ob_clean
In reference to <geoff at spacevs dot com> where he states, "If you call ob_end_clean in a function registered with 'register_shutdown_function', it is too late, any buffers will have already been sent out to the client.", here is a workaround I came up with.
<?php
function ClearBuffer($Buffer) {
return "";
}
function Shutdown() {
ob_start("ClearBuffer");
}
register_shutdown_function("Shutdown");
?>
This will wipe out all the contents of the output buffer as it comes in. Basically its the same as "STDOUT > /dev/null".
ob_end_clean
(PHP 4, PHP 5)
ob_end_clean — Détruit les données du tampon de sortie et éteint la tamporisation de sortie
Description
bool ob_end_clean
( void
)
Cette fonction vide le contenu du premier tampon de sortie et désactive la tamporisation de sortie. Si vous voulez traiter le contenu du tampon, vous devrez appeler ob_get_contents() avant ob_end_clean(), car le tampon est détruit par ob_end_clean().
Valeurs de retour
Cette fonction retourne TRUE en cas de succès, FALSE en cas d'échec. Les raisons d'un tel échec sont que la tamporisation de sortie pouvait ne pas être activée, ou que, pour une raison quelconque, le tampon n'a pu être détruit.
Erreurs / Exceptions
Si la fonction échoue, elle génère une note E_NOTICE.
Historique
| Version | Description |
|---|---|
| 4.2.0 | La valeur booléen retournée par la fonction a été ajoutée. |
Exemples
L'exemple suivant montre comment se débarrasser de tous les tampons de sortie :
Exemple #1 Exemple avec ob_end_clean()
<?php
ob_start();
echo 'Texte qui ne sera pas affiché.';
ob_end_clean();
?>
Voir aussi
- ob_start() - Enclenche la tamporisation de sortie
- ob_get_contents() - Retourne le contenu du tampon de sortie
- ob_flush() - Envoie le tampon de sortie
add a note
User Contributed Notesob_end_clean
tyler @
10-Aug-2008 11:39
10-Aug-2008 11:39
geoff at spacevs dot com
23-Jul-2007 12:47
23-Jul-2007 12:47
If you call ob_end_clean in a function registered with "register_shutdown_function", it is too late, any buffers will have already been sent out to the client.
everling
11-Nov-2006 10:04
11-Nov-2006 10:04
Keep in mind that mrfritz379's example (#49800) is just an example. You can achieve that example's result in a more efficient manner without using output buffering functions:
echo "<p>Search running. Please be patient. . .";
$output = "<p>FileList: </p>\n";
if (is_dir($dir)) {
$dh = opendir($dir);
while (($fd = readdir($dh)) != false) {
echo " .";
$output .= $fd;
}
}
echo "</br>Search Complete!</p>\n";
echo $output;
In addition to John Smith's comment (#42939), ob_gzhandler() may still set the HTTP header "Content-Encoding" to "gzip" or "deflate" even if you call ob_end_clean(). This will cause a problem in the following situation:
1. Call ob_gzhandler().
2. Echo "Some content";
3. Call ob_end_clean().
4. Echo "New content";
In the above case, the browser may receive the "Content-Encoding: gzip" HTTP header and attempts to decompress the uncompressed "New content". The browser will fail.
In the following situation, this behaviour will go unnoticed:
1. Call ob_gzhandler().
2. Echo "Some content";
3. Call ob_end_clean().
4. Call ob_gzhandler().
5. Echo "New content";
This is because the second ob_gzhandler() will mask the absence of the first ob_gzhandler().
A solution would be to write a wrapper, like John Smith did, for the ob_gzhandler().
Adam of Fusion Bay
18-May-2006 07:38
18-May-2006 07:38
You may want to be careful about calling ob_end_clean() from within your call-back function. I believe this can produce an endless-loop within PHP.
mrfritz379
09-Feb-2005 02:14
09-Feb-2005 02:14
This may be posted elsewhere, but I haven't seen it.
To run a progress indicator while the program is running without outputting the output buffer, the following will work:
echo "<p>Search running. Please be patient. . .";
$output = "<p>FileList: </p>\n";
if (is_dir($dir)) {
$dh = opendir($dir);
while (($fd = readdir($dh)) != false) {
echo " .";
ob_start();
echo $fd;
$output .= ob_get_contents();
ob_end_clean();
}
}
echo "</br>Search Complete!</p>\n";
echo $output;
The program will continue to print the " ." without printing the file list. Then the "Search Complete" message will print followed by the buffered file list.
John Smith
04-Jun-2004 11:39
04-Jun-2004 11:39
Note that if you started called ob_start with a callback, that callback will still be called even if you discard the OB with ob_end_clean.
Because there is no way of removing the callback from the OB once you've set it, the only way to stop the callback function from having any effect is to do something like:
<?php
$ignore_callback = false;
ob_start('my_callback');
...
if($need_to_abort) {
$ignore_callback = true;
ob_end_clean();
...
}
function my_callback(&$buffer) {
if($GLOBALS['ignore_callback']) {
return "";
}
...
}
?>
daijoubuNOSP at Mvideotron dot com
22-Feb-2004 09:11
22-Feb-2004 09:11
About the previous comment:
You can also relay on ETag and simply use time()
<?php
$time = time();
$mins = 1;
if (isset($_SERVER['HTTP_IF_NONE_MATCH']) and str_replace('"', '', $_SERVER['HTTP_IF_NONE_MATCH'])+($mins*60) > $time)
{
header('HTTP/1.1 304 Not Modified');
exit();
}
else
{
header('ETag: "'.$time.'"');
}
echo 'Caching for ', $mins*60, 'secs<br/>', date('G:i:s');
?>
programmer at bardware dot de
27-Jun-2003 01:32
27-Jun-2003 01:32
You might want to prevent your script from executing if the client already has the latest version.
You can do it like so:
ob_start();
$mtime=filemtime($_SERVER["SCRIPT_FILENAME"])-date("Z");
$gmt_mtime = date('D, d M Y H:i:s', $mtime) . ' GMT';
$headers = getallheaders();
if(isset($headers["If-Modified-Since"])) {
if ($headers["If-Modified-Since"] == $gmt_mtime) {
header("HTTP/1.1 304 Not Modified");
ob_end_clean();
exit;
}
}
$size=ob_get_length();
header("Last-Modified: ".$gmt_mtime);
header("Content-Length: $size");
ob_end_flush();
Instead of checking the If-Modified-Since-Header against the date of the last modification of the script, you can of course query a database or take any other date that is somehow related to the modification of the result of your script.
You can for instance use this technique to generate images dynamically. If the user indicates he already has a version of the image by the If-Modified-Since-Header, there's no need to generate it and let the server finally discard it because the server only then interpretes the If-Modified-Since-Header.
This saves server load and shortens response-times.