Building GraphQL API in Rails: A Quick Setup Guide

GraphQL, a modern query language for APIs, paired with Ruby on Rails, offers a powerful combination for streamlined API development. In this quick guide, we’ll walk through the essential steps to set up a GraphQL API in a Ruby on Rails application, providing you with a solid foundation for efficient and flexible web development.

Step 1: Create a new Rails project

bash

rails new graphql_example

cd graphql_example

Step 2: Add necessary gems to your Gemfile

Add the following gems to your Gemfile:

ruby

gem 'graphql'

gem 'graphiql-rails', group: :development

Run bundle install to install the new gems.

Step 3: Create a GraphQL schema

Create a file named app/graphql/types/query_type.rb:

ruby

# app/graphql/types/query_type.rb

Types::QueryType = GraphQL::ObjectType.define do
 name 'Query'
 description 'The root query type'
 field :hello do
 type types.String
 description 'An example field'
 resolve ->(_obj, _args, _ctx) { 'Hello, GraphQL!' }
 end
end

Step 4: Create a GraphQL controller

Generate a controller to handle GraphQL queries:

bash

rails generate controller graphql execute

Replace the content of app/controllers/graphql_controller.rb with the following:

ruby

# app/controllers/graphql_controller.rb

class GraphqlController < ApplicationController
 def execute
 variables = ensure_hash(params[:variables])
 query = params[:query]
 operation_name = params[:operationName]
 context = {
 # Add any necessary context values here, such as current_user or session
 }
 result = Schema.execute(query, variables: variables, context: context, operation_name: operation_name)
 render json: result
 end
 private
 def ensure_hash(variables)
 case variables
 when String
 JSON.parse(variables) || {}
 when Hash
 variables
 when nil
 {}
 else
 raise ArgumentError, "Invalid variables: #{variables}"
 end
 end
end

Step 5: Create the GraphQL schema

Create a file named app/graphql/schema.rb:

ruby

# app/graphql/schema.rb

Schema = GraphQL::Schema.define do
 query(Types::QueryType)
 # Add mutation types if needed
end

Step 6: Configure routes

Update your config/routes.rb to include the GraphQL endpoint:

ruby

# config/routes.rb

Rails.application.routes.draw do
 post '/graphql', to: 'graphql#execute'
 if Rails.env.development?
 mount GraphiQL::Rails::Engine, at: '/graphiql', graphql_path: '/graphql'
 end
end

Step 7: Run your Rails server

bash

rails s

Visit http://localhost:3000/graphiql in your browser to use GraphiQL, an in-browser IDE for exploring GraphQL.

In the GraphiQL interface, you can enter a query like:

graphql

{

 hello
}

And you should receive a response:

json

{

 "data": {
 "hello": "Hello, GraphQL!"
 }
}

This is a simple example, but you can expand your GraphQL schema with more types and mutations to suit your application’s needs.

Conclusion

By following this quick setup guide, you’ll be well-equipped to integrate GraphQL into your Ruby on Rails projects seamlessly. Harness the power of GraphQL to create APIs that cater to your application’s specific needs while providing an excellent developer and user experience. Get ready to elevate your API development game with the simplicity and flexibility of GraphQL in Ruby on Rails. Elevate your company’s digital presence with top-tier Ruby on Rails developers from RailsCarma. Our seasoned professionals bring a wealth of experience and innovation to the table, ensuring your projects are not only executed seamlessly but exceed industry standards.