Express
If you already have an existing Express HTTP server (created with createServer), you can add subscriptions on a specific path.
For example: if your server is already running on port 3000 and accepts GraphQL HTTP connections (POST) on the /graphql endpoint, you can expose /subscriptions as your WebSocket subscriptions endpoint:
import express from 'express';
import bodyParser from 'body-parser';
import { ApolloServer, gql } from 'apollo-server-express';
import { createServer } from 'http';
import { execute, subscribe } from 'graphql';
import { PubSub } from 'graphql-subscriptions';
import { SubscriptionServer } from 'subscriptions-transport-ws';
import { myGraphQLSchema } from './my-schema';
const PORT = 3000;
const app = express();
app.use('/graphql', bodyParser.json());
const apolloServer = new ApolloServer({ schema: myGraphQLSchema });
apolloServer.applyMiddleware({ app });
const pubsub = new PubSub();
const server = createServer(app);
server.listen(PORT, () => {
new SubscriptionServer({
execute,
subscribe,
schema: myGraphQLSchema,
}, {
server: server,
path: '/subscriptions',
});
});