Configurable per query or per request context/dataloader batching

README.md

@@ -233,10 +233,10 @@ Here's an example of a GraphQL provider that implements three interfaces at the
 
 * [ExampleGraphQLProvider](examples/osgi/providers/src/main/java/graphql/servlet/examples/osgi/ExampleGraphQLProvider.java)
 
-## Request-scoped DataLoaders
+## Context and DataLoader settings
 
-It is possible to use dataloaders in a request scope by customizing [GraphQLContextBuilder](https://github.com/graphql-java-kickstart/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.
+It is possible to create context, and consequently dataloaders, in both a request scope and a per query scope by customizing [GraphQLContextBuilder](https://github.com/graphql-java-kickstart/graphql-java-servlet/blob/master/src/main/java/graphql/servlet/context/GraphQLContextBuilder.java) and selecting the appropriate [ContextSetting](https://github.com/graphql-java-kickstart/graphql-java-servlet/blob/master/src/main/java/graphql/servlet/context/ContextSetting.java) with the provided [GraphQLConfiguration](https://github.com/graphql-java-kickstart/graphql-java-servlet/blob/master/src/main/java/graphql/servlet/config/GraphQLConfiguration.java).
+A new [DataLoaderRegistry](https://github.com/graphql-java/java-dataloader/blob/master/src/main/java/org/dataloader/DataLoaderRegistry.java) should be created in each call to the GraphQLContextBuilder, and the servlet will call the builder at the appropriate times.
 For eg:
 ```java
 public class CustomGraphQLContextBuilder implements GraphQLContextBuilder {
@@ -249,26 +249,17 @@ public class CustomGraphQLContextBuilder implements GraphQLContextBuilder {
 
     @Override
     public GraphQLContext build(HttpServletRequest req) {
-        GraphQLContext context = new GraphQLContext(req);
-        context.setDataLoaderRegistry(buildDataLoaderRegistry());
-
-        return context;
+        return new GraphQLContext(buildDataLoaderRegistry());
     }
 
     @Override
     public GraphQLContext build() {
-        GraphQLContext context = new GraphQLContext();
-        context.setDataLoaderRegistry(buildDataLoaderRegistry());
-
-        return context;
+        return new GraphQLContext(buildDataLoaderRegistry());
     }
 
     @Override
     public GraphQLContext build(HandshakeRequest request) {
-        GraphQLContext context = new GraphQLContext(request);
-        context.setDataLoaderRegistry(buildDataLoaderRegistry());
-
-        return context;
+        return new GraphQLContext(buildDataLoaderRegistry());
     }
 
     private DataLoaderRegistry buildDataLoaderRegistry() {
@@ -290,3 +281,6 @@ public class CustomGraphQLContextBuilder implements GraphQLContextBuilder {
      }
 
  ```
+ If per request is selected this will cause all queries within the http request, if using a batch, to share dataloader caches and batch together load calls as efficently as possible. The dataloaders are dispatched using instrumentation and the correct instrumentation will be selected according to the ContextSetting. The default context setting in GraphQLConfiguration is per query.
+
+ Two additional context settings are provided, one for each of the previous settings but without the addition of the Dataloader dispatching instrumentation. This is useful for those not using Dataloaders or wanting to supply their own dispatching instrumentation though the instrumentation supplier within the GraphQLQueryInvoker.

gradle.properties

@@ -1,5 +1,5 @@
 version = 7.5.1-SNAPSHOT
 group = com.graphql-java-kickstart
 
-LIB_GRAPHQL_JAVA_VER = 12.0
+LIB_GRAPHQL_JAVA_VER = 13.0
 LIB_JACKSON_VER = 2.9.8

src/main/java/graphql/servlet/AbstractGraphQLHttpServlet.java

@@ -5,8 +5,19 @@
 import graphql.ExecutionResult;
 import graphql.introspection.IntrospectionQuery;
 import graphql.schema.GraphQLFieldDefinition;
-import graphql.servlet.internal.GraphQLRequest;
-import graphql.servlet.internal.VariableMapper;
+import graphql.servlet.core.GraphQLMBean;
+import graphql.servlet.core.GraphQLObjectMapper;
+import graphql.servlet.core.GraphQLQueryInvoker;
+import graphql.servlet.core.GraphQLServletListener;
+import graphql.servlet.config.GraphQLConfiguration;
+import graphql.servlet.context.ContextSetting;
+import graphql.servlet.input.BatchInputPreProcessResult;
+import graphql.servlet.input.BatchInputPreProcessor;
+import graphql.servlet.input.GraphQLBatchedInvocationInput;
+import graphql.servlet.input.GraphQLSingleInvocationInput;
+import graphql.servlet.input.GraphQLInvocationInputFactory;
+import graphql.servlet.core.internal.GraphQLRequest;
+import graphql.servlet.core.internal.VariableMapper;
 import org.reactivestreams.Publisher;
 import org.reactivestreams.Subscriber;
 import org.reactivestreams.Subscription;
@@ -30,6 +41,7 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
@@ -46,13 +58,13 @@
  */
 public abstract class AbstractGraphQLHttpServlet extends HttpServlet implements Servlet, GraphQLMBean {
 
-    public static final Logger log = LoggerFactory.getLogger(AbstractGraphQLHttpServlet.class);
+    private static final Logger log = LoggerFactory.getLogger(AbstractGraphQLHttpServlet.class);
 
-    public static final String APPLICATION_JSON_UTF8 = "application/json;charset=UTF-8";
-    public static final String APPLICATION_EVENT_STREAM_UTF8 = "text/event-stream;charset=UTF-8";
-    public static final String APPLICATION_GRAPHQL = "application/graphql";
-    public static final int STATUS_OK = 200;
-    public static final int STATUS_BAD_REQUEST = 400;
+    private static final String APPLICATION_JSON_UTF8 = "application/json;charset=UTF-8";
+    private static final String APPLICATION_EVENT_STREAM_UTF8 = "text/event-stream;charset=UTF-8";
+    private static final String APPLICATION_GRAPHQL = "application/graphql";
+    private static final int STATUS_OK = 200;
+    private static final int STATUS_BAD_REQUEST = 400;
 
     private static final GraphQLRequest INTROSPECTION_REQUEST = new GraphQLRequest(IntrospectionQuery.INTROSPECTION_QUERY, new HashMap<>(), null);
     private static final String[] MULTIPART_KEYS = new String[]{"operations", "graphql", "query"};
@@ -123,13 +135,17 @@ public void init() {
                 path = request.getServletPath();
             }
             if (path.contentEquals("/schema.json")) {
-                query(queryInvoker, graphQLObjectMapper, invocationInputFactory.create(INTROSPECTION_REQUEST, request, response), response);
+                query(queryInvoker, graphQLObjectMapper, invocationInputFactory.create(INTROSPECTION_REQUEST, request, response),
+                    request, response);
             } else {
                 String query = request.getParameter("query");
                 if (query != null) {
 
                     if (isBatchedQuery(query)) {
-                        queryBatched(queryInvoker, graphQLObjectMapper, invocationInputFactory.createReadOnly(graphQLObjectMapper.readBatchedGraphQLRequest(query), request, response), response);
+                        List<GraphQLRequest> requests = graphQLObjectMapper.readBatchedGraphQLRequest(query);
+                        GraphQLBatchedInvocationInput batchedInvocationInput =
+                            invocationInputFactory.createReadOnly(configuration.getContextSetting(), requests, request, response);
+                        queryBatched(queryInvoker, batchedInvocationInput, request, response, configuration);
                     } else {
                         final Map<String, Object> variables = new HashMap<>();
                         if (request.getParameter("variables") != null) {
@@ -138,7 +154,9 @@ public void init() {
 
                         String operationName = request.getParameter("operationName");
 
-                        query(queryInvoker, graphQLObjectMapper, invocationInputFactory.createReadOnly(new GraphQLRequest(query, variables, operationName), request, response), response);
+                        query(queryInvoker, graphQLObjectMapper,
+                            invocationInputFactory.createReadOnly(new GraphQLRequest(query, variables, operationName), request, response),
+                            request, response);
                     }
                 } else {
                     response.setStatus(STATUS_BAD_REQUEST);
@@ -155,7 +173,9 @@ public void init() {
             try {
                 if (APPLICATION_GRAPHQL.equals(request.getContentType())) {
                     String query = CharStreams.toString(request.getReader());
-                    query(queryInvoker, graphQLObjectMapper, invocationInputFactory.create(new GraphQLRequest(query, null, null), request, response), response);
+                    query(queryInvoker, graphQLObjectMapper,
+                        invocationInputFactory.create(new GraphQLRequest(query, null, null), request, response),
+                        request, response);
                 } else if (request.getContentType() != null && request.getContentType().startsWith("multipart/form-data") && !request.getParts().isEmpty()) {
                     final Map<String, List<Part>> fileItems = request.getParts()
                             .stream()
@@ -182,10 +202,9 @@ public void init() {
                             List<GraphQLRequest> graphQLRequests =
                                     graphQLObjectMapper.readBatchedGraphQLRequest(inputStream);
                             variablesMap.ifPresent(map -> graphQLRequests.forEach(r -> mapMultipartVariables(r, map, fileItems)));
-                            GraphQLBatchedInvocationInput invocationInput =
-                                    invocationInputFactory.create(graphQLRequests, request, response);
-                            invocationInput.getContext().setParts(fileItems);
-                            queryBatched(queryInvoker, graphQLObjectMapper, invocationInput, response);
+                            GraphQLBatchedInvocationInput batchedInvocationInput = invocationInputFactory.create(configuration.getContextSetting(),
+                                graphQLRequests, request, response);
+                            queryBatched(queryInvoker, batchedInvocationInput, request, response, configuration);
                             return;
                         } else {
                             GraphQLRequest graphQLRequest;
@@ -198,8 +217,7 @@ public void init() {
                             variablesMap.ifPresent(m -> mapMultipartVariables(graphQLRequest, m, fileItems));
                             GraphQLSingleInvocationInput invocationInput =
                                     invocationInputFactory.create(graphQLRequest, request, response);
-                            invocationInput.getContext().setParts(fileItems);
-                            query(queryInvoker, graphQLObjectMapper, invocationInput, response);
+                            query(queryInvoker, graphQLObjectMapper, invocationInput, request, response);
                             return;
                         }
                     }
@@ -211,9 +229,12 @@ public void init() {
                     InputStream inputStream = asMarkableInputStream(request.getInputStream());
 
                     if (isBatchedQuery(inputStream)) {
-                        queryBatched(queryInvoker, graphQLObjectMapper, invocationInputFactory.create(graphQLObjectMapper.readBatchedGraphQLRequest(inputStream), request, response), response);
+                        List<GraphQLRequest> requests = graphQLObjectMapper.readBatchedGraphQLRequest(inputStream);
+                        GraphQLBatchedInvocationInput batchedInvocationInput =
+                            invocationInputFactory.create(configuration.getContextSetting(), requests, request, response);
+                        queryBatched(queryInvoker, batchedInvocationInput, request, response, configuration);
                     } else {
-                        query(queryInvoker, graphQLObjectMapper, invocationInputFactory.create(graphQLObjectMapper.readGraphQLRequest(inputStream), request, response), response);
+                        query(queryInvoker, graphQLObjectMapper, invocationInputFactory.create(graphQLObjectMapper.readGraphQLRequest(inputStream), request, response), request, response);
                     }
                 }
             } catch (Exception e) {
@@ -348,18 +369,21 @@ private Optional<Part> getFileItem(Map<String, List<Part>> fileItems, String nam
         return Optional.ofNullable(fileItems.get(name)).filter(list -> !list.isEmpty()).map(list -> list.get(0));
     }
 
-    private void query(GraphQLQueryInvoker queryInvoker, GraphQLObjectMapper graphQLObjectMapper, GraphQLSingleInvocationInput invocationInput, HttpServletResponse resp) throws IOException {
+    private void query(GraphQLQueryInvoker queryInvoker, GraphQLObjectMapper graphQLObjectMapper, GraphQLSingleInvocationInput invocationInput,
+                       HttpServletRequest req, HttpServletResponse resp) throws IOException {
         ExecutionResult result = queryInvoker.query(invocationInput);
 
         if (!(result.getData() instanceof Publisher)) {
             resp.setContentType(APPLICATION_JSON_UTF8);
             resp.setStatus(STATUS_OK);
             resp.getWriter().write(graphQLObjectMapper.serializeResultAsJson(result));
         } else {
+            if (req == null) {
+                throw new IllegalStateException("Http servlet request can not be null");
+            }
             resp.setContentType(APPLICATION_EVENT_STREAM_UTF8);
             resp.setStatus(STATUS_OK);
 
-            HttpServletRequest req = invocationInput.getContext().getHttpServletRequest().orElseThrow(IllegalStateException::new);
             boolean isInAsyncThread = req.isAsyncStarted();
             AsyncContext asyncContext = isInAsyncThread ? req.getAsyncContext() : req.startAsync(req, resp);
             asyncContext.setTimeout(configuration.getSubscriptionTimeout());
@@ -378,8 +402,30 @@ private void query(GraphQLQueryInvoker queryInvoker, GraphQLObjectMapper graphQL
         }
     }
 
-    private void queryBatched(GraphQLQueryInvoker queryInvoker, GraphQLObjectMapper graphQLObjectMapper, GraphQLBatchedInvocationInput invocationInput, HttpServletResponse resp) throws Exception {
-        queryInvoker.query(invocationInput, resp, graphQLObjectMapper);
+    private void queryBatched(GraphQLQueryInvoker queryInvoker, GraphQLBatchedInvocationInput batchedInvocationInput, HttpServletRequest request,
+                              HttpServletResponse response, GraphQLConfiguration configuration) throws IOException {
+        BatchInputPreProcessor batchInputPreProcessor = configuration.getBatchInputPreProcessor();
+        ContextSetting contextSetting = configuration.getContextSetting();
+        BatchInputPreProcessResult batchInputPreProcessResult = batchInputPreProcessor.preProcessBatch(batchedInvocationInput, request, response);
+        if (batchInputPreProcessResult.isExecutable()) {
+            List<ExecutionResult> results = queryInvoker.query(batchInputPreProcessResult.getBatchedInvocationInput().getExecutionInputs(),
+                contextSetting);
+            response.setContentType(AbstractGraphQLHttpServlet.APPLICATION_JSON_UTF8);
+            response.setStatus(AbstractGraphQLHttpServlet.STATUS_OK);
+            Writer writer = response.getWriter();
+            Iterator<ExecutionResult> executionInputIterator = results.iterator();
+            writer.write("[");
+            GraphQLObjectMapper graphQLObjectMapper = configuration.getObjectMapper();
+            while (executionInputIterator.hasNext()) {
+                writer.write(graphQLObjectMapper.serializeResultAsJson(executionInputIterator.next()));
+                if (executionInputIterator.hasNext()) {
+                    writer.write(",");
+                }
+            }
+            writer.write("]");
+        } else {
+            response.sendError(batchInputPreProcessResult.getStatusCode(), batchInputPreProcessResult.getStatusMessage());
+        }
     }
 
     private <R> List<R> runListeners(Function<? super GraphQLServletListener, R> action) {

src/main/java/graphql/servlet/ConfiguredGraphQLHttpServlet.java

@@ -1,5 +1,7 @@
 package graphql.servlet;
 
+import graphql.servlet.config.GraphQLConfiguration;
+
 import java.util.Objects;
 
 class ConfiguredGraphQLHttpServlet extends GraphQLHttpServlet {

src/main/java/graphql/servlet/DefaultGraphQLServlet.java

@@ -1,5 +1,9 @@
 package graphql.servlet;
 
+import graphql.servlet.core.GraphQLObjectMapper;
+import graphql.servlet.core.GraphQLQueryInvoker;
+import graphql.servlet.input.GraphQLInvocationInputFactory;
+
 public class DefaultGraphQLServlet extends AbstractGraphQLHttpServlet {
 
     @Override