Get Context.User.Identity from signalr hub in blazor server app (.NET 7)

I had the same issue. The problem is when you hook the request in your hub, there is no JWT token. (If you use JWT token also)

(I'm in .NET 6)

So you need to create a PostConfigureOptions class:

public class ConfigureJwtBearerOptions : IPostConfigureOptions<JwtBearerOptions>
{
    public void PostConfigure(string name, JwtBearerOptions options)
    {
        var originalOnMessageReceived = options.Events.OnMessageReceived;
        options.Events.OnMessageReceived = async context =>
        {
            await originalOnMessageReceived(context);

            if (string.IsNullOrEmpty(context.Token))
            {
                var accessToken = context.Request.Query["access_token"];
                var path = context.HttpContext.Request.Path;

                if (!string.IsNullOrEmpty(accessToken) &&
                    path.StartsWithSegments("/hub"))
                {
                    context.Token = accessToken;
                }
            }
        };
    }
}

in you Program.cs :

services.TryAddEnumerable(ServiceDescriptor.Singleton<IPostConfigureOptions<JwtBearerOptions>, ConfigureJwtBearerOptions>());

Everything is detailled here : SignalR authentication & authorization

I also created a AppClaimsPrincipalFactory. But I'm not sure you would need this:

public class AppClaimsPrincipalFactory : UserClaimsPrincipalFactory<ApplicationUser, IdentityRole>
{
    public AppClaimsPrincipalFactory(UserManager<ApplicationUser> userManager, RoleManager<IdentityRole> roleManager, IOptions<IdentityOptions> optionsAccessor)
        : base(userManager, roleManager, optionsAccessor)
    { 

    }

    public async override Task<ClaimsPrincipal> CreateAsync(ApplicationUser user)
    {
        var principal = await base.CreateAsync(user);
        if (!string.IsNullOrWhiteSpace(user.FirstName))
            ((ClaimsIdentity)principal.Identity).AddClaims(new[] {new Claim(ClaimTypes.GivenName, user.FirstName)});
            
        if (!string.IsNullOrWhiteSpace(user.LastName))
            ((ClaimsIdentity)principal.Identity).AddClaims(new[] {new Claim(ClaimTypes.Surname, user.LastName)});

        if (!string.IsNullOrWhiteSpace(user.Email))
            ((ClaimsIdentity)principal.Identity).AddClaims(new[] { new Claim(ClaimTypes.Email, user.Email) });

        return principal;
    }
}



services.AddScoped<IUserClaimsPrincipalFactory<ApplicationUser>, AppClaimsPrincipalFactory>();

Get username in blazor .Net6 .Net8

in page:

    @using BlazorApp1.Data
    @using Microsoft.EntityFrameworkCore
    @inject AuthenticationStateProvider GetAuthenticationStateAsync

@email


@code{
string email;
    protected override async Task OnInitializedAsync()
    {
        var authstate = await GetAuthenticationStateAsync.GetAuthenticationStateAsync();
        var user = authstate.User;
        var name = user.Identity.Name;
        email = name;
    }
}