require 'active_support/core_ext/array' require 'active_support/core_ext/hash/except' require 'active_support/core_ext/object/metaclass' module ActiveRecord module NamedScope extend ActiveSupport::Concern module ClassMethods # Returns a relation if invoked without any arguments. # # posts = Post.scoped # posts.size # Fires "select count(*) from posts" and returns the count # posts.each {|p| puts p.name } # Fires "select * from posts" and loads post objects # # Returns an anonymous named scope if any options are supplied. # # shirts = Shirt.scoped(:conditions => {:color => 'red'}) # shirts = shirts.scoped(:include => :washing_instructions) # # Anonymous \scopes tend to be useful when procedurally generating complex queries, where passing # intermediate values (scopes) around as first-class objects is convenient. # # You can define a scope that applies to all finders using ActiveRecord::Base.default_scope. def scoped(options = {}, &block) if options.present? Scope.init(self, options, &block) else current_scoped_methods ? unscoped.merge(current_scoped_methods) : unscoped.spawn end end def scopes read_inheritable_attribute(:scopes) || write_inheritable_attribute(:scopes, {}) end # Adds a class method for retrieving and querying objects. A scope represents a narrowing of a database query, # such as :conditions => {:color => :red}, :select => 'shirts.*', :include => :washing_instructions. # # class Shirt < ActiveRecord::Base # scope :red, :conditions => {:color => 'red'} # scope :dry_clean_only, :joins => :washing_instructions, :conditions => ['washing_instructions.dry_clean_only = ?', true] # end # # The above calls to scope define class methods Shirt.red and Shirt.dry_clean_only. Shirt.red, # in effect, represents the query Shirt.find(:all, :conditions => {:color => 'red'}). # # Unlike Shirt.find(...), however, the object returned by Shirt.red is not an Array; it resembles the association object # constructed by a has_many declaration. For instance, you can invoke Shirt.red.find(:first), Shirt.red.count, # Shirt.red.find(:all, :conditions => {:size => 'small'}). Also, just # as with the association objects, named \scopes act like an Array, implementing Enumerable; Shirt.red.each(&block), # Shirt.red.first, and Shirt.red.inject(memo, &block) all behave as if Shirt.red really was an Array. # # These named \scopes are composable. For instance, Shirt.red.dry_clean_only will produce all shirts that are both red and dry clean only. # Nested finds and calculations also work with these compositions: Shirt.red.dry_clean_only.count returns the number of garments # for which these criteria obtain. Similarly with Shirt.red.dry_clean_only.average(:thread_count). # # All \scopes are available as class methods on the ActiveRecord::Base descendant upon which the \scopes were defined. But they are also available to # has_many associations. If, # # class Person < ActiveRecord::Base # has_many :shirts # end # # then elton.shirts.red.dry_clean_only will return all of Elton's red, dry clean # only shirts. # # Named \scopes can also be procedural: # # class Shirt < ActiveRecord::Base # scope :colored, lambda { |color| # { :conditions => { :color => color } } # } # end # # In this example, Shirt.colored('puce') finds all puce shirts. # # Named \scopes can also have extensions, just as with has_many declarations: # # class Shirt < ActiveRecord::Base # scope :red, :conditions => {:color => 'red'} do # def dom_id # 'red_shirts' # end # end # end # # # For testing complex named \scopes, you can examine the scoping options using the # proxy_options method on the proxy itself. # # class Shirt < ActiveRecord::Base # scope :colored, lambda { |color| # { :conditions => { :color => color } } # } # end # # expected_options = { :conditions => { :colored => 'red' } } # assert_equal expected_options, Shirt.colored('red').proxy_options def scope(name, options = {}, &block) name = name.to_sym if !scopes[name] && respond_to?(name, true) raise ArgumentError, "Cannot define scope :#{name} because #{self.name}.#{name} method already exists." end scopes[name] = lambda do |parent_scope, *args| Scope.init(parent_scope, case options when Hash, Relation options when Proc options.call(*args) end, &block) end metaclass.instance_eval do define_method name do |*args| scopes[name].call(self, *args) end end end def named_scope(*args, &block) ActiveSupport::Deprecation.warn("Base.named_scope has been deprecated, please use Base.scope instead", caller) scope(*args, &block) end end class Scope < Relation attr_accessor :current_scoped_methods_when_defined delegate :scopes, :with_scope, :with_exclusive_scope, :scoped_methods, :scoped, :to => :klass def self.init(klass, options, &block) relation = new(klass, klass.arel_table) scope = if options.is_a?(Hash) klass.scoped.apply_finder_options(options.except(:extend)) else options ? klass.scoped.merge(options) : klass.scoped end relation = relation.merge(scope) Array.wrap(options[:extend]).each {|extension| relation.send(:extend, extension) } if options.is_a?(Hash) relation.send(:extend, Module.new(&block)) if block_given? relation.current_scoped_methods_when_defined = klass.send(:current_scoped_methods) relation end def first(*args) if args.first.kind_of?(Integer) || (loaded? && !args.first.kind_of?(Hash)) to_a.first(*args) else args.first.present? ? apply_finder_options(args.first).first : super end end def last(*args) if args.first.kind_of?(Integer) || (loaded? && !args.first.kind_of?(Hash)) to_a.last(*args) else args.first.present? ? apply_finder_options(args.first).last : super end end def ==(other) other.respond_to?(:to_a) ? to_a == other.to_a : false end private def method_missing(method, *args, &block) if klass.respond_to?(method) with_scope(self) do if current_scoped_methods_when_defined && !scoped_methods.include?(current_scoped_methods_when_defined) && !scopes.include?(method) with_scope(current_scoped_methods_when_defined) { klass.send(method, *args, &block) } else klass.send(method, *args, &block) end end else super end end end end end