PHP 8.4.2 Released!

    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

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    ＋添加备注

    用户贡献的备注 4 notes

    up
    9
    Mark Clements
    10 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
    13 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
    -1
    m227 ( at ) poczta dot onet dot pl
    19 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
    -4
    DrDreistein at dontknow dot at
    13 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
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