The ever-present trips_year variable

One of the main design goals of the database rewrite was to make the database self sustaining and eliminate the need to deploy a new codebase every year. To this end, there is one TripsYear object for each year of Trips. Every other model in the database (except for User and a few configuration singletons) has a trips_year ForeignKey inherited from DatabaseModel.

Since every object has this field, we end up passing around trips_year values a lot.

The CBV TripsYearMixin handles trips_year in views. All views which have a trips_year url kwarg should inherit from it. It pulls the trips_year from url kwargs, filters querysets, automatically restricts related objects choices in forms to those of the same trips_year, and adds the trips_year of the view to the template context.

Objects for any trips_year may only relate (via ForeignKey, etc.) to objects of the same trips_year. Custom forms needs to filter field.queryset. TripsYearMixin takes care of this by default (see TripsYearMixin.get_form_class and tripsyear_modelform_factory()), but you need to be careful when using explicit form_class values in CBVs.

• Core Models
• Core Views
• Trips Year ModelForm Factory