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    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
    ＋add a note
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