Add student count to course's classes, prevent empty add student

apiserver/export_class_report.py

@@ -0,0 +1,22 @@
+import django, sys, os
+os.environ['DJANGO_SETTINGS_MODULE'] = 'apiserver.settings'
+django.setup()
+
+import csv
+from apiserver.api import models
+
+sessions = models.Session.objects.filter(datetime__gte='2021-01-01')
+
+with open('output.csv', 'w', newline='') as csvfile:
+    fields = ['date', 'name', 'num_students']
+    writer = csv.DictWriter(csvfile, fieldnames=fields)
+
+    writer.writeheader()
+
+    for s in sessions:
+        writer.writerow(dict(
+            date=s.datetime.date(),
+            name=s.course.name,
+            num_students=s.students.filter(attendance_status='Attended').count(),
+        ))
+