ASP.net Core 3 IdentityErrorDescriber错误消息

如何解决ASP.net Core 3 IdentityErrorDescriber错误消息

我有一个ASP.net Core 3.1 Web应用程序。我正在尝试在创建新用户时为“无效用户名”自定义错误消息。我创建了一个自定义类“ CustomIdentityErrorDescriber”，该类继承了Microsoft.AspNetCore.Identity.IdentityErrorDescriber

public class CustomIdentityErrorDescriber : IdentityErrorDescriber
  {
        public override IdentityError DefaultError() { return new IdentityError { Code = nameof(DefaultError),Description = $"An unknown failure has occurred." }; }
        public override IdentityError ConcurrencyFailure() { return new IdentityError { Code = nameof(ConcurrencyFailure),Description = "Optimistic concurrency failure,object has been modified." }; }
        public override IdentityError PasswordMismatch() { return new IdentityError { Code = nameof(PasswordMismatch),Description = "Incorrect password." }; }
        public override IdentityError InvalidToken() { return new IdentityError { Code = nameof(InvalidToken),Description = "Invalid token." }; }
        public override IdentityError LoginAlreadyAssociated() { return new IdentityError { Code = nameof(LoginAlreadyAssociated),Description = "A user with this login already exists." }; }
        public override IdentityError InvalidUserName(string userName) { return new IdentityError { Code = nameof(InvalidUserName),Description = $"User name '{userName}' is invalid,allowable characters 'a-z 'A-Z'." }; }
        public override IdentityError InvalidEmail(string email) { return new IdentityError { Code = nameof(InvalidEmail),Description = $"Email '{email}' is invalid." }; }
        public override IdentityError DuplicateUserName(string userName) { return new IdentityError { Code = nameof(DuplicateUserName),Description = $"User Name '{userName}' is already taken." }; }
        public override IdentityError DuplicateEmail(string email) { return new IdentityError { Code = nameof(DuplicateEmail),Description = $"Email '{email}' is already taken." }; }
        public override IdentityError InvalidRoleName(string role) { return new IdentityError { Code = nameof(InvalidRoleName),Description = $"Role name '{role}' is invalid." }; }
        public override IdentityError DuplicateRoleName(string role) { return new IdentityError { Code = nameof(DuplicateRoleName),Description = $"Role name '{role}' is already taken." }; }
        public override IdentityError UserAlreadyHasPassword() { return new IdentityError { Code = nameof(UserAlreadyHasPassword),Description = "User already has a password set." }; }
        public override IdentityError UserLockoutNotEnabled() { return new IdentityError { Code = nameof(UserLockoutNotEnabled),Description = "Lockout is not enabled for this user." }; }
        public override IdentityError UserAlreadyInRole(string role) { return new IdentityError { Code = nameof(UserAlreadyInRole),Description = $"User already in role '{role}'." }; }
        public override IdentityError PasswordTooShort(int length) { return new IdentityError { Code = nameof(PasswordTooShort),Description = $"Passwords must be at least {length} characters." }; }
        public override IdentityError PasswordRequiresNonAlphanumeric() { return new IdentityError { Code = nameof(PasswordRequiresNonAlphanumeric),Description = "Passwords must have at least one non alphanumeric character." }; }
        public override IdentityError PasswordRequiresDigit() { return new IdentityError { Code = nameof(PasswordRequiresDigit),Description = "Passwords must have at least one digit ('0'-'9')." }; }
        public override IdentityError PasswordRequiresLower() { return new IdentityError { Code = nameof(PasswordRequiresLower),Description = "Passwords must have at least one lowercase ('a'-'z')." }; }
        public override IdentityError PasswordRequiresUpper() { return new IdentityError { Code = nameof(PasswordRequiresUpper),Description = "Passwords must have at least one uppercase ('A'-'Z')." }; }
    }

我已经在startup.cs文件中实现了自定义类，如下所示：

services.AddTransient<IdentityErrorDescriber,CustomIdentityErrorDescriber>();

            services.Configure<IdentityOptions>(opts =>
            {
                // opts.User.RequireUniqueEmail = true;
                opts.User.AllowedUserNameCharacters =
                        "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-._";
                 opts.Password.RequiredLength = 8;
                opts.Password.RequireNonAlphanumeric = false;
                opts.Password.RequireLowercase = false;
                opts.Password.RequireUppercase = false;
                opts.Password.RequireDigit = false;
            
            });

该错误被代码检测到，并且确实从框架中收到一条错误消息。但是，错误消息包含有关角色的字词，对我而言这毫无意义。所以在弹出对话框中显示给用户的错误消息是

“已经具有角色用户名'xxx xxx'的用户无效，允许的字符'a-z'A-Z'。”

在何处以及为何为何出现““已经有角色的用户”，并在错误消息的正确最后部分之前显示，这已经超出了我的范围。

解决方法

由于您创建了 IdentityErroDescriber 的扩展，您还必须通知 Identity 将右侧直接指向您的新扩展方法。

这是通过在 startup.cs 中的 ConfigureServices 方法中提供身份注册的扩展方法来实现的：

services.AddIdentity<AppUser,AppRole>()
        .AddErrorDescriber<CustomIdentityErrorDescriber>(); //<== Here

这样，所有错误都会按照您的扩展方法中的描述显示。