adapting exception handling and error responses for 400 responses. Using a simplified format, which only uses the keys 'error_field' and 'error_description'

src/server/BreCal/impl/shipcalls.py

@@ -10,6 +10,7 @@ from ..services.auth_guard import check_jwt
 from BreCal.database.update_database import evaluate_shipcall_state
 from BreCal.database.sql_queries import create_sql_query_shipcall_get, create_sql_query_shipcall_post, create_sql_query_shipcall_put, create_sql_query_history_post, create_sql_query_history_put, SQLQuery
 from marshmallow import Schema, fields, ValidationError
+from BreCal.validators.validation_error import create_validation_error_response
 
 def GetShipcalls(options):
     """
@@ -152,9 +153,7 @@ def PostShipcalls(schemaModel):
         return json.dumps({"id" : new_id}), 201, {'Content-Type': 'application/json; charset=utf-8'}
         
     except ValidationError as ex:
-        logging.error(ex)
-        print(ex)
-        return json.dumps({"message":f"bad format. \nError Messages: {ex.messages}. \nValid Data: {ex.valid_data}"}), 400
+        return create_validation_error_response(ex, status_code=400, create_log=True)
 
     except Exception as ex:
         logging.error(traceback.format_exc())
@@ -265,9 +264,7 @@ def PutShipcalls(schemaModel):
         return json.dumps({"id" : schemaModel["id"]}), 200
         
     except ValidationError as ex:
-        logging.error(ex)
-        print(ex)
-        return json.dumps({"message":f"bad format. \nError Messages: {ex.messages}. \nValid Data: {ex.valid_data}"}), 400
+        return create_validation_error_response(ex, status_code=400, create_log=True)
 
     except Exception as ex:
         logging.error(traceback.format_exc())

src/server/BreCal/validators/validation_error.py

@@ -1,58 +1,59 @@
 import logging
 import typing
 import json
+import sys
 from marshmallow import ValidationError
-import werkzeug
 from werkzeug.exceptions import Forbidden
 
 
-def create_default_error_format(error_description):
+def create_default_json_response_format(error_field:str, error_description:str):
+    """
+    The default format of a JSON response for exceptions is:
+        {
+            "message":str,
+            "errors":typing.Optional[
+                list[dict[str,list[str]]]
+            ]
+        }
+    """
     json_response = {
-        "message":f"{error_description}",
-        "errors":[],
-        "valid_data":{}
+        "error_field":error_field,
+        "error_description":error_description
     }
     return json_response
 
+def unbundle_(errors, unbundled=[]):
+    """
+    unbundles a dictionary entry into separate items and appends them to the list {unbundled}.
+    Example:
+        errors = {"key1":{"keya":"keyb","keyc":{"keyc12":12}}}
+    Returns:
+        [{'error_field':'keya', 'error_description':['keyb']}, {'error_field':'keyc12', 'error_description':[12]}]
+    As can be seen, only the subkeys and their respective value are received. Each value is *always* a list.
+    """
+    {k:unbundle_(v,unbundled=unbundled) if isinstance(v,dict) else unbundled.append({"error_field":k, "error_description":v[0] if isinstance(v,list) else str(v)}) for k,v in errors.items()}
+    return
+
+def unbundle_validation_error_message(message):
+    """
+    inputs:
+        message: ValidationError.messages object. A str, list or dictionary
+    """
+    unbundled = []
+    unbundle_(message, unbundled=unbundled)
+    if len(unbundled)>0:
+        error_field = "ValidationError in the following field(s): " + " & ".join([unb["error_field"] for unb in unbundled])
+        error_description = "Error Description(s): " + " & ".join([unb["error_description"] for unb in unbundled])
+    else:
+        error_field = "ValidationError"
+        error_description = "unknown validation error"
+    return (error_field, error_description)
 
 def create_validation_error_response(ex:ValidationError, status_code:int=400, create_log:bool=True)->typing.Tuple[str,int]:
-    # generate an overview the errors
-    #example: 
-    #    {'lock_time': ['The provided value must be in the future. Current Time: 2024-09-02 08:23:32.600791, Value: 2024-09-01 08:20:41.853000']}
-    # when the model schema returns an error, 'messages' is by default a dictionary.
-    # e.g., loadedModel = model.TimesSchema().load(data=content, many=False, partial=True)
-    # returns: {'eta_berth': ['The provided value must be in the future}
-
-    # when raising a custom ValidationError, it can return a string, list or dict.
-    # we would like to ensure, that the content of the .messages is a dictionary. This can be accomplished by calling
-    # raise ValidationError({"example_key_which_fails":"the respective error message"})
-    errors = ex.messages
-
-    # raise ValidationError("example error")
-    # creates a .messages object, which is an array. e.g., ex.messages = ["example error"]
-    # the following conversion snipped ensures a dictionary output
-    if isinstance(errors, (str,list)):
-        errors = {"undefined_schema":errors}
-    errors = {k:v if isinstance(v,list) else [v] for k,v in errors.items()}
-
-    # hence, errors always has the following type: list[dict[str, list[str]]]
-    errors = [errors]
-
-
-    # example: 
-    #    "Valid Data": {
-    #        "id": 2894,
-    #        "eta_berth": "datetime.datetime(2024, 9, 2, 11, 11, 43)",
-    #        "eta_berth_fixed": false
-    #    }
-    valid_data = ex.valid_data
-
-    message = "ValidationError"
-    json_response = create_default_error_format(error_description=message)
-    json_response.update({
-        "errors":errors,
-        "valid_data":valid_data
-    })
+    # unbundles ValidationError into a dictionary of {'error_field':str, 'error_description':str}-format
+    message = ex.messages
+    (error_field, error_description) = unbundle_validation_error_message(message)
+    json_response = create_default_json_response_format(error_field=error_field, error_description=error_description)
 
     # json.dumps with default=str automatically converts non-serializable values to strings. Hence, datetime objects (which are not)
     # natively serializable are properly serialized.
@@ -67,7 +68,7 @@ def create_werkzeug_error_response(ex:Forbidden, status_code:int=403, create_log
     # json.dumps with default=str automatically converts non-serializable values to strings. Hence, datetime objects (which are not)
     # natively serializable are properly serialized.
     message = ex.description
-    json_response = create_default_error_format(error_description=message)
+    json_response = create_default_json_response_format(error_field=str(repr(ex)), error_description=message)
     serialized_response = json.dumps(json_response, default=str)
 
     if create_log:
@@ -77,7 +78,8 @@ def create_werkzeug_error_response(ex:Forbidden, status_code:int=403, create_log
 
 def create_dynamic_exception_response(ex, status_code:int=400, message:typing.Optional[str]=None, create_log:bool=True):
     message = repr(ex) if message is None else message
-    json_response = create_default_error_format(error_description=message)
+    json_response = create_default_json_response_format(error_field="Exception", error_description=message)
+    json_response["message"] = "call failed"
 
     serialized_response = json.dumps(json_response, default=str)