development REST API service

[Artem T]

hello, i develop  rest api for my project and using grape

And i have two questions:

1. For every error i want to have some specific code. Like twillio. where should I store these codes?
2. How should I organize the work with the codes and grape?

For example:

I have user model

class User < ActiveRecord::Base
  validates :phone, presence: true   # code 1001
  validated :phone, uniqueness: true  # code 1002
  validates :first_name, presence: true # code 1003
  validates :last_name, presence: true #code 1004
end

In grape api i have something like this

post do
        authenticated!
         user = User.new(params)
        if user.save
          { id: user.id }
        else
          error!({ errors: user.errors }, 422)
        end
      end



I thought to use the function fail and using Grape rescue_from generate response

but I'm not sure that this is true