GH-2872: Parse all the multi-part files (#2878)

* GH-2872: Parse all the multi-part files

Fixes https://github.com/spring-projects/spring-integration/issues/2872

The same HTML form entry may have several files in the multi-part request.
Parse all of them in the `MultipartAwareFormHttpMessageConverter.java`
 and re-map to the result `MultiValueMap`

**Cherry-pick to 5.1.x**

* * Add test for multi-part files

spring-integration-http/src/main/java/org/springframework/integration/http/converter/MultipartAwareFormHttpMessageConverter.java

@@ -20,11 +20,11 @@ import java.io.IOException;
 import java.nio.charset.Charset;
 import java.util.List;
 import java.util.Map;
-import java.util.Map.Entry;
 
 import org.springframework.http.HttpInputMessage;
 import org.springframework.http.HttpOutputMessage;
 import org.springframework.http.MediaType;
+import org.springframework.http.converter.FormHttpMessageConverter;
 import org.springframework.http.converter.HttpMessageConverter;
 import org.springframework.http.converter.HttpMessageNotReadableException;
 import org.springframework.http.converter.HttpMessageNotWritableException;
@@ -44,18 +44,19 @@ import org.springframework.web.multipart.MultipartFile;
  *
  * @author Mark Fisher
  * @author Gary Russell
+ * @author Artem Bilan
+ *
  * @since 2.0
  */
 public class MultipartAwareFormHttpMessageConverter implements HttpMessageConverter<MultiValueMap<String, ?>> {
 
-	private volatile MultipartFileReader<?> multipartFileReader = new DefaultMultipartFileReader();
+	private final FormHttpMessageConverter wrappedConverter = new AllEncompassingFormHttpMessageConverter();
 
-	private final AllEncompassingFormHttpMessageConverter wrappedConverter = new AllEncompassingFormHttpMessageConverter();
+	private MultipartFileReader<?> multipartFileReader = new DefaultMultipartFileReader();
 
 
 	/**
 	 * Sets the character set used for writing form data.
-	 *
 	 * @param charset The charset.
 	 */
 	public void setCharset(Charset charset) {
@@ -64,11 +65,10 @@ public class MultipartAwareFormHttpMessageConverter implements HttpMessageConver
 
 	/**
 	 * Specify the {@link MultipartFileReader} to use when reading {@link MultipartFile} content.
-	 *
 	 * @param multipartFileReader The multipart file reader.
 	 */
 	public void setMultipartFileReader(MultipartFileReader<?> multipartFileReader) {
-		Assert.notNull(multipartFileReader, "multipartFileReader must not be null");
+		Assert.notNull(multipartFileReader, "'multipartFileReader' must not be null");
 		this.multipartFileReader = multipartFileReader;
 	}
 
@@ -106,23 +106,22 @@ public class MultipartAwareFormHttpMessageConverter implements HttpMessageConver
 		}
 		Assert.state(inputMessage instanceof MultipartHttpInputMessage,
 				"A request with 'multipart/form-data' Content-Type must be a MultipartHttpInputMessage. "
-				+ "Be sure to provide a 'multipartResolver' bean in the ApplicationContext.");
+						+ "Be sure to provide a 'multipartResolver' bean in the ApplicationContext.");
-		MultipartHttpInputMessage multipartInputMessage = (MultipartHttpInputMessage) inputMessage;
+		return readMultipart((MultipartHttpInputMessage) inputMessage);
-		return this.readMultipart(multipartInputMessage);
 	}
 
 	private MultiValueMap<String, ?> readMultipart(MultipartHttpInputMessage multipartRequest) throws IOException {
-		MultiValueMap<String, Object> resultMap = new LinkedMultiValueMap<String, Object>();
+		MultiValueMap<String, Object> resultMap = new LinkedMultiValueMap<>();
 		Map<?, ?> parameterMap = multipartRequest.getParameterMap();
-		for (Entry<?, ?> entry : parameterMap.entrySet()) {
+		parameterMap.forEach((key, value) -> resultMap.add((String) key, value));
-			resultMap.add((String) entry.getKey(), entry.getValue());
+
-		}
+		for (Map.Entry<String, List<MultipartFile>> entry : multipartRequest.getMultiFileMap().entrySet()) {
-		for (Map.Entry<String, MultipartFile> entry : multipartRequest.getFileMap().entrySet()) {
+			List<MultipartFile> multipartFiles = entry.getValue();
-			MultipartFile multipartFile = entry.getValue();
+			for (MultipartFile multipartFile : multipartFiles) {
-			if (multipartFile.isEmpty()) {
+				if (!multipartFile.isEmpty()) {
-				continue;
+					resultMap.add(entry.getKey(), this.multipartFileReader.readMultipartFile(multipartFile));
+				}
 			}
-			resultMap.add(entry.getKey(), this.multipartFileReader.readMultipartFile(multipartFile));
 		}
 		return resultMap;
 	}
@@ -130,6 +129,7 @@ public class MultipartAwareFormHttpMessageConverter implements HttpMessageConver
 	@Override
 	public void write(MultiValueMap<String, ?> map, MediaType contentType, HttpOutputMessage outputMessage)
 			throws IOException, HttpMessageNotWritableException {
+
 		this.wrappedConverter.write(map, contentType, outputMessage);
 	}
 

spring-integration-http/src/test/java/org/springframework/integration/http/dsl/HttpDslTests.java

@@ -16,23 +16,29 @@
 
 package org.springframework.integration.http.dsl;
 
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.springframework.security.test.web.servlet.request.SecurityMockMvcRequestPostProcessors.httpBasic;
 import static org.springframework.security.test.web.servlet.setup.SecurityMockMvcConfigurers.springSecurity;
 import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.multipart;
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
 
 import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
 import org.springframework.http.client.ClientHttpRequestFactory;
 import org.springframework.http.client.ClientHttpResponse;
@@ -41,10 +47,14 @@ import org.springframework.integration.config.EnableIntegration;
 import org.springframework.integration.dsl.IntegrationFlow;
 import org.springframework.integration.dsl.IntegrationFlows;
 import org.springframework.integration.dsl.context.IntegrationFlowContext;
+import org.springframework.integration.http.multipart.UploadedMultipartFile;
 import org.springframework.integration.http.outbound.HttpRequestExecutingMessageHandler;
 import org.springframework.integration.security.channel.ChannelSecurityInterceptor;
 import org.springframework.integration.security.channel.SecuredChannel;
+import org.springframework.messaging.Message;
 import org.springframework.messaging.MessageChannel;
+import org.springframework.messaging.PollableChannel;
+import org.springframework.mock.web.MockPart;
 import org.springframework.security.access.AccessDecisionManager;
 import org.springframework.security.access.vote.AffirmativeBased;
 import org.springframework.security.access.vote.RoleVoter;
@@ -64,6 +74,9 @@ import org.springframework.test.web.servlet.setup.MockMvcBuilders;
 import org.springframework.web.client.DefaultResponseErrorHandler;
 import org.springframework.web.client.HttpClientErrorException;
 import org.springframework.web.context.WebApplicationContext;
+import org.springframework.web.multipart.MultipartResolver;
+import org.springframework.web.multipart.support.StandardServletMultipartResolver;
+import org.springframework.web.servlet.DispatcherServlet;
 
 /**
  * @author Artem Bilan
@@ -107,20 +120,14 @@ public class HttpDslTests {
 				get("/service")
 						.with(httpBasic("admin", "admin"))
 						.param("name", "foo"))
-				.andExpect(
+				.andExpect(content().string("FOO"));
-						content()
-								.string("FOO"));
 
 		this.mockMvc.perform(
 				get("/service")
 						.with(httpBasic("user", "user"))
 						.param("name", "name"))
-				.andExpect(
+				.andExpect(status().isForbidden())
-						status()
+				.andExpect(content().string("Error"));
-								.isForbidden())
-				.andExpect(
-						content()
-								.string("Error"));
 	}
 
 	@Test
@@ -137,21 +144,59 @@ public class HttpDslTests {
 
 		this.mockMvc.perform(
 				get("/dynamic")
-						.with(httpBasic("admin", "admin"))
+						.with(httpBasic("user", "user"))
 						.param("name", "BAR"))
-				.andExpect(
+				.andExpect(content().string("bar"));
-						content()
-								.string("bar"));
 
 		flowRegistration.destroy();
 
 		this.mockMvc.perform(
 				get("/dynamic")
-						.with(httpBasic("admin", "admin"))
+						.with(httpBasic("user", "user"))
 						.param("name", "BAZ"))
-				.andExpect(
+				.andExpect(status().isNotFound());
-						status()
+	}
-								.isNotFound());
+
+	@Autowired
+	@Qualifier("multiPartFilesChannel")
+	private PollableChannel multiPartFilesChannel;
+
+	@Test
+	@SuppressWarnings("unchecked")
+	public void testMultiPartFiles() throws Exception {
+		MockPart mockPart1 = new MockPart("a1", "file1", "ABC".getBytes(StandardCharsets.UTF_8));
+		mockPart1.getHeaders().setContentType(MediaType.TEXT_PLAIN);
+		MockPart mockPart2 = new MockPart("a1", "file2", "DEF".getBytes(StandardCharsets.UTF_8));
+		mockPart2.getHeaders().setContentType(MediaType.TEXT_PLAIN);
+		this.mockMvc.perform(
+				multipart("/multiPartFiles")
+						.part(mockPart1, mockPart2)
+						.with(httpBasic("user", "user")))
+				.andExpect(status().isOk());
+
+		Message<?> result = this.multiPartFilesChannel.receive(10_000);
+
+		assertThat(result)
+				.isNotNull()
+				.extracting(Message::getPayload)
+				.satisfies((payload) ->
+						assertThat((Map<String, ?>) payload)
+								.hasSize(1)
+								.extracting((map) -> map.get("a1"))
+								.asList()
+								.hasSize(2)
+								.satisfies((list) -> {
+									assertThat(list)
+											.element(0)
+											.extracting((file) ->
+													((UploadedMultipartFile) file).getOriginalFilename())
+											.isEqualTo("file1");
+									assertThat(list)
+											.element(1)
+											.extracting((file) ->
+													((UploadedMultipartFile) file).getOriginalFilename())
+											.isEqualTo("file2");
+								}));
 	}
 
 	@Configuration
@@ -237,6 +282,19 @@ public class HttpDslTests {
 							new ResponseEntity<>(p.getResponseBodyAsString(), p.getStatusCode()));
 		}
 
+		@Bean
+		public IntegrationFlow multiPartFilesFlow() {
+			return IntegrationFlows
+					.from(Http.inboundChannelAdapter("/multiPartFiles"))
+					.channel((c) -> c.queue("multiPartFilesChannel"))
+					.get();
+		}
+
+		@Bean(name = DispatcherServlet.MULTIPART_RESOLVER_BEAN_NAME)
+		public MultipartResolver multipartResolver() {
+			return new StandardServletMultipartResolver();
+		}
+
 		@Bean
 		public AccessDecisionManager accessDecisionManager() {
 			return new AffirmativeBased(Collections.singletonList(new RoleVoter()));