PHP & the MVC Pattern

PHPBelgium event 2009-06-24

PHP & the MVC Pattern

http://joind.in/609 Patrick Allaert

PHPBelgium – Belgian PHP community
http://www.phpbelgium.be/

About Me
Started developping using PHP 3
Ten years of FOSS evangelism
Contribute to different FOSS:
Tabellio (Open Source Collaboration for assemblies)
Xoo°f (eXtensible Open Object Oriented Framework)
KDESvn (Subversion frontend for KDE)
PHP (ext/ldap)
APM lead developer (Alternative PHP Monitor)
Working @ AUSY
PHPBelgium staff member
Blog: http://patrickallaert.blogspot.com/
Twitter: http://twitter.com/patrick_allaert

Model-View-Controller (1)
“… is an architectural pattern used in software
engineering. Successful use of the pattern
isolates business logic from user interface
considerations, resulting in an application
where it is easier to modify either the visual
appearance of the application or the underlying
business rules without affecting the other.”
Wikipedia


Model-View-Controller (2)

Model
DB

Requests Controller

(X)HTML
View XML


Design of some PHP applications


Managing this is sometimes...

very difficult...

Demo application

/index.php /team.php?id=<TeamID>


Spaghetti code
<?php <table id="ranking">
$db = new mysqli("localhost", "foot", "footpw", "foot");   <tr>

$result = $db->query(
    <th>Name</th>Presentation
    <th>Points</th>
"SELECT name, won, lost, draw, coach,   </tr>
Business Logic
won * 3 + draw AS points <?php
FROM team
WHERE id = " . (int) $_GET['id']); Business Logic
$result = $db->query("SELECT * FROM ranking");
while ($row = $result->fetch_assoc()) {
$team = $result->fetch_assoc(); ?>
?>   <tr>
<html>     <td class="name">
<head>       <a href="team.php?id=<?= $row['id'] ?>">
  <title>Team - <?= $team['name'] ?></title>         <?= $row['name'] ?>
</head>       </a>
<body id="team">     </td>
<h1>Team: <?= $team['name'] ?></h1>     <td class="points">
<table id="info"> <?= $row['points'] ?>
Presentation
  <tr><th>Won:</th>   <td><?= $team['won'] ?></td></tr> </td> Presentation
  <tr><th>Lost:</th>  <td><?= $team['lost'] ?></td></tr>   </tr>
  <tr><th>Draw:</th>  <td><?= $team['draw'] ?></td></tr> <?php
  <tr><th>Points:</th><td><?= $team['points'] ? }
></td></tr> ?>
  <tr><th>Coach:</th> <td><?= $team['coach'] ?></td></tr> </table>
</table> <a href="/">Ranking</a>
</body>
</html>


Taking the Business Logic apart (1)


class Team {
  public static function getInformationById($id) {
    return Database::getInstance()
->query(
      "SELECT name, won, lost, draw, coach, won*3+draw AS points " .
      "FROM team WHERE id = " . (int) $id)
->fetch_assoc();
  }
}

class Ranking {
  public static function generate() {
    return Database::getInstance()
->query("SELECT * FROM ranking")
->fetch_all();
  }
}

class Database {
  public static function getInstance() {
    static $connection = null;

    if ($connection === null) {
      $connection = new mysqli("localhost", "foot", "footpw", "foot");
    }

    return $connection;
  }
}


$position = 1;
foreach (Ranking::generate() as $team) {
?>
    <tr>
        <td class="position"><?= $position++ ?></td>
        <td class="name"><a href="team.php?id=<?= $team['id'] ?>"><?= $team['name'] ?></a></td>
        <td class="played"><?= $team['played'] ?></td>
        <td class="won"><?= $team['won'] ?></td>
        <td class="lost"><?= $team['lost'] ?></td>
        <td class="draw"><?= $team['draw'] ?></td>
        <td class="points"><?= $team['points'] ?></td>
    </tr>
<?php
}

<?php
require 'Team.php';
require 'Ranking.php';
$team = Team::getInformationById($_GET['id']);
?>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

foreach (Ranking::generate() as $row) {
?>
    <tr<?php if ($row['id'] === $_GET['id']) { ?> class="selected"<?php } ?>>
        <td class="name"><a href="team.php?id=<?= $row['id'] ?>"><?= $row['name'] ?></a></td>
        <td class="points"><?= $row['points'] ?></td>
    </tr>
<?php
}


Evaluating the situation
Model is reusable Views tightly linked to
Changes to the the model
business logic does Views impacted if the
not require inspecting API of the model
all files change
Calls to the model may
be difficult to find:
spread everywhere in
views


On the path to MVC (1)
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
  <title>Team - <?= $GLOBALS['team']['name'] ?></title>
</head>
<body id="team">
<h1>Team: <?= $GLOBALS['team']['name'] ?></h1>
<table id="info">
  <tr><th>Won:</th>   <td><?= $GLOBALS['team']['won'] ?></td></tr>
  <tr><th>Lost:</th>  <td><?= $GLOBALS['team']['lost'] ?></td></tr>
  <tr><th>Draw:</th>  <td><?= $GLOBALS['team']['draw'] ?></td></tr>
  <tr><th>Points:</th><td><?= $GLOBALS['team']['points'] ?></td></tr>
  <tr><th>Coach:</th> <td><?= $GLOBALS['team']['coach'] ?></td></tr>
</table>
<table id="ranking">
  <tr>
<?php
    <th>Name</th><th>Points</th>
require 'Ranking.php';
  </tr>
<?php
// View variables
foreach ($GLOBALS['ranking'] as $row) {
$ranking = Ranking::generate();
?>
  <tr>
require 'home.tpl';
    <td class="name">
<a href="team.php?id=<?= $row['id'] ?>"><?= $row['name'] ?></a>
<?php </td>
require 'Team.php';     <td class="points"><?= $row['points'] ?></td>
require 'Ranking.php';   </tr>
<?php
// View variables }
$teamId = $_GET['id']; ?>
$team = Team::getInformationById($teamId); </table>
$ranking = Ranking::generate(); </body>
</html>
require 'team.tpl';


On the path to MVC (2)
View parameters are passed using global
variables
Hint: $variableName may also be written:
$GLOBALS['variableName']
The latest form may be used to differentiate
variables defined by the controller file from the
local view variables
“htdocs” could be renamed “controllers”


Howto: Clean URL
Clean URL: Transforming
http://example.com/index.php?type=article&id=25&date=20020322
into:
http://example.com/article/200203226
Enables better search engine indexing
URIs are not supposed to change (Cool URIs don't change)
Doesn't expose the server-side language
Most MVC Frameworks provide clean URL mechanism, how to setup one with
our structure?


Clean URL: method #1
Using Apache's mod_rewrite:
RewriteEngine On
RewriteRule ^/team/([0-9]*)$ /team.php?id=$1 [L]

Ability to transform URLs on the fly and mapping
part of the URL directly to a $_GET variable


Clean URL: method #2
Dropping the “.php” extension and forcing the
mime-type/handler used in the Apache
configuration

<FilesMatch "^(index|team)$">
ForceType application/x-httpd-php
</FilesMatch>
or:
<FilesMatch "^(index|team)$">
SetHandler application/x-httpd-php
</FilesMatch>


Performance impact (index page)

Concurrency 1 15
“spaghetti” 1776.65 3545.77
Model-View 1615.43 3137.52
MVC 1602.57 3091.74
Clean URL #1 1554.86 3032.25
Clean URL #2 1686.85 3294.60
Zend Framework 246.36 421.15
In requests/second, higher = better


Performance impact (team page)

Concurrency 1 15
“spaghetti” 1778.89 3507.61
Model-View 1580.92 3065.41
MVC 1546.32 3032.64
Clean URL #1 1519.59 2986.12
Clean URL #2 1465.43 2896.54
Zend Framework 233.94 402.54
In requests/second, higher = better


Questions ?


Thanks :-)

These slides will be available through:
http://patrickallaert.blogspot.com/

You can vote for this talk on:
http://joind.in/609


License
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PHP & the MVC Pattern

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