網站製作學習誌

<?php
/**
 * Test
 */
class Test
{
    /**
     * 某個方法
     */
    public function doSomething()
    {
        // 建立 Log 物件
        $logger = new Log();
 
        // 寫入前置 Log
        $logger->save('before do something.');
 
        // 主要的動作
        // ...
 
        // 寫入 Log
        $logger->save('before do something.');
    }
}

<?php
/**
 * Test class
 *
 */
class TestClass
{
    /**
     * Method 1
     *
     * @param string $message
     */
    public function method1($message)
    {
        echo "\n", __METHOD__, ":\n", $message, "\n";
    }
 
    /**
     * Method 2
     *
     * @return int
     */
    public function method2()
    {
        echo "\n", __METHOD__, ":\n";
        return rand(1, 10);
    }
 
    /**
     * Method 3
     *
     * @throws Exception
     */
    public function method3()
    {
        echo "\n", __METHOD__, ":\n";
        throw new Exception('Test Exception.');
    }
}

<?php
/**
 * Log
 *
 */
class Log
{
    /**
     * log message
     *
     * @param string $message
     */
    public function save($message)
    {
        echo $message, "\n";
    }
}

<?php
/**
 * Aspect
 *
 */
class Aspect
{
    /**
     * Name of target class
     *
     * @var string
     */
    private $_className = null;
 
    /**
     * Target object
     *
     * @var object
     */
    private $_target = null;
 
    /**
     * Event callback
     *
     * @var array
     */
    private $_eventCallbacks = array();
 
    /**
     * Add object
     *
     * @param object $target
     * @return Aspect
     */
    public static function addObject($target)
    {
        return new Aspect($target);
    }
 
    /**
     * Contructor
     *
     * @param object $target
     */
    public function __construct($target)
    {
        if (is_object($target)) {
            $this->_target = $target;
            $this->_className = get_class($this->_target);
        }
    }
 
    /**
     * Register event
     *
     * @param string $eventName
     * @param string $methodName
     * @param callback $callback
     */
    private function _registerEvent($eventName, $methodName, $callback, $args)
    {
        if (!isset($this->_eventCallbacks[$methodName])) {
            $this->_eventCallbacks[$methodName] = array();
        }
 
        if (!is_callable(array($this->_target, $methodName))) {
            throw new Exception(get_class($this->_target) . '::' . $methodName . ' is not exists.');
        }
 
        if (is_callable($callback)) {
            $this->_eventCallbacks[$methodName][$eventName] = array($callback, $args);
        } else {
            $callbackName = Aspect::getCallbackName($callback);
            throw new Exception($callbackName . ' is not callable.');
        }
    }
 
    /**
     * Register 'before' handler
     *
     * @param string $methodName
     * @param callback $callback
     */
    public function before($methodName, $callback, $args = array())
    {
        $this->_registerEvent('before', $methodName, $callback, (array) $args);
    }
 
    /**
     * Register 'after' handler
     *
     * @param string $methodName
     * @param callback $callback
     */
    public function after($methodName, $callback, $args = array())
    {
        $this->_registerEvent('after', $methodName, $callback, (array) $args);
    }
 
    /**
     * Register 'on catch exception' handler
     *
     * @param string $methodName
     * @param callback $callback
     */
    public function onCatchException($methodName, $callback, $args = array())
    {
        $this->_registerEvent('onCatchException', $methodName, $callback, (array) $args);
    }
 
    /**
     * Trigger event
     *
     * @param string $eventName
     */
    private function _trigger($eventName, $methodName, $target)
    {
        if (isset($this->_eventCallbacks[$methodName][$eventName])) {
            list($callback, $args) = $this->_eventCallbacks[$methodName][$eventName];
            $args[] = $target;
            call_user_func_array($callback, $args);
        }
    }
 
    /**
     * Execute method
     *
     * @param string $methodName
     * @param array $args
     * @return mixed
     */
    public function __call($methodName, $args)
    {
        if (is_callable(array($this->_target, $methodName))) {
            try {
                $this->_trigger('before', $methodName, $this->_target);
                $result = call_user_func_array(array($this->_target, $methodName), $args);
                $this->_trigger('after', $methodName, $this->_target);
                return $result ? $result : null;
            } catch (Exception $e) {
                $this->_trigger('onCatchException', $methodName, $e);
                throw $e;
            }
        } else {
            throw new Exception("Call to undefined method {$this->_className}::$methodName.");
        }
    }
 
    /**
     * Get name of callback
     *
     * @param callback $callback
     * @return string
     */
    public static function getCallbackName($callback)
    {
        $className  = '';
        $methodName = '';
 
        if (is_array($callback) && 2 == count($callback)) {
            if (is_object($callback[0])) {
                $className = get_class($callback[0]);
            } else {
                $className = (string) $callback[0];
            }
            $methodName = (string) $callback[1];
        } elseif (is_string($callback)) {
            $methodName = $callback;
        }
 
        return $className . (($className) ? '::' : '') . $methodName;
    }
}

<?php
require_once 'TestClass.php';
 
$test = new TestClass();
 
/* @var $test TestClass */
echo "=======\n";
$test->method1('abc');
echo "=======\n";
echo $test->method2(), "\n";
echo "=======\n";
$test->method3();
echo "=======\n";
 
/* 執行結果：
=======
 
TestClass::method1:
abc
=======
 
TestClass::method2:
2
=======
 
TestClass::method3:
 
Exception: Test Exception. in TestClass.php on line 38
*/

<?php
require_once 'Aspect.php';
require_once 'TestClass.php';
require_once 'Log.php';
 
$test = Aspect::addObject(new TestClass());
$logger = new Log();
 
$test->before('method1', array($logger, 'save'), 'Log saved (method1).');
$test->after('method2', array($logger, 'save'), 'Log saved (method2).');
$test->onCatchException('method3', array($logger, 'save'), 'Log saved (method3).');
 
/* @var $test TestClass */
echo "=======\n";
$test->method1('abc');
echo "=======\n";
echo $test->method2(), "\n";
echo "=======\n";
$test->method3();
echo "=======\n";
 
/* 執行結果：
=======
Log saved (method1).
 
TestClass::method1:
abc
=======
 
TestClass::method2:
Log saved (method2).
8
=======
 
TestClass::method3:
Log saved (method3).
 
Exception: Test Exception. in TestClass.php on line 38
*/