Handle Token Refresh

Access tokens normally have short expiration windows, so you'll want to use the refresh token to get new access tokens for users in your C# server.

Refresh Tokens in Auth Middleware

Use the Wristband SDK in your auth middleware to call the RefreshTokenIfExpired() function.

// AuthMiddleware.cs

public class AuthMiddleware
{
    private readonly RequestDelegate _next;
    public AuthMiddleware(RequestDelegate next) => _next = next;

    public async Task InvokeAsync(HttpContext context, IWristbandAuthService wristbandAuth)
    {
        if (context.GetEndpoint()?.Metadata.GetMetadata<RequireWristbandAuthAttribute>() == null)
        {
            await _next(context);
            return;
        }

        if (!await IsAuthenticated(context))
        {
            context.Response.StatusCode = StatusCodes.Status401Unauthorized;
            return;
        }
      
        /* ***** BEGIN TOKEN REFRESH LOGIC ***** */

        try
        {
            var refreshToken = context.User.FindFirst("refreshToken")?.Value ?? string.Empty;
            var expiresAt = long.TryParse(context.User.FindFirst("expiresAt")?.Value, out var exp) ? exp : 0;
            var tokenData = await wristbandAuth.RefreshTokenIfExpired(refreshToken, expiresAt);

            // Update token claims if refresh was necessary
            var claims = context.User.Claims;    
            if (tokenData != null)
            {
                claims = claims
                    .Where(c => !new[] { "accessToken", "refreshToken", "expiresAt" }.Contains(c.Type))
                    .Concat(new[]
                    {
                        new Claim("accessToken", tokenData.AccessToken),
                        new Claim("refreshToken", tokenData.RefreshToken ?? string.Empty),
                        new Claim("expiresAt", $"{DateTimeOffset.Now.ToUnixTimeMilliseconds() + (tokenData.ExpiresIn * 1000)}")
                    });
            }

            await context.SignInAsync(
                CookieAuthenticationDefaults.AuthenticationScheme,
                    new ClaimsPrincipal(new ClaimsIdentity(claims, CookieAuthenticationDefaults.AuthenticationScheme)),
                new AuthenticationProperties { IsPersistent = true });
            await _next(context);
        }
        catch (Exception ex)
        {
            context.Response.StatusCode = StatusCodes.Status401Unauthorized;
        }
      
        /* ***** END TOKEN REFRESH LOGIC ***** */
    }

    ...
}