Question

How can a validation exclude a regexp?

I’m looking for something like this:

validates_format_of :string, :without => /\A(something)\Z/

which is mentioned here, but I don’t think is a real thing (Unknown validator: 'WithoutValidator).

Answer 1

You could write your own:

validate :name_exclude_pattern

def name_exclude_pattern
  unless self.name !~ /\A(something)\Z/
    errors.add(:name, "invalid format.")
  end
end

Though of course, this would have to be done for each attribute you want to check.