Rails: Validating min and max length of a string but allowing it to be blank

Question

I have a field that I would like to validate. I want the field to be able to be left blank, but if a user is entering data I want it to be in a certain format. Currently I am us

Answer 1

In your model e.g.

def validate
  errors.add_to_base 'error message' unless self.foo.length == 5 or self.foo.blanc?
end