Tolerate invalid mimetype in Reactory Netty compression predicate

Fixes gh-18018

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/netty/CompressionCustomizer.java

@@ -28,6 +28,7 @@ import reactor.netty.http.server.HttpServerRequest;
 import reactor.netty.http.server.HttpServerResponse;
 
 import org.springframework.boot.web.server.Compression;
+import org.springframework.util.InvalidMimeTypeException;
 import org.springframework.util.MimeType;
 import org.springframework.util.MimeTypeUtils;
 import org.springframework.util.ObjectUtils;
@@ -73,8 +74,13 @@ final class CompressionCustomizer implements NettyServerCustomizer {
 			if (StringUtils.isEmpty(contentType)) {
 				return false;
 			}
-			MimeType contentMimeType = MimeTypeUtils.parseMimeType(contentType);
+			try {
-			return mimeTypes.stream().anyMatch((candidate) -> candidate.isCompatibleWith(contentMimeType));
+				MimeType contentMimeType = MimeTypeUtils.parseMimeType(contentType);
+				return mimeTypes.stream().anyMatch((candidate) -> candidate.isCompatibleWith(contentMimeType));
+			}
+			catch (InvalidMimeTypeException ex) {
+				return false;
+			}
 		};
 	}
 

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/netty/NettyReactiveWebServerFactoryTests.java

@@ -16,6 +16,7 @@
 
 package org.springframework.boot.web.embedded.netty;
 
+import java.time.Duration;
 import java.util.Arrays;
 
 import org.junit.Test;
@@ -24,7 +25,10 @@ import reactor.netty.http.server.HttpServer;
 
 import org.springframework.boot.web.reactive.server.AbstractReactiveWebServerFactory;
 import org.springframework.boot.web.reactive.server.AbstractReactiveWebServerFactoryTests;
+import org.springframework.boot.web.server.Compression;
 import org.springframework.boot.web.server.PortInUseException;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.reactive.function.client.WebClient;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
@@ -83,4 +87,15 @@ public class NettyReactiveWebServerFactoryTests extends AbstractReactiveWebServe
 		assertForwardHeaderIsUsed(factory);
 	}
 
+	@Test
+	public void noCompressionForResponseWithInvalidContentType() {
+		Compression compression = new Compression();
+		compression.setEnabled(true);
+		compression.setMimeTypes(new String[] { "application/json" });
+		WebClient client = prepareCompressionTest(compression, "test~plain");
+		ResponseEntity<Void> response = client.get().exchange().flatMap((res) -> res.toEntity(Void.class))
+				.block(Duration.ofSeconds(30));
+		assertResponseIsNotCompressed(response);
+	}
+
 }

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/reactive/server/AbstractReactiveWebServerFactoryTests.java

@@ -53,6 +53,7 @@ import org.springframework.boot.web.server.WebServer;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DataBufferFactory;
 import org.springframework.core.io.buffer.DefaultDataBufferFactory;
+import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
@@ -273,6 +274,7 @@ public abstract class AbstractReactiveWebServerFactoryTests {
 	@Test
 	public void noCompressionForMimeType() {
 		Compression compression = new Compression();
+		compression.setEnabled(true);
 		compression.setMimeTypes(new String[] { "application/json" });
 		WebClient client = prepareCompressionTest(compression);
 		ResponseEntity<Void> response = client.get().exchange().flatMap((res) -> res.toEntity(Void.class))
@@ -305,9 +307,13 @@ public abstract class AbstractReactiveWebServerFactoryTests {
 	}
 
 	protected WebClient prepareCompressionTest(Compression compression) {
+		return prepareCompressionTest(compression, MediaType.TEXT_PLAIN_VALUE);
+	}
+
+	protected WebClient prepareCompressionTest(Compression compression, String responseContentType) {
 		AbstractReactiveWebServerFactory factory = getFactory();
 		factory.setCompression(compression);
-		this.webServer = factory.getWebServer(new CharsHandler(3000, MediaType.TEXT_PLAIN));
+		this.webServer = factory.getWebServer(new CharsHandler(3000, responseContentType));
 		this.webServer.start();
 
 		HttpClient client = HttpClient.create().wiretap(true).compress(true)
@@ -368,9 +374,9 @@ public abstract class AbstractReactiveWebServerFactoryTests {
 
 		private final DataBuffer bytes;
 
-		private final MediaType mediaType;
+		private final String mediaType;
 
-		public CharsHandler(int contentSize, MediaType mediaType) {
+		public CharsHandler(int contentSize, String mediaType) {
 			char[] chars = new char[contentSize];
 			Arrays.fill(chars, 'F');
 			this.bytes = factory.wrap(new String(chars).getBytes(StandardCharsets.UTF_8));
@@ -380,7 +386,7 @@ public abstract class AbstractReactiveWebServerFactoryTests {
 		@Override
 		public Mono<Void> handle(ServerHttpRequest request, ServerHttpResponse response) {
 			response.setStatusCode(HttpStatus.OK);
-			response.getHeaders().setContentType(this.mediaType);
+			response.getHeaders().set(HttpHeaders.CONTENT_TYPE, this.mediaType);
 			response.getHeaders().setContentLength(this.bytes.readableByteCount());
 			return response.writeWith(Mono.just(this.bytes));
 		}