ChatGPT를 통해 PHP에서 AOP를 구현하는 방법(코드 포함)을 배웠습니다.

// 定义一个代理类，用于代表目标类并增强其行为
class LogProxy {
    private $target;   // 目标类的实例
    public function __construct($target) {
        $this->target = $target;
    }
    public function foo() {
        echo "before calling foo()\n";
        $result = $this->target->foo();
        echo "after calling foo()\n";
        return $result;
    }
}
// 定义一个目标类
class Foo {
    public function foo() {
        echo "executing foo()\n";
    }
}
// 编译期间使用代理类替换目标类，并返回代理类的实例
function compile($className) {
    $code = file_get_contents("$className.php");
    $code = str_replace("class $className", "class ${className}_proxy extends $className", $code);
    $code .= "\n\nnew ${className}_proxy();";
    eval($code);
    return new ${className}_proxy(new $className());
}
// 使用静态AOP增强Foo类的行为
$foo = compile('Foo');
$foo->foo();  // output: before calling foo() executing foo() after calling foo()

// 定义一个目标类
class Foo {
    public function foo() {
        echo "executing foo()\n";
    }
}
// 定义一个AOP代理类，用于动态织入横切处理逻辑
class AopProxy {
    private $target;   // 目标类的实例
    public function __construct($target) {
        $this->target = $target;
    }
    // 在目标方法前插入日志记录的逻辑
    public function before() {
        echo "before calling foo()\n";
    }
    // 在目标方法后插入日志记录的逻辑
    public function after() {
        echo "after calling foo()\n";
    }
    // 在目标方法出现异常时插入异常处理的逻辑
    public function exception($exception) {
        echo "exception occurred: " . $exception->getMessage() . "\n";
    }
    // 在目标方法返回结果时插入结果处理的逻辑
    public function return($result) {
        echo "returned result: " . $result . "\n";
    }
    // 动态生成代理对象，并织入横切处理逻辑
    public static function proxy($target, $aspect) {
        $proxy = new self($target);
        return new class($proxy, $aspect) extends \ReflectionClass {
            private $proxy;
            private $aspect;
            public function __construct($proxy, $aspect) {
                parent::__construct($proxy);
                $this->proxy = $proxy;
                $this->aspect = $aspect;
            }
            public function __call($name, $args) {
                if (!method_exists($this->proxy->target, $name)) {
                    throw new \BadMethodCallException("Method $name not exists");
                }
                $this->aspect->before();
                try {
                    $result = parent::__call($name, $args);
                    $this->aspect->return($result);
                } catch (\Throwable $e) {
                    $this->aspect->exception($e);
                    throw $e;
                } finally {
                    $this->aspect->after();
                }
                return $result;
            }
        };
    }
}
// 使用动态AOP增强Foo类的行为
$foo = new Foo();
$proxy = AopProxy::proxy($foo, new AopProxy());
$proxy->foo();  // output: before calling foo() executing foo() returned result: after calling foo()