fix the plots

The date was validated when the application startet not everytime the
view was called. This commit moves the date calculation to the view.

sensors/collector/plot.py

@@ -1,13 +1,9 @@
-from datetime import timedelta
-from datetime import datetime
 from plotly.offline import plot
 from plotly.graph_objs import Scatter
 from collector.models import Temperature, Humidity, Pressure
 
 
-start_time = datetime.now() - timedelta(hours=12)
-
-def temperature():
+def temperature(start_time):
     data = Temperature.objects.filter(time__gt=start_time)
     x_axis = []
     y_axis = []
@@ -22,7 +18,7 @@ def temperature():
     return plot_div
 
 
-def humidity():
+def humidity(start_time):
     data = Humidity.objects.filter(time__gt=start_time)
     x_axis = []
     y_axis = []
@@ -37,7 +33,7 @@ def humidity():
     return plot_div
 
 
-def pressure():
+def pressure(start_time):
     data = Pressure.objects.filter(time__gt=start_time)
     x_axis = []
     y_axis = []

sensors/collector/views.py

@@ -1,10 +1,12 @@
+from datetime import datetime, timedelta
 from django.shortcuts import render
 from . import plot
 
 def index_view(request):
-    plot_temp = plot.temperature()
-    plot_humidity = plot.humidity()
-    plot_pressure = plot.pressure()
+    start_time = datetime.now() - timedelta(hours=24)
+    plot_temp = plot.temperature(start_time)
+    plot_humidity = plot.humidity(start_time)
+    plot_pressure = plot.pressure(start_time)
     return render(request, "collector/index.html",
                   context={'plot_temp': plot_temp,
                            'plot_humidity': plot_humidity,