", form.getFirst("name 3"));
+				})
+				.expectComplete()
+				.verify();
+
+	}
+
 	@Test
 	public void toDataBuffers() throws Exception {
 		BodyExtractor<Flux<DataBuffer>, ReactiveHttpInputMessage> extractor = BodyExtractors.toDataBuffers();

spring-web-reactive/src/test/java/org/springframework/web/reactive/function/BodyInsertersTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * 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.
@@ -16,6 +16,7 @@
 
 package org.springframework.web.reactive.function;
 
+import java.net.URI;
 import java.nio.ByteBuffer;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
@@ -41,8 +42,11 @@ import org.springframework.core.io.Resource;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DefaultDataBuffer;
 import org.springframework.core.io.buffer.DefaultDataBufferFactory;
+import org.springframework.http.HttpMethod;
 import org.springframework.http.ReactiveHttpOutputMessage;
+import org.springframework.http.client.reactive.ClientHttpRequest;
 import org.springframework.http.codec.EncoderHttpMessageWriter;
+import org.springframework.http.codec.FormHttpMessageWriter;
 import org.springframework.http.codec.HttpMessageWriter;
 import org.springframework.http.codec.ResourceHttpMessageWriter;
 import org.springframework.http.codec.ServerSentEvent;
@@ -50,7 +54,10 @@ import org.springframework.http.codec.ServerSentEventHttpMessageWriter;
 import org.springframework.http.codec.json.Jackson2JsonEncoder;
 import org.springframework.http.codec.xml.Jaxb2XmlEncoder;
 import org.springframework.http.server.reactive.ServerHttpResponse;
+import org.springframework.mock.http.client.reactive.test.MockClientHttpRequest;
 import org.springframework.mock.http.server.reactive.test.MockServerHttpResponse;
+import org.springframework.util.LinkedMultiValueMap;
+import org.springframework.util.MultiValueMap;
 
 import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.junit.Assert.assertArrayEquals;
@@ -77,6 +84,7 @@ public class BodyInsertersTests {
 		messageWriters.add(new EncoderHttpMessageWriter<>(jsonEncoder));
 		messageWriters
 				.add(new ServerSentEventHttpMessageWriter(Collections.singletonList(jsonEncoder)));
+		messageWriters.add(new FormHttpMessageWriter());
 
 		this.context = new BodyInserter.Context() {
 			@Override
@@ -198,6 +206,33 @@ public class BodyInsertersTests {
 		StepVerifier.create(result).expectNextCount(0).expectComplete().verify();
 	}
 
+	@Test
+	public void ofFormData() throws Exception {
+		MultiValueMap<String, String> body = new LinkedMultiValueMap<>();
+		body.set("name 1", "value 1");
+		body.add("name 2", "value 2+1");
+		body.add("name 2", "value 2+2");
+		body.add("name 3", null);
+
+		BodyInserter<MultiValueMap<String, String>, ClientHttpRequest>
+				inserter = BodyInserters.fromFormData(body);
+
+		MockClientHttpRequest request = new MockClientHttpRequest(HttpMethod.GET, URI.create("http://example.com"));
+		Mono<Void> result = inserter.insert(request, this.context);
+		StepVerifier.create(result).expectComplete().verify();
+
+		StepVerifier.create(request.getBody())
+				.consumeNextWith(dataBuffer -> {
+					byte[] resultBytes = new byte[dataBuffer.readableByteCount()];
+					dataBuffer.read(resultBytes);
+					assertArrayEquals("name+1=value+1&name+2=value+2%2B1&name+2=value+2%2B2&name+3".getBytes(StandardCharsets.UTF_8),
+							resultBytes);
+				})
+				.expectComplete()
+				.verify();
+
+	}
+
 	@Test
 	public void ofDataBuffers() throws Exception {
 		DefaultDataBufferFactory factory = new DefaultDataBufferFactory();