Connect Apollo with mongodb

Question

I want to connect my Apollo server with my mongoDB. I know there are many examples out there, but I get stuck at the async part and did not found a solution or example for that (that's strange, am I completly wrong?)

I started with the example from next.js https://github.com/zeit/next.js/tree/master/examples/api-routes-apollo-server-and-client . But the mongodb integration is missing.

My code

pages/api/graphql.js

    import {ApolloServer} from 'apollo-server-micro';
    import {schema} from '../../apollo/schema';

    const apolloServer = new ApolloServer({schema});

    export const config = {
        api: {
            bodyParser: false
        }
    };

    export default apolloServer.createHandler({path: '/api/graphql'});

apollo/schema.js

    import {makeExecutableSchema} from 'graphql-tools';
    import {typeDefs} from './type-defs';
    import {resolvers} from './resolvers';

    export const schema = makeExecutableSchema({
        typeDefs,
        resolvers
    });

apollo/resolvers.js

    const Items = require('./connector').Items;
    export const resolvers = {
        Query: {
            item: async (_parent, args) => {
                const {id} = args;
                const item = await Items.findOne(objectId(id));
                return item;
            },
            ...
        }
    }

apollo/connector.js

    require('dotenv').config();
    const MongoClient = require('mongodb').MongoClient;

    const password = process.env.MONGO_PASSWORD;
    const username = process.env.MONGO_USER;
    const uri = `mongodb+srv://${username}:${password}@example.com`;

    const client = await MongoClient.connect(uri);
    const db = await client.db('databaseName')
    const Items = db.collection('items')

    module.exports = {Items}

So the problem is the await in connector.js. I have no idea how to call this in an async function or how to provide the MongoClient on an other way to the resolver. If I just remove the await, it returns – obviously – an pending promise and can't call the function .db('databaseName') on it.

Answer 1

Unfortunately, we're still a ways off from having top-level await.

You can delay running the rest of your code until the Promise resolves by putting it inside the then callback of the Promise.

async function getDb () {
  const client = await MongoClient.connect(uri)
  return client.db('databaseName')
}

getDb()
  .then(db => {
    const apollo = new ApolloServer({
      schema,
      context: { db },
    })
    apollo.listen()
  })
  .catch(e => {
    // handle any errors
  })

Alternatively, you can create your connection the first time you need it and just cache it:

let db

const apollo = new ApolloServer({
  schema,
  context: async () => {
    if (!db) {
      try {
        const client = await MongoClient.connect(uri)
        db = await client.db('databaseName')
      catch (e) {
        // handle any errors
      }
    }
    return { db }
  },
})
apollo.listen()