Session Auth With FastEndpoints + Swagger

Endpoint.cs

public sealed class Endpoint : EndpointWithoutRequest
{
    public override void Configure()
    {
        Get("/protected");
        Claims("userId");
        Roles("Some_Role_Name");
        Permissions("Some_Permission");
    }

    public override async Task HandleAsync(CancellationToken c)
    {
        await Send.OkAsync(new
        {
            SessionId = HttpContext.Request.Headers[SessionAuth.SessionIdHdrName].FirstOrDefault(),
            UserId = User.ClaimValue("userId"),
            HasSomeRole = User.IsInRole("Some_Role_Name"),
            HasSomePermission = User.HasPermission("Some_Permission")
        });
    }
}

Program.cs

using FastEndpoints;
using FastEndpoints.Security;
using FastEndpoints.Swagger;
using Microsoft.AspNetCore.Authentication;
using Microsoft.AspNetCore.Authorization;
using Microsoft.Extensions.Options;
using Microsoft.Extensions.Primitives;
using NSwag;
using System.Security.Claims;
using System.Security.Principal;
using System.Text.Encodings.Web;

var bld = WebApplication.CreateBuilder();
bld.Services
   .AddFastEndpoints()
   .AddAuthorization()
   .AddAuthentication(SessionAuth.SchemeName)
   .AddScheme<AuthenticationSchemeOptions, SessionAuth>(SessionAuth.SchemeName, null);
bld.Services
   .SwaggerDocument(o =>
   {
       o.EnableJWTBearerAuth = false;
       o.DocumentSettings = s =>
       {
           s.AddAuth(SessionAuth.SchemeName, new()
           {
               Name = SessionAuth.SessionIdHdrName,
               In = OpenApiSecurityApiKeyLocation.Header,
               Type = OpenApiSecuritySchemeType.ApiKey, //this is the only usable option :-(
           });
       };
   });

var app = bld.Build();
app.UseAuthorization()
   .UseFastEndpoints()
   .UseSwaggerGen();
app.Run();

SessionAuth.cs

public sealed class SessionAuth : AuthenticationHandler<AuthenticationSchemeOptions>
{
    internal const string SchemeName = "Session";
    internal const string SessionIdHdrName = "x-session-id";

    public SessionAuth(IOptionsMonitor<AuthenticationSchemeOptions> options,
                       ILoggerFactory logger,
                       UrlEncoder encoder,
                       ISystemClock clock) : base(options, logger, encoder, clock) { }

    protected override Task<AuthenticateResult> HandleAuthenticateAsync()
    {
        if (IsPublicEndpoint())
            return Task.FromResult(AuthenticateResult.NoResult());

        var hdrIsPresent = Request.Headers.TryGetValue(SessionIdHdrName, out var sessionId);

        if (!hdrIsPresent && !IsValidSession(sessionId))
            return Task.FromResult(AuthenticateResult.Fail("Invalid Session!"));

        //retrieve the user's claims/roles/permissions from a db/cache and create an auth ticket

        var identity = new ClaimsIdentity(
            claims: new[]
            {
                new Claim("userId", "001"),
                new Claim("permissions","Some_Permission"),
                new Claim("permissions","Another_Permission")
            },
            authenticationType: Scheme.Name);
        var roles = new[]
        {
            "Some_Role_Name",
            "Another_Role_Name"
        };
        var principal = new GenericPrincipal(identity, roles);
        var ticket = new AuthenticationTicket(principal, Scheme.Name);

        return Task.FromResult(AuthenticateResult.Success(ticket));
    }

    private bool IsPublicEndpoint() => Context
        .GetEndpoint()?
        .Metadata.OfType<AllowAnonymousAttribute>()
        .Any() is null or true;

    private static bool IsValidSession(StringValues sessionId)
    {
        //validate the session however you wish
        return sessionId == "xyz";
    }
}

Hi! I'm getting a 403 - Forbidden response even though my auth code produces a successful AuthenticateResult with a ticket. What else is there that could be causing this issue?

EDIT: It seems to be caused by the authenticationType that points to the wrong scheme.

@samld so all good?

@dj-nitehawk Yeah but I think lines 30 and 37 have to changed to SchemeName instead of Scheme.Name. That's how I fixed it.