From 1488a0e72f94a018b3802107c70af981bee116e5 Mon Sep 17 00:00:00 2001
From: Oliver Walters <oliver.henry.walters@gmail.com>
Date: Tue, 17 May 2022 00:18:47 +1000
Subject: [PATCH] Adds a custom exception handler for DRF

- Handles common exceptions not captured by DRF
- Returns exeption data as a JSON object
---
 InvenTree/InvenTree/exceptions.py | 80 +++++++++++++++++++++++++++++++
 InvenTree/InvenTree/settings.py   |  2 +-
 2 files changed, 81 insertions(+), 1 deletion(-)
 create mode 100644 InvenTree/InvenTree/exceptions.py

diff --git a/InvenTree/InvenTree/exceptions.py b/InvenTree/InvenTree/exceptions.py
new file mode 100644
index 0000000000..f57df8ac00
--- /dev/null
+++ b/InvenTree/InvenTree/exceptions.py
@@ -0,0 +1,80 @@
+"""
+Custom exception handling for the DRF API
+"""
+
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+import json
+
+from django.db.utils import OperationalError, ProgrammingError, IntegrityError
+from django.conf import settings
+from django.core.exceptions import ValidationError as DjangoValidationError
+from django.utils.translation import gettext_lazy as _
+
+from error_report.models import Error
+
+from rest_framework.exceptions import ValidationError as DRFValidationError
+from rest_framework.response import Response
+from rest_framework import serializers
+import rest_framework.views as drfviews
+
+
+def exception_handler(exc, context):
+    """
+    Custom exception handler for DRF framework.
+    Ref: https://www.django-rest-framework.org/api-guide/exceptions/#custom-exception-handling
+
+    Catches any errors not natively handled by DRF, and re-throws as an error DRF can handle
+    """
+
+    response = None
+
+    # Catch any django validation error, and re-throw a DRF validation error
+    if isinstance(exc, DjangoValidationError):
+        exc = DRFValidationError(detail=serializers.as_serializer_error(exc))
+
+    # Exceptions we will manually check for here
+    handled_exceptions = [
+        IntegrityError,
+        OperationalError,
+        ProgrammingError,
+        ValueError,
+        TypeError,
+        NameError,
+    ]
+
+    if any([isinstance(exc, err_type) for err_type in handled_exceptions]):
+
+        if settings.DEBUG:
+            error_detail = str(exc)
+        else:
+            error_detail = _("Error details can be found in the admin panel")
+
+        response_data = {
+            'error': type(exc).__name__,
+            'error_class': str(type(exc)),
+            'detail': error_detail,
+            'path': context['request'].path,
+            'status_code': 500,
+        }
+
+        response = Response(response_data, status=500)
+
+        # Log the exception to the database, too
+        Error.objects.create(
+            kind="Unhandled DRF API Exception",
+            info=str(type(exc)),
+            data=str(exc),
+            path=context['request'].path,
+        )
+
+    else:
+        # Fallback to the default DRF exception handler
+        response = drfviews.exception_handler(exc, context)
+
+    if response is not None:
+        # For an error response, include status code information
+        response.data['status_code'] = response.status_code
+    
+    return response
diff --git a/InvenTree/InvenTree/settings.py b/InvenTree/InvenTree/settings.py
index cba4ab4c6a..5c6bca4dea 100644
--- a/InvenTree/InvenTree/settings.py
+++ b/InvenTree/InvenTree/settings.py
@@ -353,7 +353,7 @@ TEMPLATES = [
 ]
 
 REST_FRAMEWORK = {
-    'EXCEPTION_HANDLER': 'rest_framework.views.exception_handler',
+    'EXCEPTION_HANDLER': 'InvenTree.exceptions.exception_handler',
     'DATETIME_FORMAT': '%Y-%m-%d %H:%M',
     'DEFAULT_AUTHENTICATION_CLASSES': (
         'rest_framework.authentication.BasicAuthentication',