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php 钩子实现

2026-02-28 16:01:27PHP

PHP 钩子实现方法

钩子（Hook）是一种在程序执行过程中插入自定义代码的机制，常用于插件系统或事件驱动开发。PHP中可通过以下方式实现钩子：

使用函数和数组存储钩子

定义钩子数组和添加/执行钩子的函数：

$hooks = [];

function add_hook($hook_name, $callback) {
    global $hooks;
    $hooks[$hook_name][] = $callback;
}

function do_hook($hook_name, $params = []) {
    global $hooks;
    if (isset($hooks[$hook_name])) {
        foreach ($hooks[$hook_name] as $callback) {
            call_user_func_array($callback, $params);
        }
    }
}

调用示例：

add_hook('before_save', function($data) {
    echo "Processing data before save: " . print_r($data, true);
});

$data = ['id' => 1, 'name' => 'Test'];
do_hook('before_save', [$data]);

面向对象实现

创建专门的Hook类管理钩子：

class Hook {
    private static $actions = [];

    public static function add($hook, $callback, $priority = 10) {
        self::$actions[$hook][$priority][] = $callback;
    }

    public static function run($hook, $args = []) {
        if (isset(self::$actions[$hook])) {
            ksort(self::$actions[$hook]);
            foreach (self::$actions[$hook] as $callbacks) {
                foreach ($callbacks as $callback) {
                    call_user_func_array($callback, $args);
                }
            }
        }
    }
}

使用示例：

Hook::add('init', function() {
    echo "System initializing...";
});

Hook::run('init');

WordPress风格过滤器实现

实现值过滤的钩子系统：

function apply_filter($hook, $value, ...$args) {
    global $filters;
    if (isset($filters[$hook])) {
        foreach ($filters[$hook] as $callback) {
            $value = call_user_func($callback, $value, ...$args);
        }
    }
    return $value;
}

function add_filter($hook, $callback) {
    global $filters;
    $filters[$hook][] = $callback;
}

使用示例：

add_filter('content', function($text) {
    return strtoupper($text);
});

$processed = apply_filter('content', 'hello world');
echo $processed; // 输出: HELLO WORLD

事件驱动实现

使用观察者模式实现更复杂的钩子系统：

class EventDispatcher {
    private $listeners = [];

    public function addListener($eventName, callable $listener) {
        $this->listeners[$eventName][] = $listener;
    }

    public function dispatch($eventName, $event = null) {
        if (isset($this->listeners[$eventName])) {
            foreach ($this->listeners[$eventName] as $listener) {
                $listener($event);
            }
        }
    }
}

使用示例：

php 钩子实现

$dispatcher = new EventDispatcher();
$dispatcher->addListener('user.login', function($user) {
    echo "User {$user} logged in";
});

$dispatcher->dispatch('user.login', 'admin');