Avoid loading JSON file twice

AKModel/forms.py

@@ -304,15 +304,16 @@ class JSONScheduleImportForm(AdminIntermediateForm):
         try:
             schedule = json.loads(data)
         except json.JSONDecodeError as ex:
-            return ValidationError(_("Cannot decode as JSON"), "invalid")
+            raise ValidationError(_("Cannot decode as JSON"), "invalid")
         for field in ["input", "scheduled_aks"]:
             if not field in schedule:
-                return ValidationError(
+                raise ValidationError(
                     _("Invalid JSON format: field '%(field)s' is missing"),
                     "invalid",
                     params={"field": field}
                 )
         # TODO: Add further checks on json input
+        return schedule
 
     def clean(self):
         cleaned_data = super().clean()
@@ -328,16 +329,15 @@ class JSONScheduleImportForm(AdminIntermediateForm):
             )
             self.add_error("json_data", err)
             self.add_error("json_file", err)
-        elif cleaned_data.get("json_file"):
-            data = self.cleaned_data.get("json_file")
-            with data.open() as ff:
-                read_data = ff.read()
-            err = self._check_json_data(read_data)
-            if err is not None:
-                self.add_error("json_file", err)
-        elif cleaned_data.get("json_data"):
-            err = self._check_json_data(cleaned_data.get("json_data"))
-            if err is not None:
-                self.add_error("json_data", err)
-
+        else:
+            source_field = "json_data"
+            data = cleaned_data.get(source_field)
+            if not data:
+                source_field = "json_file"
+                with cleaned_data.get(source_field).open() as ff:
+                    data = ff.read()
+            try:
+                cleaned_data["data"] = self._check_json_data(data)
+            except ValidationError as ex:
+                self.add_error(source_field, ex)
         return cleaned_data

AKModel/models.py

@@ -412,7 +412,9 @@ class Event(models.Model):
             yield from self.uniform_time_slots(slots_in_an_hour=slots_in_an_hour)
 
     @transaction.atomic
-    def schedule_from_json(self, schedule: str, *, check_for_data_inconsistency: bool = True) -> int:
+    def schedule_from_json(
+        self, schedule: str | dict[str, Any], *, check_for_data_inconsistency: bool = True
+    ) -> int:
         """Load AK schedule from a json string.
 
         :param schedule: A string that can be decoded to json, describing
@@ -420,7 +422,8 @@ class Event(models.Model):
             following the output specification of the KoMa conference optimizer, cf.
             https://github.com/Die-KoMa/ak-plan-optimierung/wiki/Input-&-output-format
         """
-        schedule = json.loads(schedule)
+        if isinstance(schedule, str):
+            schedule = json.loads(schedule)
         export_dict = self.as_json_dict()
 
         if "input" not in schedule or "scheduled_aks" not in schedule:

AKModel/views/manage.py

@@ -259,15 +259,7 @@ class AKScheduleJSONImportView(EventSlugMixin, IntermediateAdminView):
 
     def form_valid(self, form):
         try:
-            if form.cleaned_data.get("json_data"):
-                data = form.cleaned_data["json_data"]
-            elif form.cleaned_data.get("json_file"):
-                with form.cleaned_data["json_file"].open() as ff:
-                    data = ff.read()
-            else:
-                raise ValueError("No data entered!")
-
-            number_of_slots_changed = self.event.schedule_from_json(data)
+            number_of_slots_changed = self.event.schedule_from_json(form.cleaned_data["data"])
             messages.add_message(
                 self.request,
                 messages.SUCCESS,