Method: ActiveRecord::Validations::ClassMethods#validates_format_of

Defined in:
lib/active_record/validations.rb

#validates_format_of(*attr_names) ⇒ Object

Validates whether the value of the specified attribute is of the correct form by matching it against the regular expression provided.

class Person < ActiveRecord::Base
  validates_format_of :email, :with => /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\Z/i, :on => :create
end

Note: use \A and \Z to match the start and end of the string, ^ and $ match the start/end of a line.

A regular expression must be provided or else an exception will be raised.

Configuration options:

  • :message - A custom error message (default is: “is invalid”).

  • :allow_nil - If set to true, skips this validation if the attribute is nil (default is false).

  • :allow_blank - If set to true, skips this validation if the attribute is blank (default is false).

  • :with - The regular expression used to validate the format with (note: must be supplied!).

  • :on - Specifies when this validation is active (default is :save, other options :create, :update).

  • :if - Specifies a method, proc or string to call to determine if the validation should occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.

  • :unless - Specifies a method, proc or string to call to determine if the validation should not occur (e.g. :unless => :skip_validation, or :unless => Proc.new { |user| user.signup_step <= 2 }). The method, proc or string should return or evaluate to a true or false value.

Raises:

  • (ArgumentError) 


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# File 'lib/active_record/validations.rb', line 789

def validates_format_of(*attr_names)
  configuration = { :on => :save, :with => nil }
  configuration.update(attr_names.extract_options!)

  raise(ArgumentError, "A regular expression must be supplied as the :with option of the configuration hash") unless configuration[:with].is_a?(Regexp)

  validates_each(attr_names, configuration) do |record, attr_name, value|
    unless value.to_s =~ configuration[:with]
      record.errors.add(attr_name, :invalid, :default => configuration[:message], :value => value) 
    end
  end
end