PHP 8.4.2 Released!

    过滤器函数

    目录

    • filter_has_var — 检测是否存在指定类型的变量
    • filter_id — 返回与某个特定名称的过滤器相关联的id
    • filter_input — 通过名称获取特定的外部变量，并且可以通过过滤器处理它
    • filter_input_array — 获取一系列外部变量，并且可以通过过滤器处理它们
    • filter_list — 返回所支持的过滤器列表
    • filter_var — 使用特定的过滤器过滤一个变量
    • filter_var_array — 获取多个变量并且过滤它们

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    用户贡献的备注 2 notes

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    vojtech at x dot cz
    18 years ago
    Also notice that filter functions are using only the original variable values passed to the script even if you change the value in super global variable ($_GET, $_POST, ...) later in the script.

    <?php
    echo filter_input(INPUT_GET, 'var'); // print 'something'
    echo $_GET['var']; // print 'something'
    $_GET['var'] = 'changed';
    echo     filter_input(INPUT_GET, 'var'); // print 'something'
    echo $_GET['var']; // print 'changed'
    ?>

    In fact, external data are duplicated in SAPI before the script is processed and filter functions don't use super globals anymore (as explained in Filter tutorial bellow, section 'How does it work?').
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    0
    fumble1 at web dot de
    17 years ago
    I recommend you to use the FILTER_REQUIRE_SCALAR (or FILTER_REQUIRE_ARRAY) flags, since you can use array-brackets both to access string offsets and array-element -- however, not only this can lead to unexpected behaviour. Look at this example:

    <?php
    $image     = basename(filter_input(INPUT_GET, 'src', FILTER_UNSAFE_RAW, FILTER_FLAG_STRIP_LOW));
    // further checks
    ?>

    /script.php?src[0]=foobar will cause a warning. :-(
    Hence my recommendation:

    <?php
    $image     = basename(filter_input(INPUT_GET, 'src', FILTER_UNSAFE_RAW, FILTER_REQUIRE_SCALAR | FILTER_FLAG_STRIP_LOW));
    // further checks
    ?>
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