GraphQL Server Setup

1. Introduction

GraphQL is a query language for APIs and a runtime for fulfilling those queries with your existing data. This lesson will guide you through setting up a GraphQL server.

2. Prerequisites

• Node.js installed (version 12 or later).
• Basic understanding of JavaScript and APIs.
• Familiarity with npm (Node Package Manager).

3. Installation

First, create a new directory for your project and initialize it:

mkdir graphql-server
cd graphql-server
npm init -y

Next, install the necessary packages:

npm install express express-graphql graphql

4. Defining Schema

The schema defines the types and structure of your GraphQL API. Create a file named schema.js and define your schema as follows:

const { GraphQLObjectType, GraphQLSchema, GraphQLString } = require('graphql');

const RootQuery = new GraphQLObjectType({
    name: 'RootQueryType',
    fields: {
        hello: {
            type: GraphQLString,
            resolve(parent, args) {
                return 'Hello World!';
            }
        }
    }
});

module.exports = new GraphQLSchema({
    query: RootQuery
});

5. Setting Up Server

Create a new file named server.js and set up the Express server with GraphQL:

const express = require('express');
const { graphqlHTTP } = require('express-graphql');
const schema = require('./schema');

const app = express();

app.use('/graphql', graphqlHTTP({
    schema: schema,
    graphiql: true,
}));

app.listen(4000, () => {
    console.log('Server running at http://localhost:4000/graphql');
});

6. Best Practices

• Always define your schema clearly to avoid confusion.
• Use descriptive names for types and fields.
• Limit the number of top-level queries to avoid complexity.
• Implement error handling in resolvers.
• Use middleware for authentication and logging.

7. FAQ