关于ob_get_contents(),ob_end_clean(),ob_start(),的具体用法详解

摘要：ob_get_contents();ob_end_clean();ob_start()使用ob_start()把输出那同输出到缓冲区，而不是...

ob_get_contents();

ob_end_clean();

ob_start()

使用ob_start()把输出那同输出到缓冲区，而不是到浏览器。

然后用ob_get_contents得到缓冲区的数据。

ob_start()在服务器打开一个缓冲区来保存所有的输出。所以在任何时候使用echo ，输出都将被加入缓冲区中，直到程序运行结束或者使用ob_flush()来结束。然后在服务器中缓冲区的内容才会发送到浏览器，由浏览器来解析显示。

函数ob_end_clean 会清除缓冲区的内容，并将缓冲区关闭，但不会输出内容。

此时得用一个函数ob_get_contents()在ob_end_clean()前面来获得缓冲区的内容。

这样的话，能将在执行ob_end_clean()前把内容保存到一个变量中，然后在ob_end_clean()后面对这个变量做操作。

这是EG：

ob_start(); // buf1

echo ' multiple ';

ob_start(); // buf2

echo ' buffers work ';

$buf2 = ob_get_contents();

ob_end_clean();

$buf1 = ob_get_contents();

ob_end_clean();

echo $buf1;

echo '<br/>';

echo $buf2;

ob_get_contents

(PHP 4, PHP 5)

ob_get_contents -- Return the contents of the output buffer

Description

string ob_get_contents ( void )

This will return the contents of the output buffer or FALSE, if output buffering isn't active.

See also ob_start() and ob_get_length().

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.

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

ob_get_clean

(PHP 4 >= 4.3.0, PHP 5)

ob_get_clean -- Get current buffer contents and delete current output buffer

Description

string ob_get_clean ( void )

This will return the contents of the output buffer and end output buffering. If output buffering isn't active then FALSE is returned. ob_get_clean() essentially executes both ob_get_contents() and ob_end_clean().

例子 1. A simple ob_get_clean() example

复制代码代码如下:

<?php

ob_start();

echo "Hello World";

$out = ob_get_clean();

$out = strtolower($out);

var_dump($out);

Our example will output: string(11) "hello world"

See also ob_start() and ob_get_contents().

Notice that the function beneath does not catch errors, so throw in an @ before those ob_* calls

Running PHP4 < 4.3.0, you can simply add the following to use the function anyway: