在Ruby on Rails中自定义呈现对象id的格式

Question

In my application I have model User which like every model in Rails application has an id. And the question how can I customize this id to show it in the view in format not 1 but #0001. Is there any way to do it with using yml files?

Answer 1

In the case you only plan to have less than 10000 users you can generate such strings by

module UsersHelper
  def format_id user_id
    "##{user_id.to_s.rjust(4, '0')}"
  end
end

and in the view:

<%= format_id user.id %>

But please also think about the format of your idea whenever the users id is higher than 9999.

Answer 2

Getter

This might not work because you're changing the primary_key (which is a core feature of ActiveRecord / relational databases), but I'd recommend setting a specific getter for your request:

#app/models/user.rb
Class User < ActiveRecord::Base
   def id
     "#{self[:id].to_s.rjust(4, '0')}" #-> from tobago's answer
   end
end

This will allow you to call @user.id and have #000x returned as the id, although the actual id attribute will still remain as 1 etc

Answer 3

Answer is:

I create an helper:

  def format_id customer_id
    "#{t('customer_prefix')}#{customer_id.to_s.rjust(5, '0')}"
  end

and store customer_prefix in en.yml

en:
  customer_prefix: "CC"