Add formData() and multipartData() to ServerRequest

Issue: SPR-16551

spring-webflux/src/main/java/org/springframework/web/reactive/function/server/DefaultServerRequest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -39,6 +39,7 @@ import org.springframework.http.HttpRange;
 import org.springframework.http.HttpRequest;
 import org.springframework.http.MediaType;
 import org.springframework.http.codec.HttpMessageReader;
+import org.springframework.http.codec.multipart.Part;
 import org.springframework.http.server.PathContainer;
 import org.springframework.http.server.reactive.ServerHttpRequest;
 import org.springframework.http.server.reactive.ServerHttpResponse;
@@ -190,6 +191,16 @@ class DefaultServerRequest implements ServerRequest {
 		return this.exchange.getPrincipal();
 	}
 
+	@Override
+	public Mono<MultiValueMap<String, String>> formData() {
+		return this.exchange.getFormData();
+	}
+
+	@Override
+	public Mono<MultiValueMap<String, Part>> multipartData() {
+		return this.exchange.getMultipartData();
+	}
+
 	private ServerHttpRequest request() {
 		return this.exchange.getRequest();
 	}

spring-webflux/src/main/java/org/springframework/web/reactive/function/server/RequestPredicates.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -39,6 +39,7 @@ import org.springframework.core.ParameterizedTypeReference;
 import org.springframework.http.HttpCookie;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.MediaType;
+import org.springframework.http.codec.multipart.Part;
 import org.springframework.http.server.PathContainer;
 import org.springframework.http.server.reactive.ServerHttpRequest;
 import org.springframework.lang.Nullable;
@@ -582,6 +583,16 @@ public abstract class RequestPredicates {
 			return this.request.principal();
 		}
 
+		@Override
+		public Mono<MultiValueMap<String, String>> formData() {
+			return this.request.formData();
+		}
+
+		@Override
+		public Mono<MultiValueMap<String, Part>> multipartData() {
+			return this.request.multipartData();
+		}
+
 		@Override
 		public String toString() {
 			return method() + " " +  path();

spring-webflux/src/main/java/org/springframework/web/reactive/function/server/ServerRequest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -37,6 +37,7 @@ import org.springframework.http.HttpRange;
 import org.springframework.http.MediaType;
 import org.springframework.http.codec.HttpMessageReader;
 import org.springframework.http.codec.json.Jackson2CodecSupport;
+import org.springframework.http.codec.multipart.Part;
 import org.springframework.http.server.PathContainer;
 import org.springframework.http.server.reactive.ServerHttpRequest;
 import org.springframework.lang.Nullable;
@@ -244,6 +245,27 @@ public interface ServerRequest {
 	 */
 	Mono<? extends Principal> principal();
 
+	/**
+	 * Return the form data from the body of the request if the Content-Type is
+	 * {@code "application/x-www-form-urlencoded"} or an empty map otherwise.
+	 *
+	 * <p><strong>Note:</strong> calling this method causes the request body to
+	 * be read and parsed in full and the resulting {@code MultiValueMap} is
+	 * cached so that this method is safe to call more than once.
+	 */
+	Mono<MultiValueMap<String, String>> formData();
+
+	/**
+	 * Return the parts of a multipart request if the Content-Type is
+	 * {@code "multipart/form-data"} or an empty map otherwise.
+	 *
+	 * <p><strong>Note:</strong> calling this method causes the request body to
+	 * be read and parsed in full and the resulting {@code MultiValueMap} is
+	 * cached so that this method is safe to call more than once.
+	 */
+	Mono<MultiValueMap<String, Part>> multipartData();
+
+
 
 	/**
 	 * Create a new {@code ServerRequest} based on the given {@code ServerWebExchange} and

spring-webflux/src/main/java/org/springframework/web/reactive/function/server/support/ServerRequestWrapper.java

@@ -35,6 +35,7 @@ import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpRange;
 import org.springframework.http.MediaType;
+import org.springframework.http.codec.multipart.Part;
 import org.springframework.http.server.PathContainer;
 import org.springframework.http.server.reactive.ServerHttpRequest;
 import org.springframework.util.Assert;
@@ -185,6 +186,16 @@ public class ServerRequestWrapper implements ServerRequest {
 		return this.delegate.principal();
 	}
 
+	@Override
+	public Mono<MultiValueMap<String, String>> formData() {
+		return this.delegate.formData();
+	}
+
+	@Override
+	public Mono<MultiValueMap<String, Part>> multipartData() {
+		return this.delegate.multipartData();
+	}
+
 	/**
 	 * Implementation of the {@code Headers} interface that can be subclassed
 	 * to adapt the headers in a