yaaf

Using YAAF with nested forms

When you are using Rails as a JSON API, you can still use YAAF to build your models.

Usage

You probably won’t need the new or edit endpoints but you’ll still need the create and update ones. There you can use form objects to encapsulate object building logic.

For example, a bulk invites form will look like this:

# app/forms/api/v1/bulk_invites_form.rb

module Api
  module V1
    class BulkInvitesForm < ApplicationForm
      attr_accessor :invites_params
      validate :amount_of_invites

      def initialize(args = {})
        super(args)

        @models = [invites].flatten
      end

      private

      def invites
        @invites ||= invites_params&.dig(:invites)&.map { |invite_params| Api::V1::InviteForm.new(invite_params) } || []
      end

      def amount_of_invites
        return if invites.size.between?(1, 5)

        errors[:base] << 'You need to send between one and five invites'
      end
    end
  end
end

# app/forms/api/v1/invite_form.rb

module Api
  module V1
    class InviteForm < ApplicationForm
      attr_accessor :email
      validates :email, format: { with: URI::MailTo::EMAIL_REGEXP }
     
      def initialize(args = {})
        super(args)
     
        @models = [invite]
      end
     
      private
     
      def invite
        @invite ||= Invite.new(invited_user_email: email)
      end
    end
  end
end

# app/controllers/api/v1/invites_controller.rb

module Api
  module V1
    class InvitesController < ApplicationController
      skip_before_action :verify_authenticity_token

      def create
        @form = Api::V1::BulkInvitesForm.new(invites_params: invites_params)

        if @form.save
          render json: {}, status: :created
        else
          render json: {
            errors: Api::V1::ErrorsSerializer.new(@form).serialize
          }, status: :unprocessable_entity
        end
      end

      private

      def invites_params
        params.permit(invites: [:email])
      end
    end
  end
end

# app/serializers/api/v1/errors_serializer.rb

module Api
  module V1
    class ErrorsSerializer
      attr_reader :object

      def initialize(object)
        @object = object
      end

      def serialize
        object.errors.to_h.map { |message| { detail: message } }
      end
    end
  end
end

Try it out!

Successful request

curl --header "Content-Type: application/json" --data '{"invites":[{ "email": "test@example.com" }]}'  https://yaaf-examples.herokuapp.com/api/v1/invites

Error request

curl --header "Content-Type: application/json" --data '{"invites":[{ "email": "xyz" }]}'  https://yaaf-examples.herokuapp.com/api/v1/invites

Got questions?

Feel free to create an issue and we’ll discuss about it.

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