PHP Flush that works… even in Nginx

问题:

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 of printing everything when the loop is finished, I'd like to see it printing each result per time.

回答1:

FINAL SOLUTION

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);
}

Related:

• php flush not working

• How to flush output after each `echo` call?

• PHP flushing output as soon as you call echo

回答2:

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

回答3:

Easy solution on nginx server:

fastcgi_keep_conn on; # < solution

proxy_buffering off;
gzip off;

回答4:

I didn't want to have to turn off gzip for the whole server or a whole directory, just for a few scripts, in a few specific cases.

All you need is this before anything is echo'ed:

header('Content-Encoding: none;');

Then do the flush as normal:

ob_end_flush();
flush();

Nginx seems to pick up on the encoding having been turned off and doesn't gzip.

回答5:

You need to flush the php's buffer to the browser

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

See: http://php.net/manual/en/function.flush.php

回答6:

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

回答7:

I found that you can set:

header("Content-Encoding:identity");

in your php script to disable nginx gzipping without having to modify the nginx.conf

回答8:

I had a gzip problem comming from my php-fpm engine. this code is the only one working for me :

function myEchoFlush_init() {
    ini_set('zlib.output_compression', 0);
    ini_set('output_buffering', 'Off');
    ini_set('output_handler', '');
    ini_set('implicit_flush', 1);
    ob_implicit_flush(1);
    ob_end_clean();
    header('Content-Encoding: none;');

}

function myEchoFlush($str) {
    echo $str . str_repeat(' ', ini_get('output_buffering') * 4) . "<br>\n";
}

This is my test function : it checks max_execution_time :

public function timeOut($time = 1, $max = 0) {
    myEchoFlush_init();
    if ($max) ini_set('max_execution_time', $max);
    myEchoFlush("Starting infinite loop for $time seconds. It shouldn't exceed : " . (ini_get('max_execution_time')));
    $start = microtime(true);
    $lastTick = 1;
    while (true) {
        $tick = ceil(microtime(true) - $start);
        if ($tick > $lastTick) {
            myEchoFlush(microtime(true) - $start);
            $lastTick = $tick;
        }
        if ($tick > $time) break;
    }
    echo "OK";
}