# Custom validations in rails: validates\_number\_range **URL:** \ **Category:** Rails\ **Created:** [June 24, 2007, 8:59pm UTC](https://www.ruby-forum.com/t/custom-validations-in-rails-validates-number-range/107653 "2007-06-24T20:59:45Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Ye\_Dingding](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/49beb7/32.png) [@Ye\_Dingding](https://www.ruby-forum.com/u/Ye_Dingding)\ **Post date:** [June 24, 2007, 8:59pm UTC](https://www.ruby-forum.com/t/custom-validations-in-rails-validates-number-range/107653/1 "2007-06-24T20:59:45Z")
[http://sishen.lifegoo.com/?p=42](http://sishen.lifegoo.com/?p=42) I don’t know whether there exists a builtin validation that can check the number range. I think the requirement is normal, but indeed, i can’t find it. So i wrote a custome validation: validates\_number\_range, whose prototype is validates\_length\_of. If there already exists one, pls tell me, 🙂 The code is below, welcome to give me any advice on my blog. And also, more details information on the blog, 🙂 module ActiveRecord module Validations module ClassMethods def validates\_number\_range(\*attrs) validates\_numericality\_of attrs.first options = { :too\_big =\> “is too big (maximum is %d)”, :too\_small =\> “is too small (minimum is %d)”, :wrong\_number =\> “is the wrong number (should be %d)” }.merge(DEFAULT\_VALIDATION\_OPTIONS) options.update(attrs.pop.symbolize\_keys) if attrs.last.is\_a?(Hash) ``` # Ensure that one and only one range option is specified. range_options = ALL_RANGE_OPTIONS & options.keys case range_options.size when 0 raise ArgumentError, 'Range unspecified. Specify the ``` :within, :maximum, :minimum, or :is option.’ when 1 # Valid number of options; do nothing. else raise ArgumentError, ‘Too many range options specified. Choose only one.’ end ``` # Get range option and value. option = range_options.first option_value = options[range_options.first] case option when :within, :in raise ArgumentError, ":#{option} must be a Range" unless ``` option\_value.is\_a?(Range) ``` too_small = options[:too_small] % option_value.begin too_big = options[:too_big] % option_value.end validates_each(attrs, options) do |record, attr, value| if value.nil? or value < option_value.begin record.errors.add(attr, too_small) elsif value > option_value.end record.errors.add(attr, too_big) end end when :is, :minimum, :maximum raise ArgumentError, ":#{option} must be a nonnegative ``` Integer" unless option\_value.is\_a?(Integer) and option\_value \>= 0 ``` # Declare different validations per option. validity_checks = { :is => "==", :minimum => ">=", :maximum => ``` “\<=” } message\_options = { :is =\> :wrong\_number, :minimum =\> :too\_small, :maximum =\> :too\_big } ``` message = (options[:message] || ``` options[message\_options[option]]) % option\_value ``` validates_each(attrs, options) do |record, attr, value| record.errors.add(attr, message) unless !value.nil? and ``` value.method(validity\_checks[option])[option\_value] end end end end end end ---
**Author:** ![Ye\_Dingding](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/49beb7/32.png) [@Ye\_Dingding](https://www.ruby-forum.com/u/Ye_Dingding)\ **Post date:** [June 24, 2007, 9:33pm UTC](https://www.ruby-forum.com/t/custom-validations-in-rails-validates-number-range/107653/2 "2007-06-24T21:33:41Z")
If I understood what you are trying to do correctly validates\_length\_of :user\_name, :within =\> 6…20, :too\_long =\> “pick a shorter name”, :too\_short =\> “pick a longer name” from [http://railsmanual.com/module/ActiveRecord::Validations::ClassMethods/validates\_length\_of/1.1.2](http://railsmanual.com/module/ActiveRecord::Validations::ClassMethods/validates_length_of/1.1.2) Matt Ye Dingding wrote: > [LifeGoo.com is for sale | HugeDomains](http://sishen.lifegoo.com/?p=42) > > I don’t know whether there exists a builtin validation that can check > the > number range. I think the requirement is normal, but indeed, i can’t > find > it. So i wrote a custome validation: validates\_number\_range, whose > prototype is validates\_length\_of. If there already exists one, pls tell > me, > 🙂 ---
**Author:** ![Ye\_Dingding](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/49beb7/32.png) [@Ye\_Dingding](https://www.ruby-forum.com/u/Ye_Dingding)\ **Post date:** [June 24, 2007, 10:13pm UTC](https://www.ruby-forum.com/t/custom-validations-in-rails-validates-number-range/107653/3 "2007-06-24T22:13:54Z")
No, that’s not i want to do. Sorry, my blog([LifeGoo.com is for sale | HugeDomains](http://sishen.lifegoo.com/?p=42)) gives more information, so i gave less information in the mail. My scenario is that I want to check the uploaded file size, for example, less than 5M. But what validates\_length\_of is the size, when is a fixnum, is 4. So validates\_length\_of can’t be work for me. Using validates\_number\_range, now i can code as below: validates\_number\_range :file\_size, :maximum =\> 5242880, :message =\> “you can only upload file less than 5M”, :on =\> :create ---
**Author:** ![Ye\_Dingding](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/49beb7/32.png) [@Ye\_Dingding](https://www.ruby-forum.com/u/Ye_Dingding)\ **Post date:** [June 27, 2007, 11:36am UTC](https://www.ruby-forum.com/t/custom-validations-in-rails-validates-number-range/107653/4 "2007-06-27T11:36:38Z")
Today i looked through the validations.rb in rails edge. I’m glad to find that validates\_numericality\_of method already has the support for range check. The related options are - greater\_than - greater\_than\_or\_equal\_to - equal\_to - less\_than - less\_than\_or\_equal\_to - odd - even With these, life are more better, 🙂