Building a Simple Rails API
Published: 2023-09-03 19:02:18

I have really enjoyed learning about the Ruby on Rails language and using it to build my basic API was a fairly seamless process. Rails does many of the processes for you.  APIs serve as bridges between different software systems, enabling them to talk to each other and exchange information smoothly.

In this guide, I will explore the process of building a basic API using Rails.

**Setting Up Your Rails Project**
To create a new Rails project, open your terminal and run the following command:

bash

```
rails new YourApiName --api

```
The --api flag makes sure that you create a project designed for building APIs. After your project is generated, go to its folder:

bash

```
cd YourApiName

```
With your project set up, you're ready to start building your API.

**Creating Models and Migrations**
In Rails, models are like blueprints for database tables. To make a new model along with a related migration, you can use the generate command. For example, in my own app I created a Drawing model by running:

bash
`rails generate model Drawing adjective:string noun:string verb:string adverb:string 
`
<u>This command generated both the model and a migration file that defines the database schema for the drawings table.</u>

**Building Controllers**
Endpoints are essential parts of any API. They specify how clients can interact with your application. In Rails, you can make endpoints by generating controllers and setting up routes. Here's an example of how I created an endpoint for listing all drawings:

ruby
`# app/controllers/drawings_controller.rb
class DrawingsController < ApplicationController
 def index
    drawings = Drawing.all
    render json: drawings, status: :ok
  end
end
`

And my drawings config/routes.rb file:

ruby
`Rails.application.routes.draw do
  resources :drawings, only: [:index, :show, :create, :update, :destroy]
end
`

Now, when I make a GET request to /drawings, my API will respond with a JSON array of products.

**Serializers for Data Formatting**
While Rails can automatically convert model data into JSON, serializers offer precise control over the output format. The Active Model Serializers gem is a commonly used tool for this.

Here's how to set up a serializer for the Drawing model:

bash
`rails generate serializer Drawing
`

This generates a serializer file for the Drawing model, allowing me to customize the JSON representation of drawings.

**Authentication and Authorization**
Securing your API is vital. Rails offers various authentication solutions, such as Devise for user authentication or JWT (JSON Web Tokens) for token-based authentication. Choose the method that best suits your project's requirements.


**Error Handling Example**
ruby
`# app/controllers/drawings_controller.rb
class DrawingController < ApplicationController
  def create
    user = User.find(params[:user_id])
    drawing = user.drawings.create!(drawing_params)
    render json: drawing, status: :created
  end
      render json: { errors: @drawing.errors.full_messages }, status: :unprocessable_entity
    end
  end

  # ...
end`

**Challenges Faced** 
I found most of the process to be fairly seamless, however I did encounter some confusion when dealing with multiple models, controllers, and routes all at the same time.

**Positive Aspects of Rails APIs**

Building a robust API using Ruby on Rails is a fulfilling journey. By sticking to Rails conventions, like using serializers, adding authentication, and managing errors effectively, you can develop APIs that play a crucial role in modern web applications. 

I hope this simple guide to building a basic Rails API has been helpful.