# Improvement PUT API

* improves error processing and response on PUT endpoint
* consolidates improved error processing into central method for all API endpoints

api/utils/serializer/serializer.py

@@ -6,6 +6,7 @@ Created on: 24.01.22
 
 """
 import json
+import uuid
 from abc import abstractmethod
 
 from django.contrib.gis import geos
@@ -171,13 +172,20 @@ class AbstractModelAPISerializer:
         Returns:
 
         """
+        if not id:
+            raise ValueError("No id provided. The id is expected to live in the URL!")
+
         # First if there is an external identifier linked to an internal one, so we can continue with the internal
         try:
             ext_id = ExternalIdentifier.objects.get(external_id=id)
             id = ext_id.internal_id
         except ObjectDoesNotExist:
-            # No external id found - let's hope the given id exists internally
-            pass
+            # Not found as external id - let's check whether this is a valid uuid and therefore
+            # potentially an internal id
+            try:
+                uuid.UUID(id)
+            except ValueError:
+                raise AssertionError(f"'{id}' is neither a known external identifier nor a valid uuid.")
 
         obj = self.model.objects.get(
             id=id,