Re-enables MultipartEnvironmentPostProcessor

Closes gh-3527

spring-cloud-gateway-server-mvc/src/main/java/org/springframework/cloud/gateway/server/mvc/common/MultipartEnvironmentPostProcessor.java

@@ -37,7 +37,7 @@ public void postProcessEnvironment(ConfigurableEnvironment environment, SpringAp
 			// no user set property, set it to false.
 			MapPropertySource propertySource = new MapPropertySource(MULTIPART_PROPERTY_SOURCE_NAME,
 					Map.of(MULTIPART_ENABLED_PROPERTY, Boolean.FALSE));
-			// environment.getPropertySources().addFirst(propertySource);
+			environment.getPropertySources().addFirst(propertySource);
 		}
 	}
 

spring-cloud-gateway-server-mvc/src/test/java/org/springframework/cloud/gateway/server/mvc/ServerMvcIntegrationTests.java

@@ -22,6 +22,7 @@
 import java.net.URI;
 import java.nio.charset.StandardCharsets;
 import java.time.Duration;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 import java.util.Locale;
@@ -488,7 +489,7 @@ public void rewritePathPostWorks() {
 	@Test
 	public void rewritePathPostLocalWorks() {
 		restClient.post()
-			.uri("/baz/post")
+			.uri("/baz/localpost")
 			.bodyValue("hello")
 			.header("Host", "www.rewritepathpostlocal.org")
 			.exchange()
@@ -640,8 +641,21 @@ private MultiValueMap<String, HttpEntity<?>> createMultipartData() {
 	private void assertMultipartData(Map responseBody) {
 		Map<String, Object> files = (Map<String, Object>) responseBody.get("files");
 		assertThat(files).containsKey("imgpart");
-		String file = (String) files.get("imgpart");
-		assertThat(file).startsWith("data:").contains(";base64,");
+		Object imgpart = files.get("imgpart");
+		if (imgpart instanceof List l) {
+			String file = (String) l.get(0);
+			assertThat(isPNG(file.getBytes()));
+		}
+		else {
+			String file = (String) imgpart;
+			assertThat(file).startsWith("data:").contains(";base64,");
+		}
+	}
+
+	private static boolean isPNG(byte[] bytes) {
+		byte[] pngSignature = { (byte) 0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A };
+		byte[] header = Arrays.copyOf(bytes, pngSignature.length);
+		return Arrays.equals(pngSignature, header);
 	}
 
 	@Test
@@ -1288,8 +1302,7 @@ public RouterFunction<ServerResponse> gatewayRouterFunctionsForm() {
 			// @formatter:off
 			return route("testform")
 					.POST("/post", host("**.testform.org"), http())
-					.before(new LocalServerPortUriResolver())
-					.filter(prefixPath("/test"))
+					.filter(new HttpbinUriResolver())
 					.filter(addRequestHeader("X-Test", "form"))
 					.build();
 			// @formatter:on

spring-cloud-gateway-server-mvc/src/test/java/org/springframework/cloud/gateway/server/mvc/common/MultipartEnvironmentPostProcessorTests.java

@@ -16,7 +16,6 @@
 
 package org.springframework.cloud.gateway.server.mvc.common;
 
-import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.mock.env.MockEnvironment;
@@ -28,7 +27,6 @@
 public class MultipartEnvironmentPostProcessorTests {
 
 	@Test
-	@Disabled
 	void multipartDisabledByDefault() {
 		MockEnvironment environment = new MockEnvironment();
 		MultipartEnvironmentPostProcessor processor = new MultipartEnvironmentPostProcessor();

spring-cloud-gateway-server-mvc/src/test/java/org/springframework/cloud/gateway/server/mvc/test/TestController.java

@@ -16,27 +16,21 @@
 
 package org.springframework.cloud.gateway.server.mvc.test;
 
-import java.io.IOException;
 import java.util.Enumeration;
 import java.util.HashMap;
-import java.util.List;
 import java.util.Map;
 
-import jakarta.servlet.ServletException;
 import jakarta.servlet.http.HttpServletRequest;
 
 import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
-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.RequestHeader;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestMethod;
-import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.RestController;
-import org.springframework.web.multipart.MultipartFile;
 import org.springframework.web.server.ServerWebExchange;
 
 @RestController
@@ -58,35 +52,7 @@ public Map<String, Object> multiValueHeaders(ServerWebExchange exchange) {
 		return result;
 	}
 
-	@PostMapping(value = "/post", consumes = MediaType.MULTIPART_FORM_DATA_VALUE,
-			produces = MediaType.APPLICATION_JSON_VALUE)
-	public Map<String, Object> postFormData(HttpServletRequest request,
-			@RequestParam MultiValueMap<String, MultipartFile> parts) throws ServletException, IOException {
-		HashMap<String, Object> ret = new HashMap<>();
-		ret.put("headers", getHeaders(request));
-		HashMap<String, Object> files = new HashMap<>();
-		ret.put("files", files);
-
-		parts.values().stream().flatMap(List::stream).forEach(part -> {
-			String contentType = part.getContentType();
-			long contentLength = part.getSize();
-			// TODO: get part data
-			files.put(part.getName(), "data:" + contentType + ";base64," + contentLength);
-		});
-		return ret;
-	}
-
-	@PostMapping(path = "/post", consumes = MediaType.APPLICATION_FORM_URLENCODED_VALUE,
-			produces = MediaType.APPLICATION_JSON_VALUE)
-	public Map<String, Object> postUrlEncoded(HttpServletRequest request,
-			@RequestBody(required = false) MultiValueMap form) throws IOException {
-		HashMap<String, Object> ret = new HashMap<>();
-		ret.put("headers", getHeaders(request));
-		ret.put("form", form);
-		return ret;
-	}
-
-	@PostMapping(path = "/post", produces = MediaType.APPLICATION_JSON_VALUE)
+	@PostMapping(path = "/localpost", produces = MediaType.APPLICATION_JSON_VALUE)
 	public Map<String, Object> post(HttpServletRequest request, @RequestBody(required = false) String body) {
 		HashMap<String, Object> ret = new HashMap<>();
 		ret.put("headers", getHeaders(request));