Add reflection hint for GraphQlWebSocketMessage

Prior to this commit, GraphQL applications using the WebSocket transport
would fail with an `java.lang.IllegalArgumentException: No JSON Encoder`
as the JSON codec was reflecting on the `GraphQlWebSocketMessage` to
check that it can handle this type, during startup time.

`GraphQlWebSocketMessage` is the message type being used for sending and
receiving GraphQL requests. This commit registers binding reflection on
this type as soon as a `GraphQlWebSocketHandler` (mvc or webflux) is
registered as a bean in the application.

This type is also used on the client side in the client
`WebSocketGraphQlTransport`. Because clients cannot be reliably detected
here in the application context or via classpath checks, this commit
also adds a JSON metadata file that adds reflection on the type, if and
only if the `WebSocketGraphQlTransport` is reachable by the static
analysis performed by GraalVM.

Fixes gh-560

Author: bclozel

spring-graphql/src/main/java/org/springframework/graphql/server/webflux/GraphQlWebSocketHandler.java

@@ -35,6 +35,7 @@
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
+import org.springframework.aot.hint.annotation.RegisterReflectionForBinding;
 import org.springframework.graphql.server.WebGraphQlHandler;
 import org.springframework.graphql.server.WebGraphQlResponse;
 import org.springframework.graphql.server.WebSocketGraphQlInterceptor;
@@ -59,6 +60,7 @@
  * @author Rossen Stoyanchev
  * @since 1.0.0
  */
+@RegisterReflectionForBinding(GraphQlWebSocketMessage.class)
 public class GraphQlWebSocketHandler implements WebSocketHandler {
 
 	private static final Log logger = LogFactory.getLog(GraphQlWebSocketHandler.class);

spring-graphql/src/main/java/org/springframework/graphql/server/webmvc/GraphQlWebSocketHandler.java

@@ -46,6 +46,7 @@
 import reactor.core.scheduler.Scheduler;
 import reactor.core.scheduler.Schedulers;
 
+import org.springframework.aot.hint.annotation.RegisterReflectionForBinding;
 import org.springframework.graphql.execution.ErrorType;
 import org.springframework.graphql.execution.SubscriptionPublisherException;
 import org.springframework.graphql.server.WebGraphQlHandler;
@@ -84,6 +85,7 @@
  * @author Rossen Stoyanchev
  * @since 1.0.0
  */
+@RegisterReflectionForBinding(GraphQlWebSocketMessage.class)
 public class GraphQlWebSocketHandler extends TextWebSocketHandler implements SubProtocolCapable {
 
 	private static final Log logger = LogFactory.getLog(GraphQlWebSocketHandler.class);

spring-graphql/src/main/resources/META-INF/native-image/org.springframework.graphql/spring-graphql/reflect-config.json

@@ -0,0 +1,11 @@
+[
+  {
+    "name":"org.springframework.graphql.server.support.GraphQlWebSocketMessage",
+    "allDeclaredFields":true,
+    "allDeclaredMethods":true,
+    "allDeclaredConstructors":true,
+    "condition": {
+      "typeReachable": "org.springframework.graphql.client.WebSocketGraphQlTransport"
+    }
+  }
+]

spring-graphql/src/test/java/org/springframework/graphql/server/webflux/GraphQlWebSocketHandlerTests.java

@@ -32,6 +32,10 @@
 import reactor.core.publisher.Sinks;
 import reactor.test.StepVerifier;
 
+import org.springframework.aot.hint.RuntimeHints;
+import org.springframework.aot.hint.annotation.ReflectiveRuntimeHintsRegistrar;
+import org.springframework.aot.hint.predicate.ReflectionHintsPredicates;
+import org.springframework.aot.hint.predicate.RuntimeHintsPredicates;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DataBufferUtils;
@@ -353,6 +357,23 @@ void subscriptionErrorPayloadIsArray() {
 				.verify(TIMEOUT);
 	}
 
+	@Test
+	void registerBindingReflectionOnWebSocketMessage() {
+		RuntimeHints runtimeHints = new RuntimeHints();
+		new ReflectiveRuntimeHintsRegistrar().registerRuntimeHints(runtimeHints, GraphQlWebSocketHandler.class);
+		ReflectionHintsPredicates reflection = RuntimeHintsPredicates.reflection();
+		assertThat(reflection.onType(GraphQlWebSocketMessage.class)).accepts(runtimeHints);
+		assertThat(reflection.onField(GraphQlWebSocketMessage.class, "id")).accepts(runtimeHints);
+		assertThat(reflection.onMethod(GraphQlWebSocketMessage.class, "getId")).accepts(runtimeHints);
+		assertThat(reflection.onMethod(GraphQlWebSocketMessage.class, "setId")).accepts(runtimeHints);
+		assertThat(reflection.onField(GraphQlWebSocketMessage.class, "type")).accepts(runtimeHints);
+		assertThat(reflection.onMethod(GraphQlWebSocketMessage.class, "getType")).accepts(runtimeHints);
+		assertThat(reflection.onMethod(GraphQlWebSocketMessage.class, "setType")).accepts(runtimeHints);
+		assertThat(reflection.onField(GraphQlWebSocketMessage.class, "payload")).accepts(runtimeHints);
+		assertThat(reflection.onMethod(GraphQlWebSocketMessage.class, "getPayload")).accepts(runtimeHints);
+		assertThat(reflection.onMethod(GraphQlWebSocketMessage.class, "setPayload")).accepts(runtimeHints);
+	}
+
 	private TestWebSocketSession handle(Flux<WebSocketMessage> input, WebGraphQlInterceptor... interceptors) {
 		GraphQlWebSocketHandler handler = new GraphQlWebSocketHandler(
 				initHandler(interceptors),

spring-graphql/src/test/java/org/springframework/graphql/server/webmvc/GraphQlWebSocketHandlerTests.java

@@ -36,6 +36,10 @@
 import reactor.core.publisher.Mono;
 import reactor.test.StepVerifier;
 
+import org.springframework.aot.hint.RuntimeHints;
+import org.springframework.aot.hint.annotation.ReflectiveRuntimeHintsRegistrar;
+import org.springframework.aot.hint.predicate.ReflectionHintsPredicates;
+import org.springframework.aot.hint.predicate.RuntimeHintsPredicates;
 import org.springframework.graphql.GraphQlSetup;
 import org.springframework.graphql.TestThreadLocalAccessor;
 import org.springframework.graphql.execution.ErrorType;
@@ -406,6 +410,23 @@ void contextPropagation() throws Exception {
 		}
 	}
 
+	@Test
+	void registerBindingReflectionOnWebSocketMessage() {
+		RuntimeHints runtimeHints = new RuntimeHints();
+		new ReflectiveRuntimeHintsRegistrar().registerRuntimeHints(runtimeHints, GraphQlWebSocketHandler.class);
+		ReflectionHintsPredicates reflection = RuntimeHintsPredicates.reflection();
+		assertThat(reflection.onType(GraphQlWebSocketMessage.class)).accepts(runtimeHints);
+		assertThat(reflection.onField(GraphQlWebSocketMessage.class, "id")).accepts(runtimeHints);
+		assertThat(reflection.onMethod(GraphQlWebSocketMessage.class, "getId")).accepts(runtimeHints);
+		assertThat(reflection.onMethod(GraphQlWebSocketMessage.class, "setId")).accepts(runtimeHints);
+		assertThat(reflection.onField(GraphQlWebSocketMessage.class, "type")).accepts(runtimeHints);
+		assertThat(reflection.onMethod(GraphQlWebSocketMessage.class, "getType")).accepts(runtimeHints);
+		assertThat(reflection.onMethod(GraphQlWebSocketMessage.class, "setType")).accepts(runtimeHints);
+		assertThat(reflection.onField(GraphQlWebSocketMessage.class, "payload")).accepts(runtimeHints);
+		assertThat(reflection.onMethod(GraphQlWebSocketMessage.class, "getPayload")).accepts(runtimeHints);
+		assertThat(reflection.onMethod(GraphQlWebSocketMessage.class, "setPayload")).accepts(runtimeHints);
+	}
+
 	private void handle(GraphQlWebSocketHandler handler, TextMessage... textMessages) throws Exception {
 		handler.afterConnectionEstablished(this.session);