FTP File Upload with HTTP Proxy

Question

Is there a way to upload a file to a FTP server when behind an HTTP proxy ?

It seems that uploading a file is not supported behind an HTTP Proxy using .Net Webclient

Answer 1

I'm not sure if all HTTP proxies work in the same way, but I managed to cheat ours by simply creating an HTTP request to access resource on URI ftp://user:pass@your.server.com/path.

Sadly, to create an instance of HttpWebRequest you should use WebRequest.Create. And if you do that you can't create an HTTP request for ftp:// schema.

So I used a bit of reflection to invoke a non-public constructor which does that:

var ctor = typeof(HttpWebRequest).GetConstructor(
    BindingFlags.NonPublic | BindingFlags.Instance, 
    null, 
    new Type[] { typeof(Uri), typeof(ServicePoint) }, 
    null);
var req = (WebRequest)ctor.Invoke(new object[] { new Uri("ftp://user:pass@host/test.txt"), null });
req.Proxy = new WebProxy("myproxy", 8080);
req.Method = WebRequestMethods.Http.Put;

using (var inStream = req.GetRequestStream())
{
    var buffer = Encoding.ASCII.GetBytes("test upload");
    inStream.Write(buffer, 0, buffer.Length);
}

using (req.GetResponse())
{
}

You can also use other methods like "DELETE" for other tasks.

In my case, it worked like a charm.