Display number of interests in course list

apiserver/apiserver/api/models.py

@@ -144,7 +144,7 @@ class Training(models.Model):
 
 class Interest(models.Model):
     user = models.ForeignKey(User, related_name='interests', null=True, on_delete=models.SET_NULL)
-    course = models.ForeignKey(Course, related_name='courses', null=True, on_delete=models.SET_NULL)
+    course = models.ForeignKey(Course, related_name='interests', null=True, on_delete=models.SET_NULL)
 
     satisfied_by = models.ForeignKey(Session, related_name='satisfies', null=True, on_delete=models.SET_NULL)
 

apiserver/apiserver/api/serializers.py

@@ -462,9 +462,11 @@ class StudentTrainingSerializer(TrainingSerializer):
 
 
 class CourseSerializer(serializers.ModelSerializer):
+    num_interested = serializers.IntegerField(read_only=True)
+
     class Meta:
         model = models.Course
-        fields = ['id', 'name', 'is_old', 'description', 'tags']
+        fields = ['id', 'name', 'is_old', 'description', 'tags', 'num_interested']
 
 class SessionSerializer(serializers.ModelSerializer):
     student_count = serializers.SerializerMethodField()

apiserver/apiserver/api/views.py

@@ -238,7 +238,13 @@ class CardViewSet(Base, Create, Retrieve, Update, Destroy):
 #       https://stackoverflow.com/a/58689019
 class CourseViewSet(Base, List, Retrieve, Create, Update):
     permission_classes = [AllowMetadata | IsAuthenticatedOrReadOnly, IsAdminOrReadOnly | IsInstructorOrReadOnly]
-    queryset = models.Course.objects.annotate(date=Max('sessions__datetime')).order_by('-date')
+    queryset = models.Course.objects.annotate(
+        date=Max('sessions__datetime'),
+        num_interested=Count('interests', filter=Q(interests__satisfied_by__isnull=True), distinct=True),
+    ).order_by(
+        '-num_interested',
+        '-date',
+    )
 
     def get_serializer_class(self):
         if self.action == 'list':

webclient/src/Courses.js

@@ -98,6 +98,7 @@ export function Courses(props) {
 					<Table.Header>
 						<Table.Row>
 							<Table.HeaderCell>Name</Table.HeaderCell>
+							<Table.HeaderCell>Interest</Table.HeaderCell>
 							<Table.HeaderCell></Table.HeaderCell>
 						</Table.Row>
 					</Table.Header>
@@ -109,6 +110,9 @@ export function Courses(props) {
 									<Table.Cell>
 										<Link to={'/courses/'+x.id}>{x.name}</Link>
 									</Table.Cell>
+									<Table.Cell>
+										{x.num_interested}
+									</Table.Cell>
 									<Table.Cell>
 										{!!x.tags && x.tags.split(',').map(name =>
 											<Label color={tags[name]} tag>