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php 实现钩子

2026-01-30 04:35:46PHP

PHP 实现钩子（Hook）的方法

钩子（Hook）是一种允许在特定事件发生时插入自定义代码的机制，常用于插件系统或事件驱动架构。以下是几种在PHP中实现钩子的方法：

使用函数和数组存储钩子

通过维护一个全局数组来存储钩子函数，并在特定事件触发时调用这些函数。

$hooks = [];

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

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

// 示例：添加钩子并触发
add_hook('before_save', function($data) {
    echo "Processing data before save: " . json_encode($data);
});

trigger_hook('before_save', [['id' => 1, 'name' => 'test']]);

面向对象实现钩子

通过类封装钩子逻辑，提高可维护性。

class HookManager {
    private $hooks = [];

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

    public function trigger($hook_name, $args = []) {
        if (isset($this->hooks[$hook_name])) {
            foreach ($this->hooks[$hook_name] as $callback) {
                call_user_func_array($callback, $args);
            }
        }
    }
}

// 示例用法
$hookManager = new HookManager();
$hookManager->add('after_login', function($user) {
    echo "User logged in: " . $user['name'];
});

$hookManager->trigger('after_login', [['name' => 'Alice']]);

使用事件调度器

结合事件和监听器模式，实现更复杂的钩子逻辑。

class EventDispatcher {
    private $listeners = [];

    public function addListener($event_name, $callback) {
        $this->listeners[$event_name][] = $callback;
    }

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

// 示例
$dispatcher = new EventDispatcher();
$dispatcher->addListener('post.published', function($post) {
    echo "Post published: " . $post['title'];
});

$dispatcher->dispatch('post.published', ['title' => 'Hello World']);

框架中的钩子实现

许多PHP框架（如WordPress、Laravel）内置了钩子系统。以下是WordPress风格的钩子示例：

// 添加动作钩子
add_action('wp_footer', function() {
    echo "Custom footer content";
});

// 触发钩子
do_action('wp_footer');

优先级和参数传递

通过优先级控制钩子执行顺序，并支持参数传递。

class Hook {
    private $actions = [];

    public function add($hook_name, $callback, $priority = 10) {
        $this->actions[$hook_name][$priority][] = $callback;
    }

    public function run($hook_name, $args = []) {
        if (isset($this->actions[$hook_name])) {
            ksort($this->actions[$hook_name]);
            foreach ($this->actions[$hook_name] as $callbacks) {
                foreach ($callbacks as $callback) {
                    call_user_func_array($callback, $args);
                }
            }
        }
    }
}

// 示例
$hook = new Hook();
$hook->add('init', function() { echo "Early init\n"; }, 5);
$hook->add('init', function() { echo "Default init\n"; });
$hook->run('init');