Do we face any issues with creating apollo server and converting it to express server using apollo/server npm package? - express

Question

pls check the below code,
// npm install #apollo/server express graphql cors body-parser
import { ApolloServer } from '#apollo/server';
import { expressMiddleware } from '#apollo/server/express4';
import { ApolloServerPluginDrainHttpServer } from '#apollo/server/plugin/drainHttpServer';
import express from 'express';
import http from 'http';
import cors from 'cors';
import bodyParser from 'body-parser';
import { typeDefs, resolvers } from './schema';
// 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);
// Same ApolloServer initialization as before, plus the drain plugin
// for our httpServer.
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(),
bodyParser.json(),
// expressMiddleware accepts the same arguments:
// an Apollo Server instance and optional configuration options
expressMiddleware(server, {
context: async ({ req }) => ({ token: req.headers.token }),
}),
);
// Modified server startup
await new Promise((resolve) => httpServer.listen({ port: 4000 }, resolve));
console.log(`🚀 Server ready at http://localhost:4000/`);
The code is from official documentation of apollo server, My question is, here we are first creating an apollo server and converting it to express server using expressMiddleware(server),
Will there be any issues with this conversion ?
Will we face any lack of control over the converted express server ?

Answer 1

My question is, here we are first creating an apollo server and converting it to express server using expressMiddleware(server),
That's not what you're doing at all.
You created an express server (const app = express()).
You created a separate http server from that app.
You created a running executable GraphQL Server.
You created an express middleware ((req, res, next) => void) that generates a context of { token?: string }, parses the body of your request into a GraphQL payload and then executes against the GraphQL Server with that context and with that payload.
You then added that express middleware to a route you created at "/", along with other middleware you attached before it.
You started the httpServer you created in #2
Will there be any issues with this conversion ?
Will we face any lack of control over the converted express server ?
This is no conversion, as mentioned. Hopefully you now understand that.
You created all of those things. Your express app is a variable called app. Do whatever you want with it. Your http server is a variable called httpServer. Do whatever you want with it.