Question

Trying to validate the email field in a rails devise app with a word exclusion.

  validates :email, :exclusion => {:in => ["admin", "root",,
                                   :message => "is reserved"}

Wich works great on the :username field but not on the email.

I suspect that Devise is “taken over” the validation of the email field and I need to super/ overrule the registrations controller of Devise.

How could I:

• Prevent emails with words based on an :exclusion
• Prevent emails with @myapp.com so users don’t use the domain the app runs on.

Answer 1

You can always write custom validations to achieve what you want. Example from the guide:

The easiest way to add custom validators for validating individual
attributes is with the convenient ActiveModel::EachValidator. In this
case, the custom validator class must implement a validate_each method
which takes three arguments: record, attribute and value which
correspond to the instance, the attribute to be validated and the
value of the attribute in the passed instance.

class EmailValidator < ActiveModel::EachValidator
  def validate_each(record, attribute, value)
    unless value =~ /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\z/i
      record.errors[attribute] << (options[:message] || "is not an email")
    end
  end
end

class Person < ActiveRecord::Base
  validates :email, :presence => true, :email => true
end