PHP Flush that works… even in Nginx

Question

Is it possible to echo each time the loop is executed? For example:

foreach(range(1,9) as $n){
    echo $n.\"\\n\";
    sleep(1);
}

Instead

Answer 1

The easiest way to eliminate nginx's buffering is by emitting a header:

header('X-Accel-Buffering: no');

This eliminates both proxy_buffering and (if you have nginx >= 1.5.6), fastcgi_buffering. The fastcgi bit is crucial if you're using php-fpm. The header is also far more convenient to do on an as-needed basis.

Docs on X-Accel-Buffering Docs on fastcgi_buffering

Answer 2

You can accomplish this by flushing the output buffer in the middle of the loop.

Example:

ob_start();
foreach(range(1,9) as $n){
    echo $n."\n";
    ob_flush();
    flush();
    sleep(1);
}

Note that your php.ini settings can affect whether this will work or not if you have zlib compression turned on