Access Denied on Windows

[seikosantana]

Hi, I am trying to start a server on a specified port by clearing and adding prefix, but I got Access Denied when invoking server.Run(). the exception does not occur if i commented out the prefix clearing and adding prefix part. What is the cause of Access Denied? Did i miss anything?

Thanks in advace.

[scottoffen]

Can you post some code?

[seikosantana]

Sure.

using System;
using Grapevine;
using System.IO;
namespace HttpServer
{
    class Program
    {
        public static void Main(string[] args)
        {
            Run();
            Console.WriteLine("Built");
        }

        public readonly static string configPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "config.json");

        public static void Run()
        {
            var server = RestServerBuilder.UseDefaults().Build();
            server.Prefixes.Clear();
            server.Prefixes.Add("http://+:1234/");
            var materialsRoute = new Route(async (context) =>
            {
                await context.Response.SendResponseAsync(File.ReadAllText(configPath));
            }, "Get", "/materials");
            server.Router.Register(materialsRoute);
            server.Run();
        }
    }
}

The access denied exception is thrown on the server.Run().

[scottoffen]

Do you have something else on your machine that is using port 1234?

[seikosantana]

No, there isn't anything running on port 1234. I tried changing it to any port, be it 1234, 5555, 8888, 9999, i got access denied.

[seikosantana]

Current workaround is to run Visual Studio as administrator.

[scottoffen]

Access Denied

When you try to run your server for the first time, you might see an Access Denied exception occur. While annoying, this is rather easy to overcome. If you want to use HTTP.SYS to listen on a URI, you either need administrative privileges or an administrator that reserves the URI for normal users.

Run As Administrator

For development purposes, assuming you are an administrator on your Widows instance, you can simply run Visual Studio as administrator. Likewise, you can run the Windows command line as administrator if you want to test it outside of Visual Studio.

Configure Namespace Reservations

For obvious reasons, counting on your application running as administrator in production is unwise. In these instances, you'll want to configure a namespace reservation.

This reservation can be made by using the netsh utility.

$ netsh http add urlacl url=http://+:1234/ user=DOMAIN\user

This can be done programatically, but the implementation is outside the scope of Grapevine. It's important that the value of the url argument is an exact match, or the exception will still be thrown.

server.Prefixes.Add("http://+:1234/");

See the documentation for the add urlacl for a description of the parameters.