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
只是得到输出缓冲区的内容，但不清除它。
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 。
范例
示例 #1 A simple ob_get_contents() example
<?php
ob_start();
echo "Hello ";
$out1 = ob_get_contents();
echo "World";
$out2 = ob_get_contents();
ob_end_clean();
var_dump($out1, $out2);
?>
以上例程会输出：
string(6) "Hello " string(11) "Hello World"
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User Contributed Notes 6 notes
mauroasprea+php at gmail dot com ¶
11 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, $out2);
?>
Mark Clements ¶
7 years ago
Note that, unlike PHP variables which make efficient use of memory, getting the contents of the output buffer results in a new copy of the buffer being made. This can end up massively increasing the memory requirements of your script if your output is large.
Example code:
<?php
print(memory_get_usage() . "<br>");
ob_start();
for ($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
ipfound at gmail dot com ¶
7 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.
m227 ( at ) poczta dot onet dot pl ¶
17 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.
DrDreistein at dontknow dot at ¶
10 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
http://www.francescosaf.altervista.org ¶
17 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
备份地址：http://www.lvesu.com/blog/php/function.ob-get-contents.php