Symfony2 - From the Trenches

by Lukas Kahwe Smith,Kris Wallsmith,

Thibault Duplessis,Jeremy Mikola,Jordi Boggiano,

Jonathan H. Wage,Bulat Shakirzyanov

Agenda

Getting SetupCode FlowDependency InjectionConfiguration ChoicesController ChoicesApplication ChoicesDoctrine

CachingPerformance TipsAsset ManagementTestingDeploymentThird Party BundlesResources

Getting setupPHP 5.3+ with ext/intl (compat lib is in the works)

Read check.php for details (dev/prod php.ini's from Liip)Using OSX?

php53-intl from liangzhenjing or build-entropy-php from chreguBlog post on installing PHP 5.3 with intl from Justin Hileman

Initial setupsymfony-sandboxsymfony-bootstrapSymfony2Project

Read the Coding Style Guide (Code Sniffer Rules)

Managing external dependencies

Submodule: not everything is in git (svn, mercurial, etc.)Vendor install/update scripts: risk of getting out of syncMR (not cross platform)

Code Flow1. Frontend Controller (web/app[_dev].php)

Loads autoloaderCreates/boots kernelCreates request (from globals) and passes to kernel

2. KernelLoads app config (app/config/config_[prod|dev|test])Resolves URL path to a controller (go to 3)Outputs response returned by the controller

3. ControllerLoads model and viewPotentially creates a sub-request (go to 2)Creates response and returns it

Execution Flow

Describe Your Services

<?xml version="1.0" encoding="utf-8" ?><container xmlns="http://www.symfony-project.org/schema/dic/services" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

<parameters> <parameter key="sitemap.class">Bundle\Avalanche\SitemapBundle\Sitemap</parameter> </parameters>

<services> <service id="sitemap" class="%sitemap.class%" /> </services>

</container>

Service Definitions Are Dumped to Raw PHP

<?phpclass cachedDevDebugProjectContainer extends Container{ /** * Gets the 'sitemap' service. * * @return Bundle\Avalanche\SitemapBundle\Sitemap */ protected function getSitemapService() { return $this->services['sitemap'] = new \Bundle\Avalanche\SitemapBundle\Sitemap(); }

/** * Gets the default parameters. * * @return array An array of the default parameters */ protected function getDefaultParameters() { return array( 'sitemap.class' => 'Bundle\Avalanche\SitemapBundle\Sitemap' ); }}

Service Container (aka DIC)

Benefits:No performance lossLazy instantiationReadable service configurations

Gotchas:Can become hard to work with if the DI extension tries to do too muchBe aware of circular dependenciesMight lead to code that cannot be used outside of DIC

Container Injection

<?phpclass SomeClass{ private $container; public function __construct(ContainerInterface $container) { $this->container = $container; } // or public function setContainer(ContainerInterface $container) { $this->container = $container; }

public function getDocumentManager() { return $this->container->get('document_manager'); }}

<service id="some_service" class="SomeClass"> <argument type="service" id="service_container" /></service><!-- or --><service id="some_service" class="SomeClass"> <call method="setContainer"> <argument type="service" id="service_container" /> </call></service>

Constructor Injection

<?phpclass SomeClass{ private $documentManager;

public function __construct(DocumentManager $documentManager) { $this->documentManager = $documentManager; }

public function getDocumentManager() { return $this->documentManager; }}

<service id="some_service" class="SomeClass"> <argument type="service" id="document_manager" /></service>

Setter Injection

<?phpclass SomeClass{ private $documentManager;

public function setDocumentManager(DocumentManager $documentManager) { $this->documentManager = $documentManager; }

public function getDocumentManager() { return $this->documentManager; }}

<service id="some_service" class="SomeClass"> <call method="setDocumentManager"> <argument type="service" id="document_manager" /> </call></service>

Interface Injection

<?phpinterface SomeInterface{ function setDocumentManager(DocumentManager $documentManager);}

class SomeClass implements SomeInterface{ private $documentManager;

public function setDocumentManager(DocumentManager $documentManager) { $this->documentManager = $documentManager; }

public function getDocumentManager() { return $this->documentManager; }}

<interface id="some_service" class="SomeInterface"> <call method="setDocumentManager"> <argument type="service" id="document_manager" /> </call></interface>

<service id="some_service" class="SomeClass" />

Configuration Choices

Symfony supports XML, YAML and PHP for configurationYAML and PHP uses underscore to separate wordsXML uses dashes to separate wordsXML attributes usually map to array values in YAML/PHPYAML merge key syntax to reuse pieces within a fileXSD-aware editors provide auto-completion/validation

XML is recommended for Bundle/DI configurationYAML is recommended for application configurationBundle extensions can optionally utilize the Config component to normalize/parse configurations in any format

See FrameworkExtension, SecurityExtension, TwigExtension

Controller Choices

Defining Controllers as services is optionalNon-service controllers must use container injectionCreate a Bundle extension to load Bundle services

It's recommended to not extend from the base ControllerThe base controller is mainly a tool for beginnersIt provides convenience methods that invoke services, such as generateUrl(), redirect(), render()

Application Choices

Security system makes it possible to have just one application for both frontend and admin backendLocation of AppKernel is totally flexible, just update the frontend controllers accordinglyLarge projects should use multiple applications

Better separation when multiple teams workFacilitate step-by-step updating and refactoringFor example: main, mobile, API, admin

Doctrine Examples

Retrieve references to entity/document without DB queriesUsing raw SQL queries with Doctrine2 ORMSimple search engine with Doctrine MongoDB ODM

Retrieving References w/o DB Queries

$tags = array('baseball', 'basketball');foreach ($tags as $tag) { $product->addTag($em->getReference('Tag', $tag));}

Raw SQL Queries

$rsm = new ResultSetMapping;$rsm->addEntityResult('User', 'u');$rsm->addFieldResult('u', 'id', 'id');$rsm->addFieldResult('u', 'name', 'name');

$query = $this->_em->createNativeQuery('SELECT id, name FROM users WHERE name = ?', $rsm);$query->setParameter(1, 'romanb');

$users = $query->getResult();http://www.doctrine-project.org/docs/orm/2.0/en/reference/native-sql.html

Simple Search Engine

interface HasKeywords{ function setKeywords(); function getKeywords();}

Simple Search Engine/** @mongodb:EmbeddedDocument */class Keyword{ // ...

/** @mongodb:String @mongodb:Index */ private $keyword;

/** @mongodb:Integer */ private $score;

// ...}

Simple Search Engine/** @mongodb:Document */class Product implements HasKeywords{ /** @mongodb:Id */ private $id;

/** @mongodb:String */ private $title;

/** @mongodb:EmbedMany(targetDocument="Keyword") */ private $keywords = array();

// ...}

Simple Search Engineclass KeywordListener{ public function preUpdate(PreUpdateEventArgs $eventArgs) { $entity = $eventArgs->getEntity(); if ($entity instanceof HasKeywords) { $entity->setKeywords($this->buildKeywords($entity)); } }

private function buildKeywords(HasKeywords $entity) { $keywords = array(); // build keywords from title, description, etc. return $keywords; }}

Simple Search Engine

// find products by keyword$products = $dm->createQueryBuilder() ->field('keywords.keyword')->all($keywords) ->getQuery() ->execute();

Doctrine in the Real World

Go see Jon Wage's talk at later today!

Database Migrations

Deploy DB schema changes before the codePrevent DB schema BC breaksUse DoctrineMigrationBundle

app/console doctrine:migrations:diffapp/console doctrine:migrations:migrateDo not use entities in migration scripts ever!

Write fixtures as migrations or make the fixtures able to update existing data gracefully

app/console doctrine:data:load --fixtures=app/fixtures

Different Content Areas of a Page

Caching with Edge Side Includes

Symfony2 provides support for Edge Side Includes (ESI)Proxy assembles page from snippets of HTMLSnippets can have different cache rulesDevelop without ESI, test with Symfony2 internal ESI proxy, deploy using ultra-fast Varnish Proxy

Break up page into different controller actions based on cache invalidation rules

Do not worry about overhead from multiple render callsNever mix content that has different cache timeoutsConsider caching user specific content in the client

Varnish Reverse ProxySuper fast, PHP cannot match its performanceCache full pages for anonymous usersNot just for HTML, also useful for JSON/XML API's

Page Rendered Behind a Reverse Proxy

Asset Management

Go see Kris Wallsmith's talk next!

Performance Tips

Dump routes to Apache rewrite rulesapp/console router:dump-apache

Write custom cache warmersDo not explicitly inject optional services to controllers

If your controller receives many services, which are optional or unused by some actions, that's probably a hint that you should break it up into multiple controllers

Do minimal work in the controller, let templates pull additional data as neededUse a bytecode cache with MapFileClassLoader

Testing

Symfony2 rocks for unit and functional testingDependency Injection, core classes have interfaces (easy mocking)No base classes, no static dependencies, no ActiveRecordClient fakes "real" requests for functional testing (BrowserKit component)

Functional TestingPros: tests configuration, tests API not implementation

Unit TestingPros: pinpoints issues, very directed testinghttp://www.slideshare.net/avalanche123/clean-code-5609451

Recommendation:Functional testing is recommended for controller actions

Symfony2 provides WebTestCase and BrowserKitUnit testing for complex algorithms, third party API's too hard to mock

Use Liip\FunctionalTesting to load fixtures, validate HTML5

Deployment

Debian style (aka Liip Debian Packager)Write a manifest in YAMLBuild Debian packages with MAKEInstall with apt-get installServer specific settings are asked during install, change later with dpkg-reconfigureMaintain a global overview of all application dependencies in case of (security) updatesWatch Lukas' unconference talk later today!

Fabric (used at OpenSky)Repository managed with git-flowClone tagged release branch, init submodulesFix permissions (e.g. cache, log), delete dev/test controllersReplace password/API-key placeholders with prod values in config filesUpload in parallel to production nodes, swap "current" symlink

Third Party Bundles

Here's a new year's resolution: to *always* work on an existing Symfony2 bundle and never recreate my own. #focus #teamwork

@weaverryanRyan Weaver

27 Dec http://twitter.com/weaverryan/status/19565706752299009

Third Party BundlesMany vendors have already published bundles:

FriendsOfSymfony (http://github.com/friendsofsymfony)UserBundle (forked from knplabs' DoctrineUserBundle)FacebookBundle (forked from kriswallsmith)

Liip (http://github.com/liip)FunctionalTestBundleViewBundle

OpenSky (http://github.com/opensky)LdapBundle

Sonata (http://github.com/sonata-project)AdminBundle

Additionally, a couple sites currently index community bundles:

http://symfony2bundles.org/ http://symfohub.com/

Third Party Bundles

Bundles should follow the best practicesNo version-tagging or official package manager (yet)Use bundles by adding git submodules to your projectMaintain your own fork and "own" what you useNot all bundles are equally maintained

Symfony2 API changes => broken bundlesIf you track symfony/symfony, learn to migrate bundles

Avoid rewriting a bundle's services/parameters directlyThe bundle's DI extension should allow for such configuration; if not, submit a pull requestIf absolutely necessary, a CompilerPass is cleaner

Contributing to Third Party Bundles

Similar to Symfony2's own patch guidlinesFork and add remote repositoryMerge regularly to keep up-to-date

Avoid committing directly to your masterMerges from upstream should be fast-forwards

Once upstream changes are stable, bump your project's submodule pointer

Contributing to Third Party Bundles

Create branches for patches and new featuresCan't wait to use this in your project? Temporarily change your project submodule to point to your branch until your pull request is accepted.

Help ensure that your pull request merges cleanlyCreate feature branch based on upstream's master Rebase or merge upstream's master when finished

Contributing to Third Party Bundles

Was your pull request accepted? Congratulations! Don't merge your feature branch into master!

Doing so would cause your master to divert Merge upstream's master into your masterDelete your feature branchUpdate your project's submodule to point to master

Resources

If you want to jump in and contribute:http://docs.symfony-reloaded.org/master/contributing/community/other.htmlIf you are still fuzzy on Dependency Injection:http://fabien.potencier.org/article/11/what-is-dependency-injectionIf you keep up with Symfony2 repository on github:http://docs.symfony-reloaded.org/master/

Application Using Dependency Injection

Circular Dependency Example

Dependency Injection

All objects are instantiated in one of two ways:Using the "new" operatorUsing an object factory

All objects get collaborators in one of two waysPassed to object constructorSet using a setter