Python django.db.models.DateField() Examples

def get_queryset(self):
        date = self._extract_date()
        user = self.request.user
        queryset = get_user_model().objects.values("id")
        queryset = queryset.annotate(date=Value(date, DateField()))
        # last_reported_date filter is set, a date can only be calucated
        # for users with either at least one absence or report
        if date is None:
            users_with_reports = Report.objects.values("user").distinct()
            users_with_absences = Absence.objects.values("user").distinct()
            active_users = users_with_reports.union(users_with_absences)
            queryset = queryset.filter(id__in=active_users)

        queryset = queryset.annotate(
            pk=Concat("id", Value("_"), "date", output_field=CharField())
        )

        if not user.is_superuser:
            queryset = queryset.filter(Q(id=user.id) | Q(supervisors=user))

        return queryset 

def get_queryset(self):
        date = self._extract_date()
        user = self._extract_user()

        queryset = models.AbsenceType.objects.values("id")
        queryset = queryset.annotate(date=Value(date, DateField()))
        queryset = queryset.annotate(user=Value(user.id, IntegerField()))
        queryset = queryset.annotate(
            pk=Concat(
                "user", Value("_"), "id", Value("_"), "date", output_field=CharField()
            )
        )

        # only myself, superuser and supervisors may see by absence balances
        current_user = self.request.user

        if not current_user.is_superuser:
            if current_user.id != user.id:
                if not current_user.supervisees.filter(id=user.id).exists():
                    return models.AbsenceType.objects.none()

        return queryset 

def display_for_field(value, field):
    from xadmin.views.list import EMPTY_CHANGELIST_VALUE

    if field.flatchoices:
        return dict(field.flatchoices).get(value, EMPTY_CHANGELIST_VALUE)
    # NullBooleanField needs special-case null-handling, so it comes
    # before the general null test.
    elif isinstance(field, models.BooleanField) or isinstance(field, models.NullBooleanField):
        return boolean_icon(value)
    elif value is None:
        return EMPTY_CHANGELIST_VALUE
    elif isinstance(field, models.DateTimeField):
        return formats.localize(tz_localtime(value))
    elif isinstance(field, (models.DateField, models.TimeField)):
        return formats.localize(value)
    elif isinstance(field, models.DecimalField):
        return formats.number_format(value, field.decimal_places)
    elif isinstance(field, models.FloatField):
        return formats.number_format(value)
    elif isinstance(field.rel, models.ManyToManyRel):
        return ', '.join([smart_text(obj) for obj in value.all()])
    else:
        return smart_text(value) 

def display_for_field(value, field):
    from django.contrib.admin.templatetags.admin_list import _boolean_icon
    from django.contrib.admin.views.main import EMPTY_CHANGELIST_VALUE

    if field.flatchoices:
        return dict(field.flatchoices).get(value, EMPTY_CHANGELIST_VALUE)
    # NullBooleanField needs special-case null-handling, so it comes
    # before the general null test.
    elif isinstance(field, models.BooleanField) or isinstance(field, models.NullBooleanField):
        return _boolean_icon(value)
    elif value is None:
        return EMPTY_CHANGELIST_VALUE
    elif isinstance(field, models.DateTimeField):
        return formats.localize(timezone.template_localtime(value))
    elif isinstance(field, (models.DateField, models.TimeField)):
        return formats.localize(value)
    elif isinstance(field, models.DecimalField):
        return formats.number_format(value, field.decimal_places)
    elif isinstance(field, models.FloatField):
        return formats.number_format(value)
    elif isinstance(field, models.FileField) and value:
        return format_html('<a href="{}">{}</a>', value.url, value)
    else:
        return smart_text(value) 

def _check_date_hierarchy(self, cls, model):
        """ Check that date_hierarchy refers to DateField or DateTimeField. """

        if cls.date_hierarchy is None:
            return []
        else:
            try:
                field = model._meta.get_field(cls.date_hierarchy)
            except FieldDoesNotExist:
                return refer_to_missing_field(option='date_hierarchy',
                                              field=cls.date_hierarchy,
                                              model=model, obj=cls, id='admin.E127')
            else:
                if not isinstance(field, (models.DateField, models.DateTimeField)):
                    return must_be('a DateField or DateTimeField', option='date_hierarchy',
                                   obj=cls, id='admin.E128')
                else:
                    return [] 

def display_for_field(value, field, empty_value_display):
    from django.contrib.admin.templatetags.admin_list import _boolean_icon

    if getattr(field, 'flatchoices', None):
        return dict(field.flatchoices).get(value, empty_value_display)
    # NullBooleanField needs special-case null-handling, so it comes
    # before the general null test.
    elif isinstance(field, (models.BooleanField, models.NullBooleanField)):
        return _boolean_icon(value)
    elif value is None:
        return empty_value_display
    elif isinstance(field, models.DateTimeField):
        return formats.localize(timezone.template_localtime(value))
    elif isinstance(field, (models.DateField, models.TimeField)):
        return formats.localize(value)
    elif isinstance(field, models.DecimalField):
        return formats.number_format(value, field.decimal_places)
    elif isinstance(field, (models.IntegerField, models.FloatField)):
        return formats.number_format(value)
    elif isinstance(field, models.FileField) and value:
        return format_html('<a href="{}">{}</a>', value.url, value)
    else:
        return display_for_value(value, empty_value_display) 

def _check_date_hierarchy(self, obj):
        """ Check that date_hierarchy refers to DateField or DateTimeField. """

        if obj.date_hierarchy is None:
            return []
        else:
            try:
                field = get_fields_from_path(obj.model, obj.date_hierarchy)[-1]
            except (NotRelationField, FieldDoesNotExist):
                return [
                    checks.Error(
                        "The value of 'date_hierarchy' refers to '%s', which "
                        "does not refer to a Field." % obj.date_hierarchy,
                        obj=obj.__class__,
                        id='admin.E127',
                    )
                ]
            else:
                if not isinstance(field, (models.DateField, models.DateTimeField)):
                    return must_be('a DateField or DateTimeField', option='date_hierarchy', obj=obj, id='admin.E128')
                else:
                    return [] 

def display_for_field(value, field):
    from xadmin.views.list import EMPTY_CHANGELIST_VALUE

    if field.flatchoices:
        return dict(field.flatchoices).get(value, EMPTY_CHANGELIST_VALUE)
    # NullBooleanField needs special-case null-handling, so it comes
    # before the general null test.
    elif isinstance(field, models.BooleanField) or isinstance(field, models.NullBooleanField):
        return boolean_icon(value)
    elif value is None:
        return EMPTY_CHANGELIST_VALUE
    elif isinstance(field, models.DateTimeField):
        return formats.localize(tz_localtime(value))
    elif isinstance(field, (models.DateField, models.TimeField)):
        return formats.localize(value)
    elif isinstance(field, models.DecimalField):
        return formats.number_format(value, field.decimal_places)
    elif isinstance(field, models.FloatField):
        return formats.number_format(value)
    elif isinstance(field.remote_field, models.ManyToManyRel):
        return ', '.join([smart_text(obj) for obj in value.all()])
    else:
        return smart_text(value) 

def build_default_field(self, field, model):
        choices = getattr(field, "choices", None)
        if choices:
            return forms.ChoiceField(
                required=False,
                label=_("Default value"),
                choices=[(None, "-----------")] + list(choices),
            )
        if not (model is Member and field.name == "number"):
            if isinstance(field, models.CharField):
                return forms.CharField(required=False, label=_("Default value"))
            elif isinstance(field, models.DecimalField):
                return forms.DecimalField(
                    required=False,
                    label=_("Default value"),
                    max_digits=field.max_digits,
                    decimal_places=field.decimal_places,
                )
            elif isinstance(field, models.DateField):
                return forms.CharField(required=False, label=_("Other/fixed date")) 

def display_for_field(value, field):
    from xadmin.views.list import EMPTY_CHANGELIST_VALUE

    if field.flatchoices:
        return dict(field.flatchoices).get(value, EMPTY_CHANGELIST_VALUE)
    # NullBooleanField needs special-case null-handling, so it comes
    # before the general null test.
    elif isinstance(field, models.BooleanField) or isinstance(field, models.NullBooleanField):
        return boolean_icon(value)
    elif value is None:
        return EMPTY_CHANGELIST_VALUE
    elif isinstance(field, models.DateTimeField):
        return formats.localize(tz_localtime(value))
    elif isinstance(field, (models.DateField, models.TimeField)):
        return formats.localize(value)
    elif isinstance(field, models.DecimalField):
        return formats.number_format(value, field.decimal_places)
    elif isinstance(field, models.FloatField):
        return formats.number_format(value)
    elif isinstance(field.remote_field, models.ManyToManyRel):
        return ', '.join([smart_text(obj) for obj in value.all()])
    else:
        return smart_text(value) 

def display_for_field(value, field):
    from xadmin.views.list import EMPTY_CHANGELIST_VALUE

    if field.flatchoices:
        return dict(field.flatchoices).get(value, EMPTY_CHANGELIST_VALUE)
    # NullBooleanField needs special-case null-handling, so it comes
    # before the general null test.
    elif isinstance(field, models.BooleanField) or isinstance(field, models.NullBooleanField):
        return boolean_icon(value)
    elif value is None:
        return EMPTY_CHANGELIST_VALUE
    elif isinstance(field, models.DateTimeField):
        return formats.localize(tz_localtime(value))
    elif isinstance(field, (models.DateField, models.TimeField)):
        return formats.localize(value)
    elif isinstance(field, models.DecimalField):
        return formats.number_format(value, field.decimal_places)
    elif isinstance(field, models.FloatField):
        return formats.number_format(value)
    elif isinstance(field.remote_field, models.ManyToManyRel):
        return ', '.join([smart_text(obj) for obj in value.all()])
    else:
        return smart_text(value) 

def display_for_field(value, field):
    from xadmin.views.list import EMPTY_CHANGELIST_VALUE

    if field.flatchoices:
        return dict(field.flatchoices).get(value, EMPTY_CHANGELIST_VALUE)
    # NullBooleanField needs special-case null-handling, so it comes
    # before the general null test.
    elif isinstance(field, models.BooleanField) or isinstance(field, models.NullBooleanField):
        return boolean_icon(value)
    elif value is None:
        return EMPTY_CHANGELIST_VALUE
    elif isinstance(field, models.DateTimeField):
        return formats.localize(tz_localtime(value))
    elif isinstance(field, (models.DateField, models.TimeField)):
        return formats.localize(value)
    elif isinstance(field, models.DecimalField):
        return formats.number_format(value, field.decimal_places)
    elif isinstance(field, models.FloatField):
        return formats.number_format(value)
    elif isinstance(field.remote_field, models.ManyToManyRel):
        return ', '.join([smart_text(obj) for obj in value.all()])
    else:
        return smart_text(value) 

def load_dates(context):
    data = {}
    cl = context.get('cl')
    if cl.has_filters:
        for spec in cl.filter_specs:
            # 自定义的filter，没有field
            if not hasattr(spec, 'field'):
                continue

            field = spec.field
            field_type = None
            if isinstance(field, models.DateTimeField):
                field_type = 'datetime'
            elif isinstance(field, models.DateField):
                field_type = 'date'
            elif isinstance(field, models.TimeField):
                field_type = 'time'

            if field_type:
                data[spec.field_path] = field_type
    context['date_field'] = data

    return '<script type="text/javascript">var searchDates={}</script>'.format(json.dumps(data, cls=LazyEncoder)) 

def display_for_field(value, field, empty_value_display):
    from django.contrib.admin.templatetags.admin_list import _boolean_icon

    if getattr(field, 'flatchoices', None):
        return dict(field.flatchoices).get(value, empty_value_display)
    # BooleanField needs special-case null-handling, so it comes before the
    # general null test.
    elif isinstance(field, models.BooleanField):
        return _boolean_icon(value)
    elif value is None:
        return empty_value_display
    elif isinstance(field, models.DateTimeField):
        return formats.localize(timezone.template_localtime(value))
    elif isinstance(field, (models.DateField, models.TimeField)):
        return formats.localize(value)
    elif isinstance(field, models.DecimalField):
        return formats.number_format(value, field.decimal_places)
    elif isinstance(field, (models.IntegerField, models.FloatField)):
        return formats.number_format(value)
    elif isinstance(field, models.FileField) and value:
        return format_html('<a href="{}">{}</a>', value.url, value)
    else:
        return display_for_value(value, empty_value_display) 

def _check_date_hierarchy(self, obj):
        """ Check that date_hierarchy refers to DateField or DateTimeField. """

        if obj.date_hierarchy is None:
            return []
        else:
            try:
                field = get_fields_from_path(obj.model, obj.date_hierarchy)[-1]
            except (NotRelationField, FieldDoesNotExist):
                return [
                    checks.Error(
                        "The value of 'date_hierarchy' refers to '%s', which "
                        "does not refer to a Field." % obj.date_hierarchy,
                        obj=obj.__class__,
                        id='admin.E127',
                    )
                ]
            else:
                if not isinstance(field, (models.DateField, models.DateTimeField)):
                    return must_be('a DateField or DateTimeField', option='date_hierarchy', obj=obj, id='admin.E128')
                else:
                    return [] 

def display_for_field(value, field, empty_value_display):
    from django.contrib.admin.templatetags.admin_list import _boolean_icon

    if getattr(field, 'flatchoices', None):
        return dict(field.flatchoices).get(value, empty_value_display)
    # NullBooleanField needs special-case null-handling, so it comes
    # before the general null test.
    elif isinstance(field, models.BooleanField) or isinstance(field, models.NullBooleanField):
        return _boolean_icon(value)
    elif value is None:
        return empty_value_display
    elif isinstance(field, models.DateTimeField):
        return formats.localize(timezone.template_localtime(value))
    elif isinstance(field, (models.DateField, models.TimeField)):
        return formats.localize(value)
    elif isinstance(field, models.DecimalField):
        return formats.number_format(value, field.decimal_places)
    elif isinstance(field, (models.IntegerField, models.FloatField)):
        return formats.number_format(value)
    elif isinstance(field, models.FileField) and value:
        return format_html('<a href="{}">{}</a>', value.url, value)
    else:
        return display_for_value(value, empty_value_display) 

def _check_date_hierarchy(self, obj):
        """ Check that date_hierarchy refers to DateField or DateTimeField. """

        if obj.date_hierarchy is None:
            return []
        else:
            try:
                field = get_fields_from_path(obj.model, obj.date_hierarchy)[-1]
            except (NotRelationField, FieldDoesNotExist):
                return [
                    checks.Error(
                        "The value of 'date_hierarchy' refers to '%s', which "
                        "does not refer to a Field." % obj.date_hierarchy,
                        obj=obj.__class__,
                        id='admin.E127',
                    )
                ]
            else:
                if not isinstance(field, (models.DateField, models.DateTimeField)):
                    return must_be('a DateField or DateTimeField', option='date_hierarchy', obj=obj, id='admin.E128')
                else:
                    return [] 

def display_for_field(value, field, empty_value_display):
    from django.contrib.admin.templatetags.admin_list import _boolean_icon

    if field.flatchoices:
        return dict(field.flatchoices).get(value, empty_value_display)
    # NullBooleanField needs special-case null-handling, so it comes
    # before the general null test.
    elif isinstance(field, models.BooleanField) or isinstance(field, models.NullBooleanField):
        return _boolean_icon(value)
    elif value is None:
        return empty_value_display
    elif isinstance(field, models.DateTimeField):
        return formats.localize(timezone.template_localtime(value))
    elif isinstance(field, (models.DateField, models.TimeField)):
        return formats.localize(value)
    elif isinstance(field, models.DecimalField):
        return formats.number_format(value, field.decimal_places)
    elif isinstance(field, (models.IntegerField, models.FloatField)):
        return formats.number_format(value)
    elif isinstance(field, models.FileField) and value:
        return format_html('<a href="{}">{}</a>', value.url, value)
    else:
        return smart_text(value) 

def _check_date_hierarchy(self, obj):
        """ Check that date_hierarchy refers to DateField or DateTimeField. """

        if obj.date_hierarchy is None:
            return []
        else:
            try:
                field = obj.model._meta.get_field(obj.date_hierarchy)
            except FieldDoesNotExist:
                return refer_to_missing_field(option='date_hierarchy',
                                              field=obj.date_hierarchy,
                                              model=obj.model, obj=obj, id='admin.E127')
            else:
                if not isinstance(field, (models.DateField, models.DateTimeField)):
                    return must_be('a DateField or DateTimeField', option='date_hierarchy',
                                   obj=obj, id='admin.E128')
                else:
                    return [] 

def display_for_field(value, field):
    from xadmin.views.list import EMPTY_CHANGELIST_VALUE

    if field.flatchoices:
        return dict(field.flatchoices).get(value, EMPTY_CHANGELIST_VALUE)
    # NullBooleanField needs special-case null-handling, so it comes
    # before the general null test.
    elif isinstance(field, models.BooleanField) or isinstance(field, models.NullBooleanField):
        return boolean_icon(value)
    elif value is None:
        return EMPTY_CHANGELIST_VALUE
    elif isinstance(field, models.DateTimeField):
        return formats.localize(tz_localtime(value))
    elif isinstance(field, (models.DateField, models.TimeField)):
        return formats.localize(value)
    elif isinstance(field, models.DecimalField):
        return formats.number_format(value, field.decimal_places)
    elif isinstance(field, models.FloatField):
        return formats.number_format(value)
    elif isinstance(field.remote_field, models.ManyToManyRel):
        return ', '.join([smart_text(obj) for obj in value.all()])
    else:
        return smart_text(value) 

def display_for_field(value, field, empty_value_display):
    from django.contrib.admin.templatetags.admin_list import _boolean_icon

    if getattr(field, 'flatchoices', None):
        return dict(field.flatchoices).get(value, empty_value_display)
    # NullBooleanField needs special-case null-handling, so it comes
    # before the general null test.
    elif isinstance(field, models.BooleanField) or isinstance(field, models.NullBooleanField):
        return _boolean_icon(value)
    elif value is None:
        return empty_value_display
    elif isinstance(field, models.DateTimeField):
        return formats.localize(timezone.template_localtime(value))
    elif isinstance(field, (models.DateField, models.TimeField)):
        return formats.localize(value)
    elif isinstance(field, models.DecimalField):
        return formats.number_format(value, field.decimal_places)
    elif isinstance(field, (models.IntegerField, models.FloatField)):
        return formats.number_format(value)
    elif isinstance(field, models.FileField) and value:
        return format_html('<a href="{}">{}</a>', value.url, value)
    else:
        return display_for_value(value, empty_value_display) 

def _check_date_hierarchy(self, obj):
        """ Check that date_hierarchy refers to DateField or DateTimeField. """

        if obj.date_hierarchy is None:
            return []
        else:
            try:
                field = get_fields_from_path(obj.model, obj.date_hierarchy)[-1]
            except (NotRelationField, FieldDoesNotExist):
                return [
                    checks.Error(
                        "The value of 'date_hierarchy' refers to '%s', which "
                        "does not refer to a Field." % obj.date_hierarchy,
                        obj=obj.__class__,
                        id='admin.E127',
                    )
                ]
            else:
                if not isinstance(field, (models.DateField, models.DateTimeField)):
                    return must_be('a DateField or DateTimeField', option='date_hierarchy', obj=obj, id='admin.E128')
                else:
                    return [] 

def display_for_field(value, field):
    from xadmin.views.list import EMPTY_CHANGELIST_VALUE

    if field.flatchoices:
        return dict(field.flatchoices).get(value, EMPTY_CHANGELIST_VALUE)
    # NullBooleanField needs special-case null-handling, so it comes
    # before the general null test.
    elif isinstance(field, models.BooleanField) or isinstance(field, models.NullBooleanField):
        return boolean_icon(value)
    elif value is None:
        return EMPTY_CHANGELIST_VALUE
    elif isinstance(field, models.DateTimeField):
        return formats.localize(tz_localtime(value))
    elif isinstance(field, (models.DateField, models.TimeField)):
        return formats.localize(value)
    elif isinstance(field, models.DecimalField):
        return formats.number_format(value, field.decimal_places)
    elif isinstance(field, models.FloatField):
        return formats.number_format(value)
    elif isinstance(field.rel, models.ManyToManyRel):
        return ', '.join([smart_text(obj) for obj in value.all()])
    else:
        return smart_text(value) 

def test(cls, field, request, params, model, admin_view, field_path):
        return isinstance(field, models.DateField) 

def display_for_field(value, field, html=True, only_date=True):
    if getattr(field, 'flatchoices', None):
        if html and field.name == 'color' and value:
            return make_color_icon(value)
        return dict(field.flatchoices).get(value, '')
    elif html and (isinstance(field, (models.BooleanField, models.NullBooleanField))):
        return make_boolean_icon(value)
    elif isinstance(field, (models.BooleanField, models.NullBooleanField)):
        boolchoice = {False: "否", True: "是"}
        return boolchoice.get(value)
    elif value is None:
        return ""
    elif isinstance(field, models.DecimalField):
        return formats.number_format(value, field.decimal_places)
    elif isinstance(field, (models.IntegerField, models.FloatField)):
        return formats.number_format(value)
    elif isinstance(field, models.ForeignKey) and value:
        rel_obj = field.related_model.objects.get(pk=value)
        if html and COLOR_FK_FIELD and isinstance(rel_obj, Option):
            text_color = rel_obj.color
            if not text_color:
                text_color = 'text-info'
            safe_value = format_html(
                '<span class="text-{}">{}</span>', text_color, rel_obj.text)
            return safe_value
        return force_text(rel_obj)
    elif isinstance(field, models.TextField) and value:
        return force_text(value)
    elif isinstance(field, models.DateTimeField):
        if only_date:
            return formats.date_format(value)
        return formats.localize(timezone.template_localtime(value))
    elif isinstance(field, (models.DateField, models.TimeField)):
        return formats.localize(value)
    elif isinstance(field, models.FileField) and value:
        return format_html('<a href="{}">{}</a>', value.url, value)
    else:
        return display_for_value(value) 

def validate_date_hierarchy(self, cls, model):
        " Validate that date_hierarchy refers to DateField or DateTimeField. "
        if cls.date_hierarchy:
            f = get_field(cls, model, 'date_hierarchy', cls.date_hierarchy)
            if not isinstance(f, (models.DateField, models.DateTimeField)):
                raise ImproperlyConfigured("'%s.date_hierarchy is "
                        "neither an instance of DateField nor DateTimeField."
                        % cls.__name__) 

def _generate_added_field(self, app_label, model_name, field_name):
        field = self.new_apps.get_model(app_label, model_name)._meta.get_field(field_name)
        # You can't just add NOT NULL fields with no default or fields
        # which don't allow empty strings as default.
        # CHANGED
        # < # Fields that are foreignkeys/m2ms depend on stuff
        # < dependencies = []
        # < if field.remote_field and field.remote_field.model:
        # <     dependencies.extend(self._get_dependencies_for_foreign_key(field))
        # XXX
        preserve_default = True
        time_fields = (models.DateField, models.DateTimeField, models.TimeField)
        if (not field.null and not field.has_default() and
                not field.many_to_many and
                not (field.blank and field.empty_strings_allowed) and
                not (isinstance(field, time_fields) and field.auto_now)):
            field = field.clone()
            if isinstance(field, time_fields) and field.auto_now_add:
                field.default = self.questioner.ask_auto_now_add_addition(field_name, model_name)
            else:
                field.default = self.questioner.ask_not_null_addition(field_name, model_name)
            preserve_default = False
        self.add_operation(
            app_label,
            operations.AddField(
                model_name=model_name,
                name=field_name,
                field=field,
                preserve_default=preserve_default,
            ),
            # CHANGED
            # < preserve_default=preserve_default,
            dependencies=field.dependencies,
            # XXX
        )

    # Replace dependencies logic 

def _generate_added_field(self, app_label, model_name, field_name):
        field = self.new_apps.get_model(app_label, model_name)._meta.get_field(field_name)
        # Fields that are foreignkeys/m2ms depend on stuff
        dependencies = []
        if field.remote_field and field.remote_field.model:
            dependencies.extend(self._get_dependencies_for_foreign_key(field))
        # You can't just add NOT NULL fields with no default or fields
        # which don't allow empty strings as default.
        preserve_default = True
        time_fields = (models.DateField, models.DateTimeField, models.TimeField)
        if (not field.null and not field.has_default() and
                not field.many_to_many and
                not (field.blank and field.empty_strings_allowed) and
                not (isinstance(field, time_fields) and field.auto_now)):
            field = field.clone()
            if isinstance(field, time_fields) and field.auto_now_add:
                field.default = self.questioner.ask_auto_now_add_addition(field_name, model_name)
            else:
                field.default = self.questioner.ask_not_null_addition(field_name, model_name)
            preserve_default = False
        self.add_operation(
            app_label,
            operations.AddField(
                model_name=model_name,
                name=field_name,
                field=field,
                preserve_default=preserve_default,
            ),
            dependencies=dependencies,
        ) 

def dates(self, field_name, kind, order='ASC'):
        """
        Return a list of date objects representing all available dates for
        the given field_name, scoped to 'kind'.
        """
        assert kind in ("year", "month", "day"), \
            "'kind' must be one of 'year', 'month' or 'day'."
        assert order in ('ASC', 'DESC'), \
            "'order' must be either 'ASC' or 'DESC'."
        return self.annotate(
            datefield=Trunc(field_name, kind, output_field=DateField()),
            plain_field=F(field_name)
        ).values_list(
            'datefield', flat=True
        ).distinct().filter(plain_field__isnull=False).order_by(('-' if order == 'DESC' else '') + 'datefield') 

def test(cls, field, request, params, model, admin_view, field_path):
        return isinstance(field, models.DateField)