Adding your own filter specs works easily by simply using this code within an applications admin.py
from django.contrib.admin.filterspecs import FilterSpec
class MyFilterSpec(FilterSpec):
...
FilterSpec.register(...)
However, since the last default FilterSpec? is always evaluated as True, and new FilterSpec?'s never get tested. It doesn't seem right to require a library file be modified in order to add a a feature to an application (for example, django-tagging which is what I was messing with when I found this.)
Since I don't know exactly what channels I should be going through to submit this as a patch, I'll just put the solution I found here. It's easy to fix if you add the following the FilterSpec?.
class FilterSpec(object):
filter_specs = []
default = None #added
...
def create(cls, f, request, params, model, model_admin):
for test, factory in cls.filter_specs:
if test(f):
return factory(f, request, params, model, model_admin)
### added after this point
if callable(default):
return default(f, request, params, model, model_admin)
create = classmethod(create)
# new method
def set_default(cls, factory):
if callable(factory):
cls.default = factory
set_default = classmethod(set_default)
Then, just replace the last line (which registers AllValuesFilterSpec?) with:
FilterSpec.set_default(AllValuesFilterSpec)
