DevelpmentWallMiddleware.cs

public class DevelpmentWallMiddleware
{
    private readonly RequestDelegate _next;
    private readonly string _password;
    private readonly string _username;

    public DevelpmentWallMiddleware(RequestDelegate next, string username, string password)
    {
        _next = next;
        _username = username;
        _password = password;
    }

    public Task Invoke(HttpContext httpContext)
    {
        var request = httpContext.Request;
        var response = httpContext.Response;
        if (request.Host.Value.StartsWith("localhost")) return _next(httpContext);

        StringValues authHeader;

        if (request.Headers.TryGetValue("Authorization", out authHeader) &&
            authHeader.Any() &&
            authHeader.First().StartsWith("Basic "))
        {
            try
            {
                string pair = Encoding.UTF8.GetString(
                    Convert.FromBase64String(authHeader.FirstOrDefault().Substring("Basic ".Length)));

                var ix = pair.IndexOf(':');

                var credentialId = pair.Substring(0, ix);
                var credentialSecret = pair.Substring(ix + 1);

                if (credentialId == _username && credentialSecret == _password)
                {
                    return _next(httpContext);
                }
            }
            catch (Exception)
            {

            }
        }
        response.StatusCode = 401;
        response.Headers.AppendCommaSeparatedValues("WWW-Authenticate", $"Basic realm=basic");

        return Task.FromResult<object>(null);
    }
}

public static class DevelpmentWallMiddlewareExtensions
{
    public static IApplicationBuilder UseDevelpmentWallMiddleware(this IApplicationBuilder builder, string username, string password)
    {
        return builder.UseMiddleware<DevelpmentWallMiddleware>(username, password);
    }
}