public void Login(Stream stream)
{
    string username = null;
    string password = null;

    HttpContentParser parser = new HttpContentParser(stream);
    if (parser.Success)
    {
        username = HttpUtility.UrlDecode(parser.Parameters["username"]);
        password = HttpUtility.UrlDecode(parser.Parameters["password"]);
    }
}

public void Upload(Stream stream)
{
    HttpMultipartParser parser = new HttpMultipartParser(stream, "image");

    if (parser.Success)
    {
        string user = HttpUtility.UrlDecode(parser.Parameters["user"]);
        string title = HttpUtility.UrlDecode(parser.Parameters["title"]);

        // Save the file somewhere
        File.WriteAllBytes(FILE_PATH + title + FILE_EXT, parser.FileContents);
    }
}

Microsoft.AspNetCore.Http.IFormCollection form;
        form = ControllerContext.HttpContext.Request.Form;

        using (var fileStream = System.IO.File.Create(strFile))
        {
            form.Files[0].OpenReadStream().Seek(0, System.IO.SeekOrigin.Begin);
            form.Files[0].OpenReadStream().CopyTo(fileStream);
        }