Add support for customValidateFn and rename formatError to customFormatErrorFn

README.md

@@ -107,10 +107,6 @@ The `graphqlHTTP` function accepts the following options:
 
 - **`pretty`**: If `true`, any JSON response will be pretty-printed.
 
-- **`formatError`**: An optional function which will be used to format any
-  errors produced by fulfilling a GraphQL operation. If no function is
-  provided, GraphQL's default spec-compliant [`formatError`][] function will be used.
-
 - **`extensions`**: An optional function for adding additional metadata to the
   GraphQL response as a key-value object. The result will be added to
   `"extensions"` field in the resulting JSON. This is often a useful place to
@@ -121,11 +117,21 @@ The `graphqlHTTP` function accepts the following options:
 - **`validationRules`**: Optional additional validation rules queries must
   satisfy in addition to those defined by the GraphQL spec.
 
-- **`fieldResolver`**
+- **`customValidateFn`**: An optional function which will be used to validate
+  instead of default `validate` from `graphql-js`.
 
 - **`customExecuteFn`**: An optional function which will be used to execute
   instead of default `execute` from `graphql-js`.
 
+- **`customFormatErrorFn`**: An optional function which will be used to format any
+  errors produced by fulfilling a GraphQL operation. If no function is
+  provided, GraphQL's default spec-compliant [`formatError`][] function will be used.
+
+- **`formatError`**: is deprecated and replaced by `customFormatErrorFn`. It will be
+  removed in version 1.0.0.
+
+- **`fieldResolver`**
+
 ## HTTP Usage
 
 Once installed at a path, `koa-graphql` will accept requests with
@@ -350,10 +356,10 @@ export function DisallowMetadataQueries(context) {
 ## Debugging Tips
 
 During development, it's useful to get more information from errors, such as
-stack traces. Providing a function to `formatError` enables this:
+stack traces. Providing a function to `customFormatErrorFn` enables this:
 
 ```js
-formatError: (error, ctx) => ({
+customFormatErrorFn: (error, ctx) => ({
   message: error.message,
   locations: error.locations,
   stack: error.stack ? error.stack.split('\n') : [],

package.json

@@ -96,6 +96,7 @@
     "prettier": "^2.3.2",
     "raw-body": "^2.4.1",
     "sane": "^4.1.0",
+    "sinon": "^11.1.2",
     "supertest": "^4.0.2"
   },
   "peerDependencies": {

src/__tests__/http-test.js

@@ -4,6 +4,7 @@
 
 import { expect } from 'chai';
 import { describe, it } from 'mocha';
+import sinon from 'sinon';
 import { stringify } from 'querystring';
 import zlib from 'zlib';
 import multer from 'multer';
@@ -22,6 +23,7 @@ import {
   GraphQLString,
   GraphQLError,
   BREAK,
+  validate,
   execute,
 } from 'graphql';
 import graphqlHTTP from '../';
@@ -1144,7 +1146,7 @@ describe('GraphQL-HTTP tests', () => {
           urlString(),
           graphqlHTTP({
             schema: TestSchema,
-            formatError(error) {
+            customFormatErrorFn(error) {
               return { message: 'Custom error format: ' + error.message };
             },
           }),
@@ -1176,7 +1178,7 @@ describe('GraphQL-HTTP tests', () => {
           urlString(),
           graphqlHTTP({
             schema: TestSchema,
-            formatError(error) {
+            customFormatErrorFn(error) {
               return {
                 message: error.message,
                 locations: error.locations,
@@ -1422,7 +1424,7 @@ describe('GraphQL-HTTP tests', () => {
       });
     });
 
-    it('allows for custom error formatting of poorly formed requests', async () => {
+    it('`formatError` is deprecated', async () => {
       const app = server();
 
       app.use(
@@ -1437,6 +1439,47 @@ describe('GraphQL-HTTP tests', () => {
         ),
       );
 
+      const spy = sinon.spy(console, 'warn');
+
+      const response = await request(app.listen()).get(
+        urlString({
+          variables: 'who:You',
+          query: 'query helloWho($who: String){ test(who: $who) }',
+        }),
+      );
+
+      expect(
+        spy.calledWith(
+          '`formatError` is deprecated and replaced by `customFormatErrorFn`. It will be removed in version 1.0.0.',
+        ),
+      );
+      expect(response.status).to.equal(400);
+      expect(JSON.parse(response.text)).to.deep.equal({
+        errors: [
+          {
+            message: 'Custom error format: Variables are invalid JSON.',
+          },
+        ],
+      });
+
+      spy.restore();
+    });
+
+    it('allows for custom error formatting of poorly formed requests', async () => {
+      const app = server();
+
+      app.use(
+        mount(
+          urlString(),
+          graphqlHTTP({
+            schema: TestSchema,
+            customFormatErrorFn(error) {
+              return { message: 'Custom error format: ' + error.message };
+            },
+          }),
+        ),
+      );
+
       const response = await request(app.listen()).get(
         urlString({
           variables: 'who:You',
@@ -1832,6 +1875,66 @@ describe('GraphQL-HTTP tests', () => {
     });
   });
 
+  describe('Custom validate function', () => {
+    it('returns data', async () => {
+      const app = server();
+
+      app.use(
+        mount(
+          urlString(),
+          graphqlHTTP({
+            schema: TestSchema,
+            customValidateFn(schema, documentAST, validationRules) {
+              return validate(schema, documentAST, validationRules);
+            },
+          }),
+        ),
+      );
+
+      const response = await request(app.listen())
+        .get(urlString({ query: '{test}', raw: '' }))
+        .set('Accept', 'text/html');
+
+      expect(response.status).to.equal(200);
+      expect(response.text).to.equal('{"data":{"test":"Hello World"}}');
+    });
+
+    it('returns validation errors', async () => {
+      const app = server();
+
+      app.use(
+        mount(
+          urlString(),
+          graphqlHTTP({
+            schema: TestSchema,
+            customValidateFn(schema, documentAST, validationRules) {
+              const errors = validate(schema, documentAST, validationRules);
+
+              const error = new GraphQLError(`custom error ${errors.length}`);
+
+              return [error];
+            },
+          }),
+        ),
+      );
+
+      const response = await request(app.listen()).get(
+        urlString({
+          query: '{thrower}',
+        }),
+      );
+
+      expect(response.status).to.equal(400);
+      expect(JSON.parse(response.text)).to.deep.equal({
+        errors: [
+          {
+            message: 'custom error 0',
+          },
+        ],
+      });
+    });
+  });
+
   describe('Custom validation rules', () => {
     const AlwaysInvalidRule = function (context) {
       return {
@@ -1963,7 +2066,7 @@ describe('GraphQL-HTTP tests', () => {
           urlString(),
           graphqlHTTP({
             schema: TestSchema,
-            formatError: () => null,
+            customFormatErrorFn: () => null,
             extensions({ result }) {
               return { preservedErrors: (result: any).errors };
             },