From c1839938ea42cd444be4d678b13ea04847960ed0 Mon Sep 17 00:00:00 2001
From: Kamil Doroszkiewicz <kamil.doroszkiewicz@gmail.com>
Date: Tue, 25 Mar 2025 10:37:29 +0100
Subject: [PATCH] Add support for "application/*+x-protobuf" media type

See gh-34645

Signed-off-by: Kamil Doroszkiewicz <kamil.doroszkiewicz@gmail.com>
---
 .../ProtobufHttpMessageConverter.java         | 22 ++++++++++++-------
 .../ProtobufHttpMessageConverterTests.java    |  3 +++
 ...ufJsonFormatHttpMessageConverterTests.java |  3 +++
 3 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/spring-web/src/main/java/org/springframework/http/converter/protobuf/ProtobufHttpMessageConverter.java b/spring-web/src/main/java/org/springframework/http/converter/protobuf/ProtobufHttpMessageConverter.java
index c8fc030aa29..4fcbf0d34c6 100644
--- a/spring-web/src/main/java/org/springframework/http/converter/protobuf/ProtobufHttpMessageConverter.java
+++ b/spring-web/src/main/java/org/springframework/http/converter/protobuf/ProtobufHttpMessageConverter.java
@@ -41,7 +41,6 @@ import org.springframework.http.converter.AbstractHttpMessageConverter;
 import org.springframework.http.converter.HttpMessageConversionException;
 import org.springframework.http.converter.HttpMessageNotReadableException;
 import org.springframework.http.converter.HttpMessageNotWritableException;
-import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.ConcurrentReferenceHashMap;
 
@@ -55,8 +54,8 @@ import static org.springframework.http.MediaType.TEXT_PLAIN;
  *
  * <p>To generate {@code Message} Java classes, you need to install the {@code protoc} binary.
  *
- * <p>This converter supports by default {@code "application/x-protobuf"} and {@code "text/plain"}
- * with the official {@code "com.google.protobuf:protobuf-java"} library.
+ * <p>This converter supports by default {@code "application/x-protobuf"}, {@code "application/*+x-protobuf"}
+ * and {@code "text/plain"} with the official {@code "com.google.protobuf:protobuf-java"} library.
  * The {@code "application/json"} format is also supported with the {@code "com.google.protobuf:protobuf-java-util"}
  * dependency. See {@link ProtobufJsonFormatHttpMessageConverter} for a configurable variant.
  *
@@ -66,6 +65,7 @@ import static org.springframework.http.MediaType.TEXT_PLAIN;
  * @author Brian Clozel
  * @author Juergen Hoeller
  * @author Sebastien Deleuze
+ * @author Kamil Doroszkiewicz
  * @since 4.1
  * @see JsonFormat
  * @see ProtobufJsonFormatHttpMessageConverter
@@ -82,6 +82,11 @@ public class ProtobufHttpMessageConverter extends AbstractHttpMessageConverter<M
 	 */
 	public static final MediaType PROTOBUF = new MediaType("application", "x-protobuf", DEFAULT_CHARSET);
 
+	/**
+	 * The media-type for protobuf {@code application/*+x-protobuf}.
+	 */
+	public static final MediaType PLUS_PROTOBUF = new MediaType("application", "*+x-protobuf", DEFAULT_CHARSET);
+
 	/**
 	 * The HTTP header containing the protobuf schema.
 	 */
@@ -132,7 +137,7 @@ public class ProtobufHttpMessageConverter extends AbstractHttpMessageConverter<M
 		}
 
 		setSupportedMediaTypes(Arrays.asList(this.protobufFormatSupport != null ?
-				this.protobufFormatSupport.supportedMediaTypes() : new MediaType[] {PROTOBUF, TEXT_PLAIN}));
+				this.protobufFormatSupport.supportedMediaTypes() : new MediaType[] {PROTOBUF, PLUS_PROTOBUF, TEXT_PLAIN}));
 
 		this.extensionRegistry = (extensionRegistry == null ? ExtensionRegistry.newInstance() : extensionRegistry);
 	}
@@ -162,7 +167,8 @@ public class ProtobufHttpMessageConverter extends AbstractHttpMessageConverter<M
 		}
 
 		Message.Builder builder = getMessageBuilder(clazz);
-		if (PROTOBUF.isCompatibleWith(contentType)) {
+		if (PROTOBUF.isCompatibleWith(contentType) ||
+				PLUS_PROTOBUF.isCompatibleWith(contentType)) {
 			builder.mergeFrom(inputMessage.getBody(), this.extensionRegistry);
 		}
 		else if (TEXT_PLAIN.isCompatibleWith(contentType)) {
@@ -209,14 +215,14 @@ public class ProtobufHttpMessageConverter extends AbstractHttpMessageConverter<M
 		MediaType contentType = outputMessage.getHeaders().getContentType();
 		if (contentType == null) {
 			contentType = getDefaultContentType(message);
-			Assert.state(contentType != null, "No content type");
 		}
 		Charset charset = contentType.getCharset();
 		if (charset == null) {
 			charset = DEFAULT_CHARSET;
 		}
 
-		if (PROTOBUF.isCompatibleWith(contentType)) {
+		if (PROTOBUF.isCompatibleWith(contentType) ||
+				PLUS_PROTOBUF.isCompatibleWith(contentType)) {
 			setProtoHeader(outputMessage, message);
 			CodedOutputStream codedOutputStream = CodedOutputStream.newInstance(outputMessage.getBody());
 			message.writeTo(codedOutputStream);
@@ -285,7 +291,7 @@ public class ProtobufHttpMessageConverter extends AbstractHttpMessageConverter<M
 
 		@Override
 		public MediaType[] supportedMediaTypes() {
-			return new MediaType[] {PROTOBUF, TEXT_PLAIN, APPLICATION_JSON};
+			return new MediaType[] {PROTOBUF, PLUS_PROTOBUF, TEXT_PLAIN, APPLICATION_JSON};
 		}
 
 		@Override
diff --git a/spring-web/src/test/java/org/springframework/http/converter/protobuf/ProtobufHttpMessageConverterTests.java b/spring-web/src/test/java/org/springframework/http/converter/protobuf/ProtobufHttpMessageConverterTests.java
index fe5f0d95f32..31068d79a14 100644
--- a/spring-web/src/test/java/org/springframework/http/converter/protobuf/ProtobufHttpMessageConverterTests.java
+++ b/spring-web/src/test/java/org/springframework/http/converter/protobuf/ProtobufHttpMessageConverterTests.java
@@ -48,12 +48,14 @@ class ProtobufHttpMessageConverterTests {
 	private ExtensionRegistry extensionRegistry = mock();
 
 	private Msg testMsg = Msg.newBuilder().setFoo("Foo").setBlah(SecondMsg.newBuilder().setBlah(123).build()).build();
+	private MediaType testPlusProtoMediaType = MediaType.parseMediaType("application/vnd.example.public.v1+x-protobuf");
 
 
 	@Test
 	void canRead() {
 		assertThat(this.converter.canRead(Msg.class, null)).isTrue();
 		assertThat(this.converter.canRead(Msg.class, ProtobufHttpMessageConverter.PROTOBUF)).isTrue();
+		assertThat(this.converter.canRead(Msg.class, this.testPlusProtoMediaType)).isTrue();
 		assertThat(this.converter.canRead(Msg.class, MediaType.APPLICATION_JSON)).isTrue();
 		assertThat(this.converter.canRead(Msg.class, MediaType.TEXT_PLAIN)).isTrue();
 	}
@@ -62,6 +64,7 @@ class ProtobufHttpMessageConverterTests {
 	void canWrite() {
 		assertThat(this.converter.canWrite(Msg.class, null)).isTrue();
 		assertThat(this.converter.canWrite(Msg.class, ProtobufHttpMessageConverter.PROTOBUF)).isTrue();
+		assertThat(this.converter.canRead(Msg.class, this.testPlusProtoMediaType)).isTrue();
 		assertThat(this.converter.canWrite(Msg.class, MediaType.APPLICATION_JSON)).isTrue();
 		assertThat(this.converter.canWrite(Msg.class, MediaType.TEXT_PLAIN)).isTrue();
 	}
diff --git a/spring-web/src/test/java/org/springframework/http/converter/protobuf/ProtobufJsonFormatHttpMessageConverterTests.java b/spring-web/src/test/java/org/springframework/http/converter/protobuf/ProtobufJsonFormatHttpMessageConverterTests.java
index 33e2b800844..52a7e58f86d 100644
--- a/spring-web/src/test/java/org/springframework/http/converter/protobuf/ProtobufJsonFormatHttpMessageConverterTests.java
+++ b/spring-web/src/test/java/org/springframework/http/converter/protobuf/ProtobufJsonFormatHttpMessageConverterTests.java
@@ -42,12 +42,14 @@ class ProtobufJsonFormatHttpMessageConverterTests {
 			JsonFormat.parser(), JsonFormat.printer());
 
 	private final Msg testMsg = Msg.newBuilder().setFoo("Foo").setBlah(SecondMsg.newBuilder().setBlah(123).build()).build();
+	private MediaType testPlusProtoMediaType = MediaType.parseMediaType("application/vnd.examle.public.v1+x-protobuf");
 
 
 	@Test
 	void canRead() {
 		assertThat(this.converter.canRead(Msg.class, null)).isTrue();
 		assertThat(this.converter.canRead(Msg.class, ProtobufHttpMessageConverter.PROTOBUF)).isTrue();
+		assertThat(this.converter.canRead(Msg.class, this.testPlusProtoMediaType)).isTrue();
 		assertThat(this.converter.canRead(Msg.class, MediaType.APPLICATION_JSON)).isTrue();
 		assertThat(this.converter.canRead(Msg.class, MediaType.TEXT_PLAIN)).isTrue();
 	}
@@ -56,6 +58,7 @@ class ProtobufJsonFormatHttpMessageConverterTests {
 	void canWrite() {
 		assertThat(this.converter.canWrite(Msg.class, null)).isTrue();
 		assertThat(this.converter.canWrite(Msg.class, ProtobufHttpMessageConverter.PROTOBUF)).isTrue();
+		assertThat(this.converter.canWrite(Msg.class, this.testPlusProtoMediaType)).isTrue();
 		assertThat(this.converter.canWrite(Msg.class, MediaType.APPLICATION_JSON)).isTrue();
 		assertThat(this.converter.canWrite(Msg.class, MediaType.TEXT_PLAIN)).isTrue();
 	}