Following this tutorial http://johnsquibb.com/tutorials/mvc-framework-in-1-hour-part-one Im trying to write my first MVC Blog.
I understood how it works, router.php Calls the suitable page controller. This controller calls the model, Then calls the View page with the returned value.
My question is, What if I want to add to the same news.php page a header\footer. Normally I would write “include(“header.php”). But now when using MVC, how could I implement that?
These are my files:
router.php:
<?php
/**
* This controller routes all incoming requests to the appropriate controller
*/
//Automatically includes files containing classes that are called
//fetch the passed request
$pageURL = $_SERVER["SERVER_NAME"].$_SERVER["REQUEST_URI"];
$path_parts = pathinfo($pageURL);
$page_name = $path_parts['filename'];
$parsed = explode('?' , $page_name);
//the page is the first element
$page = array_shift($parsed);
// If there is any variables, GET them.
if(!empty($parsed))
{
$parsed = explode('&' , $parsed[0]);
$getVars = array();
foreach ($parsed as $argument)
{
//explode GET vars along '=' symbol to separate variable, values
list($variable , $value) = explode('=' , $argument);
$getVars[$variable] = urldecode($value);
}
}
//compute the path to the suitable file
$target ='controllers/' . $page . '_controller.php';
//get target controller
if (file_exists($target))
{
include_once($target);
//modify page to fit naming convention
$class = ucfirst($page) . '_Controller';
//instantiate the appropriate class
if (class_exists($class))
{
$controller = new $class;
}
else
{
//did we name our class correctly?
die('class does not exist!');
}
}
else
{
//can't find the file in 'controllers'!
die('page does not exist!');
}
//once we have the controller instantiated, execute the default function
//pass any GET varaibles to the main method
$controller->main($getVars);
// AutoLoad
function __autoload($className)
{
// Parse out filename where class should be located
// This supports names like 'Example_Model' as well as 'Example_Two_Model'
list($suffix, $filename) = preg_split('/_/', strrev($className), 2);
$filename = strrev($filename);
$suffix = strrev($suffix);
//select the folder where class should be located based on suffix
switch (strtolower($suffix))
{
case 'model':
$folder = '/models/';
$filename = ($className);
break;
case 'library':
$folder = '/libraries/';
break;
case 'driver':
$folder = '/libraries/drivers/';
break;
}
//compose file name
$file = SERVER_ROOT . $folder . strtolower($filename) . '.php';
//fetch file
if (file_exists($file))
{
//get file
include_once($file);
}
else
{
//file does not exist!
die("File '$filename' containing class '$className' not found in
'$folder'.");
}
}
?>
post_controller.php
<?php
/**
* This file handles the retrieval and serving of posts posts
*/
class Posts_Controller
{
/**
* This template variable will hold the 'view' portion of our MVC for this
* controller
*/
public $template = 'posts';
/**
* This is the default function that will be called by router.php
*
* @param array $getVars the GET variables posted to index.php
*/
public function main(array $getVars)
{
//$b_controller =new Bottom_Bar_Controller;
//$b_controller->main($getVars);
$postsModel = new Posts_Model;
//get an post
$post = $postsModel->get_post($getVars['id']);
//create a new view and pass it our template
$header = new View_Model('header_template');
$bottom_bar = new View_Model('bottom_bar');
$view = new View_Model($this->template);
//assign post data to view
$view->assign('header', $header->render(FALSE));
$view->assign('bottom', $bottom_bar->render(FALSE));
$view->assign('title' , $post['title']);
$view->assign('content' , $post['content']);
$view->assign('date' , $post['date']);
$view->assign('by' , $post['added_by']);
$view->render();
}
}
posts_model.php
<?php
/**
* The Posts Model does the back-end heavy lifting for the Posts Controller
*/
class Posts_Model
{
/**
* Holds instance of database connection
*/
private $db;
public function __construct()
{
$this->db = new MysqlImproved_Driver;
}
/**
* Fetches article based on supplied name
*
* @param string $author
*
* @return array $article
*/
public function get_post($id)
{
//connect to database
$this->db->connect();
//sanitize data
$author = $this->db->escape($id);
//prepare query
$this->db->prepare
(
"
SELECT * FROM `posts`
WHERE
`id` = '$id'
LIMIT 1
;
"
);
//execute query
$this->db->query();
$article = $this->db->fetch('array');
return $article;
}
}
?>
view_model.php
<?php
/**
* Handles the view functionality of our MVC framework
*/
class View_Model
{
/**
* Holds variables assigned to template
*/
private $data = array();
/**
* Holds render status of view.
*/
private $render = FALSE;
/**
* Accept a template to load
*/
public function __construct($template)
{
//compose file name
$file = SERVER_ROOT . '/views/' . strtolower($template) . '.php';
if (file_exists($file))
{
/**
* trigger render to include file when this model is destroyed
* if we render it now, we wouldn't be able to assign variables
* to the view!
*/
$this->render = $file;
}
}
/**
* Receives assignments from controller and stores in local data array
*
* @param $variable
* @param $value
*/
public function assign($variable , $value)
{
$this->data[$variable] = $value;
}
/**
* Render the output directly to the page, or optionally, return the
* generated output to caller.
*
* @param $direct_output Set to any non-TRUE value to have the
* output returned rather than displayed directly.
*/
public function render($direct_output = TRUE)
{
// Turn output buffering on, capturing all output
if ($direct_output !== TRUE)
{
ob_start();
}
// Parse data variables into local variables
$data = $this->data;
// Get template
include($this->render);
// Get the contents of the buffer and return it
if ($direct_output !== TRUE)
{
return ob_get_clean();
}
}
public function __destruct()
{
}
}
posts.php
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<link href="../style/style.css" rel="stylesheet" type="text/css" media="screen" />
<title> Posts (View)</title>
</head>
<body>
<div id="main">
<div class="container">
<?=$data['header'];?>
<div id="content">
<div class="content-background">
<h2> <?=$data['title'];?></h2>
<h4> <?=$data['date'];?> </h4>
<p><?=$data['content'];?></p>
</div>
</div>
</div>
</div>
</body>
</html>
Part of the problem is, that your tutorial has a pretty primitive interpretation of MVC-inspired design pattern (you actually cannot implement classical MVC in PHP, but there are patterns, that are based on it).
View is not just a template. Views are supposed to be class instances, which contain all presentation logic and deal with multiple templates. What you actually have there is a
layouttemplate which containspoststemplate.Also, one of the things, that a view instance should do, is requesting information from the model layer.
Few materials that you might find useful:
And if you want to expand you knowledge in OOP, this post contains a list of recommended lectures and books.