我想对ActiveRecord模型像这样的一包非常通用的命名范围的:
I am trying to have a pack of very generic named scopes for ActiveRecord models like this one:
module Scopes
def self.included(base)
base.class_eval do
named_scope :not_older_than, lambda {|interval|
{:conditions => ["#{table_name}.created_at >= ?", interval.ago]
}
end
end
end
ActiveRecord::Base.send(:include, Scopes)
class User < ActiveRecord::Base
end
如果指定的范围应是一般情况下,我们需要指定* table_name的*为prevent命名问题,如果他们的就是加入了来自其他链接命名范围。
If the named scope should be general, we need to specify *table_name* to prevent naming problems if their is joins that came from other chained named scope.
现在的问题是,我们不能得到table_name的,因为它要求的ActiveRecord :: Base的而不是在用户。
The problem is that we can't get table_name because it is called on ActiveRecord::Base rather then on User.
User.not_older_than(1.week)
NoMethodError: undefined method `abstract_class?' for Object:Class
from /var/lib/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:2207:in `class_of_active_record_descendant'
from /var/lib/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:1462:in `base_class'
from /var/lib/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:1138:in `reset_table_name'
from /var/lib/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:1134:in `table_name'
from /home/bogdan/makabu/railsware/startwire/repository/lib/core_ext/active_record/base.rb:15:in `included'
from /var/lib/gems/1.8/gems/activerecord-2.3.5/lib/active_record/named_scope.rb:92:in `call'
from /var/lib/gems/1.8/gems/activerecord-2.3.5/lib/active_record/named_scope.rb:92:in `named_scope'
from /var/lib/gems/1.8/gems/activerecord-2.3.5/lib/active_record/named_scope.rb:97:in `call'
from /var/lib/gems/1.8/gems/activerecord-2.3.5/lib/active_record/named_scope.rb:97:in `not_older_than'
我怎样才能得到实际的table_name的在作用域模块?
How can I get actual table_name at Scopes module?
尝试使用#scoped方法中的ActiveRecord :: Base的类方法。这应该工作:
Try using the #scoped method inside a class method of ActiveRecord::Base. This should work:
module Scopes
def self.included(base)
base.class_eval do
def self.not_older_than(interval)
scoped(:conditions => ["#{table_name}.created_at > ?", interval.ago])
end
end
end
end
ActiveRecord::Base.send(:include, Scopes)