GH-597 Add support for handling MultipartFile(s)

This initial fix ensures that functions can process single MultipartFile as well as multiple.

Resolves #597

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

@@ -18,8 +18,11 @@ package org.springframework.cloud.function.web.mvc;
 
 import java.util.Arrays;
 import java.util.Iterator;
+import java.util.List;
+import java.util.stream.Collectors;
 
 import org.reactivestreams.Publisher;
+import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
 import org.springframework.cloud.function.context.catalog.SimpleFunctionRegistry.FunctionInvocationWrapper;
@@ -28,12 +31,20 @@ import org.springframework.cloud.function.web.RequestProcessor.FunctionWrapper;
 import org.springframework.cloud.function.web.constants.WebRequestConstants;
 import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
+import org.springframework.http.ResponseEntity.BodyBuilder;
+import org.springframework.messaging.Message;
+import org.springframework.messaging.support.MessageBuilder;
 import org.springframework.stereotype.Component;
+import org.springframework.util.CollectionUtils;
+import org.springframework.util.MultiValueMap;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.ResponseBody;
+import org.springframework.web.context.request.ServletWebRequest;
 import org.springframework.web.context.request.WebRequest;
+import org.springframework.web.multipart.MultipartFile;
+import org.springframework.web.multipart.support.StandardMultipartHttpServletRequest;
 
 /**
  * @author Dave Syer
@@ -48,14 +59,44 @@ public class FunctionController {
 		this.processor = processor;
 	}
 
+
+
 	@PostMapping(path = "/**", consumes = { MediaType.APPLICATION_FORM_URLENCODED_VALUE,
 			MediaType.MULTIPART_FORM_DATA_VALUE })
 	@ResponseBody
 	public Mono<ResponseEntity<?>> form(WebRequest request) {
 		FunctionWrapper wrapper = wrapper(request);
+
+		if (((ServletWebRequest) request).getRequest() instanceof StandardMultipartHttpServletRequest) {
+			MultiValueMap<String, MultipartFile> multiFileMap = ((StandardMultipartHttpServletRequest) ((ServletWebRequest) request)
+														.getRequest()).getMultiFileMap();
+			if (!CollectionUtils.isEmpty(multiFileMap)) {
+				List<Message<MultipartFile>> files = multiFileMap.values().stream().flatMap(v -> v.stream())
+						.map(file -> MessageBuilder.withPayload(file).copyHeaders(wrapper.headers()).build())
+						.collect(Collectors.toList());
+				FunctionInvocationWrapper function = wrapper.function();
+
+				Publisher<?> result = (Publisher<?>) function.apply(Flux.fromIterable(files));
+				BodyBuilder builder = ResponseEntity.ok();
+				if (result instanceof Flux) {
+					result = Flux.from(result).map(message -> ((Message<?>) message).getPayload()).collectList();
+				}
+				return Mono.from(result).flatMap(body -> Mono.just(builder.body(body)));
+			}
+		}
 		return this.processor.post(wrapper, null, false);
 	}
 
+//	@PostMapping(path = "/**", consumes = { MediaType.APPLICATION_FORM_URLENCODED_VALUE,
+//			MediaType.MULTIPART_FORM_DATA_VALUE })
+//	public Mono<ResponseEntity<?>> handleFileUpload(@RequestParam("file") MultipartFile file, WebRequest request) {
+//		FunctionWrapper wrapper = wrapper(request);
+//
+//		Object result = wrapper.function().apply(file);
+//
+//		return Mono.just(ResponseEntity.status(HttpStatus.OK).body(result));
+//	}
+
 	@PostMapping(path = "/**")
 	@ResponseBody
 	public Mono<ResponseEntity<?>> post(WebRequest request,

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

@@ -0,0 +1,114 @@
+/*
+ * Copyright 2012-2019 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.function.web.mvc;
+
+import java.net.URI;
+import java.util.List;
+import java.util.function.Function;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.test.web.client.TestRestTemplate;
+import org.springframework.cloud.function.json.JsonMapper;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.http.HttpEntity;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.util.LinkedMultiValueMap;
+import org.springframework.util.SocketUtils;
+import org.springframework.web.multipart.MultipartFile;
+
+import static org.assertj.core.api.Assertions.assertThat;
+/**
+ *
+ * @author Oleg Zhurakousky
+ *
+ */
+public class MultipartFileTests {
+
+	@BeforeEach
+	public void init() throws Exception {
+		String port = "" + SocketUtils.findAvailableTcpPort();
+		System.setProperty("server.port", port);
+	}
+
+	@AfterEach
+	public void close() throws Exception {
+		System.clearProperty("server.port");
+	}
+
+	@Test
+	public void testMultipartFileUpload() throws Exception {
+		ApplicationContext context = SpringApplication.run(TestConfiguration.class);
+		JsonMapper mapper = context.getBean(JsonMapper.class);
+		TestRestTemplate template = new TestRestTemplate();
+		String port = System.getProperty("server.port");
+
+		LinkedMultiValueMap<String, Object> map = new LinkedMultiValueMap<>();
+		map.add("file", new ClassPathResource("META-INF/spring.factories"));
+		HttpHeaders headers = new HttpHeaders();
+		headers.setContentType(MediaType.MULTIPART_FORM_DATA);
+
+		HttpEntity<LinkedMultiValueMap<String, Object>> requestEntity = new HttpEntity<LinkedMultiValueMap<String, Object>>(
+				map, headers);
+		ResponseEntity<String> result = template.exchange(new URI("http://localhost:" + port + "/uppercase"),
+				HttpMethod.POST, requestEntity, String.class);
+		List<String> resultCollection = mapper.fromJson(result.getBody(), List.class);
+		assertThat(resultCollection.get(0)).isEqualTo("SPRING.FACTORIES");
+	}
+
+	@Test
+	public void testMultipartFilesUpload() throws Exception {
+		ApplicationContext context = SpringApplication.run(TestConfiguration.class);
+		JsonMapper mapper = context.getBean(JsonMapper.class);
+		TestRestTemplate template = new TestRestTemplate();
+		String port = System.getProperty("server.port");
+
+		LinkedMultiValueMap<String, Object> map = new LinkedMultiValueMap<>();
+		map.add("fileA", new ClassPathResource("META-INF/spring.factories"));
+		map.add("fileB", new ClassPathResource("static/test.html"));
+		HttpHeaders headers = new HttpHeaders();
+		headers.setContentType(MediaType.MULTIPART_FORM_DATA);
+
+		HttpEntity<LinkedMultiValueMap<String, Object>> requestEntity = new HttpEntity<LinkedMultiValueMap<String, Object>>(
+				map, headers);
+		ResponseEntity<String> result = template.exchange(new URI("http://localhost:" + port + "/uppercase"),
+				HttpMethod.POST, requestEntity, String.class);
+		List<String> resultCollection = mapper.fromJson(result.getBody(), List.class);
+		assertThat(resultCollection.get(0)).isEqualTo("SPRING.FACTORIES");
+		assertThat(resultCollection.get(1)).isEqualTo("TEST.HTML");
+	}
+
+	@EnableAutoConfiguration
+	protected static class TestConfiguration {
+
+		@Bean
+		public Function<MultipartFile, String> uppercase() {
+			return value -> {
+				return value.getOriginalFilename().toUpperCase();
+			};
+		}
+	}
+}