View Full Version : Ajax+Sessions doesn't allow page close/refresh (Comet)

09-15-2009, 03:58 PM
Ok, I'm working on ajax chat app, but not with regular ajax request per second. It is based on ajax long polling.

So It is pretty simple.
Ajax requests php page -> php sleeps in loop waiting for new data from DB -> when new data show up php echo that data and ajax request is killed.
Even when I close/refresh page the ajax request is killed, so everything is perfect.

But when I use sessions i got problem.
If session_start() is called, than i can't refresh page, or when i close it ajax request is still working in background.
Any ideas?

09-15-2009, 04:10 PM
How is your request being killed when you close the page? By nature, when you call a PHP script, it will run until it errors out, times out, or finishes - closing the web browser will not stop your PHP script from running on the server...it only kills the javascript.

Using sessions shouldn't affect how that works. If you are interested in stopping your PHP when you close the browser, then just have it echo back some result every X seconds and finish executing. If that result means that nothing was found yet, then call the script again, otherwise finish executing.

09-15-2009, 09:43 PM
I found what was wrong... I didn't know that PHP doesn't write sessions until the whole code is executed... So simple session_write_close(); fixed everything.

header('Expires: Mon, 26 Jul 1997 05:00:00 GMT');
header('Cache-Control: no-store, no-cache, must-revalidate');
header('Cache-Control: post-check=0, pre-check=0', FALSE);
header('Pragma: no-cache');

$vreme = $_SESSION['vreme'];

$time = time();

$mysqli = new mysqli('localhost','root','ajaje3budja','karte');

while((time() - $time) < 29)
$result = $mysqli->query("SELECT * FROM test");

$row = $result->fetch_object();

if($row->vreme !== $vreme)
$_SESSION['vreme'] = $row->vreme;


echo str_replace("<br />", "\n", $row->poruka) . "[BRK]" . $row->vreme;