method

method_missing

v1.0.0 - Show latest stable - Class: ActiveRecord::Base

method_missing(method_id, *arguments)

private

Enables dynamic finders like find_by_user_name(user_name) and find_by_user_name_and_password(user_name, password) that are turned into find(:first, :conditions => ["user_name = ?", user_name]) and find(:first, :conditions => ["user_name = ? AND password = ?", user_name, password]) respectively. Also works for find(:all), but using find_all_by_amount(50) that are turned into find(:all, :conditions => ["amount = ?", 50]).

It’s even possible to use all the additional parameters to find. For example, the full interface for find_all_by_amount is actually find_all_by_amount(amount, options).

# File activerecord/lib/active_record/base.rb, line 970
        def method_missing(method_id, *arguments)
          if match = /find_(all_by|by)_([_a-zA-Z]\w*)/.match(method_id.to_s)
            finder = determine_finder(match)

            attribute_names = extract_attribute_names_from_match(match)
            super unless all_attributes_exists?(attribute_names)

            conditions = construct_conditions_from_arguments(attribute_names, arguments)

            if arguments[attribute_names.length].is_a?(Hash)
              find(finder, { :conditions => conditions }.update(arguments[attribute_names.length]))
            else
              send("find_#{finder}", conditions, *arguments[attribute_names.length..-1]) # deprecated API
            end
          elsif match = /find_or_create_by_([_a-zA-Z]\w*)/.match(method_id.to_s)
            attribute_names = extract_attribute_names_from_match(match)
            super unless all_attributes_exists?(attribute_names)

            find(:first, :conditions => construct_conditions_from_arguments(attribute_names, arguments)) || 
              create(construct_attributes_from_arguments(attribute_names, arguments))
          else
            super
          end
        end

method_missing

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