Apollo-server: cannot disable apollo server gui in browser

[monkingame]

• [x ] feature

I cannot disable apollo server gui in browser.

here codes:

const { ApolloServer } = require('apollo-server-express');     
const schema = require('./graphql');      
const server = new ApolloServer({ schema });  
server.applyMiddleware({  
  app,  
  path: '/gql',  
  bodyParserConfig: bodyParser.json(),  
  gui: null,  
});

I donot want users to find my backgroud graphql list or he will use to hack/analyze my server.
I config with {gui:null} but when access http://localhost:4000/gql, the gui shows again.

How can I remove/disable the browser gui?
(The purpose is to access apollo server only with get/post query string)

[monkingame]

Sorry ,please close the issue.
I found the solution:
https://www.apollographql.com/docs/apollo-server/features/graphql-playground.html

const server = new ApolloServer({
  schema, 
  introspection: false,
  playground: false,
});

will disable playground gui