Add configurable GraphQL error masking with whitelist support

- Introduce GRAPHENE_ERRORS settings for masking error messages in GraphQL responses
- Support masking sensitive errors while allowing whitelisted exceptions to show full details
- Enable customization of generic error message for better user experience and security

Author: DrillableBit

docs/error-masking.rst

@@ -0,0 +1,49 @@
+Custom GraphQL Error Masking
+============================
+
+This project includes a custom error formatting function for GraphQL
+responses that masks sensitive error details from clients.
+
+Purpose
+-------
+
+- Prevent exposing internal error details for security and user experience.
+- Allow whitelisting of exception classes that should be exposed as-is.
+- Return a generic error message for all other exceptions.
+
+Configuration
+-------------
+
+You can control the behavior using the ``GRAPHENE_ERRORS`` setting in your
+Django settings file under the ``GRAPHENE`` namespace:
+
+.. code-block:: python
+
+    GRAPHENE = {
+        "GRAPHENE_ERRORS": {
+            "MASK_EXCEPTIONS": True,  # Enable or disable masking
+            "ERROR_MESSAGE": "A custom error message.",  # Defaults to "Something went wrong. Please try again later."
+            "WHITELISTED_EXCEPTIONS": [
+                "ValidationError",  # Whitelist by class name
+                "django.core.exceptions.ValidationError", # Whitelist by full module path
+                "myapp.custom_exceptions.MyCustomException", # Custom exception whitelist by full path
+            ],
+        }
+    }
+
+Behavior
+--------
+
+- If ``MASK_EXCEPTIONS`` is False, all errors are returned fully formatted.
+- If True, errors not in the whitelist will return only the generic message.
+- Whitelisted exceptions are returned with full error details.
+
+Usage
+-----
+
+The masking is automatically applied to the error responses of GraphQL
+queries and mutations through a custom error formatter method.
+
+You can modify or extend the whitelisted exceptions as needed to suit your
+project's error handling policy.
+

graphene_django/settings.py

@@ -46,6 +46,7 @@
     "ATOMIC_MUTATIONS": False,
     "TESTING_ENDPOINT": "/graphql",
     "MAX_VALIDATION_ERRORS": None,
+    "GRAPHENE_ERRORS": {},
 }
 
 if settings.DEBUG:

graphene_django/views.py

@@ -228,9 +228,32 @@ def get_response(self, request, data, show_graphiql=False):
 
             if execution_result.errors:
                 set_rollback()
-                response["errors"] = [
-                    self.format_error(e) for e in execution_result.errors
-                ]
+
+                def safe_format(error):
+                    config = getattr(graphene_settings, "GRAPHENE_ERRORS", {})
+                    mask_exceptions = config.get("MASK_EXCEPTIONS", False)
+                    error_message= config.get("ERROR_MESSAGE", "Something went wrong. Please try again later.")
+                    whitelist = config.get("WHITELISTED_EXCEPTIONS", [])
+
+                    if not mask_exceptions:
+                        return self.format_error(error)
+
+                    original_error = getattr(error, "original_error", None)
+                    if not original_error:
+                        return {"message": error_message}
+
+                    error_class = type(original_error)
+                    class_name = error_class.__name__
+                    full_path = f"{error_class.__module__}.{class_name}" 
+
+                    if class_name in whitelist or full_path in whitelist:
+                        return self.format_error(error)
+
+                    formatted = self.format_error(error)
+                    formatted["message"] = error_message
+                    return formatted
+
+                response["errors"] = [safe_format(e) for e in execution_result.errors]
 
             if execution_result.errors and any(
                 not getattr(e, "path", None) for e in execution_result.errors