Create default `IdentityErrorDescriber` for some languages

Hi, I know that we have the ability to extend IdentityErrorDescriber and create our custom messages but shouldn’t be better if we have already some default IdentityErrorDescriber for the most used languages? (I don’t know right now the most used languages)

This is just an issue I would like to comment because I’m translating it right now, but for sure another person is doing the same in his code. So everybody need to create a custom in each new project?

Well, if someone falls into this issue searching how to do it, follow this steps:

• Create a class with the name CustomIdentityErrorDescriber, copy the code below:

using Microsoft.AspNetCore.Identity;
namespace YourNamespace
{
    public class CustomIdentityErrorDescriber : IdentityErrorDescriber
    {
        public override IdentityError DefaultError() { return new IdentityError { Code = nameof(DefaultError), Description = $"Um erro desconhecido ocorreu." }; }
        public override IdentityError ConcurrencyFailure() { return new IdentityError { Code = nameof(ConcurrencyFailure), Description = "Falha de concorrência otimista, o objeto foi modificado." }; }
        public override IdentityError PasswordMismatch() { return new IdentityError { Code = nameof(PasswordMismatch), Description = "Senha incorreta." }; }
        public override IdentityError InvalidToken() { return new IdentityError { Code = nameof(InvalidToken), Description = "Token inválido." }; }
        public override IdentityError LoginAlreadyAssociated() { return new IdentityError { Code = nameof(LoginAlreadyAssociated), Description = "Já existe um usuário com este login." }; }
        public override IdentityError InvalidUserName(string userName) { return new IdentityError { Code = nameof(InvalidUserName), Description = $"Login '{userName}' é inválido, pode conter apenas letras ou dígitos." }; }
        public override IdentityError InvalidEmail(string email) { return new IdentityError { Code = nameof(InvalidEmail), Description = $"Email '{email}' é inválido." }; }
        public override IdentityError DuplicateUserName(string userName) { return new IdentityError { Code = nameof(DuplicateUserName), Description = $"Login '{userName}' já está sendo utilizado." }; }
        public override IdentityError DuplicateEmail(string email) { return new IdentityError { Code = nameof(DuplicateEmail), Description = $"Email '{email}' já está sendo utilizado." }; }
        public override IdentityError InvalidRoleName(string role) { return new IdentityError { Code = nameof(InvalidRoleName), Description = $"A permissão '{role}' é inválida." }; }
        public override IdentityError DuplicateRoleName(string role) { return new IdentityError { Code = nameof(DuplicateRoleName), Description = $"A permissão '{role}' já está sendo utilizada." }; }
        public override IdentityError UserAlreadyHasPassword() { return new IdentityError { Code = nameof(UserAlreadyHasPassword), Description = "Usuário já possui uma senha definida." }; }
        public override IdentityError UserLockoutNotEnabled() { return new IdentityError { Code = nameof(UserLockoutNotEnabled), Description = "Lockout não está habilitado para este usuário." }; }
        public override IdentityError UserAlreadyInRole(string role) { return new IdentityError { Code = nameof(UserAlreadyInRole), Description = $"Usuário já possui a permissão '{role}'." }; }
        public override IdentityError UserNotInRole(string role) { return new IdentityError { Code = nameof(UserNotInRole), Description = $"Usuário não tem a permissão '{role}'." }; }
        public override IdentityError PasswordTooShort(int length) { return new IdentityError { Code = nameof(PasswordTooShort), Description = $"Senhas devem conter ao menos {length} caracteres." }; }
        public override IdentityError PasswordRequiresNonAlphanumeric() { return new IdentityError { Code = nameof(PasswordRequiresNonAlphanumeric), Description = "Senhas devem conter ao menos um caracter não alfanumérico." }; }
        public override IdentityError PasswordRequiresDigit() { return new IdentityError { Code = nameof(PasswordRequiresDigit), Description = "Senhas devem conter ao menos um digito ('0'-'9')." }; }
        public override IdentityError PasswordRequiresLower() { return new IdentityError { Code = nameof(PasswordRequiresLower), Description = "Senhas devem conter ao menos um caracter em caixa baixa ('a'-'z')." }; }
        public override IdentityError PasswordRequiresUpper() { return new IdentityError { Code = nameof(PasswordRequiresUpper), Description = "Senhas devem conter ao menos um caracter em caixa alta ('A'-'Z')." }; }
    }
}

• Go into your Startup.cs and when configuring the services.AddIdentity part, add the following code:

services.AddIdentity<User, IdentityRole>()
        .AddErrorDescriber<CustomIdentityErrorDescriber>();

In this example, the code was translated to pt-BR.

Would be nice if we have all those translations ready in the Identity package. The custom implementation is really nice but I don’t know if it’s just me felling that I will have to copy and paste this custom class into each project that I need to use.

[moeinifar]

this is for dear Farsi(Persian) speakers

using Microsoft.AspNetCore.Identity;

namespace WebApplication.Admin.Helpers
{
    public class CustomIdentityErrorDescriber : IdentityErrorDescriber
    {
        public override IdentityError DefaultError() { return new IdentityError { Code = nameof(DefaultError), Description = $"یک خطای ناشناخته رخ داده است." }; }
        public override IdentityError ConcurrencyFailure() { return new IdentityError { Code = nameof(ConcurrencyFailure), Description = "رکورد جاری پیشتر ویرایش شده‌است و تغییرات شما آن‌را بازنویسی خواهد کرد." }; }
        public override IdentityError PasswordMismatch() { return new IdentityError { Code = nameof(PasswordMismatch), Description = "کلمه عبور نادرست است." }; }
        public override IdentityError InvalidToken() { return new IdentityError { Code = nameof(InvalidToken), Description = "کلمه عبور نامعتبر است." }; }
        public override IdentityError LoginAlreadyAssociated() { return new IdentityError { Code = nameof(LoginAlreadyAssociated), Description = "این کاربر قبلأ اضافه شده‌است." }; }
        public override IdentityError InvalidUserName(string userName) { return new IdentityError { Code = nameof(InvalidUserName), Description = $"نام کاربری '{userName}' نامعتبر است، فقط می تواند حاوی حروف ویا اعداد باشد." }; }
        public override IdentityError InvalidEmail(string email) { return new IdentityError { Code = nameof(InvalidEmail), Description = $"ایمیل '{email}' نامعتبر است." }; }
        public override IdentityError DuplicateUserName(string userName) { return new IdentityError { Code = nameof(DuplicateUserName), Description = $"این نام کاربری '{userName}' به کاربر دیگری اختصاص یافته است." }; }
        public override IdentityError DuplicateEmail(string email) { return new IdentityError { Code = nameof(DuplicateEmail), Description = $"ایمیل '{email}' به کاربر دیگری اختصاص یافته است." }; }
        public override IdentityError InvalidRoleName(string role) { return new IdentityError { Code = nameof(InvalidRoleName), Description = $"نام نقش '{role}' نامعتبر است." }; }
        public override IdentityError DuplicateRoleName(string role) { return new IdentityError { Code = nameof(DuplicateRoleName), Description = $"این نام نقش '{role}' به کاربر دیگری اختصاص یافته است." }; }
        public override IdentityError UserAlreadyHasPassword() { return new IdentityError { Code = nameof(UserAlreadyHasPassword), Description = "کلمه‌ی عبور کاربر قبلأ تنظیم شده‌است." }; }
        public override IdentityError UserLockoutNotEnabled() { return new IdentityError { Code = nameof(UserLockoutNotEnabled), Description = "این کاربر فعال است." }; }
        public override IdentityError UserAlreadyInRole(string role) { return new IdentityError { Code = nameof(UserAlreadyInRole), Description = $"این نقش '{role}' قبلأ به این کاربر اختصاص یافته است." }; }
        public override IdentityError UserNotInRole(string role) { return new IdentityError { Code = nameof(UserNotInRole), Description = $"این نقش '{role}' قبلأ به این کاربر اختصاص نیافته است." }; }
        public override IdentityError PasswordTooShort(int length) { return new IdentityError { Code = nameof(PasswordTooShort), Description = $"کلمه عبور باید حداقل {length} کاراکتر باشد." }; }
        public override IdentityError PasswordRequiresNonAlphanumeric() { return new IdentityError { Code = nameof(PasswordRequiresNonAlphanumeric), Description = "کلمه عبور باید حداقل یک کاراکتر غیر از حروف الفبا داشته باشد." }; }
        public override IdentityError PasswordRequiresDigit() { return new IdentityError { Code = nameof(PasswordRequiresDigit), Description = "کلمه عبور باید حداقل یک عدد داشته باشد." }; }
        public override IdentityError PasswordRequiresLower() { return new IdentityError { Code = nameof(PasswordRequiresLower), Description = "کلمه عبور باید حداقل یک حروف کوچک داشته باشد." }; }
        public override IdentityError PasswordRequiresUpper() { return new IdentityError { Code = nameof(PasswordRequiresUpper), Description = "کلمه عبور باید حداقل یک حروف بزرگ داشته باشد." }; }
        public override IdentityError RecoveryCodeRedemptionFailed() { return new IdentityError { Code = nameof(RecoveryCodeRedemptionFailed), Description = "بازیابی ناموفق بود." }; }
        public override IdentityError PasswordRequiresUniqueChars(int uniqueChars) { return new IdentityError { Code = nameof(PasswordRequiresUniqueChars), Description = $"کلمه‌ی عبور باید حداقل داراى {0} حرف متفاوت باشد." }; }
    }
}

[andrewbasarab]

For anyone looking for multi language approach, see this workaround: http://stackoverflow.com/a/40801250/5338908