Module: Handler::ClassMethods

Defined in:
lib/handler.rb

Instance Method Summary collapse

Instance Method Details

#handle_based_on(attribute, options = {}) ⇒ Object

Declare that a model generates a handle based on a given attribute or method. Options include:

:separator - character to place between words :store - attribute in which to store handle :unique - generate a handle which is unique among all records



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# File 'lib/handler.rb', line 97

def handle_based_on(attribute, options = {})
  options[:separator] ||= "_"
  options[:write_to]  ||= :handle
  options[:unique]      = true if options[:unique].nil?

  ##
  # Generate a URL-friendly name.
  #
  define_method :generate_handle do
    h = Handler.generate_handle(send(attribute), options[:separator])
    if options[:unique]

      # generate a condition for finding an existing record with a
      # given handle
      find_dupe = lambda{ |h|
        conds = ["#{options[:write_to]} = ?", h]
        unless new_record?
          conds[0] << " AND id != ?"
          conds << id
        end
        conds
      }

      # increase number while *other* records exist with the same handle
      # (record might be saved and should keep its handle)
      while self.class.where(find_dupe.call(h)).size > 0
        h = Handler.next_handle(h, options[:separator])
      end
    end
    h
  end

  ##
  # Assign the generated handle to the specified attribute.
  #
  define_method :assign_handle do
    write_attribute(options[:write_to], generate_handle)
  end
end