Upgrade example Apollo Server implementation to Apollo Server 4 (arda…

…tan#1619)

Fixes n1ru4l/envelop#1618

examples/apollo-server/index.ts

@@ -1,9 +1,18 @@
 /* eslint-disable no-console */
-import { ApolloServer } from 'apollo-server';
-import { envelop, useSchema } from '@envelop/core';
+import { ApolloServer } from '@apollo/server';
+import { envelop, useEngine, useSchema } from '@envelop/core';
 import { parse, validate, subscribe, execute } from 'graphql';
 import { makeExecutableSchema } from '@graphql-tools/schema';
-import { ApolloServerPluginLandingPageGraphQLPlayground } from 'apollo-server-core';
+import { startStandaloneServer } from '@apollo/server/standalone';
+import { ApolloServerPluginLandingPageGraphQLPlayground } from '@apollo/server-plugin-landing-page-graphql-playground';
+import {
+  GatewayApolloConfig,
+  GatewayExecutor,
+  GatewayInterface,
+  GatewayLoadResult,
+  GatewaySchemaLoadOrUpdateCallback,
+  GatewayUnsubscriber,
+} from '@apollo/server-gateway-interface';
 
 const schema = makeExecutableSchema({
   typeDefs: /* GraphQL */ `
@@ -19,27 +28,49 @@ const schema = makeExecutableSchema({
 });
 
 const getEnveloped = envelop({
-  parse,
-  validate,
-  subscribe,
-  execute,
-  plugins: [useSchema(schema)],
+  plugins: [useEngine({ parse, validate, subscribe, execute }), useSchema(schema)],
 });
 
+const executor: GatewayExecutor = async requestContext => {
+  const { schema, execute, contextFactory } = getEnveloped({ req: requestContext.request.http });
+
+  return execute({
+    schema,
+    document: requestContext.document,
+    contextValue: await contextFactory(),
+    variableValues: requestContext.request.variables,
+    operationName: requestContext.operationName,
+  });
+};
+
+// Apollo Server 4 requires a custom gateway to enable custom executors:
+// https://www.apollographql.com/docs/apollo-server/migration/#executor
+class Gateway implements GatewayInterface {
+  private schemaCallback?: GatewaySchemaLoadOrUpdateCallback;
+
+  async load(options: { apollo: GatewayApolloConfig }): Promise<GatewayLoadResult> {
+    // Apollo expects this schema to be called before this function resolves:
+    // https://github.com/apollographql/apollo-server/issues/7340#issuecomment-1407071706
+    this.schemaCallback?.({ apiSchema: schema, coreSupergraphSdl: '' });
+
+    return { executor };
+  }
+
+  onSchemaLoadOrUpdate(callback: GatewaySchemaLoadOrUpdateCallback): GatewayUnsubscriber {
+    this.schemaCallback = callback;
+    return () => {};
+  }
+
+  async stop() {}
+}
+
 const server = new ApolloServer({
-  schema,
-  executor: async requestContext => {
-    const { schema, execute, contextFactory } = getEnveloped({ req: requestContext.request.http });
-
-    return execute({
-      schema,
-      document: requestContext.document,
-      contextValue: await contextFactory(),
-      variableValues: requestContext.request.variables,
-      operationName: requestContext.operationName,
-    });
-  },
+  gateway: new Gateway(),
   plugins: [ApolloServerPluginLandingPageGraphQLPlayground({ endpoint: '/graphql' })],
 });
 
-server.listen(3000);
+(async () => {
+  await startStandaloneServer(server, {
+    listen: { port: 3000 },
+  });
+})();

examples/apollo-server/package.json

@@ -6,15 +6,15 @@
   "author": "Dotan Simha",
   "license": "MIT",
   "dependencies": {
+    "@apollo/server": "^4.3.2",
+    "@apollo/server-plugin-landing-page-graphql-playground": "^4.0.0",
     "@envelop/core": "*",
-    "apollo-server": "3.5.0",
-    "apollo-server-core": "3.5.0",
     "@graphql-tools/schema": "8.5.0",
     "graphql": "16.6.0"
   },
   "devDependencies": {
     "@types/node": "15.6.1",
-    "ts-node": "10.0.0",
+    "ts-node": "10.6.0",
     "typescript": "4.8.4"
   },
   "scripts": {