Add client side interception

Closes gh-332

Author: rstoyanchev

spring-graphql-test/src/main/java/org/springframework/graphql/test/tester/AbstractDirectGraphQlTransport.java

@@ -28,9 +28,9 @@
 import org.springframework.graphql.GraphQlRequest;
 import org.springframework.graphql.GraphQlResponse;
 import org.springframework.graphql.ResponseError;
+import org.springframework.graphql.client.GraphQlTransport;
 import org.springframework.graphql.support.DefaultExecutionGraphQlRequest;
 import org.springframework.graphql.support.DefaultExecutionGraphQlResponse;
-import org.springframework.graphql.client.GraphQlTransport;
 import org.springframework.test.util.AssertionErrors;
 import org.springframework.util.AlternativeJdkIdGenerator;
 import org.springframework.util.CollectionUtils;

spring-graphql-test/src/main/java/org/springframework/graphql/test/tester/WebTestClientTransport.java

@@ -66,7 +66,7 @@ public Mono<GraphQlResponse> execute(GraphQlRequest request) {
 				.getResponseBody();
 
 		responseMap = (responseMap != null ? responseMap : Collections.emptyMap());
-		GraphQlResponse response = GraphQlTransport.wrapResponseMap(responseMap);
+		GraphQlResponse response = GraphQlTransport.createResponse(responseMap);
 		return Mono.just(response);
 	}
 

spring-graphql/src/main/java/org/springframework/graphql/client/AbstractGraphQlClientBuilder.java

@@ -16,10 +16,15 @@
 
 package org.springframework.graphql.client;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
 import java.util.function.Consumer;
 
 import org.springframework.core.codec.Decoder;
 import org.springframework.core.codec.Encoder;
+import org.springframework.graphql.client.GraphQlClientInterceptor.Chain;
+import org.springframework.graphql.client.GraphQlClientInterceptor.SubscriptionChain;
 import org.springframework.graphql.support.CachingDocumentSource;
 import org.springframework.graphql.support.DocumentSource;
 import org.springframework.graphql.support.ResourceDocumentSource;
@@ -49,6 +54,8 @@ public abstract class AbstractGraphQlClientBuilder<B extends AbstractGraphQlClie
 			"com.fasterxml.jackson.databind.ObjectMapper", AbstractGraphQlClientBuilder.class.getClassLoader());
 
 
+	private final List<GraphQlClientInterceptor> interceptors = new ArrayList<>();
+
 	private DocumentSource documentSource = new CachingDocumentSource(new ResourceDocumentSource());
 
 	@Nullable
@@ -67,6 +74,18 @@ protected AbstractGraphQlClientBuilder() {
 	}
 
 
+	@Override
+	public B interceptor(GraphQlClientInterceptor... interceptors) {
+		this.interceptors.addAll(Arrays.asList(interceptors));
+		return self();
+	}
+
+	@Override
+	public B interceptors(Consumer<List<GraphQlClientInterceptor>> interceptorsConsumer) {
+		interceptorsConsumer.accept(this.interceptors);
+		return self();
+	}
+
 	@Override
 	public B documentSource(DocumentSource contentLoader) {
 		this.documentSource = contentLoader;
@@ -104,25 +123,48 @@ protected GraphQlClient buildGraphQlClient(GraphQlTransport transport) {
 		}
 
 		return new DefaultGraphQlClient(
-				this.documentSource, transport, getJsonEncoder(), getJsonDecoder(), getBuilderInitializer());
+				this.documentSource, createExecuteChain(transport), createExecuteSubscriptionChain(transport));
 	}
 
 	/**
 	 * Return a {@code Consumer} to initialize new builders from "this" builder.
 	 */
 	protected Consumer<AbstractGraphQlClientBuilder<?>> getBuilderInitializer() {
 		return builder -> {
+			builder.interceptors(interceptorList -> interceptorList.addAll(interceptors));
 			builder.documentSource(documentSource);
-			builder.setJsonCodecs(getJsonEncoder(), getJsonDecoder());
+			builder.setJsonCodecs(getEncoder(), getDecoder());
 		};
 	}
 
-	private Encoder<?> getJsonEncoder() {
+	private Chain createExecuteChain(GraphQlTransport transport) {
+
+		Chain chain = request -> transport.execute(request).map(response ->
+				new DefaultClientGraphQlResponse(request, response, getEncoder(), getDecoder()));
+
+		return this.interceptors.stream()
+				.reduce(GraphQlClientInterceptor::andThen)
+				.map(interceptor -> (Chain) (request) -> interceptor.intercept(request, chain))
+				.orElse(chain);
+	}
+
+	private SubscriptionChain createExecuteSubscriptionChain(GraphQlTransport transport) {
+
+		SubscriptionChain chain = request -> transport.executeSubscription(request)
+				.map(response -> new DefaultClientGraphQlResponse(request, response, getEncoder(), getDecoder()));
+
+		return this.interceptors.stream()
+				.reduce(GraphQlClientInterceptor::andThen)
+				.map(interceptor -> (SubscriptionChain) (request) -> interceptor.interceptSubscription(request, chain))
+				.orElse(chain);
+	}
+
+	private Encoder<?> getEncoder() {
 		Assert.notNull(this.jsonEncoder, "jsonEncoder has not been set");
 		return this.jsonEncoder;
 	}
 
-	private Decoder<?> getJsonDecoder() {
+	private Decoder<?> getDecoder() {
 		Assert.notNull(this.jsonDecoder, "jsonDecoder has not been set");
 		return this.jsonDecoder;
 	}

spring-graphql/src/main/java/org/springframework/graphql/client/ClientGraphQlRequest.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2020-2022 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.client;
+
+import java.util.Map;
+
+import org.springframework.graphql.GraphQlRequest;
+
+
+/**
+ * {@link GraphQlRequest} for client side use.
+ *
+ * @author Rossen Stoyanchev
+ * @since 1.0.0
+ */
+public interface ClientGraphQlRequest extends GraphQlRequest {
+
+	/**
+	 * Return the client request attributes.
+	 * <p>The attributes purely for client side request processing, i.e. available
+	 * throughout the {@link GraphQlClientInterceptor} chain, but not sent.
+	 */
+	Map<String, Object> getAttributes();
+
+}
+

spring-graphql/src/main/java/org/springframework/graphql/client/ClientGraphQlResponse.java

@@ -18,7 +18,6 @@
 
 
 import org.springframework.core.ParameterizedTypeReference;
-import org.springframework.graphql.GraphQlRequest;
 import org.springframework.graphql.GraphQlResponse;
 
 /**
@@ -30,11 +29,6 @@
  */
 public interface ClientGraphQlResponse extends GraphQlResponse {
 
-	/**
-	 * Return the request for the response.
-	 */
-	GraphQlRequest getRequest();
-
 	/**
 	 * {@inheritDoc}
 	 */

spring-graphql/src/main/java/org/springframework/graphql/client/DefaultClientGraphQlRequest.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2020-2022 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.client;
+
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+import org.springframework.graphql.support.DefaultGraphQlRequest;
+import org.springframework.lang.Nullable;
+
+/**
+ * Default implementation of {@link ClientGraphQlRequest}.
+ *
+ * @author Rossen Stoyanchev
+ * @since 1.0.0
+ */
+final class DefaultClientGraphQlRequest extends DefaultGraphQlRequest implements ClientGraphQlRequest {
+
+	private final Map<String, Object> attributes = new ConcurrentHashMap<>();
+
+
+	DefaultClientGraphQlRequest(
+			String document, @Nullable String operationName, Map<String, Object> variables,
+			Map<String, Object> attributes) {
+
+		super(document, operationName, variables);
+		this.attributes.putAll(attributes);
+	}
+
+
+	@Override
+	public Map<String, Object> getAttributes() {
+		return this.attributes;
+	}
+
+}

spring-graphql/src/main/java/org/springframework/graphql/client/DefaultClientGraphQlResponse.java

@@ -19,7 +19,6 @@
 import org.springframework.core.ParameterizedTypeReference;
 import org.springframework.core.codec.Decoder;
 import org.springframework.core.codec.Encoder;
-import org.springframework.graphql.GraphQlRequest;
 import org.springframework.graphql.GraphQlResponse;
 
 
@@ -29,17 +28,17 @@
  * @author Rossen Stoyanchev
  * @since 1.0.0
  */
-final class DefaultClientGraphQlResponse extends MapGraphQlResponse implements ClientGraphQlResponse {
+final class DefaultClientGraphQlResponse extends ResponseMapGraphQlResponse implements ClientGraphQlResponse {
 
-	private final GraphQlRequest request;
+	private final ClientGraphQlRequest request;
 
 	private final Encoder<?> encoder;
 
 	private final Decoder<?> decoder;
 
 
 	DefaultClientGraphQlResponse(
-			GraphQlRequest request, GraphQlResponse response, Encoder<?> encoder, Decoder<?> decoder) {
+			ClientGraphQlRequest request, GraphQlResponse response, Encoder<?> encoder, Decoder<?> decoder) {
 
 		super(response);
 
@@ -49,8 +48,7 @@ final class DefaultClientGraphQlResponse extends MapGraphQlResponse implements C
 	}
 
 
-	@Override
-	public GraphQlRequest getRequest() {
+	ClientGraphQlRequest getRequest() {
 		return this.request;
 	}
 

spring-graphql/src/main/java/org/springframework/graphql/client/DefaultClientResponseField.java

@@ -107,7 +107,7 @@ public <D> List<D> toEntityList(ParameterizedTypeReference<D> elementType) {
 	@SuppressWarnings({"unchecked", "ConstantConditions"})
 	private <T> T toEntity(ResolvableType targetType) {
 		if (!hasValue()) {
-			throw new FieldAccessException(this.response, this);
+			throw new FieldAccessException(this.response.getRequest(), this.response, this);
 		}
 
 		DataBufferFactory bufferFactory = DefaultDataBufferFactory.sharedInstance;