php flush not working

Question

<?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 1

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);
}

Answer 2

You're using ob_flush without ob_start, so there is nothing to flush for it.

It also depends on the webserver and proxy and its settings.

You should disable buffering for Nginx (add proxy_buffering off; to the config file and restart Nginx)

Also, check if your php.ini contains output_buffering = Off and zlib.output_compression = Off.

Answer 3

Main php file;

<?php
header('Content-Type: text/HTML; charset=utf-8');
header( 'Content-Encoding: none; ' );//disable apache compressed
session_start();
ob_end_flush();
ob_start();
set_time_limit(0);
error_reporting(0);

..... bla bla

for(each)........
{
   bla bla..
    echo "<br>>>>".$i."<<<br>";
    ob_flush();
    flush(); //ie working must

}
?>

it's working..