Securing AspNetCore SPA Template

Startup.SecureSpa.cs

using Microsoft.AspNetCore.Authentication;

// Configure()

app.Use(async (context, next) =>
{
    if (!context.User.Identity.IsAuthenticated)
    {
        await context.ChallengeAsync();
    }
    else
    {
        // Already authenticated, call next middleware
        await next();
    }
});