GraphQL / Apollo：“没有可用的模式”。 的NodeJS

Question

I`m trying to work with GraphQL/Apollo, and my "Documentation Explorer" loading infinitely and doesnt show anything, and i can't make any queries.

After few minutes I getting an typeError "Failed to fetch" .

Here's my graphql/index.js file:

const { graphqlExpress, graphiqlExpress } = require('apollo-server-express');
const { makeExecutableSchema } = require('graphql-tools');
const User = require('../models/user.model');

const typeDefs = `

  type Query {
    users: [User]
  }

  type User {
    id: ID!
    name: String
    email: String
    password: String
  }

`;

const resolvers = {
  Query: {
    users() {
      return User.find({});
    }
  }
}

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

module.exports = (app) => {
  app.use('/graphql', () => { }, graphqlExpress({ schema }));

  app.use('/graphiql', graphiqlExpress({ endpointURL: '/graphql' }));
};

Console and DevTools both clear. Can someone explain, what`s wrong? Thank you !

Answer 1

It's a little unclear what you were trying to accomplish, but you've added a middleware to your /graphql route that does nothing:

app.use('/graphql', () => { }, graphqlExpress({ schema }))

The function you've inserted gets called anytime something hits the /graphql route, and because your function doesn't call next or end the response, the next middleware ( graphqlExpress ) is never called and the request just hangs.

The other problem is that graphqlExpress requires bodyParser middleware to run before it's called. That means you can do either:

const bodyParser = require('body-parser')

// Option A -- body parser will run prior to all routes after this point
app.use(bodyParser.json())

// Option B -- body parser will only run for the graphql route
app.use('/graphql', bodyParser.json(), graphqlExpress({ schema }))

If you fail to include bodyParser, graphqlExpress will typically complain and tell you as much as long you actually reach it in the first place.