Introduce 'batch' flag, improve loadSchema and merge wrapped schemas …

…properly (#4535)

* Introduce 'batch' flag, improve loadSchema and merge wrapped schemas properly

* Update description and param name

* Go

.changeset/angry-bobcats-double.md

@@ -0,0 +1,7 @@
+---
+'@graphql-tools/load': patch
+---
+
+No longer call `mergeSchemas` if a single schema is loaded.
+Previously all typeDefs and resolvers were extracted and the schema was rebuilt from scratch.
+But this is not necessary if there is only one schema loaded with `loadSchema`

.changeset/gold-timers-thank.md

@@ -0,0 +1,9 @@
+---
+'@graphql-tools/load': minor
+'@graphql-tools/schema': minor
+'@graphql-tools/utils': minor
+---
+
+`mergeSchemas` was skipping `defaultFieldResolver` and `defaultMergedResolver` by default while extracting resolvers for each given schema to reduce the overhead. But this doesn't work properly if you mix wrapped schemas and local schemas. So new `includeDefaultMergedResolver` flag is introduced in `getResolversFromSchema` to put default "proxy" resolvers in the extracted resolver map for `mergeSchemas`.
+
+This fixes an issue with alias issue, so nested aliased fields weren't resolved properly because of the missing `defaultMergedResolver` in the final merged schema which should come from the wrapped schema.

.changeset/sweet-clouds-grab.md

@@ -0,0 +1,5 @@
+---
+'@graphql-tools/url-loader': minor
+---
+
+New 'batch' flag! Now you can configure your remote schema to batch parallel queries to the upstream.

package.json

@@ -79,7 +79,7 @@
     "packages/**/src/**/*.{ts,tsx}": [
       "eslint --fix"
     ],
-    "**/*.{ts,tsx,graphql,yml}": [
+    "**/*.{ts,tsx,graphql,yml,md,mdx}": [
       "prettier --write"
     ]
   },

packages/load/src/schema.ts

@@ -37,13 +37,14 @@ export async function loadSchema(
   });
 
   const { schemas, typeDefs } = collectSchemasAndTypeDefs(sources);
+  schemas.push(...(options.schemas ?? []));
   const mergeSchemasOptions: MergeSchemasConfig = {
     ...options,
     schemas: schemas.concat(options.schemas ?? []),
     typeDefs,
   };
 
-  const schema = mergeSchemas(mergeSchemasOptions);
+  const schema = typeDefs?.length === 0 && schemas?.length === 1 ? schemas[0] : mergeSchemas(mergeSchemasOptions);
 
   if (options?.includeSources) {
     includeSources(schema, sources);

packages/loaders/url/src/index.ts

@@ -133,6 +133,10 @@ export interface LoadFromUrlOptions extends BaseLoaderOptions, Partial<Introspec
    * Connection Parameters for WebSockets connection
    */
   connectionParams?: any;
+  /**
+   * Enable Batching
+   */
+  batch?: boolean;
 }
 
 function isCompatibleUri(uri: string): boolean {
@@ -815,6 +819,7 @@ export class UrlLoader implements Loader<LoadFromUrlOptions> {
       source.schema = wrapSchema({
         schema: source.schema,
         executor,
+        batch: options?.batch,
       });
     }
 

packages/loaders/url/tests/url-loader.spec.ts

@@ -31,6 +31,7 @@ import { createServer } from '@graphql-yoga/node';
 import { GraphQLLiveDirectiveSDL, useLiveQuery } from '@envelop/live-query';
 import { InMemoryLiveQueryStore } from '@n1ru4l/in-memory-live-query-store';
 import { LiveExecutionResult } from '@n1ru4l/graphql-live-query';
+import { loadSchema } from '@graphql-tools/load';
 
 describe('Schema URL Loader', () => {
   const loader = new UrlLoader();
@@ -45,7 +46,27 @@ scalar Upload
 type CustomQuery {
   """Test field comment"""
   a(testVariable: String): String
+
+  complexField(complexArg: ComplexInput): ComplexType
+}
+
+input ComplexInput {
+  id: ID
+}
+
+input ComplexChildInput {
+  id: ID
+}
+
+type ComplexType {
+  id: ID
+  complexChildren(complexChildArg: ComplexChildInput): [ComplexChild]
+}
+
+type ComplexChild {
+  id: ID
 }
+
 type Mutation {
   uploadFile(file: Upload, dummyVar: TestInput, secondDummyVar: String): File
 }
@@ -69,6 +90,14 @@ input TestInput {
   const testResolvers = {
     CustomQuery: {
       a: (_: never, { testVariable }: { testVariable: string }) => testVariable || 'a',
+      complexField: (_: never, { complexArg }: { complexArg: { id: string } }) => {
+        return complexArg;
+      },
+    },
+    ComplexType: {
+      complexChildren: (_: never, { complexChildArg }: { complexChildArg: { id: string } }) => {
+        return [{ id: complexChildArg.id }];
+      },
     },
     Upload: GraphQLUpload,
     File: {
@@ -818,6 +847,36 @@ input TestInput {
       });
     });
 
+    it('should handle aliases properly', async () => {
+      const yoga = createServer({
+        schema: testSchema,
+        port: 9876,
+        logging: false,
+      });
+      httpServer = await yoga.start();
+      const schema = await loadSchema(`http://0.0.0.0:9876/graphql`, {
+        loaders: [loader],
+      });
+      const document = parse(/* GraphQL */ `
+        query {
+          b: a
+          foo: complexField(complexArg: { id: "FOO" }) {
+            id
+            bar: complexChildren(complexChildArg: { id: "BAR" }) {
+              id
+            }
+          }
+        }
+      `);
+      const result: any = await execute({
+        schema,
+        document,
+      });
+      expect(result?.data?.['b']).toBe('a');
+      expect(result?.data?.['foo']?.id).toBe('FOO');
+      expect(result?.data?.['foo']?.bar?.[0]?.id).toBe('BAR');
+    });
+
     describe('sync', () => {
       it('should handle introspection', () => {
         const [{ schema }] = loader.loadSync(`https://swapi-graphql.netlify.app/.netlify/functions/index`, {});

packages/schema/src/merge-schemas.ts

@@ -27,7 +27,7 @@ export function mergeSchemas(config: MergeSchemasConfig) {
   const schemas = config.schemas || [];
   for (const schema of schemas) {
     extractedTypeDefs.push(schema);
-    extractedResolvers.push(getResolversFromSchema(schema));
+    extractedResolvers.push(getResolversFromSchema(schema, true));
     extractedSchemaExtensions.push(extractExtensionsFromSchema(schema));
   }
 

packages/utils/src/getResolversFromSchema.ts

@@ -11,7 +11,11 @@ import {
 
 import { IResolvers } from './Interfaces';
 
-export function getResolversFromSchema(schema: GraphQLSchema): IResolvers {
+export function getResolversFromSchema(
+  schema: GraphQLSchema,
+  // Include default merged resolvers
+  includeDefaultMergedResolver?: boolean
+): IResolvers {
   const resolvers = Object.create(null);
 
   const typeMap = schema.getTypeMap();
@@ -59,11 +63,16 @@ export function getResolversFromSchema(schema: GraphQLSchema): IResolvers {
             resolvers[typeName][fieldName] = resolvers[typeName][fieldName] || {};
             resolvers[typeName][fieldName].subscribe = field.subscribe;
           }
-          if (
-            field.resolve != null &&
-            field.resolve?.name !== 'defaultFieldResolver' &&
-            field.resolve?.name !== 'defaultMergedResolver'
-          ) {
+          if (field.resolve != null && field.resolve?.name !== 'defaultFieldResolver') {
+            switch (field.resolve?.name) {
+              case 'defaultMergedResolver':
+                if (!includeDefaultMergedResolver) {
+                  continue;
+                }
+                break;
+              case 'defaultFieldResolver':
+                continue;
+            }
             resolvers[typeName][fieldName] = resolvers[typeName][fieldName] || {};
             resolvers[typeName][fieldName].resolve = field.resolve;
           }

packages/wrap/tests/makeRemoteExecutableSchema.test.ts

@@ -17,7 +17,7 @@ describe('remote queries', () => {
     schema = wrapSchema(remoteSubschemaConfig);
   });
 
-  test('should work', async () => {
+  test('should handle interfaces correctly', async () => {
     const query = /* GraphQL */ `
       {
         interfaceTest(kind: ONE) {
@@ -46,6 +46,28 @@ describe('remote queries', () => {
     const result = await graphql({ schema, source: query });
     expect(result).toEqual(expected);
   });
+
+  test('should handle aliases properly', async () => {
+    const query = /* GraphQL */ `
+      query AliasedExample {
+        propertyInAnArray: properties(limit: 1) {
+          id
+          name
+          loc: location {
+            title: name
+          }
+        }
+      }
+    `;
+
+    const result: any = await graphql({ schema, source: query });
+
+    expect(result?.data?.['propertyInAnArray']).toHaveLength(1);
+    expect(result?.data?.['propertyInAnArray'][0]['id']).toBeTruthy();
+    expect(result?.data?.['propertyInAnArray'][0]['name']).toBeTruthy();
+    expect(result?.data?.['propertyInAnArray'][0]['loc']).toBeTruthy();
+    expect(result?.data?.['propertyInAnArray'][0]['loc']['title']).toBeTruthy();
+  });
 });
 
 describe('remote subscriptions', () => {