PHP Conference Japan 2024

ob_get_clean

(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)

ob_get_cleanGet the contents of the active output buffer and turn it off

Description

ob_get_clean(): string|false

This function calls the output handler (with the PHP_OUTPUT_HANDLER_CLEAN and PHP_OUTPUT_HANDLER_FINAL flags), discards it's return value, returns the contents of the active output buffer and turns off the active output buffer.

ob_get_clean() will fail without an active output buffer started with the PHP_OUTPUT_HANDLER_REMOVABLE flag.

ob_get_clean() will discard the contents of the active output buffer even if it was started without the PHP_OUTPUT_HANDLER_CLEANABLE flag.

Parameters

This function has no parameters.

Return Values

Returns the contents of the active output buffer on success or false on failure.

Caution

ob_get_clean() will return false but will not generate an E_NOTICE if there is no active output buffer.

Errors/Exceptions

If the function fails it generates an E_NOTICE.

Examples

Example #1 A simple ob_get_clean() example

<?php

ob_start
();

echo
"Hello World";

$out = ob_get_clean();
$out = strtolower($out);

var_dump($out);
?>

The above example will output:

string(11) "hello world"

See Also

  • ob_start() - Turn on output buffering
  • ob_get_contents() - Return the contents of the output buffer
  • ob_clean() - Clean (erase) the contents of the active output buffer
  • ob_end_clean() - Clean (erase) the contents of the active output buffer and turn it off
  • ob_get_flush() - Flush (send) the return value of the active output handler, return the contents of the active output buffer and turn it off

add a note

User Contributed Notes 5 notes

up
77
geo dot artemenko at gmail dot com
10 years ago
The definition should mention that the function also "turns off output buffering", not just cleans it.
up
31
steven at bielik dot com
13 years ago
Also, don't forget that you will need to ob_start() again for any successive calls:

<?php
ob_start
();
echo
"1";
$content = ob_get_clean();

ob_start(); // This is NECESSARY for the next ob_get_clean() to work as intended.
echo "2";
$content .= ob_get_clean();

echo
$content;
?>

Output: 12

Without the second ob_start(), the output is 21 ...
up
9
paul+phpnet at earth2me dot com
11 years ago
Keep in mind that output may be buffered by default, depending on how you are running PHP (CGI, CLI, etc.). You can use ob_get_level() to determine if an output buffer has already been started. On most web servers I've used, output buffering is already one level deep before my scripts start running.

You should only end as many output buffers as you start. Assuming that your buffer is always the first buffer, or otherwise closing pre-existing buffers, could lead to problems. In PHP 5.5, you can ensure that output buffers are ended properly using a try-finally block.

Something like this is almost guaranteed to break stuff:

<?php
// Don't ever do this!
while (ob_get_level() > 1)
{
ob_end_flush();
}

$content = ob_get_clean();
?>

The problem is that number, "1". Using a fixed number there is asking for trouble. Instead, use ob_get_level() to get the number of output buffers applied when your code starts, and return to that number, if you really must use an unknown number of output buffers:

<?php
ob_start
();
$saved_ob_level = ob_get_level();

// Do stuff here:
run_something();

// If you really must close all of your output buffers except one, this'll do it:
while (ob_get_level() > $start_ob_level)
{
ob_end_flush();
}

// And now, the final output buffer that belongs to us:
$content = ob_get_clean();
?>
up
0
sergei dot solomonov at gmail dot com
12 years ago
<?php
ob_start
();
echo
"1";
$content = ob_get_clean();

echo
"2";
$content .= ob_get_clean();

echo
$content;
?>

This script outputs 21 in CLI mode and 12 otherwise (under my apache and nginx)
up
-2
Peter Smartt
7 years ago
I was trying to debug my code using error_log() and I discovered that ob_get_clean() also truncates the error_log() buffer right in the middle of its output, and well as the output buffer which it is supposed to truncate. If you are using error_log(), use ob_get_contents() and ob_end_clean() instead of ob_get_clean().
To Top