Why applyMiddleware?

[lucasconstantino]

As it is of my understanding, ApolloServer 2.0 way of integrating an existing server to it is using the applyMiddleware method. I'm wondering why not having something to extract the sub-application (such as a express's Router) instead of doing this highly side-effect based approach of connecting directly to an existing app.

The approach of an exposed sub-application would highly reduce the amount of configuration and assumptions now taken by the current implementation of the apollo-server-express version of the applyMiddleware. For instance:

• path: can be completely dropped;
• cors: should be handled by the upper application, not ApolloServer;
• bodyParserConfig: same as above;
• disableHealthCheck: health check logic should be exposed separately, not polluting the upper app;
• onHealthCheck: same as above.

My idea is it should be possible for me to do something like this:

./graphql.js

const { ApolloServer, gql } = require('apollo-server-express')

const typeDefs = gql`...`
const resolvers = { ... }

const apolloServer = new ApolloServer({ typeDefs, resolvers })

module.exports = apolloServer.middleware() // or `.app()` or `.router()`

./server.js

const express = require('express')
const graphql = require('./graphql')

express()
  .use('/graphql', graphql)
  .listen(3000, () => console.log(`> Ready on http://localhost:3000`))

This way I can invert the order of knowledge, making the graphql logic completely unaware of the application from above.

[razor-x]

I've noticed there are a lot of similar requests coming in for the missing middleware in v2. I'm wondering if we should consolidate them in one issue and close the others.

This one seems like the best candidate: #1308