ob_clean
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.
ob_end_clean
(PHP 4, PHP 5)
ob_end_clean — Limpiar (eliminar) y deshabilitar los búferes de salida
Descripción
bool ob_end_clean
( void
)
Esta función descarta los contenidos del búfer de salida en cola y lo deshabilita. Si desea continuar procesando los contenidos del búfer debe llamar ob_get_contents() antes de ob_end_clean() ya que los contenidos del búfer son descartados cuando se llama ob_end_clean().
Valores retornados
Devuelve TRUE si todo se llevó a cabo correctamente, FALSE en caso de fallo. Entre las posibles razones de fallo se encuentra llamar la función sin un búfer activo, o que por algún motivo no se pueda eliminar un búfer (posible en el caso de búferes especiales).
Errors/Exceptions
Si la función falla, genera un error de nivel E_NOTICE.
Registro de cambios
| Versión | Descripción |
|---|---|
| 4.2.0 | El valor de retorno booleano fue agregado. |
Ejemplos
El siguiente ejemplo muestra una forma sencilla de deshacerse de todos los búferes de salida:
Example #1 Ejemplo de ob_end_clean()
<?php
ob_start();
echo 'Texto que no será mostrado.';
ob_end_clean();
?>
add a note
User Contributed Notesob_end_clean
geoff at spacevs dot com
23-Jul-2007 02:47
23-Jul-2007 02:47
everling
11-Nov-2006 11:04
11-Nov-2006 11:04
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 09:38
18-May-2006 09:38
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 03:14
09-Feb-2005 03:14
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 01:39
04-Jun-2004 01:39
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 10:11
22-Feb-2004 10:11
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 03:32
27-Jun-2003 03:32
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.