Post on 15-May-2015
description
Copyright © Pham Cong Dinh. All rights un-reserved.
How to learn to build your own PHP framework
Bridging the gap between PHP, OOP and Software Architecture
Pham Cong Dinh (a.k.a pcdinh)Software Developer
Hanoi PHP Day - December 2008Hanoi - Vietnam
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IntroductionHow to develop your own frameworkHow to develop your own framework
Introduction
A foundation member of JavaVietnam since 2003 (http://www.javavietnam.org)
A foundation member of PHPVietnam Discussion Group since 2004 (http://groups.google.com/group/phpvietnam)
Lead web developer with World’Vest Base Inc. Java is my first love since 1999 PHP is my real lover since 2003. I love the way PHP
community works Sometimes I works on Python, Ruby, Erlang I am a strong believer in dynamic programming languages,
JavaScript, web standards, convergence of web as a platform and Outsourcing 2.0
I spent 2 years to play with my framework named Pone (PHP One)
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IntroductionHow to develop your own frameworkHow to develop your own framework
Objectives Where is PHP now? It is changing.
Enterprise oriented: which is driven by Yahoo, Facebook, Zend, Sun/MySQL, Oracle, OmniTI … PHP is too big. It can not just be ignored
Object Oriented Programming adoption Increased complexity of web applications Web vs. Adobe Air, MS Silverlight, JavaFX, Google Native Client Trends Will Move Applications to the Web: Consumer Innovation
Setting the Pace, Rise of the Power Collaborator, New Economics of Scale for IT, Barriers to Adoption Are Falling
Scale-out wins
Understanding what framework designers think Building up shared mindsets Providing food for thought
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IntroductionHow to develop your own frameworkHow to develop your own framework
Agenda – 40 slides
Making judgments Top notch frameworks and their shortcomings A broader view on your framework Lessons to learn
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How to develop your own frameworkHow to develop your own framework
Making judgments
• Common wisdom: Reinventing the wheel• Good
– You know it inside and out– You control its pace– It fits your needs. Sometimes, your need is unique– It teaches you how the world around you works– License: This is why GPL is sometime a bad thing
• Bad– You may not as good as other ones– No community– No outside contributors– Reinventing the square wheel
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How to develop your own frameworkHow to develop your own framework
Making judgments
• To develop a framework is just like to set up a business• Think of your limitation: time, resources, knowledge to
build/test/document/maintain your own mental baby• Know your team: how to train them• Know the market: known frameworks in the market.
Sometimes your needs are satisfied to some extent in several little-known frameworks
• Starts with pencil and paper: its components and how they interact
• Starts with API: learn how to design an API first• You never do it right from day one
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How to develop your own frameworkHow to develop your own framework
Know the market
• CakePHP shortcomings• Zend Framework shortcomings• Third party frameworks shortcomings
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How to develop your own frameworkHow to develop your own framework
Know the market - CakePHP
• Misleading terms: plugin, model… – Plugin: CakePHP allows you to set up a combination of
controllers, models, and views and release them as a packaged application
• Too database centric: CakePHP naming convention is driven by table names, not dependency injection mechanism.
• Admin routing sucks: why do we need one-and-only backend for the whole application/plugin/etc…?
• Flat application structure: plugin/controller/action and no more.
• Global space constants
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How to develop your own frameworkHow to develop your own framework
Know the market - CakePHP
• No elegant way to change media file (css, javascript, meta content) on each layout page, controlled by a Controller.
<head> <?php echo $html->charset(); ?> <title> <?php echo $title_for_layout; ?> </title> <?php echo $html->css('cake.generic'); echo $javascript->link('prototype-1.6.0.2'); echo $scripts_for_layout; echo $html->meta('icon','/myapp/img/favicon.ico', array ('type' =>'icon')); ?>
</head>
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How to develop your own frameworkHow to develop your own framework
Know the market - CakePHP
• loadModel(), loadController() are not about dependency injection
• E.x: You want to provide access to a model from a ComponentSay you have a model called FooBar in a file called foo_bar.php
loadModel('FooBar');
$this->FooBar = &new FooBar(); • loadModel() maybe deprecated in favor of
App::import('Model', 'ModelName');
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How to develop your own frameworkHow to develop your own framework
Know the market - CakePHP
• beforeFilter(), afterFilter() are coupled with a certain controller (controller is a heavy object. It should avoid being hit too soon)
<?php class AppController extends Controller { var $beforeFilter = array('checkAccess');
var $components = array('Acl');
function checkAccess(){ } }
?>
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How to develop your own frameworkHow to develop your own framework
Know the market - CakePHP
• Reuse of view via elements with requestAction() is bad and expensive– The dispatcher is called for each call to a controller
(routing, figures out what (Plugin)/Controller/Action is request, loops through all $paths->controllerPaths files, to figure out what Controller to load)
– The controller is set up again• Behavior: controllerActAsModel• Controller is an interface to another tier• Controller is not designed to provide data for internal
components• Cache unfriendly
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How to develop your own frameworkHow to develop your own framework
Know the market - CakePHP
• Caching hits its hard time because there is no way to get generated view content
<?php
$this->element('helpbox', array("cache" => array('time'=> "+7 days",'key'=>'unique value')));
?>
• What about URL-based caching, session/cookie-based caching, geo-based caching, date-based caching(there are a lot of things to tell about CakePHP but it is all for today)
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How to develop your own frameworkHow to develop your own framework
Know the market – Zend Framework
• Zend Framework tries to be a better PEAR– Powered by a solid foundation– A solid and controllable licensing (CLA)– More strictly controlled development environment– Enterprise-oriented class library– A well-defined roadmap and versioning
• Zend Framework is a glue framework or framework-oriented class library
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How to develop your own frameworkHow to develop your own framework
Know the market – Zend Framework
• Zend Framework is extremely big and bloated– Zend Framework 1.6.2: 1261 file, 267 folders– Zend_Mail: 33 files– Zend_Pdf: 89 files– Zend_Controller: 50 files– Zend_View: 57 files– Drupal includes folders: 33 files
• Zend Framework is designed most like Java frameworks– Small class file– Lot of classes: object graph is hard (see next)– Atomic responsibility– Strongly embrace design patterns
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How to develop your own frameworkHow to develop your own framework
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How to develop your own frameworkHow to develop your own framework
Know the market – Zend Framework
• Everything is an object, even a HTML button or checkbox. The same to Java (see Apache Wicket, Tapestry, JBoss Seam)class Zend_View_Helper_FormReset extends Zend_View_Helper_FormElement{ public function formReset($name = '', $value = 'Reset', $attribs = null) { $info = $this->_getInfo($name, $value, $attribs); extract($info); // name, value, attribs, options, listsep, disable
// check if disabled $disabled = ''; if ($disable) { $disabled = ' disabled="disabled"'; }
// get closing tag $endTag = '>'; if ($this->view->doctype()->isXhtml()) { $endTag = ' />'; }
// Render button $xhtml = '<input type="reset"' . ' name="' . $this->view->escape($name) . '"' . ' id="' . $this->view->escape($id) . '"' . $disabled; . . . . . . . . . }}
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How to develop your own frameworkHow to develop your own framework
Know the market – Zend Framework
• What Zend Framework brings– Lot of files are loaded per request which is a bad thing for a
dynamic, interpreted language and stateless platform like PHP– Much more memory usage– Bad thing for PHP memory management model in which
memory is allocated in small chunks– Zend Framework code: There are lot of require_once() call
inside an if statement which is bad for opcode caching mechanism
– Zend Framework leaves shared hosting in the cold. • 700 sites per server are quite normal• No control over file system optimization• No control over memory• No control over opcode caching
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How to develop your own frameworkHow to develop your own framework
Know the market – Zend Framework
• A glue framework requires you to know every concrete class and how to use them in a application life cycle
• A lot of things to consider means bootstrapping is a mess
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How to develop your own frameworkHow to develop your own framework
Know the market – Zend Framework
define('ROOT_DIR', dirname(dirname(dirname(__FILE__))));define('APP_DIR',dirname(dirname(__FILE__))); set_include_path('.' . PATH_SEPARATOR . APP_DIR . '/lib/' . PATH_SEPARATOR . APP_DIR .
'/application/default/models/' . PATH_SEPARATOR . ROOT_DIR . '/shared/lib/' . PATH_SEPARATOR . get_include_path());
//This requires that your Zend library lies in ROOT_DIR/shared/lib/ //make classes autoload without doing requirerequire_once('Zend/Loader.php');Zend_Loader::registerAutoload(); if(defined('ENV') !== TRUE) {
define('ENV','production'); //change staging to production to go to production settings} $config = new Zend_Config_Xml(APP_DIR . '/config/config.xml', ENV);Zend_Registry::set('config',$config); //init session$session = new Zend_Session_Namespace($config->session_name);Zend_Registry::set('session',$session); Zend_Db_Table::setDefaultAdapter(Zend_Db::factory(Zend_Registry::get('config')->database)); /** * Init the Smarty view wrapper and set smarty suffix to the view scripts. */$view = new EZ_View_Smarty($config->smarty->toArray());
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How to develop your own frameworkHow to develop your own framework
Know the market – Zend Framework
// use the viewrenderer to keep the code DRY instantiate and add the helper in one go$viewRenderer = Zend_Controller_Action_HelperBroker::getStaticHelper('ViewRenderer');$viewRenderer->setView($view);$viewRenderer->setViewSuffix($config->smarty->suffix); /** * Set inflector for Zend_Layout */$inflector = new Zend_Filter_Inflector(':script.:suffix');$inflector->addRules(array(':script' => array('Word_CamelCaseToDash', 'StringToLower'), 'suffix' => $config->layout->suffix)); // Initialise Zend_Layout's MVC helpersZend_Layout::startMvc(array('layoutPath' => ROOT_DIR.$config->layout->layoutPath,'view' => $view,'contentKey' => $config->layout->contentKey,'inflector' => $inflector)); $front = Zend_Controller_Front::getInstance(); $front->setControllerDirectory(array( 'default' => '../application/default/controllers', 'blog' => '../application/blog/controllers',)); $front->throwExceptions(true); // enable logging to default.log$writer = new Zend_Log_Writer_Stream(APP_DIR.'/data/log/default.log');$logger = new Zend_Log($writer); // give easy access to the loggerZend_Registry::set('logger', $logger); try { $front->dispatch();} catch(Exception $e) { echo nl2br($e->__toString());}
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How to develop your own frameworkHow to develop your own framework
Know the market – Zend Framework
• Zend Framework is different.– It is not a solid application framework like CakePHP, it is
designed to be a platform on which other frameworks are built
• Technical details should be mentioned in another talk (enough for today)
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How to develop your own frameworkHow to develop your own framework
A broader view on your framework
• MVC Push or Pull– MVC Push or Passive View
<?php
// Load the Savant3 class file and create an instance.require_once 'Savant3.php';$tpl = new Savant3();
// Create a title.$name = "Some Of My Favorite Books";
// Generate an array of book authors and titles.$booklist = array( array( 'author' => 'Hernando de Soto', 'title' => 'The Mystery of Capitalism' ), array( 'author' => 'Neal Stephenson', 'title' => 'Cryptonomicon' ), array( 'author' => 'Milton Friedman', 'title' => 'Free to Choose' ));
// Assign values to the Savant instance.$tpl->title = $name;$tpl->books = $booklist;
// Display a template using the assigned values.$tpl->display('books.tpl.php');?>
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How to develop your own frameworkHow to develop your own framework
A broader view on your framework
• MVC Push or Pull– MVC Pull or so-called HMVC (see next): break a big
controller into small ones
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How to develop your own frameworkHow to develop your own framework
A broader view on your framework
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How to develop your own frameworkHow to develop your own framework
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How to develop your own frameworkHow to develop your own framework
A broader view on your framework
• MVC Push or Pull: HMVC implementation– Master Controller
/** * Show the home page * * @link http://www.wvbresearch.com/home/index/index * @name index * @access public */ public function indexAction() { // Attach placeholder: the name of ElementGroup $this->_layout->registerBody('homeIndex');
// Set content for the response $this->_response->setContent($this->_layout->render('index3col')); }
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How to develop your own frameworkHow to develop your own framework
A broader view on your framework
• MVC Push or Pull: HMVC implementation– Group Controllerclass Group_HomeIndex extends Pone_View_ElementGroup{
/** * Elements in in this group * * @var array */protected $_elementsInGroup = array(
'homeTopNegativeEpsSurprises', 'homeTopPositiveEpsSurprises','homeIntroduction', 'brokerRatingsUpgrades', 'homeAnalystEstimatesSearchBox','homeResearchReportSearchBox', 'latestResearchReports'
);
protected $_templateFile = 'homeIndex';
public function setup() {
}}
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How to develop your own frameworkHow to develop your own framework
A broader view on your framework
• MVC Push or Pull: HMVC implementation– Element Controllerclass Element_LatestResearchReports extends Pone_View_Element{ protected $_templateFile = 'latestResearchReportsOnHome'; /** * List of recent research reports * * @var Pone_DataSet */ public $researchReports;
public function setup() { $module = Pone::getContext()->getFront()->getRequest()->getModuleName(); $numberOfItems = 7; if ('home' !== $module) { $this->_templateFile = 'latestResearchReports'; $numberOfItems = 10; }
$dbConn = Pone_Action_Helper_Database::getInstance()->getConnection('oracleweb', true); $researchReportDs = ResearchReportDatabaseService::getInstance($dbConn); $this->researchReports = $researchReportDs->findRecentList($numberOfItems); }}
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How to develop your own frameworkHow to develop your own framework
A broader view on your framework
• MVC Push or Pull: HMVC implementation– Element Controller template<div class="featureBlockHeader"> <h2>Latest reports</h2> </div> <div class="textBox"> <div class="textBoxContent"> <?php if (true === $this->researchReports->isReadable()): $iter = $this-
>researchReports->getIterator(); ?> <ul class="imgList"> <?php foreach ($iter as $report): ?> <li><a href="research/detail/view/rpid/<?php echo $report-
>get('report_id') ?>"><?php echo $report->get('title'); ?></a></li> <?php endforeach; ?> </ul> <?php else: echo $this->researchReports->getMessage(); endif;?> </div></div>
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How to develop your own frameworkHow to develop your own framework
A broader view on your framework
• IDE support– Code completion rocks– MVC Push is bad for view data documentation– Zend_Registry is bad for code completion
Zend_Registry::set('logger', $logger);– Think of interface because implementing a way to load
dynamic class from a variable or an array element.– Learn how to write DocBlock
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How to develop your own frameworkHow to develop your own framework
A broader view on your framework
• Core feature set– MVC framework
• Model layer: DBO, File handling/transformation, business rules, workflows, search, messaging, memory, remote resource access …
– Validation framework instead of form handling– Unified directory structure: model classes, controllers, views
(page fragments, layouts), plugins, filters, custom exceptions, helpers
– Session– Authentication and ACL: Abstract and extensible
• HTTP Digest• Database backed• SAML/SSO• Serializable Unified Session User Object
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How to develop your own frameworkHow to develop your own framework
A broader view on your framework
• Core feature set– Validation frameworkclass Form_Signup extends Pone_Form_Input{
. . . . . .public function onPost(){
// Email$emailRules = array(Pone_Form_Rule::EMAIL => array('feedback' => _t('common.error.email.notvalid')));$this->setValidationRule('email', $emailRules);
// Email 2$email2Rules = array(Pone_Form_Rule::STRING_EQUAL => array('feedback' => _t('common.error.reemail.not_match'),'reference' => 'email'));$this->setValidationRule('email2', $email2Rules);
// password$passwordRules = array(Pone_Form_Rule::NOT_EMPTY => array('feedback' => _t('common.error.password.empty')));$this->setValidationRule('password', $passwordRules);
// password 2$password2Rules = array(Pone_Form_Rule::STRING_EQUAL => array('feedback' => _t('common.error.repassword.not_match'),'reference' => 'password'));$this->setValidationRule('password2', $password2Rules);
}}
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How to develop your own frameworkHow to develop your own framework
A broader view on your framework
• Much more things that need to take into account– Behavior layer– Caching
• Distributed caching• Local caching
– Dependency Injection framework– Internationalization
(enough for today)
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How to develop your own frameworkHow to develop your own framework
Lessons to learn
• Take your hand dirty please.• Singleton is bad thing when dependency injection
and unit testing are taken into consideration– can't replace it with an interface – Factory allows for both discovery and instance
management of the service providers – Final classes should keep singleton objects
$dbConn = Pone_Action_Helper_Database::getInstance()->getConnection('oracleweb', true);
$researchReportDs = ResearchReportDatabaseService::getInstance($dbConn);
$this->researchReports = $researchReportDs->findRecentList($numberOfItems);
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How to develop your own frameworkHow to develop your own framework
Lessons to learn
• Factory and interface make good things– Factory and Adapter are good for service providers
$conn = Pone_Database_ConnectionFactory::getConnection($config);
$stmt = $conn->createStatement();
$stmt->addBatch("INSERT INTO test2 VALUES (1007, 'pcdinh1007', 1)");
$stmt->addBatch("INSERT INTO test2 VALUES (1009, 'pcdinh1009', 1)");
$stmt->addBatch("INSERT INTO test2 VALUES (1010, 'pcdinh1010', 1)");
$conn->beginTransaction();
$updateCounts = $stmt->executeBatch();
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How to develop your own frameworkHow to develop your own framework
Lessons to learn
• Fluent interface/object chaining sometimes is a bad thing– Law of Demeter
$module = Pone::getContext()->getFront()->getRequest()->getModuleName();
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How to develop your own frameworkHow to develop your own framework
Lessons to learn
• Don’t think DAO or ActiveRecord, think Domain Respository
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How to develop your own frameworkHow to develop your own framework
Lessons to learn
• An interface between Model and Controller must be defined– Model class returns an array: bad thing. How to catch
errors and deal with them in the view template
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How to develop your own frameworkHow to develop your own framework
Lessons to learn
• Dependency Injection– Does all injection through the constructor$libBasePath = $basePath.'/libs';$appBasePath = $basePath.'/apps';Pone::executeContext(new BenchmarkContext(), $basePath, $appBasePath, $libBasePath);
OR
$front->setRequest(new Pone_Request(new Pone_Request_SimpleUrlParser()));
– Use Template Method design pattern• Seam
if (session_id() === '' && PHP_SAPI != 'cli'){ Pone::getContext()->loadSessionUserClass(); $started = session_start(); // PHP 5.3: returns false or true $this->_started = true;}
– Use XML/YAML like in Spring, Symfony which is somewhat heavy in an interpreted language like PHP
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How to develop your own frameworkHow to develop your own framework
Design by Interface
• Rule: Don’t call me, I will call you• Template Method• Convention over configuration
That’s end for today
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How to develop your own frameworkHow to develop your own framework
Thanks you
• Any question?