PHP 5.4.31 Released

Funciones del Control de la salida

Ver también

Véase también header() y setcookie().

Tabla de contenidos

  • flush — Vaciar el búfer de salida del sistema
  • ob_clean — Limpiar (eliminar) el búfer de salida
  • ob_end_clean — Limpiar (eliminar) el búfer de salida y deshabilitar el almacenamiento en el mismo
  • ob_end_flush — Volcar (enviar) el búfer de salida y deshabilitar el almacenamiento en el mismo
  • ob_flush — Vaciar (enviar) el búfer de salida
  • ob_get_clean — Obtener el contenido del búfer actual y eliminar el búfer de salida actual
  • ob_get_contents — Devolver el contenido del búfer de salida
  • ob_get_flush — Volcar el búfer de salida, devolverlo como una cadena de caracteres y deshabilitar el almacenamiento en el búfer de salida
  • ob_get_length — Devolver la longitud del búfer de salida
  • ob_get_level — Devolver el nivel de anidamiento del mecanismo de almacenamiento en el búfer de salida
  • ob_get_status — Obtener el estado de los búferes de salida
  • ob_gzhandler — Función de llamada de retorno de ob_start para comprimir el búfer de salida con gzip
  • ob_implicit_flush — Habilitar/deshabilitar el volcado implícito
  • ob_list_handlers — Enumerar todos los gestores de salida en uso
  • ob_start — Activa el almacenamiento en búfer de la salida
  • output_add_rewrite_var — Aladir valores al mecanismo de reescritura de URLs
  • output_reset_rewrite_vars — Restablecer los valores del mecanismo de reescritura de URLs
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User Contributed Notes 9 notes

up
3
della at sun dot com
5 years ago
Sometimes users are blaming about slow pages ... not being aware that mostly this is due to network issues.
So I've decided to add some statistics at the end of my pages:

At beginning I start the counters:

<?php
 
function microtime_float() {
    if (
version_compare(PHP_VERSION, '5.0.0', '>'))  return microtime(true);
    list(
$u,$s)=explode(' ',microtime()); return ((float)$u+(float)$s); 
  }
 
$initime=microtime_float();
 
ob_start();
 
ob_implicit_flush();
?>

And at the end I show the statistics:

<?php
 
echo "PHP Time: ".round((microtime_float()-$initime)*1000)." msecs. ";
  echo
"Size: ".round_byte(strlen(ob_get_contents()));
 
ob_end_flush();
?>

(round_byte is my function to print byte sizes)
up
0
Anonymous
5 years ago
You possibly also want to end your benchmark after the output is flushed.

<?php
your_benchmark_start_function
();

ob_start ();
for (
$i = 0; $i < 5000; $i++)
    echo
str_repeat ("your string blablabla bla bla", (rand() % 4) + 1)."<br>\n";

                              <----------
echo
your_benchmark_end_function();      |
ob_end_flush (); ------------------------
?>
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0
jgeewax a t gmail
7 years ago
It seems that while using output buffering, an included file which calls die() before the output buffer is closed is flushed rather than cleaned. That is, ob_end_flush() is called by default.

<?php
// a.php (this file should never display anything)
ob_start();
include(
'b.php');
ob_end_clean();
?>

<?php
// b.php
print "b";
die();
?>

This ends up printing "b" rather than nothing as ob_end_flush() is called instead of ob_end_clean(). That is, die() flushes the buffer rather than cleans it. This took me a while to determine what was causing the flush, so I thought I'd share.
up
0
basicartsstudios at hotmail dot com
7 years ago
Sometimes you might not want to include a php-file under the specifications defined in the functions include() or require(), but you might want to have in return the string that the script in the file "echoes".

Include() and require() both directly put out the evaluated code.

For avoiding this, try output-buffering:
<?php
ob_start
();
eval(
file_get_contents($file));
$result = ob_get_contents();
ob_end_clean();
?>
or
<?php
ob_start
();
include(
$file);
$result = ob_get_contents();
ob_end_clean();
?>
which i consider the same, correct me if I'm wrong.

Best regards, BasicArtsStudios
up
0
trucex [um, at] gmail [um, dot] com
7 years ago
Unfortunately, the PHP guys didn't build support into any of the image output functions to return the image instead of outputting it.

Fortunately, we have output buffering to fix that.

<?php

$im
= imagecreatetruecolor(200, 200);

// Other image functions here...

ob_start();
imagepng($im);
$imageData = ob_get_contents();
ob_clean();

?>

You can now use the $imageData variable to either create another GD image, save it, put it in a database, make modifications to the binary, or output it to the user. You can easily check the size of it as well without having to access the disk...just use strlen();
up
0
webmaster at wistex dot com
7 years ago
Now this just blew my mind. I had a problem with MySQL being incredibly slow on Windows 2003 running IIS... on ASP/VBScript pages. PHP is also installed on the server and so is Microsoft SQL 2005 Express. (Yes, we're running ASP, PHP, MySQL and MS SQL on the same Windows 2003 Server using IIS.)

I was browsing the internet for a solution and saw a suggestion that I change output_buffering to on if MySQL was slow for PHP pages.  Since we also served PHP pages with MySQL from the same server, it caught my eye.  For the hell of it, I went into php.ini and changed output_buffering to on and suddenly MySQL and ASP was faster... MySQL and PHP was faster... Microsoft SQL Server 2005 Express and ASP was faster.... everything was faster... even stuff that had no PHP!

And I didn't even have to restart IIS. As soon as I saved the php.ini file with the change, everything got faster.

Apparently PHP and MySQL and IIS are so intertwined somehow that changing the buffering setting really effects the performance of the entire server.

So, if you are having performance problems on Windows 2003 & IIS, you might try setting output_buffering = On in php.ini if you happen to have PHP installed.  Having it set to off apparently effects the performance of Windows 2003 and IIS severely... even for webpages that do not use PHP or MySQL.
up
0
kamermans at teratechnologies dot net
7 years ago
Output buffering is set to '4096' instead of 'Off' or '0' by default in the php-5.0.4-10.5 RPM for Fedora Core release 4 (Stentz).  This has cost me much time!
up
0
kend52 at verizon dot net
9 years ago
I ran out of memory, while output buffering and drawing text on imported images. Only the top portion of the 5MP image was displayed by the browser.  Try increasing the memory limit in either the php.ini file( memory_limit = 16M; ) or in the .htaccess file( php_value memory_limit "16M" ). Also see function memory_get_usage() .
up
-1
gruik at libertysurf dot fr
10 years ago
For those who are looking for optimization, try using buffered output.

I noticed that an output function call (i.e echo()) is somehow time expensive. When using buffered output, only one output function call is made and it seems to be much faster.
Try this :

<?php
your_benchmark_start_function
();

for (
$i = 0; $i < 5000; $i++)
    echo
str_repeat ("your string blablabla bla bla", (rand() % 4) + 1)."<br>\n";

echo
your_benchmark_end_function();
?>

And then :

<?php
your_benchmark_start_function
();

ob_start ();
for (
$i = 0; $i < 5000; $i++)
    echo
str_repeat ("your string blablabla bla bla", (rand() % 4) + 1)."<br>\n";

echo
your_benchmark_end_function();
ob_end_flush ();
?>
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