500 when response.data is null.

This matches the described spec behavior that when response.data is null, that indicates a query error. This happens when a top field is Non-Null and produces an error. In that case there is no data for the query and a 500 is an appropriate response status.

Suggested in #118

Author: leebyron

src/__tests__/http-test.js

@@ -45,10 +45,14 @@ const QueryRootType = new GraphQLObjectType({
       },
       resolve: (root, { who }) => 'Hello ' + (who || 'World')
     },
-    thrower: {
+    nonNullThrower: {
       type: new GraphQLNonNull(GraphQLString),
       resolve: () => { throw new Error('Throws!'); }
     },
+    thrower: {
+      type: GraphQLString,
+      resolve: () => { throw new Error('Throws!'); }
+    },
     context: {
       type: GraphQLString,
       resolve: (obj, args, context) => context,
@@ -974,6 +978,30 @@ describe('test harness', () => {
 
         expect(response.status).to.equal(200);
         expect(JSON.parse(response.text)).to.deep.equal({
+          data: { thrower: null },
+          errors: [ {
+            message: 'Throws!',
+            locations: [ { line: 1, column: 2 } ]
+          } ]
+        });
+      });
+
+      it('handles query errors from non-null top field errors', async () => {
+        const app = server();
+
+        app.use(urlString(), graphqlHTTP({
+          schema: TestSchema
+        }));
+
+        const error = await catchError(
+          request(app)
+            .get(urlString({
+              query: '{nonNullThrower}',
+            }))
+        );
+
+        expect(error.response.status).to.equal(500);
+        expect(JSON.parse(error.response.text)).to.deep.equal({
           data: null,
           errors: [ {
             message: 'Throws!',
@@ -999,7 +1027,7 @@ describe('test harness', () => {
 
         expect(response.status).to.equal(200);
         expect(JSON.parse(response.text)).to.deep.equal({
-          data: null,
+          data: { thrower: null },
           errors: [ {
             message: 'Custom error format: Throws!',
           } ]
@@ -1027,7 +1055,7 @@ describe('test harness', () => {
 
         expect(response.status).to.equal(200);
         expect(JSON.parse(response.text)).to.deep.equal({
-          data: null,
+          data: { thrower: null },
           errors: [ {
             message: 'Throws!',
             locations: [ { line: 1, column: 2 } ],

src/index.js

@@ -234,23 +234,31 @@ export default function graphqlHTTP(options: Options): Middleware {
       response.statusCode = error.status || 500;
       return { errors: [ error ] };
     }).then(result => {
+      // If no data was included in the result, that indicates a runtime query
+      // error, indicate as such with a generic status code.
+      // Note: Information about the error itself will still be contained in
+      // the resulting JSON payload.
+      // http://facebook.github.io/graphql/#sec-Data
+      if (result && result.data === null) {
+        response.statusCode = 500;
+      }
       // Format any encountered errors.
       if (result && result.errors) {
         result.errors = result.errors.map(formatErrorFn || formatError);
       }
       // If allowed to show GraphiQL, present it instead of JSON.
       if (showGraphiQL) {
-        const data = renderGraphiQL({
+        const payload = renderGraphiQL({
           query, variables,
           operationName, result
         });
         response.setHeader('Content-Type', 'text/html; charset=utf-8');
-        sendResponse(response, data);
+        sendResponse(response, payload);
       } else {
         // Otherwise, present JSON directly.
-        const data = JSON.stringify(result, null, pretty ? 2 : 0);
+        const payload = JSON.stringify(result, null, pretty ? 2 : 0);
         response.setHeader('Content-Type', 'application/json; charset=utf-8');
-        sendResponse(response, data);
+        sendResponse(response, payload);
       }
     });
   };