add custom validation method in Ruby on Rails

Question

I need create a method the custom validation called findUpperCaseLetter or similar

I have a attribute called password that belongs to the model called User

My method is somewhat similar to the following. The password attribute must have at least a uppercase letter

  def findUpperCaseLetter(username)
     username.each_char do |character| 
          return true if  character=~/[[:upper:]]/  
     end

   return false

  end

I want add this validation to the User model

class User < ActiveRecord::Base
  attr_accessible :user_name,:email, :password
  validates_presence_of :user_name,:email, :password
  validates_uniqueness_of :user_name,:email
  ????
end  

I have already the following regular expreession

 validates_format_of :password, :with => /^[a-z0-9_-]{6,30}$/i, 
   message: "The password format is invalid"

How I modify it for add the following

The password must have at least one uppercase letter

Answer 1

You don't need custom validation to do this, you can use regex to validate the format of password. Add this to your model

validates :password, format: { with: /^(?=.*[A-Z]).+$/, allow_blank: true }

In Rails, you can do this by using format validator, I have added allow_blank: true to make sure when the field is empty it only throws Can't be blank error message and not format validator error message.

The work of this regular expression is to allow the password to be saved in the database only if it contains at least one capital letter. I have created a permalink on rubular, click here http://rubular.com/r/mOpUwmELjD

Hope this helps!