method_missing(method_id, *arguments, &block) — ActiveRecord::DynamicMatchers

method_missing(method_id, *arguments, &block)

Enables dynamic finders like User.find_by_user_name(user_name) and <tt>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.

Parameters

method_id req
arguments rest
block block

Source

# File activerecord/lib/active_record/dynamic_matchers.rb, line 24
    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)
        if !(match.is_a?(DynamicFinderMatch) && match.instantiator? && arguments.first.is_a?(Hash)) && arguments.size < attribute_names.size
          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 = if arguments.length > attribute_names.size
                      arguments.extract_options!
                    else
                      {}
                    end

          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

Defined in activerecord/lib/active_record/dynamic_matchers.rb line 24 · View on GitHub · Improve this page · Find usages on GitHub

Defined in ActiveRecord::DynamicMatchers

Signature

Parameters