php flush not working

Speedy Wap picture Speedy Wap · Jan 16, 2011 · Viewed 43.4k times · Source
<?php
for($i=0;$i<20;$i++)
{
    echo 'printing...<br />';
    ob_flush();
    flush();

    usleep(300000);
}

?>

Url that contains the code: http://domainsoutlook.com/sandbox/delayed.php

I have a dedicated server so I can make the changes. I am running apache and nginx as the proxy server.

Answer

Roger picture Roger · Feb 12, 2011

So that's what I found out:

Flush would not work under Apache's mod_gzip or Nginx's gzip because, logically, it is gzipping the content, and to do that it must buffer content to gzip it. Any sort of web server gzipping would affect this. In short, at the server side, we need to disable gzip and decrease the fastcgi buffer size. So:

  • In php.ini:

    . output_buffering = Off

    . zlib.output_compression = Off

  • In nginx.conf:

    . gzip off;

    . proxy_buffering off;

Also have this lines at hand, specially if you don't have acces to php.ini:

  • @ini_set('zlib.output_compression',0);

  • @ini_set('implicit_flush',1);

  • @ob_end_clean();

  • set_time_limit(0);

Last, if you have it, coment the code bellow:

  • ob_start('ob_gzhandler');

  • ob_flush();

PHP test code:

ob_implicit_flush(1);

for($i=0; $i<10; $i++){
    echo $i;

    //this is for the buffer achieve the minimum size in order to flush data
    echo str_repeat(' ',1024*64);

    sleep(1);
}