This post originated from an RSS feed registered with Ruby Buzz by rwdaigle. Original Post: What's New in Edge Rails: Custom Length Validation Tokenizer Feed Title: Ryan's Scraps Feed URL: http://feeds.feedburner.com/RyansScraps Feed Description: Ryan Daigle's various technically inclined rants along w/ the "What's new in Edge Rails" series. Latest Ruby Buzz Posts Latest Ruby Buzz Posts by rwdaigle Latest Posts From Ryan's Scraps

The various ActiveRecord validation methods are some of the hardest working bits of ActiveRecord and yet they get so little love. In what may be a little-noticed change, you can now specify how validates_length_of parses the attribute value. While the default behavior is to just count the number of characters in the attribute value, you can now also do something like this to make sure the value has a minimum number of words:

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validates_length_of :article, :minimum => 10,
  :too_short => "Your article must be at least %d words in length.",
  :tokenizer => lambda {|str| str.scan(/\w+/) }

Just pass a proc to the :tokenizer option that chops the attribute value into its relevant parts for measure by the length validation routine. You can do most anything, like ensure a minimum or maximum number of vowels, digits etc…

tags: ruby, rubyonrails