python - many - Custom Filter in Django Admin on Django 1.3 or below




django admin many to many (6)

How can I add a custom filter to django admin (the filters that appear on the right side of a model dashboard)? I know its easy to include a filter based on a field of that model, but what about a "calculated" field like this:

class NewsItem(models.Model):
    headline = models.CharField(max_length=4096, blank=False)
    byline_1 = models.CharField(max_length=4096, blank=True)
    dateline = models.DateTimeField(help_text=_("date/time that appears on article"))
    body_copy = models.TextField(blank=False)

    when_to_publish = models.DateTimeField(verbose_name="When to publish",  blank=True, null=True)

    # HOW CAN I HAVE "is_live" as part of the admin filter?  It's a calculated state!!
    def is_live(self):
        if self.when_to_publish is not None:
            if ( self.when_to_publish < datetime.now() ):
                return """ <img alt="True" src="/media/img/admin/icon-yes.gif"/> """
        else:
            return """ <img alt="False" src="/media/img/admin/icon-no.gif"/> """      

    is_live.allow_tags = True

class NewsItemAdmin(admin.ModelAdmin):
    form = NewsItemAdminForm
    list_display = ('headline', 'id', 'is_live')
    list_filter = ('is_live')  #  how can i make this work??



Not an optimal way (CPU-wise) but simple and will work, so I do it this way (for my small database). My Django version is 1.6.

In admin.py:

class IsLiveFilter(admin.SimpleListFilter):
    title = 'Live'
    parameter_name = 'islive'
    def lookups(self, request, model_admin):
        return (
            ('1', 'islive'),
        )
    def queryset(self, request, queryset):
        if self.value():
            array = []
            for element in queryset:
                if element.is_live.__call__() == True:
                    q_array.append(element.id)
            return queryset.filter(pk__in=q_array)

...

class NewsItemAdmin(admin.ModelAdmin):
    form = NewsItemAdminForm
    list_display = ('headline', 'id', 'is_live')
    list_filter = (IsLiveFilter)

Key idea here is to access custom fields in a QuerySet via __call__() function.


Thanks to gpilotino for giving me the push into the right direction for implementing this.

I noticed the question's code is using a datetime to figure out when its live . So I used the DateFieldFilterSpec and subclassed it.

from django.db import models
from django.contrib.admin.filterspecs import FilterSpec, ChoicesFilterSpec,DateFieldFilterSpec
from django.utils.encoding import smart_unicode
from django.utils.translation import ugettext as _
from datetime import datetime

class IsLiveFilterSpec(DateFieldFilterSpec):
    """
    Adds filtering by future and previous values in the admin
    filter sidebar. Set the is_live_filter filter in the model field attribute
    'is_live_filter'.    my_model_field.is_live_filter = True
    """

    def __init__(self, f, request, params, model, model_admin):
        super(IsLiveFilterSpec, self).__init__(f, request, params, model,
                                               model_admin)
        today = datetime.now()
        self.links = (
            (_('Any'), {}),
            (_('Yes'), {'%s__lte' % self.field.name: str(today),
                       }),
            (_('No'), {'%s__gte' % self.field.name: str(today),
                    }),

        )


    def title(self):
        return "Is Live"

# registering the filter
FilterSpec.filter_specs.insert(0, (lambda f: getattr(f, 'is_live_filter', False),
                               IsLiveFilterSpec))

To use you can put the above code into a filters.py, and import it in the model you want to add the filter to


You can't, unfortunately. Currently non-field items can not be used as list_filter entries.

Note that your admin class wouldn't have worked even if it was a field, as a single-item tuple needs a comma: ('is_live',)








django-admin