Creating a Simple API with Rails

Creating Simple APIS with Rails

You probably have heard talk about Rails and how Rails is handy when creating web-apps. In this tutorial, I will try to explain in a few words how to create simple and RESTful APIs with Rails.

Rails-API

Rails::API is a subset of a normal Rails application, created for applications that don't require all functionality as a web app. For example, assets, and frontend things such as CSS and JavaScript.

Using Rails-API will allow you to utilize the following benefits from Rails.

• URL generation
• Resourceful generation
• Header and Redirection Responses
• Plugins: Many third-party libraries come with support for Rails

Related to many third-party libraries, we are using in this tutorial Active Model Serializers.

Active Model Serializers

Active Model Serializers brings convention over configuration to JSON generation. Basically, it has adapters and serializers.

• Adapters: Describe which attributes and relationships should be serialized.
• Serializers: Describe how attributes and relationships should be serialized.

Active Model Serializer is under-development version in Rails 5, and Rails 5 will use AMS by default.

Creating our API

Our API will be for a TODO List application.

For this tutorial I'm using:

• Rails 4.2.1 (remembering rails-api will be included on rails 5)
• Ruby 2.1.1

rails-api new todo

Doing this will create the application without assets/helpers/views. As you can see here

Add Active Model Serializer in your Gemfile

gem 'active_model_serializers', '~> 0.10.0.rc2'

• Creating a model

In our API, we will have a model called Task.

bash rails g scaffold task title completed:boolean order:integer

• Creating a serializer

bash rails g serializer task title completed order

The serializer should look like:

class TaskSerializer < ActiveModel::Serializer
  attributes :id, :title, :completed
end

Here is one interesting thing about AMS and Serializers: If you have some relationship between models, you can just use a similar Active Record syntax in your serializer: has_many or belongs_to.

Let's try to test our API and send a request:

curl -H "Content-Type:application/json; charset=utf-8" -d "'task':{'title':'something to do','order':1,'completed':false}" http://localhost:3000/tasks

And we can check in the browser:

As you can see above, it worked out! There are others interesting aspects about Active Model Serializers and you can check it here.

Hope you have enjoyed the combo Rails-API + AMS!