This chapter is from the book
This chapter is from the book
This chapter is from the book
This chapter is from the book
5.6 Hooks
DataMapper hooks differ from those used in Merb controllers. This is because controller filter chains require a decently specific form of logic. DataMapper models, on the other hand, have the benefit of using the more generic Hook class of Extlib.
From the application developer’s perspective, the two methods used to create hooks are before and after. DataMapper registers specific hooks for the methods save, create, update, and destroy. Each of these can be used with before and after.
module DataMapper
module Hook
def self.included(model)
model.class_eval <<-EOS, _ _FILE_ _, _ _LINE_ _
include Extlib::Hook
register_instance_hooks :save, :create,
:update, :destroy
EOS
end
end
DataMapper::Resource.append_inclusions Hook
end # module DataMapper