module ActiveModel module Validations module ClassMethods # Validates that the value of the specified attribute is not in a particular enumerable object. # # class Person < ActiveRecord::Base # validates_exclusion_of :username, :in => %w( admin superuser ), :message => "You don't belong here" # validates_exclusion_of :age, :in => 30..60, :message => "This site is only for under 30 and over 60" # validates_exclusion_of :format, :in => %w( mov avi ), :message => "extension %s is not allowed" # end # # Configuration options: # * <tt>:in</tt> - An enumerable object of items that the value shouldn't be part of # * <tt>:message</tt> - Specifies a custom error message (default is: "is reserved") # * <tt>:allow_nil</tt> - If set to +true+, skips this validation if the attribute is +nil+ (default is: +false+) # * <tt>:allow_blank</tt> - If set to +true+, skips this validation if the attribute is blank (default is: +false+) # * <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_exclusion_of(*attr_names) configuration = { :message => ActiveRecord::Errors.default_error_messages[:exclusion], :on => :save } configuration.update(attr_names.extract_options!) enum = configuration[:in] || configuration[:within] raise(ArgumentError, "An object with the method include? is required must be supplied as the :in option of the configuration hash") unless enum.respond_to?(:include?) validates_each(attr_names, configuration) do |record, attr_name, value| record.errors.add(attr_name, configuration[:message] % value) if enum.include?(value) end end end end end