Merge pull request #35 from MEHRSHAD-MIRSHEKARY/fix/exception-handler

Fix/exception handler

Author: ARYAN-NIKNEZHAD

README.md

@@ -300,6 +300,7 @@ Here are the default settings that are automatically applied:
 # settings.py
 
 RESPONSE_SHAPER_DEBUG_MODE = False
+RESPONSE_SHAPER_RETURN_ERROR_AS_DICT = True
 RESPONSE_SHAPER_EXCLUDED_PATHS = ["/admin/", "/schema/swagger-ui/", "/schema/redoc/", "/schema/"]
 RESPONSE_SHAPER_SUCCESS_HANDLER = ""
 RESPONSE_SHAPER_ERROR_HANDLER = ""
@@ -313,6 +314,24 @@ RESPONSE_SHAPER_ERROR_HANDLER = ""
 - **Description**: When set to `True`, disables response shaping for debugging purposes.
 - **Default**: `False`
 
+`RESPONSE_SHAPER_RETURN_ERROR_AS_DICT`
+--------------------------------------
+
+- **Type**: `bool`
+- **Description**: Controls the format of dict error messages extracted by the ExceptionHandler. When `True`, errors with **nested dictionary** structure are returned as a dictionary containing the innermost key-value pair from nested error structures. When `False`, only the innermost error message is returned as a string. This applies to error responses shaped by the handler, particularly for validation.
+- **Default**: `True`
+
+**Example**:
+```python
+# With RESPONSE_SHAPER_RETURN_ERROR_AS_DICT = True
+error_input = {"field": {"detail": {"code": "invalid"}}}
+# Result: {"code": "invalid"}
+
+# With RESPONSE_SHAPER_RETURN_ERROR_AS_DICT = False
+error_input = {"field": {"detail": {"code": "invalid"}}}
+# Result: "invalid"
+```
+
 `RESPONSE_SHAPER_EXCLUDED_PATHS`
 --------------------------------
 

response_shaper/exceptions.py

@@ -26,6 +26,8 @@
 )
 from django.http import JsonResponse
 
+from response_shaper.settings.conf import response_shaper_config
+
 
 class ExceptionHandler:
     """Handles exception responses consistently across the application.
@@ -165,28 +167,38 @@ def extract_first_error(error_data: Any) -> Union[Any, Dict]:
         """Extract the first error message from various data structures (dict,
         list, string). Stops at the first error encountered.
 
-        This method is useful for extracting the first error message from
-        complex error data structures, such as those returned by Django's
-        validation framework.
+        Behavior is controlled by settings.EXTRACT_ERROR_AS_DICT:
+        - If True: Returns the innermost dict with a string value
+        - If False: Returns the first string value
 
         Args:
             error_data (Any): The error data structure, which can be a string,
                 list, or dictionary.
 
         Returns:
-            Union[str, dict]: The extracted error message or structure. If the
-                input is a list, it returns the first element. If the input is
-                a dictionary, it returns the first key-value pair. If the input
-                is a string, it returns the string itself.
+            Union[str, dict]: The extracted error message or structure based on settings.
 
         """
         if isinstance(error_data, str):
             return error_data
         if isinstance(error_data, list) and error_data:
             return ExceptionHandler.extract_first_error(error_data[0])
         if isinstance(error_data, dict):
-            for key, value in error_data.items():
-                return {key: ExceptionHandler.extract_first_error(value)}
+            if not error_data:
+                return str(error_data)
+            first_key = next(iter(error_data))
+            first_value = error_data[first_key]
+
+            # Recursively process the value
+            extracted = ExceptionHandler.extract_first_error(first_value)
+
+            if response_shaper_config.return_dict_error:
+                # If the extracted result is a string, return it as a single key-value dict
+                if isinstance(extracted, str):
+                    return {first_key: extracted}
+                # If it's already a dict (from deeper recursion), return it as-is
+                return extracted
+            return extracted
         return str(error_data)
 
     @staticmethod

response_shaper/settings/check.py

@@ -32,6 +32,12 @@ def check_response_shaper_settings(app_configs: Any, **kwargs: Any) -> List[Erro
             response_shaper_config.debug, "RESPONSE_SHAPER_DEBUG_MODE"
         )
     )
+    errors.extend(
+        validate_boolean_setting(
+            response_shaper_config.return_dict_error,
+            "RESPONSE_SHAPER_RETURN_ERROR_AS_DICT",
+        )
+    )
 
     # Validate optional excluded path settings
     errors.extend(

response_shaper/settings/conf.py

@@ -14,6 +14,9 @@ class ResponseShaperConfig:
     def __init__(self) -> None:
         self.config_prefix = "RESPONSE_SHAPER_"
         self.debug = self.get_setting(f"{self.config_prefix}DEBUG_MODE", False)
+        self.return_dict_error = self.get_setting(
+            f"{self.config_prefix}RETURN_ERROR_AS_DICT", True
+        )
         self.excluded_paths = self.get_setting(
             f"{self.config_prefix}EXCLUDED_PATHS",
             ["/admin/", "/schema/swagger-ui/", "/schema/redoc/", "/schema/"],

response_shaper/tests/test_exceptions.py

@@ -125,14 +125,12 @@ def test_extract_first_error(self):
         )
 
         # Test with a dictionary
-        assert ExceptionHandler.extract_first_error({"field": ["Invalid value"]}) == {
-            "field": "Invalid value"
-        }
+        assert ExceptionHandler.extract_first_error({"field": ["Invalid value"]}) == {"field": "Invalid value"}
 
         # Test with nested structures
         assert ExceptionHandler.extract_first_error(
             {"field": [{"nested": "Invalid value"}]}
-        ) == {"field": {"nested": "Invalid value"}}
+        ) == {"nested": "Invalid value"}
 
     def test_get_detailed_error_info(self):
         """Test the _get_detailed_error_info method in debug mode."""

response_shaper/tests/test_middleware.py

@@ -290,7 +290,7 @@ def custom_error_handler(response):
             response.data = {"key": "value"}
             response = middleware._default_error_handler(response)
             response_data = self.parse_json_response(response)
-            assert response_data["error"] == {"key": "value"}
+            assert response_data["error"] == {'key': 'value'}
 
     def test_process_object_does_not_exist_exception(
         self, request_factory: RequestFactory, get_response: Callable
@@ -356,17 +356,19 @@ def test_extract_dict_of_errors(self) -> None:
         """
         Test that the middleware correctly extracts the first error from a dictionary of errors.
         """
+        response_shaper_config.return_dict_error = False
         errors = {"field1": "Field1 error", "field2": "Field2 error"}
         result = ExceptionHandler.extract_first_error(errors)
-        assert result == {"field1": "Field1 error"}
+        assert result == "Field1 error"
 
     def test_extract_nested_dict_of_errors(self) -> None:
         """
         Test that the middleware correctly extracts the first error from a nested dictionary of errors.
         """
+        response_shaper_config.return_dict_error = True
         errors = {"field1": {"subfield": "Subfield error"}, "field2": "Field2 error"}
         result = ExceptionHandler.extract_first_error(errors)
-        assert result == {"field1": {"subfield": "Subfield error"}}
+        assert result == {"subfield": "Subfield error"}
 
     def test_extract_empty_list(self) -> None:
         """
@@ -396,7 +398,7 @@ def test_extract_complex_structure(self) -> None:
             "field2": "Field2 error",
         }
         result = ExceptionHandler.extract_first_error(errors)
-        assert result == {"field1": {"subfield": "Subfield error"}}
+        assert result == {"subfield": "Subfield error"}
 
     def test_skip_non_json_content_type(
         self, request_factory: RequestFactory, get_response: Callable

response_shaper/tests/test_settings.py

@@ -26,6 +26,7 @@ def test_valid_settings(self, mock_config: MagicMock) -> None:
         """
         # Mock valid configuration values
         mock_config.debug = True
+        mock_config.return_dict_error = True
         mock_config.excluded_paths = ["/admin/"]
         mock_config.success_handler = "myapp.handlers.custom_success_handler"
         mock_config.error_handler = "myapp.handlers.custom_error_handler"
@@ -47,25 +48,26 @@ def test_invalid_settings(self, mock_config: MagicMock) -> None:
         """
         # Mock invalid settings
         mock_config.debug = "invalid_bool"  # must be bool
+        mock_config.return_dict_error = "invalid_bool"  # must be bool
         mock_config.excluded_paths = {}  # must be a list
         mock_config.success_handler = "myapp.handlers.custom_success_handler"
         mock_config.error_handler = "myapp.handlers.custom_error_handler"
 
         # Run check and assert there is an error
         errors = check_response_shaper_settings(None)
-        assert len(errors) == 2
+        assert len(errors) == 3
         assert errors[0].id == "response_shaper.E001.RESPONSE_SHAPER_DEBUG_MODE"
         assert "should be a boolean value" in errors[0].msg
 
         mock_config.excluded_paths = [1, 2]
         errors = check_response_shaper_settings(None)
 
-        assert len(errors) == 2
+        assert len(errors) == 3
 
         mock_config.excluded_paths = ["admin"]  # path without /
         errors = check_response_shaper_settings(None)
 
-        assert len(errors) == 2
+        assert len(errors) == 3
 
     @patch("response_shaper.settings.check.response_shaper_config")
     def test_invalid_class_path_settings(self, mock_config: MagicMock) -> None:
@@ -80,6 +82,7 @@ def test_invalid_class_path_settings(self, mock_config: MagicMock) -> None:
         """
         # Mock invalid class path settings
         mock_config.debug = True
+        mock_config.return_dict_error = True
         mock_config.excluded_paths = ["/admin/"]
         mock_config.success_handler = 123  # invalid type
         mock_config.error_handler = 456  # invalid type
@@ -104,6 +107,7 @@ def test_missing_optional_settings(self, mock_config: MagicMock) -> None:
         """
         # Mock valid optional settings (None or empty)
         mock_config.debug = True
+        mock_config.return_dict_error = True
         mock_config.excluded_paths = ["/admin/"]
         mock_config.success_handler = None  # Optional and valid
         mock_config.error_handler = ""  # Empty string is valid