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php hook 实现

2026-02-28 17:09:05PHP

PHP Hook 实现方法

Hook（钩子）是一种在特定事件发生时插入自定义代码的机制。PHP中可以通过多种方式实现Hook功能。

使用函数和变量钩子

通过定义可替换的函数或变量实现基础钩子功能：

$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);
        }
    }
}

面向对象实现

采用面向对象方式创建更结构化的Hook系统：

class HookSystem {
    private $hooks = [];

    public function add($name, $callback) {
        $this->hooks[$name][] = $callback;
    }

    public function run($name, $params = []) {
        if (!empty($this->hooks[$name])) {
            foreach ($this->hooks[$name] as $callback) {
                call_user_func_array($callback, $params);
            }
        }
    }
}

WordPress风格的Hook实现

参考WordPress的add_action和do_action机制：

function add_action($tag, $function_to_add, $priority = 10) {
    global $wp_actions;
    $wp_actions[$tag][$priority][] = $function_to_add;
    ksort($wp_actions[$tag]);
}

function do_action($tag, $arg = '') {
    global $wp_actions;
    if (isset($wp_actions[$tag])) {
        foreach ($wp_actions[$tag] as $priority => $functions) {
            foreach ($functions as $function) {
                call_user_func($function, $arg);
            }
        }
    }
}

事件驱动实现

使用SplSubject和SplObserver接口实现观察者模式：

class Event implements \SplSubject {
    private $observers;

    public function __construct() {
        $this->observers = new \SplObjectStorage();
    }

    public function attach(\SplObserver $observer) {
        $this->observers->attach($observer);
    }

    public function detach(\SplObserver $observer) {
        $this->observers->detach($observer);
    }

    public function notify() {
        foreach ($this->observers as $observer) {
            $observer->update($this);
        }
    }
}

PSR-14兼容实现

遵循PSR-14标准的事件分发器实现：

interface EventDispatcherInterface {
    public function dispatch(object $event);
}

class EventDispatcher implements EventDispatcherInterface {
    private $listeners = [];

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

    public function dispatch(object $event) {
        foreach ($this->listeners[get_class($event)] ?? [] as $listener) {
            $listener($event);
        }
    }
}

实际应用示例

在MVC框架中实现前置和后置钩子：

class Controller {
    protected $beforeFilters = [];
    protected $afterFilters = [];

    public function beforeFilter($method, $callback) {
        $this->beforeFilters[$method][] = $callback;
    }

    public function afterFilter($method, $callback) {
        $this->afterFilters[$method][] = $callback;
    }

    protected function runFilters($type, $method) {
        $var = $type.'Filters';
        if (!empty($this->$var[$method])) {
            foreach ($this->$var[$method] as $filter) {
                call_user_func([$this, $filter]);
            }
        }
    }
}

每种实现方式适用于不同场景，从简单的函数钩子到符合标准的事件系统，可根据项目需求选择合适的方法。

php hook 实现