class SFTP
{
    private $resource = false;

    public function connect( $host, $port = 22 )
    {
        $this->resource = ssh2_connect( $host, $port, [ 'hostkey'=>'ssh-rsa' ] );
    }

    public function auth( $username, $privKey )
    {
        if( $this->resource )
        {
            ssh2_auth_pubkey_file( $this->resource, $username, $privKey . '.pub', $privKey );
        }
    }

    public function sendFile( $file, $filename  )
    {
        if( $this->resource )
        {
            ssh2_scp_send( $this->resource, $file, $filename, 0644 );
        }
    }
}