Module: ActiveRecord::Has::Features::ClassMethods

Defined in:
lib/has_features/active_record/has/features.rb

Overview

This has extension provides the capabilities for sorting and reordering a number of objects in a list. The class that has this specified needs to have a featured_position column defined as an integer on the mapped database table.

Todo list example:

class TodoList < ActiveRecord::Base
  has_many :todo_items, :order => "featured_position"
end

class Author < ActiveRecord::Base
  belongs_to :todo_list
  has_features :scope => :organization
end

author.featured = true

Instance Method Summary collapse

Instance Method Details

#has_features(options = {}) ⇒ Object

Configuration options are:

  • column - specifies the column name to use for keeping the featured_position integer (default: featured_position)

  • scope - restricts what is to be considered a list. Given a symbol, it’ll attach _id (if it hasn’t already been added) and use that as the foreign key restriction. It’s also possible to give it an entire string that is interpolated if you need a tighter scope than just a foreign key. Example: has_features :scope => 'todo_list_id = #{todo_list_id} AND completed = 0'



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# File 'lib/has_features/active_record/has/features.rb', line 32

def has_features(options = {})
  configuration = { :column => "featured_position", :scope => "1 = 1" }
  configuration.update(options) if options.is_a?(Hash)

  configuration[:scope] = "#{configuration[:scope]}_id".intern if configuration[:scope].is_a?(Symbol) && configuration[:scope].to_s !~ /_id$/

  if configuration[:scope].is_a?(Symbol)
    scope_condition_method = %(
      def scope_condition
        self.class.send(:sanitize_sql_hash_for_conditions, { :#{configuration[:scope].to_s} => send(:#{configuration[:scope].to_s}) })
      end
    )
  elsif configuration[:scope].is_a?(Array)
    scope_condition_method = %(
      def scope_condition
        attrs = %w(#{configuration[:scope].join(" ")}).inject({}) do |memo,column| 
          memo[column.intern] = send(column.intern); memo
        end
        self.class.send(:sanitize_sql_hash_for_conditions, attrs)
      end
    )
  else
    scope_condition_method = "def scope_condition() \"#{configuration[:scope]}\" end"
  end

  class_eval <<-EOV
    include ActiveRecord::Has::Features::InstanceMethods
    
    def featured_position_column
      '#{configuration[:column]}'
    end
    
    def has_features_class
      ::#{self.name}
    end
    
    scope :featured, order("#{configuration[:column]} asc").where("#{configuration[:column]} is not null")

    #{scope_condition_method}
    
    before_destroy :decrement_positions_on_lower_featured_items
  EOV
end