Memcached::get

    (PECL memcached >= 0.1.0)

    Memcached::get — 检索元素

    说明

    public Memcached::get(string $key, ?callable $cache_cb = null, int $get_flags = 0): mixed

    Memcached::get() 返回之前存储在 key 下的元素。如果元素被找到，并且 get_flags 指定为 Memcached::GET_EXTENDED，也会返回该元素的 CAS 记号。关于 CAS 记号的使用，参阅 Memcached::cas()。可以通过 cache_cb 参数指定 通读缓存回调。

    参数

    key

    要检索的元素的 key。

    cache_cb

    通读缓存回掉函数或 null。

    get_flags

    flag 控制返回结果。当指定为 Memcached::GET_EXTENDED 时，该函数还将返回 CAS 记号。

    返回值

    返回存储在缓存中的值，否则返回 false。 如果 get_flags 设置为 Memcached::GET_EXTENDED，则返回包含值和 CAS 记号的数组，而不仅仅返回值。如果 key 不存在，Memcached::getResultCode() 将返回 Memcached::RES_NOTFOUND。

    更新日志

    版本 说明
    PECL memcached 3.0.0 移除 &cas_token 参数。 相反，添加 get_flags，当赋予 Memcached::GET_EXTENDED 的值时，将确保获取 CAS 记号。

    示例

    示例 #1 Memcached::get() 示例

    <?php
    $m     = new Memcached();
    $m->addServer('localhost', 11211);

    $m->set('foo', 100);
    var_dump($m->get('foo'));
    ?>

    以上示例会输出：

    int(100)

    示例 #2 Memcached::get() 示例

    <?php
    $m     = new Memcached();
    $m->addServer('localhost', 11211);

    if (!(    $ip = $m->get('ip_block'))) {
    if (    $m->getResultCode() == Memcached::RES_NOTFOUND) {
    $ip = array();
    $m->set('ip_block', $ip);
    } else {
    /* log error */
    /* ... */
    }
    }
    ?>

    参见

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    用户贡献的备注 3 notes

    up
    12
    letynsoft at gmail dot com
    7 years ago
    As of some version of php7 (i was not able to determine which exactly).
    The $cas_token is no longer valid argument. It has been removed in favor of flags argument, as it appears to be causing issues when subclassing the Memcached class.

    See https://github.com/php-memcached-dev/php-memcached/pull/214 for more details.

    Basically you need to
    <?php
    function memcacheGet($key, $cb = null, &$cas = null) {
    $m = memcacheGetObject();
    if(empty(    $m))
    return     false;
    if(    defined('Memcached::GET_EXTENDED')) {
    //Incompatible change in php7, took me 2 hours to figure this out, grrr
    $_o = $m->get($key, $cb, Memcached::GET_EXTENDED);
    $o = $_o['value'];
    $cas = $_o['cas'];
    } else {
    $o = $m->get($key, $cb, $cas);
    }
    return     $o;
    }
    ?>
    up
    10
    miha at hribar dot info
    15 years ago
    This method also returns false in case you set the value to false, so in order to have a proper fault mechanism in place you need to check the result code to be certain that a key really does not exist in memcached.

    <?php
    $Memcached     = new Memcached();
    $Memcached->addServer('localhost', 11211);
    $Memcached->set('key', false);
    var_dump($Memcached->get('key')); // boolean false
    var_dump($Memcached->getResultCode()); // int 0 which is Memcached::RES_SUCCESS
    ?>

    Or just make sure the values are not false :)
    up
    -2
    denis_truffaut[A-T]hotmail[D-O-T]com
    13 years ago
    Note that this function can return NULL as FALSE, so don't make checks with === FALSE as with the old Memcache class, because it won't work. :O

    Use the not (!) operator and check the result code with getResultCode() as mentioned in the documentation :)
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