module ActiveRecord module DynamicMatchers def respond_to?(method_id, include_private = false) if match = DynamicFinderMatch.match(method_id) return true if all_attributes_exists?(match.attribute_names) elsif match = DynamicScopeMatch.match(method_id) return true if all_attributes_exists?(match.attribute_names) end super end private # Enables dynamic finders like User.find_by_user_name(user_name) and # User.scoped_by_user_name(user_name). Refer to Dynamic attribute-based finders # section at the top of this file for more detailed information. # # 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). # # Each dynamic finder using scoped_by_* is also defined in the class after it # is first invoked, so that future attempts to use it do not run through method_missing. def method_missing(method_id, *arguments, &block) if match = (DynamicFinderMatch.match(method_id) || DynamicScopeMatch.match(method_id)) attribute_names = match.attribute_names super unless all_attributes_exists?(attribute_names) unless match.valid_arguments?(arguments) method_trace = "#{__FILE__}:#{__LINE__}:in `#{method_id}'" backtrace = [method_trace] + caller raise ArgumentError, "wrong number of arguments (#{arguments.size} for #{attribute_names.size})", backtrace end if match.respond_to?(:scope?) && match.scope? self.class_eval <<-METHOD, __FILE__, __LINE__ + 1 def self.#{method_id}(*args) # def self.scoped_by_user_name_and_password(*args) attributes = Hash[[:#{attribute_names.join(',:')}].zip(args)] # attributes = Hash[[:user_name, :password].zip(args)] # scoped(:conditions => attributes) # scoped(:conditions => attributes) end # end METHOD send(method_id, *arguments) elsif match.finder? options = arguments.extract_options! relation = options.any? ? scoped(options) : scoped relation.send :find_by_attributes, match, attribute_names, *arguments, &block elsif match.instantiator? scoped.send :find_or_instantiator_by_attributes, match, attribute_names, *arguments, &block end else super end end # Similar in purpose to +expand_hash_conditions_for_aggregates+. def expand_attribute_names_for_aggregates(attribute_names) attribute_names.map { |attribute_name| unless (aggregation = reflect_on_aggregation(attribute_name.to_sym)).nil? aggregate_mapping(aggregation).map do |field_attr, _| field_attr.to_sym end else attribute_name.to_sym end }.flatten end def all_attributes_exists?(attribute_names) (expand_attribute_names_for_aggregates(attribute_names) - column_methods_hash.keys).empty? end def aggregate_mapping(reflection) mapping = reflection.options[:mapping] || [reflection.name, reflection.name] mapping.first.is_a?(Array) ? mapping : [mapping] end end end