Let's write a simple PHP MVC structure_PHP tutorial-PHP Tutorial-php.cn

MVC structure is actually the abbreviation of the three words Model, Controller and View. The main task of Model is to read the data from the database or other file systems in the way we need. View, which is mainly responsible for the page, displays the data to the user in the form of html. Controller is mainly responsible for business logic and allocates requests according to the user's Request. For example, to display the login interface, you need to call the loginAction method of a controller userController to display it.

Below we use PHP to create a simple MVC structure system.

First create a single point of entry, the bootstrap file index.php, as the only entry point for the entire MVC system. What is a single point of entry? The so-called single point of entry means that there is only one entrance for the entire application, and all implementations are forwarded through this entrance. Why do we need a single point of entry? There are several advantages to a single point of entry: First, some variables, classes, and methods processed globally by the system can be processed here. For example, you need to perform preliminary filtering of data, you need to simulate session processing, you need to define some global variables, and you even need to register some objects or variables into the register. Second, the program structure is clearer. Of course there are many benefits. :)

<?php
include("core/ini.php");
initializer::initialize();
$router = loader::load("router");
dispatcher::dispatch($router);
?>

Copy after login

This document only has 4 sentences, let’s analyze them sentence by sentence now.

include("core/ini.php"); Let’s look at core/ini.php.

<?php
set_include_path(get_include_path() . PATH_SEPARATOR . "core/main");
//set_include_path — Sets the include_path configuration option
function __autoload($object){
  require_once("{$object}.php");
}
?>

Copy after login

This file first sets include_path, that is, if we want to find included files, we tell the system to search in this directory. In fact, we define the __autoload() method. This method was added in PHP5. When we instantiate a function, if the file does not exist, the file will be automatically loaded. The official explanation is:

In PHP 5, this is no longer necessary. You may define an __autoload function which is automatically called in case you are trying to use a class/interface which hasn't been defined yet. By calling this function the scripting engine is given a last chance to load the class before PHP fails with an error.

Next let’s look at the following sentence: initializer::initialize();

This means calling initialize, a static function of the initializer class. Because we set include_path and defined __autoload in ini.php, the program will automatically search for initializer.php in the core/main directory.

The initializer.php file is as follows:

<?php
class initializer
{
	public static function initialize()	{
		set_include_path(get_include_path().PATH_SEPARATOR . "core/main");
		set_include_path(get_include_path().PATH_SEPARATOR . "core/main/cache");
		set_include_path(get_include_path().PATH_SEPARATOR . "core/helpers");
		set_include_path(get_include_path().PATH_SEPARATOR . "core/libraries");
		set_include_path(get_include_path().PATH_SEPARATOR . "app/controllers");
		set_include_path(get_include_path().PATH_SEPARATOR."app/models");
		set_include_path(get_include_path().PATH_SEPARATOR."app/views");
		//include_once("core/config/config.php");
	}
}
?>

Copy after login

This function is very simple. It only defines a static function, the initialize function. This function is to set include_path. In this way, if files or __autoload are included in the future, they will be searched in these directories.

OK, let’s continue and look at the third sentence $router = loader::load("router");

This sentence is also very simple, it is the static function load that loads the loader function. Next, let’s loader.php

<?php
class loader
{
  private static $loaded = array();
  public static function load($object){
    $valid = array(  "library",
	                    "view",
                            "model",
                            "helper",
                            "router",
                            "config",
                            "hook",
                            "cache",
                            "db");
    if (!in_array($object,$valid)){
 	  throw new Exception("Not a valid object '{$object}' to load");
    }
    if (empty(self::$loaded[$object])){
      self::$loaded[$object]= new $object();
    }
    return self::$loaded[$object];
  }
}
?>

Copy after login

This file is used to load objects, because in the future we may enrich this MVC system with components such as model, helper, config, etc. If the loaded component is not within the valid range, we throw an exception. If so, we instantiate an object. In fact, the singleton design pattern is used here. That is to say, this object can actually only be an instantiated object. If it is not instantiated, create one. If it exists, it will not be instantiated.

Okay, because what we want to load now is the router component, let’s take a look at the router.php file. The function of this file is to map URLs and parse URLs.

router.php

<?php
class router
{
  private $route;
  private $controller;
  private $action;
  private $params;
  public function __construct()
  {
    $path = array_keys($_GET);
    if (!isset($path[0])){
      if (!empty($default_controller))
           $path[0] = $default_controller;
      else
           $path[0] = "index";
    }
    $route= $path[0];
    $this->route = $route;
    $routeParts = split( "/",$route);
    $this->controller=$routeParts[0];
    $this->action=isset($routeParts[1])? $routeParts[1]:"base";
    array_shift($routeParts);
    array_shift($routeParts);
    $this->params=$routeParts;
  }
  public function getAction() {
    if (empty($this->action)) $this->action="main";
    return $this->action;
  }
  public function getController()  {
    return $this->controller;
  }
  public function getParams()  {
    return $this->params;
  }
}
?>

Copy after login

We can see that first we get $_GET, the URL of the user Request, and then we parse the Controller, Action, and Params from the URL. For example, our address is http://www.tinoweb.cn/user/profile/id/3, then from the above address, we can get that the controller is user, the action seems to be profile, the parameters are id and 3, OK let’s see The last sentence is: dispatcher::dispatch($router);

The meaning of this sentence is very clear, which is to get the result of URL parsing, and then use the dispatcher to distribute the controller and action to respond to the user.

Okay, let’s take a look at the dispatcher.php file:

<?
class dispatcher
{
  public static function dispatch($router)
  {
    global $app;
    ob_start();
    $start = microtime(true);
    $controller = $router->getController();
    $action = $router->getAction();
    $params = $router->getParams();
    $controllerfile = "app/controllers/{$controller}.php";
    if (file_exists($controllerfile)){
      require_once($controllerfile);
      $app = new $controller();
      $app->setParams($params);
      $app->$action();
      if (isset($start)) echo "
Tota1l time for dispatching is : ".(microtime(true)-$start)." seconds.
";
      $output = ob_get_clean();
      echo $output;
     }else{
	throw new Exception("Controller not found");
     }
   }
}
?>

Copy after login

This class is obvious. It gets $router and looks for the controller and action in the file to respond to the user's request.

OK, we have a simple MVC structure, that’s it. Of course, this is not yet a complete MVC, because it does not involve View and Model. I will add more here when I have time. Let's write a Controller file to test the above system. We create a user.php file under app/controllers/.

//user.php
<?php
class user
{
  function base()
  {
  }
  public function login()
  {
    echo 'login html page';
  }
  public function register()
  {
    echo 'register html page';
  }
  public function setParams($params){
	var_dump($params);
  }
}
?>

Copy after login

Then you can enter http://localhost/index.php?user/register or http://localhost/index.php?user/login in the browser to test it.