diff options
Diffstat (limited to 'activerecord/lib/active_record/default_scope.rb')
| -rw-r--r-- | activerecord/lib/active_record/default_scope.rb | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/default_scope.rb b/activerecord/lib/active_record/default_scope.rb new file mode 100644 index 0000000000..dd637ad6c5 --- /dev/null +++ b/activerecord/lib/active_record/default_scope.rb @@ -0,0 +1,138 @@ +require 'active_support/concern' + +module ActiveRecord + module DefaultScope + extend ActiveSupport::Concern + + included do + # Stores the default scope for the class + class_attribute :default_scopes, :instance_writer => false + self.default_scopes = [] + end + + module ClassMethods + # Returns a scope for this class without taking into account the default_scope. + # + # class Post < ActiveRecord::Base + # def self.default_scope + # where :published => true + # end + # end + # + # Post.all # Fires "SELECT * FROM posts WHERE published = true" + # Post.unscoped.all # Fires "SELECT * FROM posts" + # + # This method also accepts a block meaning that all queries inside the block will + # not use the default_scope: + # + # Post.unscoped { + # Post.limit(10) # Fires "SELECT * FROM posts LIMIT 10" + # } + # + # It is recommended to use block form of unscoped because chaining unscoped with <tt>scope</tt> + # does not work. Assuming that <tt>published</tt> is a <tt>scope</tt> following two statements are same. + # + # Post.unscoped.published + # Post.published + def unscoped #:nodoc: + block_given? ? relation.scoping { yield } : relation + end + + def before_remove_const #:nodoc: + self.current_scope = nil + end + + protected + + # Use this macro in your model to set a default scope for all operations on + # the model. + # + # class Article < ActiveRecord::Base + # default_scope where(:published => true) + # end + # + # Article.all # => SELECT * FROM articles WHERE published = true + # + # The <tt>default_scope</tt> is also applied while creating/building a record. It is not + # applied while updating a record. + # + # Article.new.published # => true + # Article.create.published # => true + # + # You can also use <tt>default_scope</tt> with a block, in order to have it lazily evaluated: + # + # class Article < ActiveRecord::Base + # default_scope { where(:published_at => Time.now - 1.week) } + # end + # + # (You can also pass any object which responds to <tt>call</tt> to the <tt>default_scope</tt> + # macro, and it will be called when building the default scope.) + # + # If you use multiple <tt>default_scope</tt> declarations in your model then they will + # be merged together: + # + # class Article < ActiveRecord::Base + # default_scope where(:published => true) + # default_scope where(:rating => 'G') + # end + # + # Article.all # => SELECT * FROM articles WHERE published = true AND rating = 'G' + # + # This is also the case with inheritance and module includes where the parent or module + # defines a <tt>default_scope</tt> and the child or including class defines a second one. + # + # If you need to do more complex things with a default scope, you can alternatively + # define it as a class method: + # + # class Article < ActiveRecord::Base + # def self.default_scope + # # Should return a scope, you can call 'super' here etc. + # end + # end + def default_scope(scope = {}) + scope = Proc.new if block_given? + self.default_scopes = default_scopes + [scope] + end + + def build_default_scope #:nodoc: + if method(:default_scope).owner != DefaultScope::ClassMethods + evaluate_default_scope { default_scope } + elsif default_scopes.any? + evaluate_default_scope do + default_scopes.inject(relation) do |default_scope, scope| + if scope.is_a?(Hash) + default_scope.apply_finder_options(scope) + elsif !scope.is_a?(Relation) && scope.respond_to?(:call) + default_scope.merge(scope.call) + else + default_scope.merge(scope) + end + end + end + end + end + + def ignore_default_scope? #:nodoc: + Thread.current["#{self}_ignore_default_scope"] + end + + def ignore_default_scope=(ignore) #:nodoc: + Thread.current["#{self}_ignore_default_scope"] = ignore + end + + # The ignore_default_scope flag is used to prevent an infinite recursion situation where + # a default scope references a scope which has a default scope which references a scope... + def evaluate_default_scope + return if ignore_default_scope? + + begin + self.ignore_default_scope = true + yield + ensure + self.ignore_default_scope = false + end + end + + end + end +end |