method

method_missing

v1.1.6 - 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 1090
        def method_missing(method_id, *arguments)
          if match = /find_(all_by|by)_([_a-zA-Z]\w*)/.match(method_id.to_s)
            finder, deprecated_finder = determine_finder(match), determine_deprecated_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)

            case extra_options = arguments[attribute_names.size]
              when nil
                options = { :conditions => conditions }
                set_readonly_option!(options)
                send(finder, options)

              when Hash
                finder_options = extra_options.merge(:conditions => conditions)
                validate_find_options(finder_options)
                set_readonly_option!(finder_options)

                if extra_options[:conditions]
                  with_scope(:find => { :conditions => extra_options[:conditions] }) do
                    send(finder, finder_options)
                  end
                else
                  send(finder, finder_options)
                end

              else
                send(deprecated_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)

            options = { :conditions => construct_conditions_from_arguments(attribute_names, arguments) }
            set_readonly_option!(options)
            find_initial(options) || create(construct_attributes_from_arguments(attribute_names, arguments))
          else
            super
          end
        end

method_missing

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