How to customize ASP.NET Identity Core Username to allow special characters and space

Question

I have changed my Register Action Method to accept user Name instead of Email.

if (ModelState.IsValid)
{
    var user = new ApplicationUser 
    {
        UserName = model.Name,
        Email = model.Email,
    };

But when I Enter Name in TextBox like Joe Smith It give me an error that is Invalid UserName. It is not allowing user Name to Accept White space. My Question is how can I modify the builtin User Name to allow space and special characters. I am using ASP.NET Core.

Thanks in Advance.

Solution 1

You can set user validation rules configuring identity with options in your Startup.cs.

services.AddIdentity<ApplicationUser, IdentityRole>(options => {
    options.User.AllowedUserNameCharacters = "allowed characters here";
    options.User.RequireUniqueEmail = true/false;
});

Related resources:

Configure Identity

Solution 2

So cloudikka's answer had it right. I'll just add explicitly (cloudikka's link explained it as well) that you need to list ALL the characters you want to allow (not just the whitespace or special characters), like this:

services.AddIdentity<ApplicationUser, IdentityRole>(options => {
    options.User.AllowedUserNameCharacters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-._@+/ ";
});

and NOT this options.User.AllowedUserNameCharacters = " "; which means 'only whitespace characters allowed'. (I reckon this was Babar's problem.)

Solution 3

The proposed solution can be tricky if you have an exhaustive list of special characters to whitelist.

If you want to blacklist instead, disable the whitelist in startup.cs:

 services.AddIdentity<User, Role>(
                options =>
                {                        
                    options.User.AllowedUserNameCharacters = string.Empty;
                })

Then create your custom user validator

 public class UsernameValidator<TUser> : IUserValidator<TUser>
where TUser : User
{
    public Task<IdentityResult> ValidateAsync(UserManager<TUser> manager, TUser user)
    {                
        if (user.UserName.Any(x=>x ==':' || x == ';' || x == ' ' || x == ','))
        {
            return Task.FromResult(IdentityResult.Failed(new IdentityError
            {
                Code = "InvalidCharactersUsername",
                Description = "Username can not contain ':', ';', ' ' or ','"
            }));
        }
        return Task.FromResult(IdentityResult.Success);
    }        
}

Then add it to startup.cs:

 services.AddIdentity<User, Role>(
                options =>
                {
                    options.Password = new PasswordOptions
                    {
                        RequiredLength = 8,
                        RequireUppercase = true,
                        RequireNonAlphanumeric = true,
                        RequireDigit = true,
                        RequireLowercase = true
                    };
                    options.User.AllowedUserNameCharacters = string.Empty;
                }).AddUserValidator<UsernameValidator<User>>()

Solution 4

services.AddIdentity<ApplicationUser, IdentityRole>(options => { options.User.AllowedUserNameCharacters = String.Empty; options.User.RequireUniqueEmail = true; })
            .AddEntityFrameworkStores<ApplicationDbContext>().AddDefaultTokenProviders();

View more solutions

Comments

[Babar]

I just want to store full Name First Name + Last Name in table and It has to a space between them.

[AJ -]

Then as I told you keep username as is and use a new property FullName in ApplicationUser class

[Babar]

Ok How can I allow duplicate username? Is this possible?

[dropoutcoder]

@Jaffal: Whitesoace is bad practice because username is handle and it is used in the address bar and Joe%20Smith is ugly. Special characters can make web page behave strange(? querystring, # fragment). That is why we are not using special characters in general. Also special characters are not exactly human friendly and readable. Except _ or -.

[dropoutcoder]

@Babar It is not good idea to have duplicity in usernames. Username is handle and have to be unique.

[AJ -]

@cloudikka that's why I told Babar to keep username as is and use new property call it FullName for the purpose he wants and username will stay as is unique doesn't accept special characters or whitespaces Babar just create new property inside ApplicationUser

[dropoutcoder]

@Jaffal: I just extend your comment! I didnt meant to disagree with you.

[Babar]

It is not allowing white space and special characters

[dropoutcoder]

I am reviewing the ASP.NET Identity source code and see nothing that will ban whitespace from usage, if you specify one in the AllowedUserNameCharacters property.

[Babar]

I always get that error 'Invalid UserName' either I use space or not. Code is not even working with plain character.

[dropoutcoder]

Without the code it will be hard to find out for anyone.

[Mog0]

I found that I needed to support a wide variety of characters as they already existed in customer installs so this worked best for me - It disables the checking on user names.

[James Rao]

this should be marked as answer. it works for me. the AllowedUserNameCharacters should be set with ALL characters we want to allow.