Django - How to filter by date with Django Rest Framework?

orange1 picture orange1 · May 12, 2016 · Viewed 20.6k times · Source

I have some model with a timestamp field:

models.py

class Event(models.Model):
    event_type = models.CharField(
        max_length=100,
        choices=EVENT_TYPE_CHOICES,
        verbose_name=_("Event Type")
    )
    event_model = models.CharField(
        max_length=100,
        choices=EVENT_MODEL_CHOICES,
        verbose_name=_("Event Model")
    )
    timestamp = models.DateTimeField(auto_now=True, verbose_name=_("Timestamp"))

I'm then using Django-rest-framework to create an API endpoint for this class, with django-filter providing a filtering functionality as follows:

from .models import Event
from .serializers import EventSerializer
from rest_framework import viewsets, filters
from rest_framework import renderers
from rest_framework_csv import renderers as csv_renderers


class EventsView(viewsets.ReadOnlyModelViewSet):
    """
    A read only view that returns all audit events in JSON or CSV.
    """
    queryset = Event.objects.all()
    renderer_classes = (csv_renderers.CSVRenderer, renderers.JSONRenderer)
    serializer_class = EventSerializer
    filter_backends = (filters.DjangoFilterBackend,)
    filter_fields = ('event_type', 'event_model', 'timestamp')

with the following settings:

REST_FRAMEWORK = {
    'DEFAULT_FILTER_BACKENDS': ('rest_framework.filters.DjangoFilterBackend',),
}

I'm able to filter by event_type and event_model, but am having trouble filtering by the timestamp field. Essentially, I want to make an API call that equates to the following:

AuditEvent.objects.filter(timestamp__gte='2016-01-02 00:00+0000')

which I would expect I could do as follows:

response = self.client.get("/api/v1/events/?timestamp=2016-01-02 00:00+0000", **{'HTTP_ACCEPT': 'application/json'})

though that is incorect. How do I make an API call that returns all objects with a timestamp greater than or equal to a certain value?

Answer

clwainwright picture clwainwright · Aug 10, 2016

To expand on Flaiming's answer, if you're only ever going to be filtering via ISO datetime formats, it helps to overwrite the defaults to always use the IsoDateTimeFilter. This can be done per filterset with e.g.

from django.db import models as django_models
import django_filters
from rest_framework import filters
from rest_framework import viewsets

class EventFilter(filters.FilterSet):
    class Meta:
        model = Event
        fields = {
            'timestamp': ('lte', 'gte')
        }

    filter_overrides = {
        django_models.DateTimeField: {
            'filter_class': django_filters.IsoDateTimeFilter
        },
    }

class EventsView(viewsets.ReadOnlyModelViewSet):
    ...
    filter_class = EventFilter

You then won't have to worry about setting a different filter for each lookup expression and each field.