GH-243, GH-257 Added reactive consumer wrapper

- Added wrapper for an already reactive consumer to ensure that consumers can be consistently represented as Function<Flux, Mono>
- Fixed the big that deal with inconsistent result in web environments due to inconsistent representation of the Consumers
- Polished tests

Resolves #243
Resolves #257

spring-cloud-function-web/src/main/java/org/springframework/cloud/function/web/RequestProcessor.java

@@ -40,7 +40,9 @@ import reactor.core.publisher.Mono;
 import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.cloud.function.context.catalog.FunctionInspector;
 import org.springframework.cloud.function.context.message.MessageUtils;
+import org.springframework.cloud.function.core.FluxConsumer;
 import org.springframework.cloud.function.core.FluxWrapper;
+import org.springframework.cloud.function.core.FluxedConsumer;
 import org.springframework.cloud.function.json.JsonMapper;
 import org.springframework.cloud.function.web.util.HeaderUtils;
 import org.springframework.core.MethodParameter;
@@ -200,7 +202,14 @@ public class RequestProcessor {
 			flux = messages(wrapper, function == null ? consumer : function, flux);
 		}
 		Mono<ResponseEntity<?>> responseEntityMono = null;
-		if (function != null) {
+
+		if (function instanceof FluxedConsumer || function instanceof FluxConsumer) {
+			((Mono<?>) function.apply(flux)).subscribe();
+			logger.debug("Handled POST with consumer");
+			responseEntityMono = Mono
+					.just(ResponseEntity.status(HttpStatus.ACCEPTED).build());
+		}
+		else {
 			Flux<?> result = Flux.from(function.apply(flux));
 			logger.debug("Handled POST with function");
 			if (stream) {
@@ -211,12 +220,6 @@ public class RequestProcessor {
 						body == null ? null : !(body instanceof Collection), false);
 			}
 		}
-		else if (consumer != null) {
-			consumer.accept(flux);
-			logger.debug("Handled POST with consumer");
-			responseEntityMono = Mono
-					.just(ResponseEntity.status(HttpStatus.ACCEPTED).build());
-		}
 		return responseEntityMono;
 	}
 

spring-cloud-function-web/src/test/java/org/springframework/cloud/function/web/flux/HttpPostIntegrationTests.java

@@ -124,14 +124,23 @@ public class HttpPostIntegrationTests {
 		assertThat(result.getBody()).isEqualTo(null);
 	}
 
+	@Test
+	public void addFoosFlux() throws Exception {
+		ResponseEntity<String> result = this.rest.exchange(RequestEntity
+				.post(new URI("/addFoosFlux")).contentType(MediaType.APPLICATION_JSON)
+				.body("[{\"value\":\"foo\"},{\"value\":\"bar\"}]"), String.class);
+		assertThat(result.getStatusCode()).isEqualTo(HttpStatus.ACCEPTED);
+		assertThat(this.test.list).hasSize(2);
+		assertThat(result.getBody()).isEqualTo(null);
+	}
+
 	@Test
 	public void bareUpdates() throws Exception {
 		ResponseEntity<String> result = this.rest.exchange(RequestEntity
 				.post(new URI("/bareUpdates")).contentType(MediaType.APPLICATION_JSON)
 				.body("[\"one\",\"two\"]"), String.class);
-		assertThat(result.getStatusCode()).isEqualTo(HttpStatus.OK);
+		assertThat(result.getStatusCode()).isEqualTo(HttpStatus.ACCEPTED);
 		assertThat(this.test.list).hasSize(2);
-		assertThat(result.getBody()).isEqualTo("[]");
 	}
 
 	@Test
@@ -399,12 +408,6 @@ public class HttpPostIntegrationTests {
 			};
 		}
 
-		// @Bean
-		// public Function<byte[],?> byteArrayInputFunction() {
-		//// return value -> new Foo(value.getValue().trim().toUpperCase());
-		// throw new UnsupportedOperationException("boom?");
-		// }
-
 		@Bean
 		public Function<Flux<Integer>, Flux<String>> wrap() {
 			return flux -> flux.log().map(value -> ".." + value + "..");
@@ -437,13 +440,22 @@ public class HttpPostIntegrationTests {
 		}
 
 		@Bean
-		public Consumer<Flux<Foo>> addFoos() {
+		public Consumer<Flux<Foo>> addFoosFlux() {
 			return flux -> flux.subscribe(value -> this.list.add(value.getValue()));
 		}
 
+		@Bean
+		public Consumer<Foo> addFoos() {
+			return value -> {
+				this.list.add(value.getValue());
+			};
+		}
+
 		@Bean
 		public Consumer<String> bareUpdates() {
-			return value -> this.list.add(value);
+			return value -> {
+				this.list.add(value);
+			};
 		}
 
 		@Bean("not/a")

spring-cloud-function-web/src/test/java/org/springframework/cloud/function/web/mvc/HttpPostIntegrationTests.java

@@ -128,9 +128,8 @@ public class HttpPostIntegrationTests {
 		ResponseEntity<String> result = this.rest.exchange(RequestEntity
 				.post(new URI("/bareUpdates")).contentType(MediaType.APPLICATION_JSON)
 				.body("[\"one\",\"two\"]"), String.class);
-		assertThat(result.getStatusCode()).isEqualTo(HttpStatus.OK);
+		assertThat(result.getStatusCode()).isEqualTo(HttpStatus.ACCEPTED);
 		assertThat(this.test.list).hasSize(2);
-		assertThat(result.getBody()).isEqualTo("[]");
 	}
 
 	@Test