Apollo Server Integration for Express v4

Introduction

This package integrates Apollo Server v4 with version 4 of the Express web framework, by exporting a middleware that executes GraphQL operations.

It is identical to the middleware exported at @apollo/server/express4 from the core @apollo/server v4 package. It is being provided separately so that we can also provide an integration with Express v5 (@as-integrations/express5); future major versions of Apollo Server will not have built-in support for Express.

Requirements

- Node.js v20 or later
- Express v4; this package does not support Express v5
- Apollo Server v4

Installation

``bash
npm install @apollo/server graphql express@4 @as-integrations/express4 cors
`

Usage

Set up Express & Apollo Server like you usually would, and then connect the two by using the expressMiddleware middleware:

`typescript
import { ApolloServer } from '@apollo/server';
import { expressMiddleware } from '@as-integrations/express4';
import { ApolloServerPluginDrainHttpServer } from '@apollo/server/plugin/drainHttpServer';
import express from 'express';
import http from 'http';
import cors from 'cors';
import { typeDefs, resolvers } from './schema';

interface MyContext {
token?: string;
}

// Required logic for integrating with Express
const app = express();
// Our httpServer handles incoming requests to our Express app.
// Below, we tell Apollo Server to "drain" this httpServer,
// enabling our servers to shut down gracefully.
const httpServer = http.createServer(app);

const server = new ApolloServer({
typeDefs,
resolvers,
plugins: [ApolloServerPluginDrainHttpServer({ httpServer })],
});
// Ensure we wait for our server to start
await server.start();

// Set up our Express middleware to handle CORS, body parsing,
// and our expressMiddleware function.
app.use(
'/',
cors(),
express.json(),
// expressMiddleware accepts the same arguments:
// an Apollo Server instance and optional configuration options
expressMiddleware(server, {
context: async ({ req }) => ({ token: req.headers.token }),
}),
);

await new Promise((resolve) =>
httpServer.listen({ port: 4000 }, resolve),
);
console.log(🚀 Server ready at http://localhost:4000/);
`

Note: You must call and await server.start()` before using the integration.