6. A Working GraphQL Server in Nodejs.md

Part 6: A working GraphQL Server

Let's build a real server which can parse GraphQL queries sent over HTTP.

First, install babel (to use ES2015 awesomeness), restify and of course, graphql

npm i babel graphql restify

Create three files- index.js, server.js and schema.js.

touch index.js server.js schema.js

index.js file will be our entry point. We'll just register babel here so that the rest of our application can use ES2015 code.

//index.js
require('babel/register');
require('./server');

Let's build our schema now. We'll use dummy data here for the sake of brevity, but as you'll see using something like Bookshelf.js/Knexjs/Sequelize will be trivial. We'll pass the ID parameter with our query like {contributor (id: "1")} to get the GraphQL contributor's github username.

Here's the code in schema.js:

//schema.js
import {
  graphql,
  GraphQLSchema,
  GraphQLObjectType,
  GraphQLString
} from 'graphql';

let dummyData = {
  '1': 'leebyron',
  '2': 'enaqx',
  '3': 'schrockn',
  '4': 'andimarek'
};

export default new GraphQLSchema({
  query: new GraphQLObjectType({
    name: 'RootQueryType',
    fields: {
      contributor: {
        type: GraphQLString,
        args: {
          id: { type: GraphQLString }
        },
        //Using Destructuring of ES2015 to assign value to id
        resolve: (root, {id}) => {
          return dummyData[id];
        }
      }
    }
  })
});

You are probably already familiar with koa/express/restify. This part is easiest for you in that case:

//server.js
import restify from 'restify';
import { graphql } from 'graphql';
import schema from './schema.js';

var server = restify.createServer({
  name: 'GraphQL Demo'
});

server.use(restify.acceptParser(server.acceptable));
server.use(restify.queryParser());
server.use(restify.bodyParser());

server.post('/', (req, res, next) => {
  graphql(schema, req.body).then((result) => {
    res.send(result);
  });
});

server.get('/', (req, res, next) => {
  let instruction = 'POST GraphQL queries to' + server.url + '. Sample query: {contributor (id: "1")}';
  res.send(instruction);
});

server.listen(process.env.PORT || 8080, () => {
  console.log('%s listening at %s', server.name, server.url);
});

In order to run the server:

node index.js

The server will start at http://localhost:8080 address.

Now we can use Postman or just simple CURL to test if it is working:

curl -XPOST -d '{contributor (id: "1")}' http://localhost:8080/

If you got {"data":{"contributor":"leebyron"}} in return, congratulations for making it this far!