Building REST APIs with Rails: Basic Serialization

••2 min read•
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Third video in a pile of LiveCoding.tv videos, shows how to use ActiveModel Serializer to shape the output of your resources. I totally forgot how links work, so watch me flap around trying to get it working and chuckle as I flail.

Source Code

Notes

To get going, you’ll need to include in your Gemfile:

gem 'active_model_serializers', '~> 0.10.0'

Install that by running bundle:

$ bundle install

Now there will be a new generator available, called resource:

$ rails g resource manufacturer name:string about:string city:string country:string manufacturer:references

$ rails g resource product name:string description:string product_type:string apv:float image_url:string references:products

These fields are taken from our API Blueprint documentation, and we already know the types.

rake db:create db:migrate

Create and generate the tables from our migrations, turning them into actual schema we can populate using the rails console:

$ rails console
manufacturer = Manufacturer.create(name: "Thatchers", about: "Pretty solid cider makers who are randomly moving their factories in the south west and going to Ireland...", city: "Dublin", country: "Ireland")

Product.create(manufacturer: manufacturer, name: 'Katies', description: "Unnecessarily strong fizzy cider that sells for the same price as normal ciders.", apv: 7.6, product_type: 'cider')

Product.create(manufacturer: manufacturer, name: 'Thatchers Dry', description: "As the name suggests this is dry, and a little tangy.", apv: 6.5, product_type: 'cider')

Go look at ./app/controllers and ./app/serializers for the rest… more notes later.

Don’t forget to make ./config/initializers/serializers.rb and fill it with:

ActiveModelSerializers.config.adapter = :json_api

Then shove this in ./config/application.rb:

config.after_initialize do
  Rails.application.routes.default_url_options[:host] = ENV['HOST'] || 'localhost:3000'
end

By the time all that’s done, you should have some slick JSON-API output:

{
   "data":{
      "id":"1",
      "type":"manufacturer",
      "attributes":{
         "name":"Thatchers",
         "about":"Pretty solid cider makers that are ditching their factories in the south west and going to Ireland...",
         "city":"Dublin",
         "country":"Ireland"
      },
      "relationships":{
         "products":{
            "data":[
               {
                  "id":"1",
                  "type":"product"
               }
            ]
         }
      },
      "links":{
         "self":"http://localhost:3000/manufacturers/1",
         "products":{
            "href":"/products?manufacturer=1"
         }
      }
   }
}

Cheers.

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