Merge remote-tracking branch 'origin/master'

Author: oliemansm

README.md

@@ -186,3 +186,61 @@ And here is a sample src/main/feature/feature.xml file to add some dependencies
 Here's an example of a GraphQL provider that implements three interfaces at the same time.
 
 * [ExampleGraphQLProvider](examples/osgi/providers/src/main/java/graphql/servlet/examples/osgi/ExampleGraphQLProvider.java)
+
+## Request-scoped DataLoaders
+
+It is possible to use dataloaders in a request scope by customizing [GraphQLContextBuilder](https://github.com/graphql-java/graphql-java-servlet/blob/master/src/main/java/graphql/servlet/GraphQLContextBuilder.java).
+And instantiating a new [DataLoaderRegistry](https://github.com/graphql-java/java-dataloader/blob/master/src/main/java/org/dataloader/DataLoaderRegistry.java) for each GraphQLContext.
+For eg:
+```java
+public class CustomGraphQLContextBuilder implements GraphQLContextBuilder {
+
+    private final DataLoader userDataLoader;
+
+    public CustomGraphQLContextBuilder(DataLoader userDataLoader) {
+        this.userDataLoader = userDataLoader;
+    }
+
+    @Override
+    public GraphQLContext build(HttpServletRequest req) {
+        GraphQLContext context = new GraphQLContext(req);
+        context.setDataLoaderRegistry(buildDataLoaderRegistry());
+
+        return context;
+    }
+
+    @Override
+    public GraphQLContext build() {
+        GraphQLContext context = new GraphQLContext();
+        context.setDataLoaderRegistry(buildDataLoaderRegistry());
+
+        return context;
+    }
+
+    @Override
+    public GraphQLContext build(HandshakeRequest request) {
+        GraphQLContext context = new GraphQLContext(request);
+        context.setDataLoaderRegistry(buildDataLoaderRegistry());
+
+        return context;
+    }
+
+    private DataLoaderRegistry buildDataLoaderRegistry() {
+        DataLoaderRegistry dataLoaderRegistry = new DataLoaderRegistry();
+        dataLoaderRegistry.register("userDataLoader", userDataLoader);
+        return dataLoaderRegistry;
+    }
+}
+
+```
+ It is then possible to access the [DataLoader](https://github.com/graphql-java/java-dataloader/blob/master/src/main/java/org/dataloader/DataLoader.java) in the resolvers by accessing the [DataLoaderRegistry] from context. For eg:
+ ```java
+ public CompletableFuture<String> getEmailAddress(User user, DataFetchingEnvironment dfe) { // User is the graphQL type
+         final DataLoader<String, UserDetail> userDataloader =
+                dfe.getContext().getDataLoaderRegistry().get().getDataLoader("userDataLoader"); // UserDetail is the data that is loaded
+
+         return userDataloader.load(User.getName())
+                 .thenApply(userDetail -> userDetail != null ? userDetail.getEmailAddress() : null);
+     }
+
+ ```

gradle.properties

@@ -1,2 +1,2 @@
-version = 6.1.3-SNAPSHOT
+version = 6.1.4
 group = com.graphql-java

src/main/java/graphql/servlet/ConfiguringObjectMapperProvider.java

@@ -0,0 +1,32 @@
+package graphql.servlet;
+
+import com.fasterxml.jackson.databind.InjectableValues;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
+import com.fasterxml.jackson.datatype.jdk8.Jdk8Module;
+
+public class ConfiguringObjectMapperProvider implements ObjectMapperProvider {
+
+  private final ObjectMapperConfigurer objectMapperConfigurer;
+
+  public ConfiguringObjectMapperProvider(ObjectMapperConfigurer objectMapperConfigurer) {
+    this.objectMapperConfigurer = objectMapperConfigurer;
+  }
+
+  public ConfiguringObjectMapperProvider() {
+    this.objectMapperConfigurer = new DefaultObjectMapperConfigurer();
+  }
+
+  @Override
+  public ObjectMapper provide() {
+    ObjectMapper mapper = new ObjectMapper().disable(
+      SerializationFeature.FAIL_ON_EMPTY_BEANS).registerModule(new Jdk8Module());
+    objectMapperConfigurer.configure(mapper);
+
+    InjectableValues.Std injectableValues = new InjectableValues.Std();
+    injectableValues.addValue(ObjectMapper.class, mapper);
+    mapper.setInjectableValues(injectableValues);
+
+    return mapper;
+  }
+}

src/main/java/graphql/servlet/GraphQLObjectMapper.java

@@ -25,13 +25,13 @@
  * @author Andrew Potter
  */
 public class GraphQLObjectMapper {
-    private final Supplier<ObjectMapperConfigurer> objectMapperConfigurerSupplier;
+    private final ObjectMapperProvider objectMapperProvider;
     private final Supplier<GraphQLErrorHandler> graphQLErrorHandlerSupplier;
 
     private volatile ObjectMapper mapper;
 
-    protected GraphQLObjectMapper(Supplier<ObjectMapperConfigurer> objectMapperConfigurerSupplier, Supplier<GraphQLErrorHandler> graphQLErrorHandlerSupplier) {
-        this.objectMapperConfigurerSupplier = objectMapperConfigurerSupplier;
+    protected GraphQLObjectMapper(ObjectMapperProvider objectMapperProvider, Supplier<GraphQLErrorHandler> graphQLErrorHandlerSupplier) {
+        this.objectMapperProvider = objectMapperProvider;
         this.graphQLErrorHandlerSupplier = graphQLErrorHandlerSupplier;
     }
 
@@ -42,24 +42,13 @@ public ObjectMapper getJacksonMapper() {
             synchronized(this) {
                 result = mapper;
                 if (result == null) // Second check (with locking)
-                    mapper = result = createObjectMapper();
+                    mapper = result = objectMapperProvider.provide();
             }
         }
 
         return result;
     }
 
-    private ObjectMapper createObjectMapper() {
-        ObjectMapper mapper = new ObjectMapper().disable(SerializationFeature.FAIL_ON_EMPTY_BEANS).registerModule(new Jdk8Module());
-        objectMapperConfigurerSupplier.get().configure(mapper);
-
-        InjectableValues.Std injectableValues = new InjectableValues.Std();
-        injectableValues.addValue(ObjectMapper.class, mapper);
-        mapper.setInjectableValues(injectableValues);
-
-        return mapper;
-    }
-
     /**
      * @return an {@link ObjectReader} for deserializing {@link GraphQLRequest}
      */
@@ -163,15 +152,20 @@ public static Builder newBuilder() {
     }
 
     public static class Builder {
-        private Supplier<ObjectMapperConfigurer> objectMapperConfigurer = DefaultObjectMapperConfigurer::new;
+        private ObjectMapperProvider objectMapperProvider = new ConfiguringObjectMapperProvider();
         private Supplier<GraphQLErrorHandler> graphQLErrorHandler = DefaultGraphQLErrorHandler::new;
 
         public Builder withObjectMapperConfigurer(ObjectMapperConfigurer objectMapperConfigurer) {
             return withObjectMapperConfigurer(() -> objectMapperConfigurer);
         }
 
         public Builder withObjectMapperConfigurer(Supplier<ObjectMapperConfigurer> objectMapperConfigurer) {
-            this.objectMapperConfigurer = objectMapperConfigurer;
+            this.objectMapperProvider = new ConfiguringObjectMapperProvider(objectMapperConfigurer.get());
+            return this;
+        }
+
+        public Builder withObjectMapperProvider(ObjectMapperProvider objectMapperProvider) {
+            this.objectMapperProvider = objectMapperProvider;
             return this;
         }
 
@@ -185,7 +179,7 @@ public Builder withGraphQLErrorHandler(Supplier<GraphQLErrorHandler> graphQLErro
         }
 
         public GraphQLObjectMapper build() {
-            return new GraphQLObjectMapper(objectMapperConfigurer, graphQLErrorHandler);
+            return new GraphQLObjectMapper(objectMapperProvider, graphQLErrorHandler);
         }
     }
 }

src/main/java/graphql/servlet/ObjectMapperProvider.java

@@ -0,0 +1,7 @@
+package graphql.servlet;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+public interface ObjectMapperProvider {
+	ObjectMapper provide();
+}