Give me :five

Yes, give me :five! Enough :first and :all, I want to find :five.

In order to do this, I checked the source code of find :first and find :all in base.rb

base.rb

    def find(*args)
      options = args.extract_options!
      validate_find_options(options)
      set_readonly_option!(options)

      case args.first
        when :first then find_initial(options)
        when :all then find_every(options)
        else find_from_ids(args, options)
      end
    end

OK, the next step is easy, override this method by defining a class method of a Model class, let's say, Blog class and add :five argument in.

Use class << self to open the Blog class object and add the find method in to override the original one. You have to implement :first and :all again. Otherwise the "Blog.find :all" will not work.

blogs.rb

class Blog < ActiveRecord::Base
  has_many :posts
 
  class << self
    def find(*args)
      options = args.extract_options!
      validate_find_options(options)
      set_readonly_option!(options)
 
      case args.first
        when :first then find_initial(options)
        when :all then find_every(options)
        when :five then find :first, 
                :limit => 1, 
                :offset => 4 #call :first instead
        else find_from_ids(args, options)
      end
    end
  end
end

Now, you can use find :five to retrive the fifth elements:

  >>b5=Blog.find :five

Bingo, I got a :five!