nginx下要使用Server-Sent Events要如何配置？

<code>date_default_timezone_set("America/New_York");
header("Content-Type:text/event-stream");

$userid = $_SESSION['userid'];
//session_write_close();

$db = get_db();

while(true) {
  $notices = $db->lRange("User:{$userid}:Notice", 0, -1);
  $notice_num = 0;
  foreach ($notices as $value) {
    $readed = $db->hGet("Notice:{$value}:Info", 'readed');
    if ($readed == false) {
      $notice_num++;
    }
  }

  echo "event: ping\n";
    $curDate = $notice_num;
    echo 'data: {"time": "' . $curDate . '"}';
    echo "\n\n";

    ob_flush();
    flush();

    sleep(30);
}
</code>

<code>var evtSource = new EventSource(serverName + 'index.php/Home/NoticePush/index');    
evtSource.addEventListener("ping", function(e) {     
    var obj = JSON.parse(e.data);     
    $('div#header div#user_notice a').text(obj.time);   
}, false);
</code>

<code>date_default_timezone_set("America/New_York");
header("Content-Type:text/event-stream");

$userid = $_SESSION['userid'];
//session_write_close();

$db = get_db();

while(true) {
  $notices = $db->lRange("User:{$userid}:Notice", 0, -1);
  $notice_num = 0;
  foreach ($notices as $value) {
    $readed = $db->hGet("Notice:{$value}:Info", 'readed');
    if ($readed == false) {
      $notice_num++;
    }
  }

  echo "event: ping\n";
    $curDate = $notice_num;
    echo 'data: {"time": "' . $curDate . '"}';
    echo "\n\n";

    ob_flush();
    flush();

    sleep(30);
}
</code>

<code>var evtSource = new EventSource(serverName + 'index.php/Home/NoticePush/index');    
evtSource.addEventListener("ping", function(e) {     
    var obj = JSON.parse(e.data);     
    $('div#header div#user_notice a').text(obj.time);   
}, false);
</code>