如何只使用一个套接字在PHP中发送许多请求HTTP？

I have a PHP Class to push message with socket like :

function __construct()
{
     $this->socket = fsockopen($this->host, $this->port, $errno, $errstr, 0); //I tried with 99999 for timeout too
}

function push($params)
{
     $req = 'GET /push?'.$params." HTTP/1.1
"
            . 'Host: '.$this->host."
"
            . "Content-Type: application/x-www-form-urlencoded
"
            . 'Content-Length: '.strlen($params)."
"
            . "Connection: keep-alive

";

     fwrite($this->socket, $req);
}

But if I tried to push 2 or more message, only one is receive by NodeJS serveur :

foreach(['foo=2', 'bar=42'] as $loop)
{
   $pusher->push($loop);
}

Now, if i put this line $this->socket = fsockopen($this->host, $this->port, $errno, $errstr, 0); just before fwrite, all messages will be send...

So why I can't use only one connexion for multiple request with same soket?

I use "keep-alive" and I don't call fclose, so I don't understand why my nodeJS server receive only one message in first case...