API improvements

bite/telemetry/serializers.py

@@ -22,6 +22,17 @@ from api.models import Device
 from telemetry.models import Telemetry
 
 
+class TelemetryStatsSerializer(serializers.Serializer):
+    count_samples = serializers.IntegerField()
+    first_sample = serializers.DateTimeField()
+    last_sample = serializers.DateTimeField()
+
+
+class TelemetrySummarySerializer(serializers.Serializer):
+    device = serializers.CharField()
+    stats = TelemetryStatsSerializer()
+
+
 class TelemetrySerializer(serializers.ModelSerializer):
     device = serializers.SlugRelatedField(
         slug_field='serial',

bite/telemetry/urls.py

@@ -33,14 +33,15 @@ Including another URLconf
     2. Add a URL to urlpatterns:  path('blog/', include('blog.urls'))
 """
 from django.urls import path
-from telemetry.views import TelemetryView, TelemetryLatest, TelemetryRange
+from telemetry.views import (TelemetryView, TelemetrySummaryView,
+                             TelemetryLatest, TelemetryRange)
 
 urlpatterns = [
     path('',
          TelemetryView.as_view({'post': 'create'}),
          name='telemetry'),
     path('<str:device>/',
-         TelemetryView.as_view({'get': 'list'}),
+         TelemetrySummaryView.as_view(),
          name='device-telemetry'),
     path('<str:device>/last/',
          TelemetryLatest.as_view({'get': 'retrieve'}),

bite/telemetry/views.py

@@ -17,12 +17,14 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-from datetime import datetime
+from datetime import datetime, timedelta
 from django.http import Http404
+from rest_framework.views import APIView
 from rest_framework.viewsets import ModelViewSet
 
 from telemetry.models import Telemetry
-from telemetry.serializers import TelemetrySerializer
+from telemetry.serializers import (TelemetrySerializer,
+                                   TelemetrySummarySerializer)
 from rest_framework.response import Response
 
 
@@ -39,15 +41,38 @@ class TelemetryView(ModelViewSet):
         return Response(serializer.data)
 
 
+class TelemetrySummaryView(APIView):
+    def get(self, request, device, format=None):
+        count = Telemetry.objects.filter(device__serial=device).count()
+        if count == 0:
+            raise Http404
+        first = Telemetry.objects.filter(
+            device__serial=device).order_by('-time')[:1][0]
+        last = Telemetry.objects.filter(
+            device__serial=device).order_by('time')[:1][0]
+        data = {
+            'device': device,
+            'stats': {
+                'count_samples': count,
+                'first_sample': first.time,
+                'last_sample': last.time}
+        }
+
+        serializer = TelemetrySummarySerializer(data)
+
+        return Response(serializer.data)
+
+
 class TelemetryRange(ModelViewSet):
     queryset = Telemetry.objects.all()
     serializer_class = TelemetrySerializer
     lookup_field = 'device'
 
     def list(self, request, device, time_from, time_to=None):
+        time_to = datetime.now() if time_to is None else time_to
         queryset = Telemetry.objects.filter(
             device__serial=device,
-            time__range=[time_from, datetime.now()])
+            time__range=[time_from, time_to])
         if not queryset:
             raise Http404
         serializer = TelemetrySerializer(queryset, many=True)
@@ -61,7 +86,7 @@ class TelemetryLatest(ModelViewSet):
 
     def retrieve(self, request, device=None):
         queryset = Telemetry.objects.filter(
-            device__serial=device).order_by('-time')
+            device__serial=device).order_by('-time')[:1]
         if not queryset:
             raise Http404
         serializer = TelemetrySerializer(queryset[0])