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rails--rails/activemodel/lib/active_model/validations/presence.rb
2009-09-08 10:26:39 -05:00

41 lines
2 KiB
Ruby

require 'active_support/core_ext/object/blank'
module ActiveModel
module Validations
module ClassMethods
# Validates that the specified attributes are not blank (as defined by Object#blank?). Happens by default on save. Example:
#
# class Person < ActiveRecord::Base
# validates_presence_of :first_name
# end
#
# The first_name attribute must be in the object and it cannot be blank.
#
# If you want to validate the presence of a boolean field (where the real values are true and false),
# you will want to use <tt>validates_inclusion_of :field_name, :in => [true, false]</tt>.
#
# This is due to the way Object#blank? handles boolean values: <tt>false.blank? # => true</tt>.
#
# Configuration options:
# * <tt>message</tt> - A custom error message (default is: "can't be blank").
# * <tt>on</tt> - Specifies when this validation is active (default is <tt>:save</tt>, other options <tt>:create</tt>,
# <tt>:update</tt>).
# * <tt>if</tt> - Specifies a method, proc or string to call to determine if the validation should
# occur (e.g. <tt>:if => :allow_validation</tt>, or <tt>:if => Proc.new { |user| user.signup_step > 2 }</tt>).
# The method, proc or string should return or evaluate to a true or false value.
# * <tt>unless</tt> - Specifies a method, proc or string to call to determine if the validation should
# not occur (e.g. <tt>:unless => :skip_validation</tt>, or <tt>:unless => Proc.new { |user| user.signup_step <= 2 }</tt>).
# The method, proc or string should return or evaluate to a true or false value.
#
def validates_presence_of(*attr_names)
configuration = attr_names.extract_options!
# can't use validates_each here, because it cannot cope with nonexistent attributes,
# while errors.add_on_empty can
validate configuration do |record|
record.errors.add_on_blank(attr_names, configuration[:message])
end
end
end
end
end