Intercept find_by_attribute method active record

Question

I have a model that has a cellphone

Cellphones are store using a particular format in the database. I'd like to intercept User.find_by_cellphone("1234567890") and normalize the cellphone, then call the "real" find_by_cellphone("123-456-7890").

How would I go about that? I was thinking of renaming find_by_cellphone to ar_find_by_cellphone then overwrite find_by_cellphone and call ar_find_by_cellphone in it. Any other ideas?

Answer 1

There actually isn't a method named find_by_cellphone, this is just ActiveRecord magically using Ruby's method_missing to dynamically do this for you.

To do what you want, just define find_by_cellphone as a class method in your Cellphone class and it'll use this rather than the built-in one:

def self.find_by_cellphone(number)
  normalized_number = ... # normalize your number
  self.where(:cellphone => normalized_number).first
end