Question

Is it possible to use validates_exclusion_of with regular expressions?

That would ensure that URLs matching these specific patterns can’t be validated nor inserted into db.

What would be the best approach to code this?

Answer 1

There are a couple ways I might do it, depending on the circumstance.

First, if I am going to have to match some patterns and then exclude others I might do something like this:

validates_format_of :url, :with => /swanky pattern/, :unless => :beavis

def beavis
  self.url.match(/beavis/)
end

Or if you just need to exclude certain patterns

validate :i_hate_beavis

def i_hate_beavis
  errors.add(:url, 'cannot be beavis') if self.url.match(/beavis/)
end

resources: http://apidock.com/rails/ActiveModel/Validations/ClassMethods/validate