ThreadLocal context propagation for DataFetcher's

The WebMvc starter now supports propagation of ThreadLocal values
extracted at the level of the HTTP handler.

Closes gh-53

samples/webmvc-http/src/main/java/io/spring/sample/graphql/SampleApplication.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.
@@ -21,7 +21,9 @@ import org.springframework.boot.autoconfigure.SpringBootApplication;
 
 @SpringBootApplication
 public class SampleApplication {
+
 	public static void main(String[] args) {
 		SpringApplication.run(SampleApplication.class, args);
 	}
+
 }

samples/webmvc-http/src/main/java/io/spring/sample/graphql/greeting/GreetingDataWiring.java

@@ -0,0 +1,24 @@
+package io.spring.sample.graphql.greeting;
+
+import graphql.schema.idl.RuntimeWiring;
+
+import org.springframework.graphql.boot.RuntimeWiringCustomizer;
+import org.springframework.stereotype.Component;
+import org.springframework.web.context.request.RequestAttributes;
+import org.springframework.web.context.request.RequestContextHolder;
+
+import static org.springframework.web.context.request.RequestAttributes.SCOPE_REQUEST;
+
+@Component
+public class GreetingDataWiring implements RuntimeWiringCustomizer {
+
+
+	@Override
+	public void customize(RuntimeWiring.Builder builder) {
+		builder.type("Query", typeWiring ->
+				typeWiring.dataFetcher("greeting", env -> {
+					RequestAttributes attributes = RequestContextHolder.getRequestAttributes();
+					return "Hello " + attributes.getAttribute(RequestAttributeFilter.NAME_ATTRIBUTE, SCOPE_REQUEST);
+				}));
+	}
+}

samples/webmvc-http/src/main/java/io/spring/sample/graphql/greeting/RequestAttributeFilter.java

@@ -0,0 +1,43 @@
+/*
+ * 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.
+ * 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 io.spring.sample.graphql.greeting;
+
+import java.io.IOException;
+
+import javax.servlet.Filter;
+import javax.servlet.FilterChain;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+
+import org.springframework.stereotype.Component;
+
+/**
+ * Servlet Filter that adds a Servlet request attribute.
+ */
+@Component
+public class RequestAttributeFilter implements Filter {
+
+	public static final String NAME_ATTRIBUTE = RequestAttributeFilter.class.getName() + ".name";
+
+
+	@Override
+	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
+		request.setAttribute(NAME_ATTRIBUTE, "007");
+		chain.doFilter(request, response);
+	}
+
+}

samples/webmvc-http/src/main/java/io/spring/sample/graphql/greeting/RequestAttributesAccessor.java

@@ -0,0 +1,60 @@
+/*
+ * 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.
+ * 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 io.spring.sample.graphql.greeting;
+
+import java.util.Collections;
+import java.util.Map;
+
+import org.springframework.graphql.execution.ThreadLocalAccessor;
+import org.springframework.stereotype.Component;
+import org.springframework.web.context.request.RequestAttributes;
+import org.springframework.web.context.request.RequestContextHolder;
+
+/**
+ * {@link ThreadLocalAccessor} to expose a thread-bound RequestAttributes object
+ * to data fetchers in Spring GraphQL.
+ */
+@Component
+public class RequestAttributesAccessor implements ThreadLocalAccessor {
+
+	private static final String ATTRIBUTES_KEY =
+			RequestAttributesAccessor.class.getName() + ".requestAttributes";
+
+
+	@Override
+	public void extractValues(Map<String, Object> container) {
+		RequestAttributes attributes = RequestContextHolder.getRequestAttributes();
+		if (attributes != null) {
+			container.put(ATTRIBUTES_KEY, attributes);
+		}
+	}
+
+	@Override
+	public void restoreValues(Map<String, Object> values) {
+		RequestAttributes attributes = (RequestAttributes) values.get(ATTRIBUTES_KEY);
+		if (attributes != null) {
+			RequestContextHolder.setRequestAttributes(attributes);
+		}
+	}
+
+	@Override
+	public void resetValues(Map<String, Object> values) {
+		if (values.get(ATTRIBUTES_KEY) != null) {
+			RequestContextHolder.resetRequestAttributes();
+		}
+	}
+
+}

samples/webmvc-http/src/main/java/io/spring/sample/graphql/greeting/package-info.java

@@ -0,0 +1,6 @@
+@NonNullApi
+@NonNullFields
+package io.spring.sample.graphql.greeting;
+
+import org.springframework.lang.NonNullApi;
+import org.springframework.lang.NonNullFields;

samples/webmvc-http/src/main/java/io/spring/sample/graphql/package-info.java

@@ -0,0 +1,6 @@
+@NonNullApi
+@NonNullFields
+package io.spring.sample.graphql;
+
+import org.springframework.lang.NonNullApi;
+import org.springframework.lang.NonNullFields;

samples/webmvc-http/src/main/java/io/spring/sample/graphql/project/package-info.java

@@ -0,0 +1,6 @@
+@NonNullApi
+@NonNullFields
+package io.spring.sample.graphql.project;
+
+import org.springframework.lang.NonNullApi;
+import org.springframework.lang.NonNullFields;

samples/webmvc-http/src/main/java/io/spring/sample/graphql/repository/package-info.java

@@ -0,0 +1,6 @@
+@NonNullApi
+@NonNullFields
+package io.spring.sample.graphql.repository;
+
+import org.springframework.lang.NonNullApi;
+import org.springframework.lang.NonNullFields;

samples/webmvc-http/src/main/resources/graphql/schema.graphqls

@@ -1,4 +1,5 @@
 type Query {
+    greeting: String
     artifactRepositories : [ArtifactRepository]
     artifactRepository(id : ID!) : ArtifactRepository
     project(slug: ID!): Project