Support "application/graphql+json" media type in GraphQL HTTP mapping

As seen in spring-projects/spring-graphql#108, the GraphQL HTTP spec now
requires the "application/graphql+json" media type and accepts
"application/json" for backwards compatibility.

This commit updates the `RouterFunction` definition for the GraphQL HTTP
endpoints so that both types are accepted.

Closes gh-30407

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/graphql/reactive/GraphQlWebFluxAutoConfiguration.java

@@ -81,8 +81,8 @@ import static org.springframework.web.reactive.function.server.RequestPredicates
 @EnableConfigurationProperties(GraphQlCorsProperties.class)
 public class GraphQlWebFluxAutoConfiguration {
 
-	private static final RequestPredicate ACCEPT_JSON_CONTENT = accept(MediaType.APPLICATION_JSON)
+	private static final RequestPredicate SUPPORTS_MEDIATYPES = accept(MediaType.APPLICATION_GRAPHQL,
-			.and(contentType(MediaType.APPLICATION_JSON));
+			MediaType.APPLICATION_JSON).and(contentType(MediaType.APPLICATION_GRAPHQL, MediaType.APPLICATION_JSON));
 
 	private static final Log logger = LogFactory.getLog(GraphQlWebFluxAutoConfiguration.class);
 
@@ -107,7 +107,7 @@ public class GraphQlWebFluxAutoConfiguration {
 		logger.info(LogMessage.format("GraphQL endpoint HTTP POST %s", path));
 		RouterFunctions.Builder builder = RouterFunctions.route();
 		builder = builder.GET(path, this::onlyAllowPost);
-		builder = builder.POST(path, ACCEPT_JSON_CONTENT, httpHandler::handleRequest);
+		builder = builder.POST(path, SUPPORTS_MEDIATYPES, httpHandler::handleRequest);
 		if (properties.getGraphiql().isEnabled()) {
 			GraphiQlHandler graphQlHandler = new GraphiQlHandler(path, properties.getWebsocket().getPath());
 			builder = builder.GET(properties.getGraphiql().getPath(), graphQlHandler::handleRequest);

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/graphql/servlet/GraphQlWebMvcAutoConfiguration.java

@@ -87,7 +87,7 @@ public class GraphQlWebMvcAutoConfiguration {
 
 	private static final Log logger = LogFactory.getLog(GraphQlWebMvcAutoConfiguration.class);
 
-	private static MediaType[] SUPPORTED_MEDIA_TYPES = new MediaType[] { MediaType.valueOf("application/graphql+json"),
+	private static MediaType[] SUPPORTED_MEDIA_TYPES = new MediaType[] { MediaType.APPLICATION_GRAPHQL,
 			MediaType.APPLICATION_JSON };
 
 	@Bean
@@ -113,8 +113,8 @@ public class GraphQlWebMvcAutoConfiguration {
 		logger.info(LogMessage.format("GraphQL endpoint HTTP POST %s", path));
 		RouterFunctions.Builder builder = RouterFunctions.route();
 		builder = builder.GET(path, this::onlyAllowPost);
-		builder = builder.POST(path, RequestPredicates.contentType(MediaType.APPLICATION_JSON)
+		builder = builder.POST(path, RequestPredicates.contentType(SUPPORTED_MEDIA_TYPES)
-				.and(RequestPredicates.accept(MediaType.APPLICATION_JSON)), httpHandler::handleRequest);
+				.and(RequestPredicates.accept(SUPPORTED_MEDIA_TYPES)), httpHandler::handleRequest);
 		if (properties.getGraphiql().isEnabled()) {
 			GraphiQlHandler graphiQLHandler = new GraphiQlHandler(path, properties.getWebsocket().getPath());
 			builder = builder.GET(properties.getGraphiql().getPath(), graphiQLHandler::handleRequest);

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/graphql/reactive/GraphQlWebFluxAutoConfigurationTests.java

@@ -75,7 +75,8 @@ class GraphQlWebFluxAutoConfigurationTests {
 		testWithWebClient((client) -> {
 			String query = "{ bookById(id: \\\"book-1\\\"){ id name pageCount author } }";
 			client.post().uri("/graphql").bodyValue("{  \"query\": \"" + query + "\"}").exchange().expectStatus().isOk()
-					.expectBody().jsonPath("data.bookById.name").isEqualTo("GraphQL for beginners");
+					.expectHeader().contentType("application/graphql+json").expectBody().jsonPath("data.bookById.name")
+					.isEqualTo("GraphQL for beginners");
 		});
 	}
 
@@ -150,8 +151,8 @@ class GraphQlWebFluxAutoConfigurationTests {
 		this.contextRunner.run((context) -> {
 			WebTestClient client = WebTestClient.bindToApplicationContext(context).configureClient()
 					.defaultHeaders((headers) -> {
-						headers.setContentType(MediaType.APPLICATION_JSON);
+						headers.setContentType(MediaType.APPLICATION_GRAPHQL);
-						headers.setAccept(Collections.singletonList(MediaType.APPLICATION_JSON));
+						headers.setAccept(Collections.singletonList(MediaType.APPLICATION_GRAPHQL));
 					}).baseUrl(BASE_URL).build();
 			consumer.accept(client);
 		});

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/graphql/servlet/GraphQlWebMvcAutoConfigurationTests.java

@@ -81,7 +81,7 @@ class GraphQlWebMvcAutoConfigurationTests {
 			String query = "{ bookById(id: \\\"book-1\\\"){ id name pageCount author } }";
 			MvcResult result = mockMvc.perform(post("/graphql").content("{\"query\": \"" + query + "\"}")).andReturn();
 			mockMvc.perform(asyncDispatch(result)).andExpect(status().isOk())
-					.andExpect(content().contentTypeCompatibleWith(MediaType.APPLICATION_JSON))
+					.andExpect(content().contentTypeCompatibleWith(MediaType.APPLICATION_GRAPHQL))
 					.andExpect(jsonPath("data.bookById.name").value("GraphQL for beginners"));
 		});
 	}
@@ -155,9 +155,9 @@ class GraphQlWebMvcAutoConfigurationTests {
 
 	private void testWith(MockMvcConsumer mockMvcConsumer) {
 		this.contextRunner.run((context) -> {
-			MediaType mediaType = MediaType.APPLICATION_JSON;
+			MockMvc mockMvc = MockMvcBuilders.webAppContextSetup(context).defaultRequest(
-			MockMvc mockMvc = MockMvcBuilders.webAppContextSetup(context)
+					post("/graphql").contentType(MediaType.APPLICATION_GRAPHQL).accept(MediaType.APPLICATION_GRAPHQL))
-					.defaultRequest(post("/graphql").contentType(mediaType).accept(mediaType)).build();
+					.build();
 			mockMvcConsumer.accept(mockMvc);
 		});
 	}

spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/graphql/tester/HttpGraphQlTesterContextCustomizerIntegrationTests.java

@@ -79,7 +79,7 @@ class HttpGraphQlTesterContextCustomizerIntegrationTests {
 		@Override
 		public Mono<Void> handle(ServerHttpRequest request, ServerHttpResponse response) {
 			response.setStatusCode(HttpStatus.OK);
-			response.getHeaders().setContentType(MediaType.APPLICATION_JSON);
+			response.getHeaders().setContentType(MediaType.APPLICATION_GRAPHQL);
 			return response.writeWith(Mono.just(factory.wrap("{\"data\":{}}".getBytes())));
 		}
 

spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/graphql/tester/HttpGraphQlTesterContextCustomizerWithCustomBasePathTests.java

@@ -79,7 +79,7 @@ class HttpGraphQlTesterContextCustomizerWithCustomBasePathTests {
 		@Override
 		public Mono<Void> handle(ServerHttpRequest request, ServerHttpResponse response) {
 			response.setStatusCode(HttpStatus.OK);
-			response.getHeaders().setContentType(MediaType.APPLICATION_JSON);
+			response.getHeaders().setContentType(MediaType.APPLICATION_GRAPHQL);
 			return response.writeWith(Mono.just(factory.wrap("{\"data\":{}}".getBytes())));
 		}
 

spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/graphql/tester/HttpGraphQlTesterContextCustomizerWithCustomContextPathTests.java

@@ -70,7 +70,7 @@ class HttpGraphQlTesterContextCustomizerWithCustomContextPathTests {
 	@RestController
 	static class TestController {
 
-		@PostMapping(path = "/graphql", produces = MediaType.APPLICATION_JSON_VALUE)
+		@PostMapping(path = "/graphql", produces = MediaType.APPLICATION_GRAPHQL_VALUE)
 		String graphql() {
 			return "{}";
 		}