Configure WebInterceptors in handlers

This commit gathers `WebInterceptor` beans from the context (in an
ordered fashion) and configures them on the relevant GraphQL handlers.

Closes spring-iogh-7

README.md

@@ -1,6 +1,6 @@
 # Spring GraphQL
 
-Experimental project to create [GraphQL](https://graphql.org/) support for Spring applications.
+Experimental project for [GraphQL](https://graphql.org/) support in Spring applications with [GraphQL Java](https://github.com/graphql-java/graphql-java).
 
 [![Build status](https://ci.spring.io/api/v1/teams/spring-graphql/pipelines/spring-graphql/jobs/build/badge)](https://ci.spring.io/teams/spring-graphql/pipelines/spring-graphql)
 
@@ -27,7 +27,7 @@ dependencies {
 
 repositories {
     mavenCentral()
-    // don't forget to add spring milestone and snapshot repositories
+    // don't forget to add spring milestone or snapshot repositories
     maven { url 'https://repo.spring.io/milestone' }
     maven { url 'https://repo.spring.io/snapshot' }
 }
@@ -55,6 +55,7 @@ repositories {
     <!-- ... -->
 </dependencies>
 
+<!-- Don't forget to add spring milestone or snapshot repositories -->
 <repositories>
     <repository>
         <id>spring-milestones</id>
@@ -85,7 +86,7 @@ type Person {
 }
 ```
 
-And then you should configure the data fetching using a `RuntimeWiringCustomizer` and custom components like
+Then you should configure the data fetching process using a `RuntimeWiringCustomizer` and custom components like
 Spring Data repositories, `WebClient` instances for Web APIs, a `@Service` bean, etc. 
 
 ```java
@@ -127,6 +128,12 @@ management.metrics.graphql.autotime.enabled=true
 
 You can contribute `RuntimeWiringCustomizer` beans to the context in order to configure the runtime wiring of your GraphQL application.
 
+### Extension points
+
+You can contribute [`WebInterceptor` beans](https://github.com/spring-projects-experimental/spring-graphql/blob/master/spring-graphql-web/src/main/java/org/springframework/graphql/WebInterceptor.java)
+to the application context, so as to customize the `ExecutionInput` or the `ExecutionResult` of the query.
+A custom `WebInterceptor` can, for example, change the HTTP request/response headers.  
+
 ### Metrics
 
 If the `spring-boot-starter-actuator` dependency is on the classpath, metrics will be collected for GraphQL queries.

graphql-spring-boot-starter/src/main/java/org/springframework/graphql/boot/WebFluxGraphQLAutoConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2020-2020 the original author or authors.
+ * Copyright 2020-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,9 +16,11 @@
 package org.springframework.graphql.boot;
 
 import java.util.Collections;
+import java.util.stream.Collectors;
 
 import graphql.GraphQL;
 
+import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.boot.autoconfigure.AutoConfigureAfter;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
@@ -28,6 +30,7 @@
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.ResourceLoader;
+import org.springframework.graphql.WebInterceptor;
 import org.springframework.graphql.webflux.GraphQLHttpHandler;
 import org.springframework.graphql.webflux.GraphQLWebSocketHandler;
 import org.springframework.http.MediaType;
@@ -50,17 +53,18 @@ public class WebFluxGraphQLAutoConfiguration {
 
 	@Bean
 	@ConditionalOnMissingBean
-	public GraphQLHttpHandler graphQLHandler(GraphQL.Builder graphQLBuilder) {
-		return new GraphQLHttpHandler(graphQLBuilder.build(), Collections.emptyList());
+	public GraphQLHttpHandler graphQLHandler(GraphQL.Builder graphQLBuilder, ObjectProvider<WebInterceptor> interceptors) {
+		return new GraphQLHttpHandler(graphQLBuilder.build(), interceptors.orderedStream().collect(Collectors.toList()));
 	}
 
 	@Bean
 	@ConditionalOnMissingBean
 	public GraphQLWebSocketHandler graphQLWebSocketHandler(
-			GraphQL.Builder graphQLBuilder, GraphQLProperties properties, ServerCodecConfigurer configurer) {
+			GraphQL.Builder graphQLBuilder, GraphQLProperties properties, ServerCodecConfigurer configurer,
+			ObjectProvider<WebInterceptor> interceptors) {
 
 		return new GraphQLWebSocketHandler(
-				graphQLBuilder.build(), Collections.emptyList(),
+				graphQLBuilder.build(), interceptors.orderedStream().collect(Collectors.toList()),
 				configurer, properties.getConnectionInitTimeoutDuration()
 		);
 	}

graphql-spring-boot-starter/src/main/java/org/springframework/graphql/boot/WebMvcGraphQLAutoConfiguration.java

@@ -17,11 +17,13 @@
 
 import java.util.Collections;
 import java.util.Map;
+import java.util.stream.Collectors;
 
 import javax.websocket.server.ServerContainer;
 
 import graphql.GraphQL;
 
+import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.boot.autoconfigure.AutoConfigureAfter;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
@@ -32,6 +34,7 @@
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.ResourceLoader;
+import org.springframework.graphql.WebInterceptor;
 import org.springframework.graphql.webmvc.GraphQLHttpHandler;
 import org.springframework.graphql.webmvc.GraphQLWebSocketHandler;
 import org.springframework.http.MediaType;
@@ -57,8 +60,9 @@ public class WebMvcGraphQLAutoConfiguration {
 
 	@Bean
 	@ConditionalOnMissingBean
-	public GraphQLHttpHandler graphQLHandler(GraphQL.Builder graphQLBuilder) {
-		return new GraphQLHttpHandler(graphQLBuilder.build(), Collections.emptyList());
+	public GraphQLHttpHandler graphQLHandler(GraphQL.Builder graphQLBuilder,
+			ObjectProvider<WebInterceptor> interceptors) {
+		return new GraphQLHttpHandler(graphQLBuilder.build(), interceptors.orderedStream().collect(Collectors.toList()));
 	}
 
 	@Bean
@@ -81,15 +85,16 @@ static class WebSocketConfiguration {
 		@Bean
 		@ConditionalOnMissingBean
 		public GraphQLWebSocketHandler graphQLWebSocketHandler(
-				GraphQL.Builder graphQLBuilder, GraphQLProperties properties, HttpMessageConverters converters) {
+				GraphQL.Builder graphQLBuilder, GraphQLProperties properties, HttpMessageConverters converters,
+				ObjectProvider<WebInterceptor> interceptors) {
 
 			HttpMessageConverter<?> converter = converters.getConverters().stream()
 					.filter(candidate -> candidate.canRead(Map.class, MediaType.APPLICATION_JSON))
 					.findFirst()
 					.orElseThrow(() -> new IllegalStateException("No JSON converter"));
 
 			return new GraphQLWebSocketHandler(
-					graphQLBuilder.build(), Collections.emptyList(),
+					graphQLBuilder.build(), interceptors.orderedStream().collect(Collectors.toList()),
 					converter, properties.getConnectionInitTimeoutDuration()
 			);
 		}

graphql-spring-boot-starter/src/test/java/org/springframework/graphql/boot/WebFluxApplicationContextTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,6 +19,7 @@
 import java.util.function.Consumer;
 
 import org.junit.jupiter.api.Test;
+import reactor.core.publisher.Mono;
 
 import org.springframework.boot.autoconfigure.AutoConfigurations;
 import org.springframework.boot.autoconfigure.http.codec.CodecsAutoConfiguration;
@@ -30,6 +31,8 @@
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.graphql.WebInterceptor;
+import org.springframework.graphql.WebOutput;
 import org.springframework.http.MediaType;
 import org.springframework.test.web.reactive.server.WebTestClient;
 
@@ -75,6 +78,26 @@ void queryIsInvalidJson() {
 		testWithWebClient(client -> client.post().uri("").bodyValue(":)").exchange().expectStatus().isBadRequest());
 	}
 
+	@Test
+	void interceptedQuery() {
+		testWithWebClient(client -> {
+			String query = "{" +
+					"  bookById(id: \\\"book-1\\\"){ " +
+					"    id" +
+					"    name" +
+					"    pageCount" +
+					"    author" +
+					"  }" +
+					"}";
+
+			client.post().uri("")
+					.bodyValue("{  \"query\": \"" + query + "\"}")
+					.exchange()
+					.expectStatus().isOk()
+					.expectHeader().valueEquals("X-Custom-Header", "42");
+		});
+	}
+
 	private void testWithWebClient(Consumer<WebTestClient> consumer) {
 		testWithApplicationContext(context -> {
 			WebTestClient client = WebTestClient.bindToApplicationContext(context)
@@ -92,7 +115,7 @@ private void testWithWebClient(Consumer<WebTestClient> consumer) {
 	private void testWithApplicationContext(ContextConsumer<ApplicationContext> consumer) {
 		new ReactiveWebApplicationContextRunner()
 				.withConfiguration(AUTO_CONFIGURATIONS)
-				.withUserConfiguration(DataFetchersConfiguration.class)
+				.withUserConfiguration(DataFetchersConfiguration.class, CustomWebInterceptor.class)
 				.withPropertyValues(
 						"spring.main.web-application-type=reactive",
 						"spring.graphql.schema-location:classpath:books/schema.graphqls")
@@ -111,4 +134,18 @@ public RuntimeWiringCustomizer bookDataFetcher() {
 		}
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	static class CustomWebInterceptor {
+
+		@Bean
+		public WebInterceptor customWebInterceptor() {
+			return new WebInterceptor() {
+				@Override
+				public Mono<WebOutput> postHandle(WebOutput webOutput) {
+					return Mono.just(webOutput.transform(output -> output.header("X-Custom-Header", "42")));
+				}
+			};
+		}
+	}
+
 }

graphql-spring-boot-starter/src/test/java/org/springframework/graphql/boot/WebMvcApplicationContextTests.java

@@ -1,7 +1,24 @@
+/*
+ * Copyright 2020-2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package org.springframework.graphql.boot;
 
 
 import org.junit.jupiter.api.Test;
+import reactor.core.publisher.Mono;
 
 import org.springframework.boot.autoconfigure.AutoConfigurations;
 import org.springframework.boot.autoconfigure.http.HttpMessageConvertersAutoConfiguration;
@@ -11,6 +28,8 @@
 import org.springframework.boot.test.context.runner.WebApplicationContextRunner;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.graphql.WebInterceptor;
+import org.springframework.graphql.WebOutput;
 import org.springframework.http.MediaType;
 import org.springframework.test.web.servlet.MockMvc;
 import org.springframework.test.web.servlet.MvcResult;
@@ -60,11 +79,28 @@ void invalidJson() {
 		testWith(mockMvc -> mockMvc.perform(post("/graphql").content(":)")).andExpect(status().isBadRequest()));
 	}
 
+	@Test
+	void interceptedQuery() {
+		testWith(mockMvc -> {
+			String query = "{" +
+					"  bookById(id: \\\"book-1\\\"){ " +
+					"    id" +
+					"    name" +
+					"    pageCount" +
+					"    author" +
+					"  }" +
+					"}";
+			MvcResult asyncResult = mockMvc.perform(post("/graphql").content("{\"query\": \"" + query + "\"}")).andReturn();
+			mockMvc.perform(asyncDispatch(asyncResult))
+					.andExpect(status().isOk())
+					.andExpect(header().string("X-Custom-Header", "42"));
+		});
+	}
 
 	private void testWith(MockMvcConsumer mockMvcConsumer) {
 		new WebApplicationContextRunner()
 				.withConfiguration(AUTO_CONFIGURATIONS)
-				.withUserConfiguration(DataFetchersConfiguration.class)
+				.withUserConfiguration(DataFetchersConfiguration.class, CustomWebInterceptor.class)
 				.withPropertyValues(
 						"spring.main.web-application-type=servlet",
 						"spring.graphql.schema-location:classpath:books/schema.graphqls")
@@ -94,4 +130,18 @@ public RuntimeWiringCustomizer bookDataFetcher() {
 		}
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	static class CustomWebInterceptor {
+
+		@Bean
+		public WebInterceptor customWebInterceptor() {
+			return new WebInterceptor() {
+				@Override
+				public Mono<WebOutput> postHandle(WebOutput webOutput) {
+					return Mono.just(webOutput.transform(output -> output.header("X-Custom-Header", "42")));
+				}
+			};
+		}
+	}
+
 }