module ActiveRecord
module DynamicMatchers
def respond_to?(method_id, include_private = false)
match = find_dynamic_match(method_id)
valid_match = match && all_attributes_exists?(match.attribute_names)
valid_match || super
end
private
# Enables dynamic finders like <tt>User.find_by_user_name(user_name)</tt> 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 <tt>find_all_by_amount(amount, options)</tt>.
#
# Each dynamic finder using <tt>scoped_by_*</tt> 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 = find_dynamic_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?
define_scope_method(method_id, attribute_names)
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
def define_scope_method(method_id, attribute_names) #:nodoc
self.class_eval <<-METHOD, __FILE__, __LINE__ + 1
def self.#{method_id}(*args) # def self.scoped_by_user_name_and_password(*args)
conditions = Hash[[:#{attribute_names.join(',:')}].zip(args)] # conditions = Hash[[:user_name, :password].zip(args)]
where(conditions) # where(conditions)
end # end
METHOD
end
def find_dynamic_match(method_id) #:nodoc:
DynamicFinderMatch.match(method_id) || DynamicScopeMatch.match(method_id)
end
# Similar in purpose to +expand_hash_conditions_for_aggregates+.
def expand_attribute_names_for_aggregates(attribute_names)
attribute_names.map do |attribute_name|
if aggregation = reflect_on_aggregation(attribute_name.to_sym)
aggregate_mapping(aggregation).map do |field_attr, _|
field_attr.to_sym
end
else
attribute_name.to_sym
end
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
