Empty body checks in ConsumesRequestCondition

Normally consumes matches the "Content-Type" header but what should be done if
there is no content? This commit adds checks for method parameters with
@RequestBody(required=false) and if "false" then also match requests with no content.

Closes gh-22010

spring-webflux/src/test/java/org/springframework/web/reactive/result/condition/ConsumesRequestConditionTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 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.
@@ -99,6 +99,24 @@ public class ConsumesRequestConditionTests {
 		assertNull(condition.getMatchingCondition(exchange));
 	}
 
+	@Test // gh-22010
+	public void consumesNoContent() {
+		ConsumesRequestCondition condition = new ConsumesRequestCondition("text/plain");
+		condition.setBodyRequired(false);
+
+		MockServerHttpRequest request = MockServerHttpRequest.get("/").build();
+		assertNotNull(condition.getMatchingCondition(MockServerWebExchange.from(request)));
+
+		request = MockServerHttpRequest.get("/").header(HttpHeaders.CONTENT_LENGTH, "0").build();
+		assertNotNull(condition.getMatchingCondition(MockServerWebExchange.from(request)));
+
+		request = MockServerHttpRequest.get("/").header(HttpHeaders.CONTENT_LENGTH, "21").build();
+		assertNull(condition.getMatchingCondition(MockServerWebExchange.from(request)));
+
+		request = MockServerHttpRequest.get("/").header(HttpHeaders.TRANSFER_ENCODING, "chunked").build();
+		assertNull(condition.getMatchingCondition(MockServerWebExchange.from(request)));
+	}
+
 	@Test
 	public void compareToSingle() throws Exception {
 		MockServerWebExchange exchange = MockServerWebExchange.from(MockServerHttpRequest.get("/"));

spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/RequestMappingHandlerMappingTests.java

@@ -22,7 +22,6 @@ import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 import java.lang.reflect.Method;
 import java.security.Principal;
-import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Set;
 
@@ -32,16 +31,20 @@ import org.junit.Test;
 import org.springframework.core.annotation.AliasFor;
 import org.springframework.http.MediaType;
 import org.springframework.stereotype.Controller;
+import org.springframework.util.ClassUtils;
 import org.springframework.web.bind.annotation.DeleteMapping;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PatchMapping;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.PutMapping;
+import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestMethod;
 import org.springframework.web.bind.annotation.RestController;
 import org.springframework.web.context.support.StaticWebApplicationContext;
 import org.springframework.web.method.HandlerTypePredicate;
+import org.springframework.web.reactive.result.condition.ConsumesRequestCondition;
+import org.springframework.web.reactive.result.condition.PatternsRequestCondition;
 import org.springframework.web.reactive.result.method.RequestMappingInfo;
 import org.springframework.web.util.pattern.PathPattern;
 import org.springframework.web.util.pattern.PathPatternParser;
@@ -103,10 +106,26 @@ public class RequestMappingHandlerMappingTests {
 
 	@Test // SPR-14988
 	public void getMappingOverridesConsumesFromTypeLevelAnnotation() throws Exception {
-		RequestMappingInfo requestMappingInfo = assertComposedAnnotationMapping(RequestMethod.GET);
+		RequestMappingInfo requestMappingInfo = assertComposedAnnotationMapping(RequestMethod.POST);
 
-		assertArrayEquals(new MediaType[]{MediaType.ALL}, new ArrayList<>(
-				requestMappingInfo.getConsumesCondition().getConsumableMediaTypes()).toArray());
+		ConsumesRequestCondition condition = requestMappingInfo.getConsumesCondition();
+		assertEquals(Collections.singleton(MediaType.APPLICATION_XML), condition.getConsumableMediaTypes());
+	}
+
+	@Test // gh-22010
+	public void consumesWithOptionalRequestBody() {
+		this.wac.registerSingleton("testController", ComposedAnnotationController.class);
+		this.wac.refresh();
+		this.handlerMapping.afterPropertiesSet();
+		RequestMappingInfo info = this.handlerMapping.getHandlerMethods().keySet().stream()
+				.filter(i -> {
+					PatternsRequestCondition condition = i.getPatternsCondition();
+					return condition.getPatterns().iterator().next().getPatternString().equals("/post");
+				})
+				.findFirst()
+				.orElseThrow(() -> new AssertionError("No /post"));
+
+		assertFalse(info.getConsumesCondition().isBodyRequired());
 	}
 
 	@Test
@@ -146,7 +165,7 @@ public class RequestMappingHandlerMappingTests {
 			RequestMethod requestMethod) throws Exception {
 
 		Class<?> clazz = ComposedAnnotationController.class;
-		Method method = clazz.getMethod(methodName);
+		Method method = ClassUtils.getMethod(clazz, methodName, null);
 		RequestMappingInfo info = this.handlerMapping.getMappingForMethod(method, clazz);
 
 		assertNotNull(info);
@@ -175,12 +194,12 @@ public class RequestMappingHandlerMappingTests {
 		public void postJson() {
 		}
 
-		@GetMapping(value = "/get", consumes = MediaType.ALL_VALUE)
+		@GetMapping("/get")
 		public void get() {
 		}
 
-		@PostMapping("/post")
-		public void post() {
+		@PostMapping(path = "/post", consumes = MediaType.APPLICATION_XML_VALUE)
+		public void post(@RequestBody(required = false) Foo foo) {
 		}
 
 		@PutMapping("/put")
@@ -196,6 +215,9 @@ public class RequestMappingHandlerMappingTests {
 		}
 	}
 
+	private static class Foo {
+	}
+
 
 	@RequestMapping(method = RequestMethod.POST,
 			produces = MediaType.APPLICATION_JSON_VALUE,