Error Handling

// AlbumErrorCode.cs public enum AlbumErrorCode { /// <summary> /// The album ID is required when deleting the Album /// </summary> ALBUM_100A, /// <summary> /// The album with id {id} was not found /// </summary> ALBUM_101A, /// <summary> /// The album is not in a valid state for this operation /// </summary> ALBUM_102A, /// <summary> /// Cannot transition from {fromState} to {toState} /// </summary> ALBUM_103A } // PhotoErrorCode.cs public enum PhotoErrorCode { /// <summary> /// The photo ID is required /// </summary> PHOTO_100A, /// <summary> /// The photo with id {id} was not found /// </summary> PHOTO_101A } // StorageErrorCode.cs public enum StorageErrorCode { /// <summary> /// Provider ID is required /// </summary> STORAGE_99, /// <summary> /// Search term exceeds maximum length /// </summary> STORAGE_008 }

public class InvalidValidatorException : Exception { public string ErrorCode { get; } public object[] Parameters { get; } public InvalidValidatorException(string errorCode, params object[] parameters) : base($"Validation error: {errorCode}") { ErrorCode = errorCode; Parameters = parameters; } } // Usage throw new InvalidValidatorException( nameof(AlbumErrorCode.ALBUM_101A), albumId);

public class DomainException : Exception { public string ErrorCode { get; } public DomainException(string errorCode, string message) : base(message) { ErrorCode = errorCode; } } // Usage throw new DomainException( nameof(AlbumErrorCode.ALBUM_103A), $"Cannot transition from {fromState} to {toState}");

public class FluentValidationState { public ValidatorType ValidationType { get; set; } public string ValidationValue { get; set; } } public enum ValidatorType { MaxLength, MinLength, Required, Email, Regex, Range }

public class ExceptionHandlingMiddleware { private readonly RequestDelegate _next; private readonly ILogger<ExceptionHandlingMiddleware> _logger; private readonly IStringLocalizer<ErrorMessages> _localizer; public async Task InvokeAsync(HttpContext context) { try { await _next(context); } catch (InvalidValidatorException ex) { await HandleValidationExceptionAsync(context, ex); } catch (DomainException ex) { await HandleDomainExceptionAsync(context, ex); } catch (Exception ex) { await HandleUnexpectedExceptionAsync(context, ex); } } private async Task HandleValidationExceptionAsync( HttpContext context, InvalidValidatorException ex) { var message = _localizer[ex.ErrorCode, ex.Parameters]; var response = new ErrorResponse { Code = ex.ErrorCode, Message = message, Timestamp = DateTime.UtcNow }; context.Response.StatusCode = 400; await context.Response.WriteAsJsonAsync(response); } }

{ "code": "ALBUM_101A", "message": "The album with ID '550e8400-e29b-41d4-a716-446655440000' was not found", "timestamp": "2024-01-15T10:30:00Z", "traceId": "abc123", "details": null }

{ "code": "VALIDATION_ERROR", "message": "One or more validation errors occurred", "timestamp": "2024-01-15T10:30:00Z", "traceId": "abc123", "details": [ { "field": "name", "code": "ALBUM_100A", "message": "The album ID is required when deleting the Album" }, { "field": "providerId", "code": "STORAGE_99", "message": "Provider ID is required" } ] }

Resources/i18n/ErrorMessage/ ├── en.json └── vi.json

{ "ALBUM_100A": "The album ID is required when deleting the Album", "ALBUM_101A": "The album with ID '{0}' was not found", "ALBUM_102A": "The album is not in a valid state for this operation", "ALBUM_103A": "Cannot transition from {0} to {1}", "PHOTO_100A": "The photo ID is required", "PHOTO_101A": "The photo with ID '{0}' was not found", "STORAGE_99": "Provider ID is required", "STORAGE_008": "Search term exceeds maximum length of {0} characters" }

{ "ALBUM_100A": "ID album là bắt buộc khi xóa Album", "ALBUM_101A": "Không tìm thấy album có ID '{0}'", "ALBUM_102A": "Album không ở trạng thái hợp lệ cho thao tác này", "ALBUM_103A": "Không thể chuyển từ trạng thái {0} sang {1}", "PHOTO_100A": "ID ảnh là bắt buộc", "PHOTO_101A": "Không tìm thấy ảnh có ID '{0}'", "STORAGE_99": "ID nhà cung cấp là bắt buộc", "STORAGE_008": "Từ khóa tìm kiếm vượt quá độ dài tối đa {0} ký tự" }

@Injectable() export class ErrorInterceptor implements HttpInterceptor { constructor( private translateService: TranslocoService, private snackBar: MatSnackBar ) {} intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> { return next.handle(request).pipe( catchError((error: HttpErrorResponse) => { if (error.error?.code) { const message = this.translateService.translate( `errors.${error.error.code}` ); this.snackBar.open(message, 'Close', { duration: 5000 }); } return throwError(() => error); }) ); } }