How to get logged in userId from Blazor Server

Question

Using the standard Blazor Server with individual accounts scaffolded by Microsoft, how do I access the logged in userId inside of a component? .NET 5.

I've tried tapping into AuthenticationStateProvider and using this to get it, but that returns null.

 var authState = await authenticationStateProvider.GetAuthenticationStateAsync();

        if (authState.User.Identity.IsAuthenticated)
        {
            var id = authState.User.FindFirst(c => c.Type == "nameidentifier")?.Value;
        }

Use ClaimTypes.NameIdentifier constant, not a magic string. — Liero
– Liero, Commented Oct 20, 2021 at 16:48
You can also use User.FindFirstValue(ClaimTypes.NameIdentifier) — Liero
– Liero, Commented Oct 20, 2021 at 16:50

Metro Smurf · Accepted Answer · 2021-10-20 16:20:39Z

1

The user information is stored in the ClaimsPrincipal. Here's a couple of extension methods I use:

public static long GetUserId( this ClaimsPrincipal principal )
{
    string val = principal.FindFirstValue( ClaimTypes.NameIdentifier );
    return long.Parse( val );
}

public static bool TryGetUserId( this ClaimsPrincipal principal, out long userId )
{
    if( principal.HasClaim( x => x.Type == ClaimTypes.NameIdentifier ) )
    {
        userId = principal.GetUserId();
        return true;
    }

    userId = -1;
    return false;
}

And usage would something along the lines of:

// from a controller
long id = User.GetUserId();

// from an HTTPContext, i.e., middleware
bool hasId = context.User.TryGetUserId( out long userId );

answered Oct 20, 2021 at 16:20

Metro Smurf

38.5k20 gold badges117 silver badges146 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

How to get logged in userId from Blazor Server

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related