feat: implement Active Model Serializers

- Implemented serialization for Contact, Phone, Address and Kind models

- Enforced JSON:API request format

Author: fatimampg

app/controllers/application_controller.rb

@@ -1,2 +1,8 @@
 class ApplicationController < ActionController::API
+  before_action :ensure_json_request
+
+  def ensure_json_request
+    return if request.headers["Accept"] =~ /json/ # check in Header, if Accept contains smt with json, and continue if true.
+    head 406 # otherwise respond with status "not acceptable"
+  end
 end

app/controllers/contacts_controller.rb

@@ -16,7 +16,7 @@ def index
 
   # GET /contacts/1
   def show
-    render json: @contact, include: [ :kind, :phones, :address ]
+    render json: @contact, include: [ :kind, :address, :phones ]# , meta: { author: "fg" }
     # render json: @contact.attributes.merge({ author: "fg" })
     # render json: { name: @contact.name, email: @contact.email }
   end

app/serializers/address_serializer.rb

@@ -0,0 +1,3 @@
+class AddressSerializer < ActiveModel::Serializer
+  attributes :id, :street, :city
+end

app/serializers/contact_serializer.rb

@@ -1,3 +1,27 @@
 class ContactSerializer < ActiveModel::Serializer
-  attributes :id
+  attributes :id, :name, :email, :birthdate, :author
+
+  belongs_to :kind do
+    link(:related) { kind_url(object.kind.id) }
+  end
+  has_many :phones
+  has_one :address
+
+  # add HATEOAS
+  # link(:self) { contact_url(object.id) }
+  # link(:kind) { kind_url(object.kind.id) } # - link added inside the relationships
+
+  meta do
+    { author: "fg" }
+  end
+
+  def attributes(*arg) # splat operator
+    h = super(*arg) # call parent ActiveModel::Serializer's attributes method - returns hash of the model's attributes
+
+    # Rails.logger.debug("Returned from super: #{h.inspect}")
+    # Ex.: Returned from super: {:id=>77, :name=>"Shena Hilpert", :email=>"rosita@oconnell-runolfsson.test", :birthdate=>"1962-06-05"}
+
+    h[:birthdate] = object.birthdate.to_time.iso8601 unless object.birthdate.blank?
+    h
+  end
 end

app/serializers/kind_serializer.rb

@@ -1,3 +1,3 @@
 class KindSerializer < ActiveModel::Serializer
-  attributes :id
+  attributes :id, :description
 end

app/serializers/phone_serializer.rb

@@ -0,0 +1,3 @@
+class PhoneSerializer < ActiveModel::Serializer
+  attributes :id, :number
+end

config/environments/development.rb

@@ -3,6 +3,10 @@
 Rails.application.configure do
   # Settings specified here will take precedence over those in config/application.rb.
 
+  Rails.application.routes.default_url_options = {
+    host: "localhost",
+    port: 3000
+  }
   # Make code changes take effect immediately without server restart.
   config.enable_reloading = true
 

config/initializers/ams.rb

@@ -0,0 +1,2 @@
+ActiveModel::Serializer.config.adapter = :json_api
+# to use use JsonApi Adapter

config/initializers/mime_types.rb

@@ -0,0 +1,2 @@
+Mime::Type.register "application/vnd.api+json", :json
+# content formatted in JSON and follows a specific API format (JSON:API specification)