custom social url validator for rails

custom_social_url_validator.rb

#lib/validators/social_url_validator.rb
class SocialUrlValidator < ActiveModel::EachValidator
  def validate_each(record, attribute, value)
    value = smart_add_scheme_url_to record, attribute, value

    case attribute
      when :facebook
        record.errors.add attribute, (options[:message] || "not a valid domain") unless
        value =~ /((http|https):\/\/)?(www[.])?facebook.com\/.+/i
      when :twitter
        record.errors.add attribute, (options[:message] || "not a valid domain") unless
        value =~ /((http|https):\/\/)?(www[.])?twitter.com\/.+/i
      when :linkedin
        record.errors.add attribute, (options[:message] || "not a valid domain") unless
        value =~ /((http|https):\/\/)?(www[.])?linkedin.com\/.+/i
      when :xing
        record.errors.add attribute, (options[:message] || "not a valid domain") unless
        value =~ /((http|https):\/\/)?(www[.])?xing.com\/profile\/.+/i
      end
  end

  def smart_add_scheme_url_to record, attribute, value
    url = value

    unless value[/^(http|https):\/\//]
      url = 'http://' << value
      record.send("#{attribute}=", url)
    end

    url
  end
end


#config/application.rb

  config.autoload_paths += %W(#{config.root}/lib #{config.root}/lib/validators)