配置与设计模式

1.PHP中使用ArrayAccess实现配置文件的加载

$config = new \IMooc\Config(__DIR__.'/configs');
var_dump($config['controller']);

<?php
namespace IMooc;

class Config implements \ArrayAccess
{
    protected $path;
    protected $configs = array();

    function __construct($path)
    {
        $this->path = $path;
    }

    public function offsetExists($key)
    {
        return isset($this->configs[$key]);
    }

    public function offsetGet($key)
    {
        if (empty($this->configs[$key]))
        {
            $file_path = $this->path.'/'.$key.'.php';
            $config = require $file_path;
            $this->configs[$key] = $config;
            return $this->configs[$key];
        }
    }

    public function offsetSet($Key, $value)
    {
        throw new \Exception("cannot write config file.");
    }

    public function offsetUnset($key)
    {
        unset($this->configs[$key]);
    }
}

<?php
namespace Configs;
$config = array(
    'home' => array(
        'decorator' => array(
            'IMooc\Decorator\Template',
        ),
    ),
    'default' => 'hello world',
);
return $config;


2.在工厂方法中读取配置，生成可配置化的对象

$db = \IMooc\Factory::getDatabase();

<?php

namespace IMooc;

class Factory
{

    static function getDatabase($id = 'master')
    {
        $key = 'database_'.$id;

        if ($id == 'slave')

        {

            $slaves = Application::getInstance()->config['database']['slave'];

            $db_conf = $slaves[array_rand($slaves)];

        }

        else

        {

            $db_conf = Application::getInstance()->config['database']
[$id];

        }

        $db = Register::get($key);

        if (!$db)

        {
            $db = new Database\MySQLi();

            $db->connect($db_conf['host'], $db_conf['user'], $db_conf['password'], $db_conf['dbname']);

            Register::set($key, $db);

        }

        return $db;
    }
}


3.使用装饰器模式实现权限验证，模板渲染，JSON串化
4.使用观察者模式实现数据更新事件的一系列更新操作
5.使用代理模式实现数据的主从自动切换

来自为知笔记(Wiz)