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Diffstat (limited to 'activerecord/lib/active_record/named_scope.rb')
| -rw-r--r-- | activerecord/lib/active_record/named_scope.rb | 200 |
1 files changed, 0 insertions, 200 deletions
diff --git a/activerecord/lib/active_record/named_scope.rb b/activerecord/lib/active_record/named_scope.rb deleted file mode 100644 index 0313abe456..0000000000 --- a/activerecord/lib/active_record/named_scope.rb +++ /dev/null @@ -1,200 +0,0 @@ -require 'active_support/core_ext/array' -require 'active_support/core_ext/hash/except' -require 'active_support/core_ext/kernel/singleton_class' -require 'active_support/core_ext/object/blank' -require 'active_support/core_ext/class/attribute' - -module ActiveRecord - # = Active Record Named \Scopes - module NamedScope - extend ActiveSupport::Concern - - module ClassMethods - # Returns an anonymous \scope. - # - # 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 - # - # fruits = Fruit.scoped - # fruits = fruits.where(:color => 'red') if options[:red_only] - # fruits = fruits.limit(10) if limited? - # - # 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 = nil) - if options - scoped.apply_finder_options(options) - else - if current_scope - current_scope.clone - else - scope = relation.clone - scope.default_scoped = true - scope - end - end - end - - ## - # Collects attributes from scopes that should be applied when creating - # an AR instance for the particular class this is called on. - def scope_attributes # :nodoc: - if current_scope - current_scope.scope_for_create - else - scope = relation.clone - scope.default_scoped = true - scope.scope_for_create - end - end - - ## - # Are there default attributes associated with this scope? - def scope_attributes? # :nodoc: - current_scope || default_scopes.any? - end - - # Adds a class method for retrieving and querying objects. A \scope represents a narrowing of a database query, - # such as <tt>where(:color => :red).select('shirts.*').includes(:washing_instructions)</tt>. - # - # class Shirt < ActiveRecord::Base - # scope :red, where(:color => 'red') - # scope :dry_clean_only, joins(:washing_instructions).where('washing_instructions.dry_clean_only = ?', true) - # end - # - # The above calls to <tt>scope</tt> define class methods Shirt.red and Shirt.dry_clean_only. Shirt.red, - # in effect, represents the query <tt>Shirt.where(:color => 'red')</tt>. - # - # Note that this is simply 'syntactic sugar' for defining an actual class method: - # - # class Shirt < ActiveRecord::Base - # def self.red - # where(:color => 'red') - # end - # end - # - # Unlike <tt>Shirt.find(...)</tt>, however, the object returned by Shirt.red is not an Array; it - # resembles the association object constructed by a <tt>has_many</tt> declaration. For instance, - # you can invoke <tt>Shirt.red.first</tt>, <tt>Shirt.red.count</tt>, <tt>Shirt.red.where(:size => 'small')</tt>. - # Also, just as with the association objects, named \scopes act like an Array, implementing Enumerable; - # <tt>Shirt.red.each(&block)</tt>, <tt>Shirt.red.first</tt>, and <tt>Shirt.red.inject(memo, &block)</tt> - # all behave as if Shirt.red really was an Array. - # - # These named \scopes are composable. For instance, <tt>Shirt.red.dry_clean_only</tt> will produce - # all shirts that are both red and dry clean only. - # Nested finds and calculations also work with these compositions: <tt>Shirt.red.dry_clean_only.count</tt> - # returns the number of garments for which these criteria obtain. Similarly with - # <tt>Shirt.red.dry_clean_only.average(:thread_count)</tt>. - # - # All \scopes are available as class methods on the ActiveRecord::Base descendant upon which - # the \scopes were defined. But they are also available to <tt>has_many</tt> associations. If, - # - # class Person < ActiveRecord::Base - # has_many :shirts - # end - # - # then <tt>elton.shirts.red.dry_clean_only</tt> 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| where(:color => color) } - # end - # - # In this example, <tt>Shirt.colored('puce')</tt> finds all puce shirts. - # - # On Ruby 1.9 you can use the 'stabby lambda' syntax: - # - # scope :colored, ->(color) { where(:color => color) } - # - # Note that scopes defined with \scope will be evaluated when they are defined, rather than - # when they are used. For example, the following would be incorrect: - # - # class Post < ActiveRecord::Base - # scope :recent, where('published_at >= ?', Time.now - 1.week) - # end - # - # The example above would be 'frozen' to the <tt>Time.now</tt> value when the <tt>Post</tt> - # class was defined, and so the resultant SQL query would always be the same. The correct - # way to do this would be via a lambda, which will re-evaluate the scope each time - # it is called: - # - # class Post < ActiveRecord::Base - # scope :recent, lambda { where('published_at >= ?', Time.now - 1.week) } - # end - # - # Named \scopes can also have extensions, just as with <tt>has_many</tt> declarations: - # - # class Shirt < ActiveRecord::Base - # scope :red, where(:color => 'red') do - # def dom_id - # 'red_shirts' - # end - # end - # end - # - # Scopes can also be used while creating/building a record. - # - # class Article < ActiveRecord::Base - # scope :published, where(:published => true) - # end - # - # Article.published.new.published # => true - # Article.published.create.published # => true - # - # Class methods on your model are automatically available - # on scopes. Assuming the following setup: - # - # class Article < ActiveRecord::Base - # scope :published, where(:published => true) - # scope :featured, where(:featured => true) - # - # def self.latest_article - # order('published_at desc').first - # end - # - # def self.titles - # map(&:title) - # end - # - # end - # - # We are able to call the methods like this: - # - # Article.published.featured.latest_article - # Article.featured.titles - - def scope(name, scope_options = {}) - name = name.to_sym - valid_scope_name?(name) - extension = Module.new(&Proc.new) if block_given? - - scope_proc = lambda do |*args| - options = scope_options.respond_to?(:call) ? scope_options.call(*args) : scope_options - options = scoped.apply_finder_options(options) if options.is_a?(Hash) - - relation = scoped.merge(options) - - extension ? relation.extending(extension) : relation - end - - singleton_class.send(:redefine_method, name, &scope_proc) - end - - protected - - def valid_scope_name?(name) - if respond_to?(name, true) - logger.warn "Creating scope :#{name}. " \ - "Overwriting existing method #{self.name}.#{name}." - end - end - end - end -end |