Use a custom message in order to fix ApiResponse message.

Author: imclint21

src/Initium/Exceptions/ApiException.cs

@@ -9,6 +9,7 @@ namespace Initium.Exceptions;
 [SuppressMessage("ReSharper", "UnusedMember.Global")]
 public class ApiException : Exception
 {
+	public string? CustomMessage { get; set; }
 	public HttpStatusCode StatusCode { get; }
 
 	/// <summary>
@@ -18,8 +19,9 @@ public class ApiException : Exception
 	/// <param name="message">The message describing the error. Defaults to a generic error message.</param>
 	/// <param name="innerException">The inner exception that caused the current exception. Optional.</param>
 	public ApiException(HttpStatusCode statusCode = HttpStatusCode.InternalServerError, string? message = null, Exception? innerException = null)
-		: base(message ?? "An error occurred during API processing.", innerException)
+		: base(message, innerException)
 	{
+		CustomMessage = message;
 		StatusCode = statusCode;
 	}
 }

src/Initium/Filters/ApiExceptionFilter.cs

@@ -35,8 +35,8 @@ public void OnException(ExceptionContext context)
 		// 2. Otherwise, get the message from [ApiResponse] attributes.
 		// 3. If none is found, use the default message for the StatusCode.
 		var message = 
-			(string.IsNullOrWhiteSpace(context.Exception.Message) ? null : context.Exception.Message)
-			?? ApiResponseHelper.GetApiResponseMessage(context.ActionDescriptor, statusCode) 
+			(context.Exception is ApiException apiException ? apiException.CustomMessage : context.Exception.Message)
+			?? ApiResponseHelper.GetApiResponseMessage(context.ActionDescriptor, statusCode)
 			?? ApiResponseHelper.GetDefaultMessageForStatusCode(statusCode);
 
 		// Construct a standardized ApiResponse object including HTTP context details.