PHP 8.3.0 RC 6 available for testing

ob_get_contents

(PHP 4, PHP 5, PHP 7, PHP 8)

ob_get_contents返回输出缓冲区的内容

说明

ob_get_contents(): string|false

只是得到输出缓冲区的内容,但不清除它。

参数

此函数没有参数。

返回值

此函数返回输出缓冲区的内容,或者如果输出缓冲区无效将返回 false

示例

示例 #1 ob_get_contents() 简单示例

<?php

ob_start
();

echo
"Hello ";

$out1 = ob_get_contents();

echo
"World";

$out2 = ob_get_contents();

ob_end_clean();

var_dump($out1, $out2);
?>

以上示例会输出:

 
string(6) "Hello "
string(11) "Hello World"

参见

add a note

User Contributed Notes 6 notes

up
7
Mark Clements
9 years ago
Note that, unlike PHP variables which make efficient use of memory, getting the contents of the output buffer results in a new copy of the buffer being made. This can end up massively increasing the memory requirements of your script if your output is large.

Example code:

<?php

print(memory_get_usage() . "<br>");

ob_start();

for (
$i = 0; $i < 5000000; $i++)
print(
" ");

print(
memory_get_usage() . "<br>");

$foo = ob_get_contents();

print(
memory_get_usage() . "<br>");

ob_end_flush();

?>

Output:

351664
5359152
10359256
up
10
mauroasprea+php at gmail dot com
12 years ago
This is an example of how the stack works:

<?php
//Level 0
ob_start();
echo
"Hello ";

//Level 1
ob_start();
echo
"Hello World";
$out2 = ob_get_contents();
ob_end_clean();

//Back to level 0
echo "Galaxy";
$out1 = ob_get_contents();
ob_end_clean();

//Just output
var_dump($out1, $out2);
?>
up
3
ipfound at gmail dot com
9 years ago
The ob_get_contents() function has different return behaivor in PHP 5.3.x and PHP 5.5.x. Take a look at very simple example for PHP 5.3

<?php
var_dump
(ob_get_contents());
?>
Output: bool(false)

but in PHP 5.5.x, the same php code will return:
Output: string (0) ""

Actually, we can use type regulation - intval(ob_get_contents()), for cheking On/Off output buffering, but it lays the possible problems in the future.
up
-2
m227 ( at ) poczta dot onet dot pl
18 years ago
if you use ob_start with a callback function as a parameter, and that function changes ob string (as in example in manual) don't expect that ob_get_contents will return changed ob.
it will work as you would use ob_start with no parameter at all. So don't be confused.
up
-5
DrDreistein at dontknow dot at
12 years ago
i made a simple test which is faster: adding some text in the normal way or by the ob stack:

<?php
$start
= microtime(true);
$var = '';
for(
$i=0 ; $i <= 1000000 ; $i++) {
$var .= ' ';
}
$middle = microtime(true);

ob_start();
for(
$i=0 ; $i <= 1000000 ; $i++) {
echo
' ';
}
$var = ob_get_contents();
ob_end_clean();

$end = microtime(true);

echo
$middle - $start;
echo
'<br />';
echo
$end - $middle;
?>

Outputs something like this:

0.33658003807068
0.30778789520264
up
-18
http://www.francescosaf.altervista.org
18 years ago
transfer image, another method (alternative to fsockopen or function socket) :

server(192.168.0.1)
makeimage.php
...........
...........
$nameimage="xxxx.jpg"
$comand=exec("plotvelocity.sh $nameimage $paramater1 $paramater2");
ob_start();
readfile($nameimage);
$image_data = ob_get_contents();
ob_end_clean();
echo $image_data;
unlink($nameimage);

Client (192.168.0.2)
$bild="images/newimage2.gif";
$host="192.168.0.1";
$url=file_get_contents("http://$host/makeimage.php?$querystring");
$fp = fopen("$bild", 'wb');
fwrite($fp, $url);
fclose($fp);
echo '<img src="'.$bild.'">';

naturally you can transfer whichever thing and not only images
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