Fixed numerous bugs related to subscription handling

* Now outputs the last seen entity ID when creating the subscription instead of a meaningless detail string
* No more SQL errors when looking up latest entity IDs
* Actually commits the deletion when clearing a subscription

api/schemas/subscriptions.py

@@ -5,3 +5,9 @@ class SubscriptionIn(BaseModel):
     """Used to update a user's subscription to mark what entity IDs they've seen."""
 
     last_seen_entity_id: int
+
+
+class SubscriptionOut(BaseModel):
+    """Returned when a subscription is created"""
+
+    last_seen_entity_id: int

api/views/subscriptions.py

@@ -5,14 +5,14 @@
 from api.exceptions import APIException, NotFoundException
 from api.models import Card, Comment, Deck, Subscription, User
 from api.schemas import DetailResponse
-from api.schemas.subscriptions import SubscriptionIn
+from api.schemas.subscriptions import SubscriptionIn, SubscriptionOut
 
 router = APIRouter()
 
 
 @router.post(
     "/subscription/{entity_id}",
-    response_model=DetailResponse,
+    response_model=SubscriptionOut,
     status_code=status.HTTP_201_CREATED,
     responses={
         400: {
@@ -50,7 +50,6 @@ def create_subscription(
         # Cards don't have this attribute, so we can safely ignore it
         pass
 
-    success_response = {"detail": "You have subscribed to this content."}
     # Check if they already have a subscription
     subscription = (
         session.query(Subscription)
@@ -61,19 +60,19 @@ def create_subscription(
         .first()
     )
     if subscription:
-        return success_response
+        return {"last_seen_entity_id": subscription.last_seen_entity_id}
 
     # Look up the most recently seen entity ID (assumes that they subscribed from the detail page, since it's silly to
     #  force them to immediately update the last seen ID after subscribing).
-    last_seen_entity_id = (
+    last_seen = (
         session.query(Comment.entity_id)
         .filter(Comment.source_entity_id == entity_id)
         .order_by(Comment.entity_id.desc())
-        .scalar()
+        .first()
     )
-    if not last_seen_entity_id and is_deck:
+    if not last_seen and is_deck:
         # If we don't have any comments on this deck, grab the latest entity ID for the most recent published snapshot
-        last_seen_entity_id = (
+        last_seen = (
             session.query(Deck.entity_id)
             .filter(
                 Deck.source_id == source.id,
@@ -82,19 +81,19 @@ def create_subscription(
                 Deck.is_public == True,
             )
             .order_by(Deck.entity_id.desc())
-            .scalar()
+            .first()
         )
 
     # Create a new subscription
     session.add(
         Subscription(
             user_id=current_user.id,
             source_entity_id=entity_id,
-            last_seen_entity_id=last_seen_entity_id,
+            last_seen_entity_id=last_seen.entity_id,
         )
     )
     session.commit()
-    return success_response
+    return {"last_seen_entity_id": last_seen.entity_id}
 
 
 @router.delete(
@@ -123,6 +122,7 @@ def delete_subscription(
         Subscription.user_id == current_user.id,
         Subscription.source_entity_id == entity_id,
     ).delete()
+    session.commit()
     return Response(status_code=status.HTTP_204_NO_CONTENT)