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Understanding MVC framework programming in PHP_PHP tutorial

Jul 15, 2016 pm 01:25 PM
modelmvcphpWhatCanyesframeunderstandofprogramming

什么是MVC

MVC是一个可以让你把“三个部分(即MVC的全称,Model、 View、Controller)”谐调地组成一个复杂应用程序的概念。一辆汽车就是一个在现实生活中非常好的MVC例子。我们看车都看两个View(显 示)部分:内部和外部。而这两个都离不开一个Controller(控制者):司机。刹车系统、方向盘和其他操控系统代表了Model(模型):他们从司 机(Controller)那里取得控制方法然后应用到内部和外观(View)。

网络上的MVC

MVC框架所涵盖的概念相当简单并且极度灵活。基本的概念就是,你有一个单独的控制器(如index.php)用来控制所有建立在参数请求基础上的框架内应用程序。这个控制器通常包含了(最小程度上)一个定义模型的参数、一个事件和一个GET参数。这样控制器就能确认所有的请求然后运行相应的事件。打个 比方来说,一个像这样/index.php?module=foo&event=bar的请求很有可能就是用来载入一个名叫foo的类,然后运行 foo::bar()[就是其中的bar()函数]。这样做的好处有:

一个对应所有应用程序的接口

同时维护一个应用程序内无数的代码非常麻烦,因为每一段代码都有自己的相对路径、数据库链接、验证等等。而这样做就免除你在这方面的烦恼,允许你合并并重复使用代码

为什么要创建自己的MVC框架

迄今为止,我没有见到过太多用PHP写的MVC框架。事实上我仅仅知道一个-Solar,是完全用PHP5写的。另外一个是Cake,一个试图成为 PHP的RoR(Ruby on Rails-一个Ruby语言开源网络框架)。我自己对这两个框架都有一些不满意的地方:它们都没有利用到PEAR,Smarty等所包含的现有代码;现 在的Cake还比较紊乱;最后,Solar是一个绝大部分由一个人写的作品(我无意说其作者Paul不是一个好人或者好程序员)。这些问题可能并不会让你 否认它们,而且很有可能你根本不关心这些问题。但是正因为如此,我请各位尽可能地审视它们。

老方式

如果回到2001看自己写的代码,作者有可能找到一个叫template.txt的文件,它看起来像这样:

<?php require_once('config.php'); // Other requires, DB info, etc. $APP_DB = 'mydb';$APP_REQUIRE_LOGIN = false; // Set to true if script requires login$APP_TEMPLATE_FILE = 'foo.php'; // Smarty template$APP_TITLE = "My Application"; if ($APP_REQUIRE_LOGIN == true) {if (!isset($_SESSION['userID'])) {header("Location: /path/to/login.php");exit();}} $db = DB::connect('mysql://'.$DB_USER.':'.$DB_PASS.'@localhost/'.$APP_DB);if (!PEAR::isError($db)) {$db->setFetchMode(DB_FETCHMODE_ASSOC);} else {die($db->getMessage());} // Put your logic here // Output the templateinclude_once(APP_TEMPLATE_PATH.'/header.php');include_once(APP_TEMPLATE_PATH.'/'.$APP_TEMPLATE_FILE);include_once(APP_TEMPLATE_PATH.'/footer.php'); ?>

只是看这些代码都会让我有退缩的欲望。这段代码的概念就是确保每一个应用程序都能适用于这个处理方法,比如我可以简单地将 template.txt拷进myapp.php,改变一些变量,瞧,它就能运行起来了。尽管如此,这个组织严密的处理方法存在一些严重的缺点:

如果我的老板想让作者用myapp.php在一些情况下输出PDF、一些情况下输出HTML、一些情况下(直接提交的XML请求)SOAP,我该怎么办?

如果这个应用程序需要IMAP或LDAP验证,我该怎么办?

我该如何处理各种不同的代码(包括编辑、升级和删除)?

我该如何处理多级验证(管理员 vs. 非管理员)?

我该如何启用输出缓存?

新方式

将所有东西都扔进这个MVC框架,你会发现生活是如此简单。请对比以下代码:

<?php class myapp extends FR_Auth_User{public function __construct(){parent::__construct();} public function __default(){// Do something here} public function delete(){ } public function __destruct(){parent::__destruct();}} ?>

Note that this code is obviously not used to link to a database, determine whether a user is logged in, or output any other information. The controller has it all.

If I want to authenticate to LDAP, I can set up FR_Auth_LDAP. The controller can recognize certain output methods (such as $_GET['output']) and can convert to PDF or SOAP at any time. The event handler delete is only responsible for deletion and does not care about anything else. Because this module has an instance of the FR_User class, it can simply determine whether a user has logged in, etc.

Smarty, as a template engine, controls the cache as a matter of course, but the controller can also control part of the cache.

From the old way mentioned above to the MVC way may be a new and unfamiliar concept to many people, but once you switch to such a concept, it will be quite difficult to switch back.


www.bkjia.comtruehttp: //www.bkjia.com/PHPjc/446665.htmlTechArticleWhat is MVC? MVC is a tool that allows you to combine "three parts (that is, the full name of MVC, Model, View, Controller)" concepts that harmoniously compose a complex application. A car is a...
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