[common][api] Implement get_object in place of get_queryset for...

[common][api] Implement get_object in place of get_queryset for RetrieveUpdateDestroyContributionView

This view shall act on one object only and the check
should already be done there rather than in furhter
methods below.

It also follows the URL routes cleanup

beat/web/common/api.py

@@ -235,46 +235,26 @@ class RetrieveUpdateDestroyContributionView(
 ):
     model = Contribution
 
-    def get_queryset(self):
-        version = self.kwargs.get("version", None)
-        author_name = self.kwargs.get("author_name")
-        object_name = self.kwargs.get("object_name")
+    def get_object(self):
+        version = self.kwargs["version"]
+        author_name = self.kwargs["author_name"]
+        object_name = self.kwargs["object_name"]
         user = self.request.user
-        if version is not None:
-            queryset = (
-                self.model.objects.for_user(user, True)
-                .filter(
-                    author__username__iexact=author_name,
-                    name__iexact=object_name,
-                    version__gte=version,
-                )
-                .order_by("version")
-            )
-        else:
-            queryset = (
-                self.model.objects.for_user(user, True)
-                .filter(author__username__iexact=author_name, name__iexact=object_name)
-                .order_by("-version")
+        try:
+            obj = self.model.objects.for_user(user, True).get(
+                author__username__iexact=author_name,
+                name__iexact=object_name,
+                version=version,
             )
-
-        return queryset
-
-    def get(self, request, *args, **kwargs):
-        db_objects = self.get_queryset()
-
-        if db_objects.count() == 0:
+        except self.model.DoesNotExist:
             raise drf_exceptions.NotFound()
+        return obj
 
-        db_object = db_objects[0]
-        version = int(self.kwargs.get("version", -1))
-
-        if version != -1 and db_object.version != version:
-            raise drf_exceptions.NotFound()
+    def get(self, request, *args, **kwargs):
+        db_object = self.get_object()
 
         # Process the query string
-        allow_sharing = hasattr(db_object, "author") and (
-            request.user == db_object.author
-        )
+        allow_sharing = request.user == db_object.author
 
         fields_to_return = self.get_serializer_fields(
             request, allow_sharing=allow_sharing