Add WebInterceptorExecution

Arguably a better way to encapsulate support for WebInterceptor vs a
base class, more testable, and reduced public API surface.

spring-graphql-web/src/main/java/org/springframework/graphql/WebFluxGraphQLHandler.java

@@ -28,11 +28,13 @@ import org.springframework.web.reactive.function.server.ServerResponse;
  * GraphQL handler to expose as a WebFlux.fn endpoint via
  * {@link org.springframework.web.reactive.function.server.RouterFunctions}.
  */
-public class WebFluxGraphQLHandler extends WebHandlerSupport implements HandlerFunction<ServerResponse> {
+public class WebFluxGraphQLHandler implements HandlerFunction<ServerResponse> {
+
+	private final WebInterceptorExecution executionChain;
 
 
 	public WebFluxGraphQLHandler(GraphQL graphQL, List<WebInterceptor> interceptors) {
-		super(graphQL, interceptors);
+		this.executionChain = new WebInterceptorExecution(graphQL, interceptors);
 	}
 
 
@@ -40,7 +42,7 @@ public class WebFluxGraphQLHandler extends WebHandlerSupport implements HandlerF
 		return request.bodyToMono(WebInput.MAP_PARAMETERIZED_TYPE_REF)
 				.flatMap(body -> {
 					WebInput webInput = new WebInput(request.uri(), request.headers().asHttpHeaders(), body);
-					return executeQuery(webInput);
+					return this.executionChain.execute(webInput);
 				})
 				.flatMap(output -> ServerResponse.ok().bodyValue(output.toSpecification()));
 	}

spring-graphql-web/src/main/java/org/springframework/graphql/WebInput.java

@@ -30,8 +30,8 @@ import org.springframework.web.util.UriComponents;
 import org.springframework.web.util.UriComponentsBuilder;
 
 /**
- * Represents the input to a GraphQL HTTP endpoint including URI, headers, and
- * the query, operationName, and variables from the request body.
+ * Container for input from an HTTP request to a GraphQL endpoint, including
+ * URI, headers, and other inputs extracted from the body of the request.
  */
 public class WebInput {
 

spring-graphql-web/src/main/java/org/springframework/graphql/WebInterceptor.java

@@ -18,11 +18,13 @@ package org.springframework.graphql;
 import java.util.function.Consumer;
 
 import graphql.ExecutionInput;
+import graphql.GraphQL;
 import reactor.core.publisher.Mono;
 
 /**
- * Allows interception of GraphQL over HTTP requests with possible customization
- * of the input and the result of query execution.
+ * Interceptor for GraphQL over HTTP requests that allows customization of the
+ * {@link ExecutionInput} and the {@link graphql.ExecutionResult} of
+ * {@link GraphQL} query execution.
  */
 public interface WebInterceptor {
 

spring-graphql-web/src/main/java/org/springframework/graphql/WebInterceptorExecution.java

@@ -18,6 +18,7 @@ package org.springframework.graphql;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.concurrent.CompletableFuture;
 
 import graphql.ExecutionInput;
 import graphql.ExecutionResult;
@@ -27,39 +28,32 @@ import reactor.core.publisher.Mono;
 import org.springframework.util.CollectionUtils;
 
 /**
- * Base class for GraphQL over HTTP handlers.
+ * Supports the use of {@link WebInterceptor}s to customize the
+ * {@link ExecutionInput} and the {@link ExecutionResult} of {@link GraphQL}
+ * query execution.
  */
-public abstract class WebHandlerSupport {
+class WebInterceptorExecution {
 
 	private final GraphQL graphQL;
 
 	private final List<WebInterceptor> interceptors;
 
 
-	public WebHandlerSupport(GraphQL graphQL, List<WebInterceptor> interceptors) {
+	WebInterceptorExecution(GraphQL graphQL, List<WebInterceptor> interceptors) {
 		this.graphQL = graphQL;
 		this.interceptors = (!CollectionUtils.isEmpty(interceptors) ?
 				Collections.unmodifiableList(new ArrayList<>(interceptors)) : Collections.emptyList());
 	}
 
 
-	public GraphQL getGraphQL() {
-		return this.graphQL;
-	}
-
-	public List<WebInterceptor> getInterceptors() {
-		return this.interceptors;
-	}
-
-
-	protected Mono<WebOutput> executeQuery(WebInput webInput) {
+	public Mono<WebOutput> execute(WebInput webInput) {
 		return createInputChain(webInput).flatMap(executionInput -> {
-			Mono<ExecutionResult> resultMono = Mono.fromFuture(getGraphQL().executeAsync(executionInput));
-			return createOutputChain(resultMono);
+			CompletableFuture<ExecutionResult> future = this.graphQL.executeAsync(executionInput);
+			return createOutputChain(Mono.fromFuture(future));
 		});
 	}
 
-	protected Mono<ExecutionInput> createInputChain(WebInput webInput) {
+	private Mono<ExecutionInput> createInputChain(WebInput webInput) {
 		Mono<ExecutionInput> preHandleMono = Mono.just(webInput.toExecutionInput());
 		for (WebInterceptor interceptor : this.interceptors) {
 			preHandleMono = preHandleMono.flatMap(input -> interceptor.preHandle(input, webInput));
@@ -67,9 +61,10 @@ public abstract class WebHandlerSupport {
 		return preHandleMono;
 	}
 
-	protected Mono<WebOutput> createOutputChain(Mono<ExecutionResult> resultMono) {
+	private Mono<WebOutput> createOutputChain(Mono<ExecutionResult> resultMono) {
 		Mono<WebOutput> outputMono = resultMono.map(WebOutput::new);
-		for (WebInterceptor interceptor : this.interceptors) {
+		for (int i = this.interceptors.size() - 1 ; i >= 0; i--) {
+			WebInterceptor interceptor = this.interceptors.get(i);
 			outputMono = outputMono.flatMap(interceptor::postHandle);
 		}
 		return outputMono;

spring-graphql-web/src/main/java/org/springframework/graphql/WebMvcGraphQLHandler.java

@@ -35,11 +35,13 @@ import org.springframework.web.servlet.function.ServerResponse;
  * GraphQL handler to expose as a WebMvc.fn endpoint via
  * {@link org.springframework.web.servlet.function.RouterFunctions}.
  */
-public class WebMvcGraphQLHandler extends WebHandlerSupport implements HandlerFunction<ServerResponse> {
+public class WebMvcGraphQLHandler implements HandlerFunction<ServerResponse> {
+
+	private final WebInterceptorExecution executionChain;
 
 
 	public WebMvcGraphQLHandler(GraphQL graphQL, List<WebInterceptor> interceptors) {
-		super(graphQL, interceptors);
+		this.executionChain = new WebInterceptorExecution(graphQL, interceptors);
 	}
 
 
@@ -51,7 +53,7 @@ public class WebMvcGraphQLHandler extends WebHandlerSupport implements HandlerFu
 	 */
 	public ServerResponse handle(ServerRequest request) throws ServletException {
 		WebInput webInput = new WebInput(request.uri(), request.headers().asHttpHeaders(), readBody(request));
-		Mono<WebOutput> outputMono = executeQuery(webInput);
+		Mono<WebOutput> outputMono = this.executionChain.execute(webInput);
 		return ServerResponse.ok().body(outputMono.map(ExecutionResult::toSpecification));
 	}
 

spring-graphql-web/src/main/java/org/springframework/graphql/WebOutput.java

@@ -27,8 +27,8 @@ import org.springframework.lang.Nullable;
 
 
 /**
- * Simple wrapper around a GraphQL {@link ExecutionResult} that allows
- * {@link #transform(Consumer) transformation} via a {@link Builder Builder}.
+ * {@link ExecutionResult} that wraps another in order to provide a convenient
+ * way to {@link #transform(Consumer) transform} it.
  */
 public class WebOutput implements ExecutionResult {
 

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

@@ -14,6 +14,7 @@ import org.springframework.boot.autoconfigure.web.reactive.WebFluxAutoConfigurat
 import org.springframework.boot.test.context.runner.ReactiveWebApplicationContextRunner;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.graphql.GraphQLDataFetchers;
 import org.springframework.http.MediaType;
 import org.springframework.test.web.reactive.server.WebTestClient;
 

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

@@ -11,6 +11,7 @@ import org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguratio
 import org.springframework.boot.test.context.runner.WebApplicationContextRunner;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.graphql.GraphQLDataFetchers;
 import org.springframework.http.MediaType;
 import org.springframework.test.web.servlet.MockMvc;
 import org.springframework.test.web.servlet.request.MockHttpServletRequestBuilder;
@@ -84,7 +85,7 @@ class WebMvcApplicationContextTests {
 
 		@Bean
 		public RuntimeWiringCustomizer bookDataFetcher() {
-			return (runtimeWiring) -> runtimeWiring.type(newTypeWiring("Query")
+			return (builder) -> builder.type(newTypeWiring("Query")
 					.dataFetcher("bookById", GraphQLDataFetchers.getBookByIdDataFetcher()));
 		}
 	}

spring-graphql-web/src/test/java/org/springframework/graphql/Book.java

@@ -1,4 +1,4 @@
-package org.springframework.boot.graphql;
+package org.springframework.graphql;
 
 public class Book {
 

spring-graphql-web/src/test/java/org/springframework/graphql/GraphQLDataFetchers.java

@@ -1,4 +1,4 @@
-package org.springframework.boot.graphql;
+package org.springframework.graphql;
 
 import java.util.Arrays;
 import java.util.List;

spring-graphql-web/src/test/java/org/springframework/graphql/WebInterceptorExecutionTests.java

@@ -0,0 +1,113 @@
+/*
+ * Copyright 2020-2020 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;
+
+import java.io.File;
+import java.net.URI;
+import java.time.Duration;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import graphql.ExecutionInput;
+import graphql.GraphQL;
+import graphql.schema.GraphQLSchema;
+import graphql.schema.idl.RuntimeWiring;
+import graphql.schema.idl.SchemaGenerator;
+import graphql.schema.idl.SchemaParser;
+import graphql.schema.idl.TypeDefinitionRegistry;
+import org.junit.jupiter.api.Test;
+import reactor.core.publisher.Mono;
+
+import org.springframework.http.HttpHeaders;
+import org.springframework.util.ResourceUtils;
+
+import static graphql.schema.idl.TypeRuntimeWiring.newTypeWiring;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Unit tests for {@link WebInterceptorExecution}.
+ */
+public class WebInterceptorExecutionTests {
+
+	@Test
+	void testInterceptorInvocation() throws Exception {
+
+		StringBuilder sb = new StringBuilder();
+		List<WebInterceptor> interceptors = Arrays.asList(
+				new TestWebInterceptor(sb, 1), new TestWebInterceptor(sb, 2), new TestWebInterceptor(sb, 3));
+
+		String query = "{" +
+				"  bookById(id: \\\"book-1\\\"){ " +
+				"    id" +
+				"    name" +
+				"    pageCount" +
+				"    author" +
+				"  }" +
+				"}";
+
+		ObjectMapper mapper = new ObjectMapper();
+		Map body = mapper.reader().readValue("{\"query\": \"" + query + "\"}", Map.class);
+		WebInput webInput = new WebInput(URI.create("/graphql"), new HttpHeaders(), body);
+
+		WebOutput webOutput = new WebInterceptorExecution(createGraphQL(), interceptors)
+				.execute(webInput).block();
+
+		assertEquals(":pre1:pre2:pre3:post3:post2:post1", sb.toString());
+		assertTrue(webOutput.isDataPresent());
+	}
+
+	private static GraphQL createGraphQL() throws Exception {
+		RuntimeWiring runtimeWiring = RuntimeWiring.newRuntimeWiring()
+				.type(newTypeWiring("Query").dataFetcher("bookById", GraphQLDataFetchers.getBookByIdDataFetcher()))
+				.build();
+
+		File file = ResourceUtils.getFile("classpath:books/schema.graphqls");
+		TypeDefinitionRegistry registry = new SchemaParser().parse(file);
+		SchemaGenerator generator = new SchemaGenerator();
+		GraphQLSchema schema = generator.makeExecutableSchema(registry, runtimeWiring);
+
+		return GraphQL.newGraphQL(schema).build();
+	}
+
+
+	private static class TestWebInterceptor implements WebInterceptor {
+
+		private final StringBuilder output;
+
+		private final int index;
+
+		public TestWebInterceptor(StringBuilder output, int index) {
+			this.output = output;
+			this.index = index;
+		}
+
+		@Override
+		public Mono<ExecutionInput> preHandle(ExecutionInput executionInput, WebInput webInput) {
+			this.output.append(":pre").append(this.index);
+			return Mono.delay(Duration.ofMillis(50)).map(aLong -> executionInput);
+		}
+
+		@Override
+		public Mono<WebOutput> postHandle(WebOutput webOutput) {
+			this.output.append(":post").append(this.index);
+			return Mono.delay(Duration.ofMillis(50)).map(aLong -> webOutput);
+		}
+	}
+
+}