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php – How to correctly show output at every echo on all browsers?

Posted by: admin July 12, 2020 Leave a comment

Questions:

I moved my files to a new server and I had a script that instantly showed output on every echo to the browser, but this isn’t working on the new server. Here is my test code:

@ini_set('output_buffering', 0); @ini_set('implicit_flush', 1);

for ($i = 0; $i < ob_get_level(); $i++) ob_end_flush();

ob_implicit_flush(1);

ignore_user_abort(true); set_time_limit(0);


$max_wait_time = 30;

$begin_time = microtime(true);

$elapsed_time = 0;


while(!connection_aborted()) {

    echo $i++.str_repeat(' ', 1020).'<br/>';

    flush(); ob_flush();

    usleep(1000000);

    if($elapsed_time > $max_wait_time){ break; }

    $elapsed_time++;

}

I’ve tried a few things which has become the above. But turning output buffering on and flushing hasn’t worked for me. I have tested this on Chrome and Firefox, they both just output everything at the end.

Any ideas?

How to&Answers:

Excerpt from the flush documentation:

flush() may not be able to override
the buffering scheme of your web
server and it has no effect on any
client-side buffering in the browser.
[…]

Several servers, especially on Win32,
will still buffer the output from your
script until it terminates before
transmitting the results to the
browser.

Server modules for Apache like
mod_gzip may do buffering of their own
that will cause flush() to not result
in data being sent immediately to the
client.

Chances are high that you changed to a different web server (or web server configuration), which buffers the output of the whole script before outputting it.

Answer:

The setting you’re looking for is in your PHP.ini and it’s called output_buffering:

; output_buffering
;   Default Value: Off
;   Development Value: 4096
;   Production Value: 4096

Set it to off manually and restart your webserver to make flush() actually flush something when you want it, not after 4kb of data 🙂

Note that ini_set doesn’t always necessarily has to work for this. If you want full control, disable it in php.ini itself, or as a .htacces php_value flag

Answer:

Browsers decide for themselves when to output content. So if you don’t meet that threshold, they’ll just wait until it is met and only then show more content to the user.

Answer:

Try to add to .htaccess

    php_value output_buffering Off