1. How to learn to buildyour 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 2008 Hanoi - Vietnam

2. 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 WorldVest 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)

3. 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

4. Agenda 40 slides

Making judgments

Top notch frameworks and their shortcomings

A broader view on your framework

Lessons to learn

5. 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

6. 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

7. Know the market

CakePHP shortcomings

Zend Framework shortcomings

Third party frameworks shortcomings

8. 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

9. Know the market - CakePHP

No elegant way to change media file (css, javascript, meta content) on each layout page, controlled by a Controller.

10. Know the market - CakePHP

loadModel(), loadController() are not about dependency injection

E.x: You want to provide access to a model from a Component Say 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');

11. Know the market - CakePHP

beforeFilter(), afterFilter() are coupled with a certain controller (controller is a heavy object. It should avoid being hit too soon)

12. Know the market - CakePHP

Reuse of view via elements withrequestAction()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

13. Know the market - CakePHP

Caching hits its hard time because there is no way to get generated view content

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)

14. 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

15. 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

16. 17. 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)

• classZend_View_Helper_FormResetextendsZend_View_Helper_FormElement

• {

• public functionformReset($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 = '

• . ' name="' . $this->view->escape($name) . '"'

• . ' id="' . $this->view->escape($id) . '"'

• . $disabled;

• . . . . . . . . .

• }

• }

18. 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

19. 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

20. 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 require

require_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

$session =newZend_Session_Namespace($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.

*/

$view =newEZ_View_Smarty($config->smarty->toArray());

21. 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 =newZend_Filter_Inflector(':script.:suffix');

$inflector->addRules(array(':script' =>array ('Word_CamelCaseToDash', 'StringToLower'), 'suffix'=> $config->layout->suffix));

// Initialise Zend_Layout's MVC helpers

Zend_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 =newZend_Log_Writer_Stream(APP_DIR.'/data/log/default.log');

$logger =newZend_Log($writer);

// give easy access to the logger

Zend_Registry::set('logger', $logger);

try{

$front->dispatch();

}catch (Exception $e) {

echonl2br($e->__toString());

}

22. 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)

23. A broader view on your framework

MVC Push or Pull

• MVC Push or Passive View

24. 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

25. A broader view on your framework 26. 27. A broader view on your framework

MVC Push or Pull:HMVC implementation

• Master Controller

• /**

• * Show the home page

• *

• * @linkhttp://www.wvbresearch.com/home/index/index

• * @nameindex

• * @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'));

• }

28. A broader view on your framework

MVC Push or Pull: HMVC implementation

• Group Controller

• classGroup_HomeIndexextendsPone_View_ElementGroup

• {

• /**

• * Elements in in this group

• *

• * @var array

• */

• protected$_elementsInGroup = array(

• 'homeTopNegativeEpsSurprises', 'homeTopPositiveEpsSurprises',

• 'homeIntroduction', 'brokerRatingsUpgrades', 'homeAnalystEstimatesSearchBox',

• 'homeResearchReportSearchBox', 'latestResearchReports'

• );

• protected$_templateFile = 'homeIndex';

• public functionsetup()

• {

• }

• }

29. A broader view on your framework

MVC Push or Pull: HMVC implementation

• Element Controller

• classElement_LatestResearchReportsextendsPone_View_Element

• {

• protected$_templateFile = 'latestResearchReportsOnHome';

• /**

• * List of recent research reports

• *

• * @var Pone_DataSet

• */

• public$researchReports;

• public functionsetup()

• {

• $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);

• }

• }

30. A broader view on your framework

MVC Push or Pull: HMVC implementation

• Element Controller template

• < div class =" featureBlockHeader ">

• < h2 >Latest reports h2 >

• div >

• < divclass=" textBox ">

• < divclass=" textBoxContent ">

• < ulclass=" imgList ">

• < li >get('report_id') ?>">

• div >

• div >

31. 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

32. 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

33. A broader view on your framework

Core feature set

• Validation framework

• class 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);

• }

• }

34. 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)

35. 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);

36. 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();

37. Lessons to learn

Fluent interface/object chaining sometimes is a bad thing

• Law of Demeter

$module = Pone::getContext()->getFront()->getRequest()->getModuleName();

38. Lessons to learn

Dont think DAO or ActiveRecord, think Domain Respository

39. 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

40. 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

41. Design by Interface

Rule: Dont call me, I will call you

Template Method

Convention over configuration

Thats end for today

42. Thanks you

Any question?