WordPress插件:如何避免"紧耦合"？

Question

我正在使用WordPress插件,我正在努力确保最佳实践.我有两个类,我的插件类"Jargonaut"是必需的,然后是另一个名为"Dictionary"的类,它包含require_once()在我的主插件文件中.

Jargonaut类中的大多数代码都处理初始化并提供类似控制器的功能,但其中大部分都高度依赖于使用Dictionary对象(即根据我对术语的理解紧密耦合).我希望将Dictionary类保持分离,因为它更像是模型(在MVC架构中)并且与我的数据库接口.

我看到紧密与松散耦合中有很多灰色区域,我很难决定多少太多了？

Answer 1

如果你的插件需要字典对象,它必须要求它:

class MyPlugin
{
    /**
     * @var Dictionary
     */
    private $dictionary;
    private function __construct(Dictionary $dictionary)
    {
        $this->dictionary = $dictionary;
    }

你现在已经将你的插件松散地耦合了Dictionary,插件类不再负责为自己创建Dictionary,因为它是注入的.它需要它所需要的东西.

那怎么会有用呢？该插件需要在某处创建,因此需要一个工厂.工厂构建方法知道您的插件需要什么:

class MyPluginFactory
{
    public static function build($pluginName)
    {
        $plugin = NULL;
        switch($pluginName)
        {
            case 'MyPlugin':
                $dictionary = new Dictionary();
                $plugin = new MyPlugin($dictionary);
        }
        return $plugin;
    }
}

由于这是wordpress,我们知道插件的引导是通过包含插件文件来完成的.所以在它开始时,需要创建插件.由于包含在全局范围内完成,我们希望将插件对象保留在内存中,但可能不作为全局变量提供.这并不妨碍您创建多个插件实例,但它将确保当wordpress初始化您的插件(加载您的插件)时,它将仅使用该单个实例.这可以通过使插件工厂有一些额外的功能来完成:

class MyPluginFactory
{
    ...
    public static $plugins;
    public static function bootstrap($pluginName)
    {
        $plugin  = self::build($pluginName);
        self::$plugins[] = $plugin;
        return $plugin;
    }

请注意,静态类成员变量的唯一用法仅是确保插件保留在内存中.它在技术上是我们通常想要防止的全局变量,但是,实例需要存储在某个地方,所以在这里(我将其更改为public,因为它是一个全局变量,它不应该对此感到害羞.公众可以在某些私人或受保护限制过多的情况下提供帮助.此外,它也不应成为问题.如果是问题,还有另一个问题需要先解决).

这基本上将你的插件代码与wordpress本身分离.你可能还想创建一个类,它提供和接口你正在使用的任何wordpress函数,所以你不直接绑定这些函数,你的插件代码保持干净,松散地耦合到wordpress本身.

class WordpressSystem
{
    public function registerFilter($name, $plugin, $methodName)
    {
        ... do what this needs with WP, e.g. call the global wordpress function to register a filter.
    }
    ...
}

如果您的插件需要WordpressSystem执行任务(通常是这种情况),请再次将其添加为依赖项:

class MyPlugin
{
    ...
    public function __construct(WordpressSystem $wp, Dictionary $dictionary)
    ...

所以要最终包装它,只需要插件php文件:

<?php
/*
 * MyPlugin
 * 
 * Copyright 2010 by hakre <hakre.wordpress.com>, some rights reserved.
 *
 * Wordpress Plugin Header:
 * 
 *   Plugin Name:    My Plugin
 *   Plugin URI:     http://hakre.wordpress.com/plugins/my-plugin/
 *   Description:    Yet another wordpress plugin, but this time mine
 *   Version:        1.2-beta-2
 *   Stable tag:     1.1
 *   Min WP Version: 2.9
 *   Author:         hakre
 *   Author URI:     http://hakre.wordpress.com/
 *   Donate link:    http://www.prisonradio.org/donate.htm
 *   Tags:           my
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
Namespace MyPlugin;

# if your file is named 'MyPlugin.php' this will be 'MyPlugin'.
return PluginFactory::bootstrap(basename($plugin, '.php'));

class PluginFactory
{
    private static $plugins;
    public static function bootstrap($pluginName)
    {
        $plugin = self::build($pluginName);
        self::$plugins[] = $plugin;
        return $plugin;
    }
    public static function build($pluginName)
    {
        $plugin = NULL;
        switch($pluginName)
        {
            case 'MyPlugin':
                # Make your plugin work with different Wordpress Implementations.
                $system = new System\Wordpress3();
                $dictionary = new Dictionary();
                $plugin = new Plugin($system, $dictionary);
        }
        return $plugin;
    }
}

class Plugin
{
    /**
     * @var System
     */
    private $system;
    /**
     * @var Dictionary
     */
    private $dictionary;
    private function __construct(System $system, Dictionary $dictionary)
    {
        $this->system = $system;
        $this->dictionary = $dictionary;
    }

...

引导方法还可以注册自动加载器或执行要求.

希望这很有用.