Django 1.4 Alpha – Custom List Filter : RIP FilterSpec

Finally, it’s here in django trunk!

Easy to use custom List Filters (previously known as FilterSpecs)!

This ticket has always around for a while awaiting documentation and tests: thank you so much to julien for making it happen.
https://code.djangoproject.com/ticket/5833

This works like a charm.

Here’s the example straight out of the brand new docs on trunk:

from django.utils.translation import ugettext_lazy as _
from django.contrib.admin import SimpleListFilter

class DecadeBornListFilter(SimpleListFilter):
   # Human-readable title which will be displayed in the
   # right admin sidebar just above the filter options.
   title = _('decade born')

   # Parameter for the filter that will be used in the URL query.
   parameter_name = 'decade'

   def lookups(self, request, model_admin):
       """
       Returns a list of tuples. The first element in each
       tuple is the coded value for the option that will
       appear in the URL query. The second element is the
       human-readable name for the option that will appear
       in the right sidebar.
       """
       return (
           ('80s', _('in the eighties')),
           ('90s', _('in the nineties')),
       )

   def queryset(self, request, queryset):
       """
       Returns the filtered queryset based on the value
       provided in the query string and retrievable via
       `self.value()`.
       """
       # Compare the requested value (either '80s' or 'other')
       # to decide how to filter the queryset.
       if self.value() == '80s':
           return queryset.filter(birthday__year__gte=1980,
                                   birthday__year__lte=1989)
       if self.value() == '90s':
           return queryset.filter(birthday__year__gte=1990,
                                  birthday__year__lte=1999)

class PersonAdmin(ModelAdmin):
   list_filter = (DecadeBornListFilter,)