Fix the birthdays calendar by refactoring the start/end date query parsing

website/events/api/viewsets.py

 """Defines the viewsets of the events package"""
-from datetime import datetime
 
 from django.utils import timezone
-from pytz.exceptions import InvalidTimeError
 from rest_framework import viewsets, filters
 from rest_framework.decorators import action
-from rest_framework.exceptions import ParseError, PermissionDenied, NotFound
+from rest_framework.exceptions import PermissionDenied, NotFound
 from rest_framework.generics import get_object_or_404
 from rest_framework.mixins import RetrieveModelMixin, UpdateModelMixin
 from rest_framework.permissions import (
@@ -26,27 +24,7 @@ from events.api.serializers import (
     RegistrationListSerializer, RegistrationSerializer)
 from events.exceptions import RegistrationError
 from events.models import Event, Registration
-
-
-def _extract_date(param):
-    """Extract the date from an arbitrary string"""
-    if param is None:
-        return None
-    try:
-        return timezone.make_aware(
-            datetime.strptime(param, '%Y-%m-%dT%H:%M:%S'))
-    except ValueError:
-        return timezone.make_aware(datetime.strptime(param, '%Y-%m-%d'))
-
-
-def _extract_date_range(request):
-    """Extract a date range from an arbitrary string"""
-    try:
-        start = _extract_date(request.query_params['start'])
-        end = _extract_date(request.query_params['end'])
-    except (ValueError, KeyError, InvalidTimeError) as e:
-        raise ParseError(detail='start or end query parameters invalid') from e
-    return end, start
+from utils.snippets import extract_date_range
 
 
 class EventViewset(viewsets.ReadOnlyModelViewSet):
@@ -65,14 +43,7 @@ class EventViewset(viewsets.ReadOnlyModelViewSet):
         if self.action == 'retrieve':
             return queryset
 
-        try:
-            start = _extract_date(self.request.query_params.get('start', None))
-        except (ValueError, InvalidTimeError) as e:
-            raise ParseError(detail='start query parameter invalid') from e
-        try:
-            end = _extract_date(self.request.query_params.get('end', None))
-        except (ValueError, InvalidTimeError) as e:
-            raise ParseError(detail='end query parameter invalid') from e
+        start, end = extract_date_range(self.request, allow_empty=True)
 
         if start is not None:
             queryset = queryset.filter(start__gte=start)
@@ -150,7 +121,7 @@ class EventViewset(viewsets.ReadOnlyModelViewSet):
 
         :return: response containing the data
         """
-        end, start = _extract_date_range(request)
+        start, end = extract_date_range(request)
 
         queryset = Event.objects.filter(
             end__gte=start,
@@ -172,7 +143,7 @@ class EventViewset(viewsets.ReadOnlyModelViewSet):
         :param request: the request object
         :return: response containing the data
         """
-        end, start = _extract_date_range(request)
+        start, end = extract_date_range(request)
 
         queryset = Event.objects.filter(
             end__gte=start,

website/members/api/viewsets.py

 import copy
-from datetime import datetime
 
-from django.utils import timezone
-from pytz.exceptions import InvalidTimeError
 from rest_framework import permissions
 from rest_framework import viewsets, filters
 from rest_framework.decorators import action
-from rest_framework.exceptions import ParseError
 from rest_framework.response import Response
 
 from members.api.serializers import (MemberBirthdaySerializer,
                                      MemberRetrieveSerializer,
                                      MemberListSerializer)
 from members.models import Member
-
-
-def _extract_date(param):
-    """Extract the date from an arbitrary string"""
-    if param is None:
-        return None
-    try:
-        return timezone.make_aware(
-                datetime.strptime(param, '%Y-%m-%dT%H:%M:%S'))
-    except ValueError:
-        return timezone.make_aware(datetime.strptime(param, '%Y-%m-%d'))
-
-
-def _extract_date_range(request):
-    """Extract a date range from an arbitrary string"""
-    try:
-        start = _extract_date(request.query_params['start'])
-        end = _extract_date(request.query_params['end'])
-    except (ValueError, KeyError, InvalidTimeError) as e:
-        raise ParseError(detail='start or end query parameters invalid') from e
-    return end, start
+from utils.snippets import extract_date_range
 
 
 class MemberViewset(viewsets.ReadOnlyModelViewSet):
@@ -77,14 +53,7 @@ class MemberViewset(viewsets.ReadOnlyModelViewSet):
 
     @action(detail=False)
     def birthdays(self, request):
-        try:
-            start = timezone.make_aware(
-                datetime.strptime(request.query_params['start'], '%Y-%m-%d')
-            )
-            end = _extract_date(request.query_params['end'])
-        except (ValueError, KeyError, InvalidTimeError) as e:
-            raise ParseError(
-                detail='start or end query parameters invalid') from e
+        start, end = extract_date_range(request)
 
         queryset = (
             Member.current_members

website/partners/api/viewsets.py

-from datetime import datetime
-
 from django.utils import timezone
-from pytz.exceptions import InvalidTimeError
 from rest_framework import viewsets, filters
 from rest_framework.decorators import action
-from rest_framework.exceptions import ParseError
 from rest_framework.permissions import (
-        IsAuthenticatedOrReadOnly, IsAuthenticated
+    IsAuthenticatedOrReadOnly, IsAuthenticated
 )
 from rest_framework.response import Response
 
 from partners.api.serializers import (
-        PartnerEventCalendarJSSerializer, PartnerEventSerializer,
-        PartnerSerializer
+    PartnerEventCalendarJSSerializer, PartnerEventSerializer,
+    PartnerSerializer
 )
 from partners.models import Partner, PartnerEvent
-
-
-def _extract_date(param):
-    """Extract the date from an arbitrary string"""
-    if param is None:
-        return None
-    try:
-        return timezone.make_aware(
-                datetime.strptime(param, '%Y-%m-%dT%H:%M:%S'))
-    except ValueError:
-        return timezone.make_aware(datetime.strptime(param, '%Y-%m-%d'))
-
-
-def _extract_date_range(request):
-    """Extract a date range from an arbitrary string"""
-    try:
-        start = _extract_date(request.query_params['start'])
-        end = _extract_date(request.query_params['end'])
-    except (ValueError, KeyError, InvalidTimeError) as e:
-        raise ParseError(detail='start or end query parameters invalid') from e
-    return end, start
+from utils.snippets import extract_date_range
 
 
 class PartnerViewset(viewsets.ReadOnlyModelViewSet):
@@ -44,7 +20,7 @@ class PartnerViewset(viewsets.ReadOnlyModelViewSet):
 
     @action(detail=False, permission_classes=(IsAuthenticatedOrReadOnly,))
     def calendarjs(self, request):
-        end, start = _extract_date_range(request)
+        start, end = extract_date_range(request)
 
         queryset = PartnerEvent.objects.filter(
             end__gte=start,

website/utils/snippets.py

@@ -2,10 +2,13 @@
 import hmac
 from _sha1 import sha1
 from base64 import urlsafe_b64decode, urlsafe_b64encode
+from datetime import datetime
 
 from django.conf import settings
 from django.utils import timezone
 from django.template.defaultfilters import urlencode
+from pytz import InvalidTimeError
+from rest_framework.exceptions import ParseError
 
 
 def datetime_to_lectureyear(date):
@@ -50,3 +53,34 @@ def create_google_maps_url(location, zoom, size):
     maps_url += f"&signature={encoded_signature.decode('utf-8')}"
 
     return "https://maps.googleapis.com" + maps_url
+
+
+def _extract_date(param):
+    """Extract the date from an arbitrary string"""
+    if param is None:
+        return None
+    try:
+        return timezone.make_aware(
+                datetime.strptime(param, '%Y-%m-%dT%H:%M:%S'))
+    except ValueError:
+        return timezone.make_aware(datetime.strptime(param, '%Y-%m-%d'))
+
+
+def extract_date_range(request, allow_empty=False):
+    """Extract a date range from an arbitrary string"""
+
+    default_value = ''
+    if allow_empty:
+        default_value = None
+
+    try:
+        start = _extract_date(request.query_params.get('start', default_value))
+    except (ValueError, InvalidTimeError) as e:
+        raise ParseError(detail='start query parameter invalid') from e
+
+    try:
+        end = _extract_date(request.query_params.get('end', default_value))
+    except (ValueError, InvalidTimeError) as e:
+        raise ParseError(detail='end query parameter invalid') from e
+
+    return start, end