Write the PHP framework step by step and gain an in-depth understanding of the MVC operation process-php手册-php.cn

1 What is MVC

MVC pattern (Model-View-Controller) is a software architecture pattern in software engineering, which divides the software system into three basic parts: Model (Model), View (View) and Controller(Controller).

The MVC pattern in PHP is also called Web MVC and evolved from the 1970s. The purpose of MVC is to implement a dynamic programming design that facilitates subsequent modification, expansion and simplification of the program, and makes it possible to reuse certain parts of the program. In addition, this mode makes the program structure more intuitive by simplifying the complexity. While the software system separates its basic parts, it also gives each basic part its due functions.

The functions of each part of MVC:

Model – manages most of the business logic and all database logic. Models provide an abstraction layer for connecting to and manipulating databases.
Controller - Responsible for responding to user requests, preparing data, and deciding how to display the data.
View – Responsible for rendering data and presenting it to users through HTML.

Write the PHP framework step by step and gain an in-depth understanding of the MVC operation process

A typical Web MVC process:

Controller intercepts requests sent by users;
Controller calls the Model to complete the read and write operations of the status;
Controller passes data to View;
View renders the final Write the PHP framework step by step and gain an in-depth understanding of the MVC operation process and presents it to the user.

2 Why should you develop your own MVC framework

There are a lot of excellent MVC frameworks available on the Internet. This tutorial is not intended to develop a comprehensive and ultimate MVC framework solution, but consider it as a good opportunity to learn PHP from the inside. In the process, you will learn object-oriented programming and MVC design pattern, and learn some precautions in development.

What’s more, you have full control over your framework and incorporate your ideas into the framework you develop. Although it is not necessarily done well, you can develop functions and modules in your own way.

3 Start developing your own MVC framework

3.1 Directory preparation

Before we start development, let us first set up the project. Assume that the project we build is todo and the MVC framework can be named FastPHP. Then the first step is to set up the directory structure.

PHP MVC简单目录

Although not all the above directories will be used in this tutorial, for the scalability of the program in the future, it is very necessary to set the program directory at the beginning. Let’s talk about the role of each directory in detail:

application – application code
config – program configuration or database configuration
fastphp - framework core directory
public – static files
runtime - Temporary data directory
scripts – command line tools

3.2 Code specifications

After the directory is set, we need to stipulate the code specifications:

MySQL的表名需小写，如：item，car
模块名（Models）需首字母大写，，并在名称后添加“Model”，如：ItemModel，CarModel
控制器（Controllers）需首字母大写，，并在名称中添加“Controller”，如：ItemController，CarController
视图（Views）部署结构为“控制器名/行为名”，如：item/view.php，car/buy.php

上述的一些规则是为了能在程序中更好的进行互相的调用。接下来就开始真正的PHP MVC编程了。

3.3 重定向

将所有的数据请求都重定向 index.php 文件，在 todo 目录下新建一个 .htaccess 文件，文件内容为：

<span class="hljs-section"><IfModule mod_rewrite.c>
    <span class="hljs-attribute"><span class="hljs-nomarkup">RewriteEngine <span class="hljs-literal">On

    <span class="hljs-comment"># 确保请求路径不是一个文件名或目录
    <span class="hljs-attribute"><span class="hljs-nomarkup">RewriteCond <span class="hljs-variable">%{REQUEST_FILENAME} !-f
    <span class="hljs-attribute"><span class="hljs-nomarkup">RewriteCond <span class="hljs-variable">%{REQUEST_FILENAME} !-d

    <span class="hljs-comment"># 重定向所有请求到 index.php?url=PATHNAME
    <span class="hljs-attribute"><span class="hljs-nomarkup">RewriteRule ^(.*)$ index.php?url=<span class="hljs-number">$1<span class="hljs-meta"> [PT,L]
<span class="hljs-section"></IfModule>
</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

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这样做的主要原因有：

程序有一个单一的入口；
除静态程序，其他所有程序都重定向到 index.php 上；
可以用来生成利于SEO的URL，想要更好的配置URL，后期可能会需要URL路由，这里先不做介绍了。

3.4 入口文件

做完上面的操作，就应该知道我们需要做什么了，没错！在 public 目录下添加 index.php 文件，文件内容为：

<span class="php"><span class="hljs-meta"><?php 

<span class="hljs-comment">// 应用目录为当前目录
define(<span class="hljs-string">'APP_PATH', <span class="hljs-keyword">__DIR__.<span class="hljs-string">'/');

<span class="hljs-comment">// 开启调试模式
define(<span class="hljs-string">'APP_DEBUG', <span class="hljs-keyword">true);

<span class="hljs-comment">// 网站根URL
define(<span class="hljs-string">'APP_URL', <span class="hljs-string">'http://localhost/fastphp');

<span class="hljs-comment">// 加载框架
<span class="hljs-keyword">require <span class="hljs-string">'./fastphp/FastPHP.php';
</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

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注意，上面的PHP代码中，并没有添加PHP结束符号”?>”，这么做的主要原因是，对于只有 PHP 代码的文件，结束标志(“?>”)最好不存在，PHP自身并不需要结束符号，不添加结束符号可以很大程度上防止末尾被添加额外的注入内容，让程序更加安全。

3.5 配置文件和主请求

在 index.php 中，我们对 fastphp 文件夹下的 FastPHP.php 发起了请求，那么 FastPHP.php 这个启动文件中到底会包含哪些内容呢？

<span class="php"><span class="hljs-meta"><?php

<span class="hljs-comment">// 初始化常量
defined(<span class="hljs-string">'FRAME_PATH') <span class="hljs-keyword">or define(<span class="hljs-string">'FRAME_PATH', <span class="hljs-keyword">__DIR__.<span class="hljs-string">'/');
defined(<span class="hljs-string">'APP_PATH') <span class="hljs-keyword">or define(<span class="hljs-string">'APP_PATH', dirname($_SERVER[<span class="hljs-string">'SCRIPT_FILENAME']).<span class="hljs-string">'/');
defined(<span class="hljs-string">'APP_DEBUG') <span class="hljs-keyword">or define(<span class="hljs-string">'APP_DEBUG', <span class="hljs-keyword">false);
defined(<span class="hljs-string">'CONFIG_PATH') <span class="hljs-keyword">or define(<span class="hljs-string">'CONFIG_PATH', APP_PATH.<span class="hljs-string">'config/');
defined(<span class="hljs-string">'RUNTIME_PATH') <span class="hljs-keyword">or define(<span class="hljs-string">'RUNTIME_PATH', APP_PATH.<span class="hljs-string">'runtime/');

<span class="hljs-comment">// 包含配置文件
<span class="hljs-keyword">require APP_PATH . <span class="hljs-string">'config/config.php';

<span class="hljs-comment">//包含核心框架类
<span class="hljs-keyword">require FRAME_PATH . <span class="hljs-string">'Core.php';

<span class="hljs-comment">// 实例化核心类
$fast = <span class="hljs-keyword">new Core;
$fast->run();
</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

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以上文件都其实可以直接在 index.php 文件中包含，常量也可以直接在 index.php 中定义，我们这么做的原因是为了在后期管理和拓展中更加的方便，所以把需要在一开始的时候就加载运行的程序统一放到一个单独的文件中引用。

先来看看config文件下的 config .php 文件，该文件的主要作用是设置一些程序的配置项及数据库连接等，主要内容为：

<span class="php"><span class="hljs-meta"><?php
 
<span class="hljs-comment">/** 变量配置 **/
 
define(<span class="hljs-string">'DB_NAME', <span class="hljs-string">'todo');
define(<span class="hljs-string">'DB_USER', <span class="hljs-string">'root');
define(<span class="hljs-string">'DB_PASSWORD', <span class="hljs-string">'root');
define(<span class="hljs-string">'DB_HOST', <span class="hljs-string">'localhost');
</span></span></span></span></span></span></span></span></span></span></span>

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应该说 config.php 涉及到的内容并不多，不过是一些基础数据库的设置，再来看看 fastphp下的共用框架入口文件 Core.php 应该怎么写。

<span class="php"><span class="hljs-meta"><?php
<span class="hljs-comment">/**
 * FastPHP核心框架
 */
<span class="hljs-class"><span class="hljs-keyword">class <span class="hljs-title">Core
{
    <span class="hljs-comment">// 运行程序
    <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">run<span class="hljs-params">()
    {
        spl_autoload_register(<span class="hljs-keyword">array($this, <span class="hljs-string">'loadClass'));
        $this->setReporting();
        $this->removeMagicQuotes();
        $this->unregisterGlobals();
        $this->Route();
    }

    <span class="hljs-comment">// 路由处理
    <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">Route<span class="hljs-params">()
    {
        $controllerName = <span class="hljs-string">'Index';
        $action = <span class="hljs-string">'index';

        <span class="hljs-keyword">if (!<span class="hljs-keyword">empty($_GET[<span class="hljs-string">'url'])) {
            $url = $_GET[<span class="hljs-string">'url'];
            $urlArray = explode(<span class="hljs-string">'/', $url);
            
            <span class="hljs-comment">// 获取控制器名
            $controllerName = ucfirst($urlArray[<span class="hljs-number">0]);
            
            <span class="hljs-comment">// 获取动作名
            array_shift($urlArray);
            $action = <span class="hljs-keyword">empty($urlArray[<span class="hljs-number">0]) ? <span class="hljs-string">'index' : $urlArray[<span class="hljs-number">0];
            
            <span class="hljs-comment">//获取URL参数
            array_shift($urlArray);
            $queryString = <span class="hljs-keyword">empty($urlArray) ? <span class="hljs-keyword">array() : $urlArray;
        }

        <span class="hljs-comment">// 数据为空的处理
        $queryString  = <span class="hljs-keyword">empty($queryString) ? <span class="hljs-keyword">array() : $queryString;

        <span class="hljs-comment">// 实例化控制器
        $controller = $controllerName . <span class="hljs-string">'Controller';
        $dispatch = <span class="hljs-keyword">new $controller($controllerName, $action);

        <span class="hljs-comment">// 如果控制器存和动作存在，这调用并传入URL参数
        <span class="hljs-keyword">if ((int)method_exists($controller, $action)) {
            call_user_func_array(<span class="hljs-keyword">array($dispatch, $action), $queryString);
        } <span class="hljs-keyword">else {
            <span class="hljs-keyword">exit($controller . <span class="hljs-string">"控制器不存在");
        }
    }

    <span class="hljs-comment">// 检测开发环境
    <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">setReporting<span class="hljs-params">()
    {
        <span class="hljs-keyword">if (APP_DEBUG === <span class="hljs-keyword">true) {
            error_reporting(E_ALL);
            ini_set(<span class="hljs-string">'display_errors',<span class="hljs-string">'On');
        } <span class="hljs-keyword">else {
            error_reporting(E_ALL);
            ini_set(<span class="hljs-string">'display_errors',<span class="hljs-string">'Off');
            ini_set(<span class="hljs-string">'log_errors', <span class="hljs-string">'On');
            ini_set(<span class="hljs-string">'error_log', RUNTIME_PATH. <span class="hljs-string">'logs/error.log');
        }
    }

    <span class="hljs-comment">// 删除敏感字符
    <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">stripSlashesDeep<span class="hljs-params">($value)
    {
        $value = is_array($value) ? array_map(<span class="hljs-string">'stripSlashesDeep', $value) : stripslashes($value);
        <span class="hljs-keyword">return $value;
    }

    <span class="hljs-comment">// 检测敏感字符并删除
    <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">removeMagicQuotes<span class="hljs-params">()
    {
        <span class="hljs-keyword">if ( get_magic_quotes_gpc()) {
            $_GET = stripSlashesDeep($_GET );
            $_POST = stripSlashesDeep($_POST );
            $_COOKIE = stripSlashesDeep($_COOKIE);
            $_SESSION = stripSlashesDeep($_SESSION);
        }
    }

    <span class="hljs-comment">// 检测自定义全局变量（register globals）并移除
    <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">unregisterGlobals<span class="hljs-params">()
    {
        <span class="hljs-keyword">if (ini_get(<span class="hljs-string">'register_globals')) {
            $array = <span class="hljs-keyword">array(<span class="hljs-string">'_SESSION', <span class="hljs-string">'_POST', <span class="hljs-string">'_GET', <span class="hljs-string">'_COOKIE', <span class="hljs-string">'_REQUEST', <span class="hljs-string">'_SERVER', <span class="hljs-string">'_ENV', <span class="hljs-string">'_FILES');
           <span class="hljs-keyword">foreach ($array <span class="hljs-keyword">as $value) {
                <span class="hljs-keyword">foreach ($GLOBALS[$value] <span class="hljs-keyword">as $key => $var) {
                    <span class="hljs-keyword">if ($var === $GLOBALS[$key]) {
                        <span class="hljs-keyword">unset($GLOBALS[$key]);
                    }
                }
            }
        }
    }

    <span class="hljs-comment">// 自动加载控制器和模型类 
    <span class="hljs-keyword">static <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">loadClass<span class="hljs-params">($class)
    {
        $frameworks = FRAME_PATH . $class . <span class="hljs-string">'.class.php';
        $controllers = APP_PATH . <span class="hljs-string">'application/controllers/' . $class . <span class="hljs-string">'.class.php';
        $models = APP_PATH . <span class="hljs-string">'application/models/' . $class . <span class="hljs-string">'.class.php';

        <span class="hljs-keyword">if (file_exists($frameworks)) {
            <span class="hljs-comment">// 加载框架核心类
            <span class="hljs-keyword">include $frameworks;
        } <span class="hljs-keyword">elseif (file_exists($controllers)) {
            <span class="hljs-comment">// 加载应用控制器类
            <span class="hljs-keyword">include $controllers;
        } <span class="hljs-keyword">elseif (file_exists($models)) {
            <span class="hljs-comment">//加载应用模型类
            <span class="hljs-keyword">include $models;
        } <span class="hljs-keyword">else {
            <span class="hljs-comment">/* 错误代码 */
        }
    }
}
</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

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下面重点讲解主请求方法 callHook()，首先我们想看看我们的 URL 会这样：

yoursite.com/controllerName/actionName/queryString

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callHook()的作用就是，从全局变量 $_GET['url']变量中获取 URL，并将其分割成三部分：$controller、$action 和 $queryString。

例如，URL链接为：todo.com/item/view/1/first-item，那么

$controller 就是：item
$action 就是：view
查询字符串Query String就是：array(1, first-item)

分割完成后，会实例化一个新的控制器：$controller.'Controller'（其中“.”是连字符），并调用其方法 $action。

3.6 控制器/Controller基类

接下来的操作就是在 fastphp 中建立程序所需的基类，包括控制器、模型和视图的基类。

新建控制器基类为 Controller.class.php，控制器的主要功能就是总调度，具体具体内容如下：

<span class="php"><span class="hljs-meta"><?php 
<span class="hljs-comment">/**
 * 控制器基类
 */
<span class="hljs-class"><span class="hljs-keyword">class <span class="hljs-title">Controller
{
    <span class="hljs-keyword">protected $_controller;
    <span class="hljs-keyword">protected $_action;
    <span class="hljs-keyword">protected $_view;
 
    <span class="hljs-comment">// 构造函数，初始化属性，并实例化对应模型
    <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">__construct<span class="hljs-params">($controller, $action)
    {
        $this->_controller = $controller;
        $this->_action = $action;
        $this->_view = <span class="hljs-keyword">new View($controller, $action);
    }

    <span class="hljs-comment">// 分配变量
    <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">assign<span class="hljs-params">($name, $value)
    {
        $this->_view->assign($name, $value);
    }

    <span class="hljs-comment">// 渲染视图
    <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">__destruct<span class="hljs-params">()
    {
        $this->_view->render();
    }
}
</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

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Controller 类实现所有控制器、模型和视图（View类）的通信。在执行析构函数时，我们可以调用 render() 来显示视图（view）文件。

3.7 模型Model基类

新建模型基类为 Model.class.php，模型基类 Model.class.php 代码如下：

<span class="php"><span class="hljs-meta"><?php

<span class="hljs-class"><span class="hljs-keyword">class <span class="hljs-title">Model <span class="hljs-keyword">extends <span class="hljs-title">Sql
{
    <span class="hljs-keyword">protected $_model;
    <span class="hljs-keyword">protected $_table;
 
    <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">__construct<span class="hljs-params">()
    {
        <span class="hljs-comment">// 连接数据库
        $this->connect(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME);
        
        <span class="hljs-comment">// 获取模型名称
        $this->_model = get_class($this);
        $this->_model = rtrim($this->_model, <span class="hljs-string">'Model');
        
        <span class="hljs-comment">// 数据库表名与类名一致
        $this->_table = strtolower($this->_model);
    }
 
    <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">__destruct<span class="hljs-params">()
    {
    }
}
</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

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考虑到模型需要对数据库进行处理，所以单独建立一个数据库基类 Sql.class.php，模型基类继承 Sql.class.php，代码如下：

<span class="php"><span class="hljs-meta"><?php 

<span class="hljs-class"><span class="hljs-keyword">class <span class="hljs-title">Sql
{
    <span class="hljs-keyword">protected $_dbHandle;
    <span class="hljs-keyword">protected $_Write the PHP framework step by step and gain an in-depth understanding of the MVC operation process;

    <span class="hljs-comment">// 连接数据库
    <span class="hljs-keyword">public <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">connect<span class="hljs-params">($host, $user, $pass, $dbname)
    {
        <span class="hljs-keyword">try {
            $dsn = sprintf(<span class="hljs-string">"mysql:host=%s;dbname=%s;charset=utf8", $host, $dbname);
            $this->_dbHandle = <span class="hljs-keyword">new PDO($dsn, $user, $pass, <span class="hljs-keyword">array(PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC));
        } <span class="hljs-keyword">catch (PDOException $e) {
            <span class="hljs-keyword">exit(<span class="hljs-string">'错误: ' . $e->getMessage());
        }
    }

    <span class="hljs-comment">// 查询所有
    <span class="hljs-keyword">public <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">selectAll<span class="hljs-params">()
    {
        $sql = sprintf(<span class="hljs-string">"select * from `%s`", $this->_table);
        $sth = $this->_dbHandle->prepare($sql);
        $sth->execute();

        <span class="hljs-keyword">return $sth->fetchAll();
    }

    <span class="hljs-comment">// 根据条件 (id) 查询
    <span class="hljs-keyword">public <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">select<span class="hljs-params">($id)
    {
        $sql = sprintf(<span class="hljs-string">"select * from `%s` where `id` = '%s'", $this->_table, $id);
        $sth = $this->_dbHandle->prepare($sql);
        $sth->execute();
        
        <span class="hljs-keyword">return $sth->fetch();
    }

    <span class="hljs-comment">// 根据条件 (id) 删除
    <span class="hljs-keyword">public <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">delete<span class="hljs-params">($id)
    {
        $sql = sprintf(<span class="hljs-string">"delete from `%s` where `id` = '%s'", $this->_table, $id);
        $sth = $this->_dbHandle->prepare($sql);
        $sth->execute();

        <span class="hljs-keyword">return $sth->rowCount();
    }

    <span class="hljs-comment">// 自定义SQL查询，返回影响的行数
    <span class="hljs-keyword">public <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">query<span class="hljs-params">($sql)
    {
        $sth = $this->_dbHandle->prepare($sql);
        $sth->execute();

        <span class="hljs-keyword">return $sth->rowCount();
    }

    <span class="hljs-comment">// 新增数据
    <span class="hljs-keyword">public <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">add<span class="hljs-params">($data)
    {
        $sql = sprintf(<span class="hljs-string">"insert into `%s` %s", $this->_table, $this->formatInsert($data));

        <span class="hljs-keyword">return $this->query($sql);
    }

    <span class="hljs-comment">// 修改数据
    <span class="hljs-keyword">public <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">update<span class="hljs-params">($id, $data)
    {
        $sql = sprintf(<span class="hljs-string">"update `%s` set %s where `id` = '%s'", $this->_table, $this->formatUpdate($data), $id);

        <span class="hljs-keyword">return $this->query($sql);
    }

    <span class="hljs-comment">// 将数组转换成插入格式的sql语句
    <span class="hljs-keyword">private <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">formatInsert<span class="hljs-params">($data)
    {
        $fields = <span class="hljs-keyword">array();
        $values = <span class="hljs-keyword">array();
        <span class="hljs-keyword">foreach ($data <span class="hljs-keyword">as $key => $value) {
            $fields[] = sprintf(<span class="hljs-string">"`%s`", $key);
            $values[] = sprintf(<span class="hljs-string">"'%s'", $value);
        }

        $field = implode(<span class="hljs-string">',', $fields);
        $value = implode(<span class="hljs-string">',', $values);

        <span class="hljs-keyword">return sprintf(<span class="hljs-string">"(%s) values (%s)", $field, $value);
    }

    <span class="hljs-comment">// 将数组转换成更新格式的sql语句
    <span class="hljs-keyword">private <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">formatUpdate<span class="hljs-params">($data)
    {
        $fields = <span class="hljs-keyword">array();
        <span class="hljs-keyword">foreach ($data <span class="hljs-keyword">as $key => $value) {
            $fields[] = sprintf(<span class="hljs-string">"`%s` = '%s'", $key, $value);
        }

        <span class="hljs-keyword">return implode(<span class="hljs-string">',', $fields);
    }
}
</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

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应该说，Sql.class.php 是框架的核心部分。为什么？因为通过它，我们创建了一个 SQL 抽象层，可以大大减少了数据库的编程工作。虽然 PDO 接口本来已经很简洁，但是抽象之后框架的可灵活性更高。

3.8 视图View类

视图类 View.class.php 内容如下：

<span class="php"><span class="hljs-meta"><?php
<span class="hljs-comment">/**
 * 视图基类
 */
<span class="hljs-class"><span class="hljs-keyword">class <span class="hljs-title">View
{
    <span class="hljs-keyword">protected $variables = <span class="hljs-keyword">array();
    <span class="hljs-keyword">protected $_controller;
    <span class="hljs-keyword">protected $_action;

    <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">__construct<span class="hljs-params">($controller, $action)
    {
        $this->_controller = $controller;
        $this->_action = $action;
    }
 
    <span class="hljs-comment">/** 分配变量 **/
    <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">assign<span class="hljs-params">($name, $value)
    {
        $this->variables[$name] = $value;
    }
 
    <span class="hljs-comment">/** 渲染显示 **/
    <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">render<span class="hljs-params">()
    {
        extract($this->variables);
        $defaultHeader = APP_PATH . <span class="hljs-string">'application/views/header.php';
        $defaultFooter = APP_PATH . <span class="hljs-string">'application/views/footer.php';
        $controllerHeader = APP_PATH . <span class="hljs-string">'application/views/' . $this->_controller . <span class="hljs-string">'/header.php';
        $controllerFooter = APP_PATH . <span class="hljs-string">'application/views/' . $this->_controller . <span class="hljs-string">'/footer.php';
        
        <span class="hljs-comment">// 页头文件
        <span class="hljs-keyword">if (file_exists($controllerHeader)) {
            <span class="hljs-keyword">include ($controllerHeader);
        } <span class="hljs-keyword">else {
            <span class="hljs-keyword">include ($defaultHeader);
        }

        <span class="hljs-comment">// 页内容文件
        <span class="hljs-keyword">include (APP_PATH . <span class="hljs-string">'application/views/' . $this->_controller . <span class="hljs-string">'/' . $this->_action . <span class="hljs-string">'.php');
        
        <span class="hljs-comment">// 页脚文件
        <span class="hljs-keyword">if (file_exists($controllerFooter)) {
            <span class="hljs-keyword">include ($controllerFooter);
        } <span class="hljs-keyword">else {
            <span class="hljs-keyword">include ($defaultFooter);
        }
    }
}
</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

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这样我们的核心的PHP MVC框架就编写完成了，下面我们开始编写应用来测试框架功能。

4 应用

4.1 数据库部署

在 SQL 中新建一个 todo 数据库，使用下面的语句增加 item 数据表并插入2条记录：

<span class="hljs-keyword">CREATE <span class="hljs-keyword">DATABASE <span class="hljs-string">`todo` <span class="hljs-keyword">DEFAULT <span class="hljs-built_in">CHARACTER <span class="hljs-keyword">SET utf8 <span class="hljs-keyword">COLLATE utf8_general_ci;
<span class="hljs-keyword">USE <span class="hljs-string">`todo`;

<span class="hljs-keyword">CREATE <span class="hljs-keyword">TABLE <span class="hljs-string">`item` (
    <span class="hljs-string">`id` <span class="hljs-built_in">int(<span class="hljs-number">11) <span class="hljs-keyword">NOT <span class="hljs-literal">NULL auto_increment,
    <span class="hljs-string">`item_name` <span class="hljs-built_in">varchar(<span class="hljs-number">255) <span class="hljs-keyword">NOT <span class="hljs-literal">NULL,
    PRIMARY <span class="hljs-keyword">KEY (<span class="hljs-string">`id`)
) <span class="hljs-keyword">ENGINE=<span class="hljs-keyword">InnoDB AUTO_INCREMENT=<span class="hljs-number">1 <span class="hljs-keyword">DEFAULT <span class="hljs-keyword">CHARSET=utf8;
 
<span class="hljs-keyword">INSERT <span class="hljs-keyword">INTO <span class="hljs-string">`item` <span class="hljs-keyword">VALUES(<span class="hljs-number">1, <span class="hljs-string">'Hello World.');
<span class="hljs-keyword">INSERT <span class="hljs-keyword">INTO <span class="hljs-string">`item` <span class="hljs-keyword">VALUES(<span class="hljs-number">2, <span class="hljs-string">'Lets go!');</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

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4.2 部署模型

然后，我们还需要在 models 目录中创建一个 ItemModel.php 模型，内容如下：

<span class="php"><span class="hljs-meta"><?php

<span class="hljs-class"><span class="hljs-keyword">class <span class="hljs-title">ItemModel <span class="hljs-keyword">extends <span class="hljs-title">Model
{
    <span class="hljs-comment">/* 业务逻辑层实现 */
}
</span></span></span></span></span></span></span></span>

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模型内容为空。因为 Item 模型继承了 Model，所以它拥有 Model 的所有功能。

4.3 部署控制器

在 controllers 目录下创建一个 ItemController.php 控制器，内容如下：

<span class="php"><span class="hljs-meta"><?php
 
<span class="hljs-class"><span class="hljs-keyword">class <span class="hljs-title">ItemController <span class="hljs-keyword">extends <span class="hljs-title">Controller
{
    <span class="hljs-comment">// 首页方法，测试框架自定义DB查询
    <span class="hljs-keyword">public <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">index<span class="hljs-params">()
    {
        $items = (<span class="hljs-keyword">new ItemModel)->selectAll();

        $this->assign(<span class="hljs-string">'title', <span class="hljs-string">'全部条目');
        $this->assign(<span class="hljs-string">'items', $items);
    }
    
    <span class="hljs-comment">// 添加记录，测试框架DB记录创建（Create）
    <span class="hljs-keyword">public <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">add<span class="hljs-params">()
    {
        $data[<span class="hljs-string">'item_name'] = $_POST[<span class="hljs-string">'value'];
        $count = (<span class="hljs-keyword">new ItemModel)->add($data);

        $this->assign(<span class="hljs-string">'title', <span class="hljs-string">'添加成功');
        $this->assign(<span class="hljs-string">'count', $count);
    }
    
    <span class="hljs-comment">// 查看记录，测试框架DB记录读取（Read）
    <span class="hljs-keyword">public <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">view<span class="hljs-params">($id = null)
    {
        $item = (<span class="hljs-keyword">new ItemModel)->select($id);

        $this->assign(<span class="hljs-string">'title', <span class="hljs-string">'正在查看' . $item[<span class="hljs-string">'item_name']);
        $this->assign(<span class="hljs-string">'item', $item);
    }
    
    <span class="hljs-comment">// 更新记录，测试框架DB记录更新（Update）
    <span class="hljs-keyword">public <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">update<span class="hljs-params">()
    {
        $data = <span class="hljs-keyword">array(<span class="hljs-string">'id' => $_POST[<span class="hljs-string">'id'], <span class="hljs-string">'item_name' => $_POST[<span class="hljs-string">'value']);
        $count = (<span class="hljs-keyword">new ItemModel)->update($data[<span class="hljs-string">'id'], $data);

        $this->assign(<span class="hljs-string">'title', <span class="hljs-string">'修改成功');
        $this->assign(<span class="hljs-string">'count', $count);
    }
    
    <span class="hljs-comment">// 删除记录，测试框架DB记录删除（Delete）
    <span class="hljs-keyword">public <span class="hljs-function"><span class="hljs-keyword">function <span class="hljs-title">delete<span class="hljs-params">($id = null)
    {
        $count = (<span class="hljs-keyword">new ItemModel)->delete($id);

        $this->assign(<span class="hljs-string">'title', <span class="hljs-string">'删除成功');
        $this->assign(<span class="hljs-string">'count', $count);
    }
}
</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

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4.4 部署视图

在 views 目录下新建 header.php 和 footer.php 两个页头页脚模板，内容如下。

header.php，内容：

<span class="hljs-tag"><<span class="hljs-name">html>
<span class="hljs-tag"><<span class="hljs-name">head>
    <span class="hljs-tag"><<span class="hljs-name">meta <span class="hljs-attr">http-equiv=<span class="hljs-string">"Content-Type" <span class="hljs-attr">content=<span class="hljs-string">"text/html; charset=utf-8" />
    <span class="hljs-tag"><<span class="hljs-name">title><span class="php"><span class="hljs-meta"><?php <span class="hljs-keyword">echo $title <span class="hljs-meta">?><span class="hljs-tag"></<span class="hljs-name">title>
    <span class="hljs-tag"><<span class="hljs-name">style><span class="css">
        <span class="hljs-selector-class">.item {
            <span class="hljs-attribute">width:<span class="hljs-number">400px;
        }
 
        <span class="hljs-selector-tag">input {
            <span class="hljs-attribute">color:<span class="hljs-number">#222222;
            <span class="hljs-attribute">font-family:georgia,times;
            <span class="hljs-attribute">font-size:<span class="hljs-number">24px;
            <span class="hljs-attribute">font-weight:normal;
            <span class="hljs-attribute">line-height:<span class="hljs-number">1.2em;
            <span class="hljs-attribute">color:black;
        }
 
        <span class="hljs-selector-tag">a {
            <span class="hljs-attribute">color:blue;
            <span class="hljs-attribute">font-family:georgia,times;
            <span class="hljs-attribute">font-size:<span class="hljs-number">20px;
            <span class="hljs-attribute">font-weight:normal;
            <span class="hljs-attribute">line-height:<span class="hljs-number">1.2em;
            <span class="hljs-attribute">text-decoration:none;
         }
 
        <span class="hljs-selector-tag">a<span class="hljs-selector-pseudo">:hover {
            <span class="hljs-attribute">text-decoration:underline;
        }

        <span class="hljs-selector-tag">h1 {
            <span class="hljs-attribute">color:<span class="hljs-number">#000000;
            <span class="hljs-attribute">font-size:<span class="hljs-number">41px;
            <span class="hljs-attribute">letter-spacing:-<span class="hljs-number">2px;
            <span class="hljs-attribute">line-height:<span class="hljs-number">1em;
            <span class="hljs-attribute">font-family:helvetica,arial,sans-serif;
            <span class="hljs-attribute">border-bottom:<span class="hljs-number">1px dotted <span class="hljs-number">#cccccc;
        }
 
        <span class="hljs-selector-tag">h2 {
            <span class="hljs-attribute">color:<span class="hljs-number">#000000;
            <span class="hljs-attribute">font-size:<span class="hljs-number">34px;
            <span class="hljs-attribute">letter-spacing:-<span class="hljs-number">2px;
            <span class="hljs-attribute">line-height:<span class="hljs-number">1em;
            <span class="hljs-attribute">font-family:helvetica,arial,sans-serif;
        }
    <span class="hljs-tag"></<span class="hljs-name">style>
<span class="hljs-tag"></<span class="hljs-name">head>
<span class="hljs-tag"><<span class="hljs-name">body>
    <span class="hljs-tag"><<span class="hljs-name">h1><span class="php"><span class="hljs-meta"><?php <span class="hljs-keyword">echo $title <span class="hljs-meta">?><span class="hljs-tag"></<span class="hljs-name">h1>
</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

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footer.php，内容：

<span class="hljs-section"></body>
<span class="hljs-section"></html>
</span></span>

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然后，在 views/item 创建以下几个视图文件。

index.php，浏览数据库内 item 表的所有记录，内容：

<span class="hljs-tag"><<span class="hljs-name">form <span class="hljs-attr">action=<span class="hljs-string">"<span class="php"><span class="hljs-meta"><?php <span class="hljs-keyword">echo APP_URL <span class="hljs-meta">?>/item/add" <span class="hljs-attr">method=<span class="hljs-string">"post">
    <span class="hljs-tag"><<span class="hljs-name">input <span class="hljs-attr">type=<span class="hljs-string">"text" <span class="hljs-attr">value=<span class="hljs-string">"点击添加" <span class="hljs-attr">onclick=<span class="hljs-string">"this.value=''" <span class="hljs-attr">name=<span class="hljs-string">"value">
    <span class="hljs-tag"><<span class="hljs-name">input <span class="hljs-attr">type=<span class="hljs-string">"submit" <span class="hljs-attr">value=<span class="hljs-string">"添加">
<span class="hljs-tag"></<span class="hljs-name">form>
<span class="hljs-tag"><<span class="hljs-name">br/><span class="hljs-tag"><<span class="hljs-name">br/>

<span class="php"><span class="hljs-meta"><?php $number = <span class="hljs-number">0<span class="hljs-meta">?>
 
<span class="php"><span class="hljs-meta"><?php <span class="hljs-keyword">foreach ($items <span class="hljs-keyword">as $item): <span class="hljs-meta">?>
    <span class="hljs-tag"><<span class="hljs-name">a <span class="hljs-attr">class=<span class="hljs-string">"big" <span class="hljs-attr">href=<span class="hljs-string">"<span class="php"><span class="hljs-meta"><?php <span class="hljs-keyword">echo APP_URL <span class="hljs-meta">?>/item/view/<span class="php"><span class="hljs-meta"><?php <span class="hljs-keyword">echo $item[<span class="hljs-string">'id'] <span class="hljs-meta">?>" <span class="hljs-attr">title=<span class="hljs-string">"点击修改">
        <span class="hljs-tag"><<span class="hljs-name">span <span class="hljs-attr">class=<span class="hljs-string">"item">
            <span class="php"><span class="hljs-meta"><?php <span class="hljs-keyword">echo ++$number <span class="hljs-meta">?>
            <span class="php"><span class="hljs-meta"><?php <span class="hljs-keyword">echo $item[<span class="hljs-string">'item_name'] <span class="hljs-meta">?>
        <span class="hljs-tag"></<span class="hljs-name">span>
    <span class="hljs-tag"></<span class="hljs-name">a>
    ----
    <span class="hljs-tag"><<span class="hljs-name">a <span class="hljs-attr">class=<span class="hljs-string">"big" <span class="hljs-attr">href=<span class="hljs-string">"<span class="php"><span class="hljs-meta"><?php <span class="hljs-keyword">echo APP_URL <span class="hljs-meta">?>/item/delete/<span class="php"><span class="hljs-meta"><?php <span class="hljs-keyword">echo $item[<span class="hljs-string">'id']<span class="hljs-meta">?>">删除<span class="hljs-tag"></<span class="hljs-name">a>
<span class="hljs-tag"><<span class="hljs-name">br/>
<span class="php"><span class="hljs-meta"><?php <span class="hljs-keyword">endforeach <span class="hljs-meta">?>
</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

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add.php，添加记录，内容：

<span class="hljs-tag"><<span class="hljs-name">a <span class="hljs-attr">class=<span class="hljs-string">"big" <span class="hljs-attr">href=<span class="hljs-string">"<span class="php"><span class="hljs-meta"><?php <span class="hljs-keyword">echo APP_URL <span class="hljs-meta">?>/item/index">成功添加<span class="php"><span class="hljs-meta"><?php <span class="hljs-keyword">echo $count <span class="hljs-meta">?>条记录，点击返回<span class="hljs-tag"></<span class="hljs-name">a>
</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

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view.php，查看单条记录，内容：

<span class="hljs-tag"><<span class="hljs-name">form <span class="hljs-attr">action=<span class="hljs-string">"<span class="php"><span class="hljs-meta"><?php <span class="hljs-keyword">echo APP_URL <span class="hljs-meta">?>/item/update" <span class="hljs-attr">method=<span class="hljs-string">"post">
    <span class="hljs-tag"><<span class="hljs-name">input <span class="hljs-attr">type=<span class="hljs-string">"text" <span class="hljs-attr">name=<span class="hljs-string">"value" <span class="hljs-attr">value=<span class="hljs-string">"<span class="php"><span class="hljs-meta"><?php <span class="hljs-keyword">echo $item[<span class="hljs-string">'item_name'] <span class="hljs-meta">?>">
    <span class="hljs-tag"><<span class="hljs-name">input <span class="hljs-attr">type=<span class="hljs-string">"hidden" <span class="hljs-attr">name=<span class="hljs-string">"id" <span class="hljs-attr">value=<span class="hljs-string">"<span class="php"><span class="hljs-meta"><?php <span class="hljs-keyword">echo $item[<span class="hljs-string">'id'] <span class="hljs-meta">?>">
    <span class="hljs-tag"><<span class="hljs-name">input <span class="hljs-attr">type=<span class="hljs-string">"submit" <span class="hljs-attr">value=<span class="hljs-string">"修改">
<span class="hljs-tag"></<span class="hljs-name">form>

<span class="hljs-tag"><<span class="hljs-name">a <span class="hljs-attr">class=<span class="hljs-string">"big" <span class="hljs-attr">href=<span class="hljs-string">"<span class="php"><span class="hljs-meta"><?php <span class="hljs-keyword">echo APP_URL <span class="hljs-meta">?>/item/index">返回<span class="hljs-tag"></<span class="hljs-name">a>
</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

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update.php，更改记录，内容：

<span class="hljs-tag"><<span class="hljs-name">a <span class="hljs-attr">class=<span class="hljs-string">"big" <span class="hljs-attr">href=<span class="hljs-string">"<span class="php"><span class="hljs-meta"><?php <span class="hljs-keyword">echo APP_URL <span class="hljs-meta">?>/item/index">成功修改<span class="php"><span class="hljs-meta"><?php <span class="hljs-keyword">echo $count <span class="hljs-meta">?>项，点击返回<span class="hljs-tag"></<span class="hljs-name">a>
</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

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delete.php，删除记录，内容：

<span class="hljs-tag"><<span class="hljs-name">a <span class="hljs-attr">href=<span class="hljs-string">"<span class="php"><span class="hljs-meta"><?php <span class="hljs-keyword">echo APP_URL <span class="hljs-meta">?>/item/index">成功删除<span class="php"><span class="hljs-meta"><?php <span class="hljs-keyword">echo $count <span class="hljs-meta">?>项，点击返回<span class="hljs-tag"></<span class="hljs-name">a>
</span></span></span></span></span></span></span></span></span></span></span></span></span></span>

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4.5 应用测试

这样，在浏览器中访问 todo 程序：http://localhost/todo/item/index/，就可以看到效果了。

Write the PHP framework step by step and gain an in-depth understanding of the MVC operation process

The above code has all been released to github, and the key parts have been commented by Air Canada. The warehouse address is: https://github.com/yeszao/fastphp. Cloning and submission are welcome.

To design a better MVC, or use it more standardizedly, please read "The Principles of Responsibility Division of MVC Architecture".