Symfony2: From the Trenches

Presented March 3, 2011 at Symfony Live: Paris.

http://www.symfony-live.com/

Transcript

1. Symfony2 - From the Trenches by Lukas Kahwe Smith, Kris Wallsmith, Thibault Duplessis, Jeremy Mikola, Jordi Boggiano, Jonathan H. Wage, Bulat Shakirzyanov
2. Agenda Getting Setup Code Flow Dependency Injection Configuration Choices Controller Choices Application Choices Doctrine Caching Performance Tips Asset Management Testing Deployment Third Party Bundles Resources
3. Getting setup PHP 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 chregu Blog post on installing PHP 5.3 with intl from Justin Hileman Initial setup symfony-sandbox symfony-bootstrap Symfony2Project 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 sync MR (not cross platform)
4. Code Flow 1. Frontend Controller (web/app[_dev].php) Loads autoloader Creates/boots kernel Creates request (from globals) and passes to kernel 2. Kernel Loads app config (app/config/config_[prod|dev|test]) Resolves URL path to a controller (go to 3) Outputs response returned by the controller 3. Controller Loads model and view Potentially creates a sub-request (go to 2) Creates response and returns it
5. Execution Flow
6. 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>
7. Service Definitions Are Dumped to Raw PHP <?php class 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' ); } }
8. Service Container (aka DIC) Benefits: No performance loss Lazy instantiation Readable service configurations Gotchas: Can become hard to work with if the DI extension tries to do too much Be aware of circular dependencies Might lead to code that cannot be used outside of DIC
9. Container Injection <?php class 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>
10. Constructor Injection <?php class 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>
11. Setter Injection <?php class 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>
12. Interface Injection <?php interface 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" />
13. Configuration Choices Symfony supports XML, YAML and PHP for configuration YAML and PHP uses underscore to separate words XML uses dashes to separate words XML attributes usually map to array values in YAML/PHP YAML merge key syntax to reuse pieces within a file XSD-aware editors provide auto-completion/validation XML is recommended for Bundle/DI configuration YAML is recommended for application configuration Bundle extensions can optionally utilize the Config component to normalize/parse configurations in any format See FrameworkExtension, SecurityExtension, TwigExtension
14. Controller Choices Defining Controllers as services is optional Non-service controllers must use container injection Create a Bundle extension to load Bundle services It's recommended to not extend from the base Controller The base controller is mainly a tool for beginners It provides convenience methods that invoke services, such as generateUrl(), redirect(), render()
15. Application Choices Security system makes it possible to have just one application for both frontend and admin backend Location of AppKernel is totally flexible, just update the frontend controllers accordingly Large projects should use multiple applications Better separation when multiple teams work Facilitate step-by-step updating and refactoring For example: main, mobile, API, admin
16. Doctrine Examples Retrieve references to entity/document without DB queries Using raw SQL queries with Doctrine2 ORM Simple search engine with Doctrine MongoDB ODM
17. Retrieving References w/o DB Queries $tags = array('baseball', 'basketball'); foreach ($tags as $tag) { $product->addTag($em->getReference('Tag', $tag)); }
18. 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
19. Simple Search Engine interface HasKeywords { function setKeywords(); function getKeywords(); }
20. Simple Search Engine /** @mongodb:EmbeddedDocument */ class Keyword { // ... /** @mongodb:String @mongodb:Index */ private $keyword; /** @mongodb:Integer */ private $score; // ... }
21. Simple Search Engine /** @mongodb:Document */ class Product implements HasKeywords { /** @mongodb:Id */ private $id; /** @mongodb:String */ private $title; /** @mongodb:EmbedMany(targetDocument="Keyword") */ private $keywords = array(); // ... }
22. Simple Search Engine class 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; } }
23. Simple Search Engine // find products by keyword $products = $dm->createQueryBuilder() ->field('keywords.keyword')->all($keywords) ->getQuery() ->execute();
24. Doctrine in the Real World Go see Jon Wage's talk at later today!
25. Database Migrations Deploy DB schema changes before the code Prevent DB schema BC breaks Use DoctrineMigrationBundle app/console doctrine:migrations:diff app/console doctrine:migrations:migrate Do 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
26. Different Content Areas of a Page
27. Caching with Edge Side Includes Symfony2 provides support for Edge Side Includes (ESI) Proxy assembles page from snippets of HTML Snippets can have different cache rules Develop 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 calls Never mix content that has different cache timeouts Consider caching user specific content in the client Varnish Reverse Proxy Super fast, PHP cannot match its performance Cache full pages for anonymous users Not just for HTML, also useful for JSON/XML API's
28. Page Rendered Behind a Reverse Proxy
29. Asset Management Go see Kris Wallsmith's talk next!
30. Performance Tips Dump routes to Apache rewrite rules app/console router:dump-apache Write custom cache warmers Do 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 needed Use a bytecode cache with MapFileClassLoader
31. Testing Symfony2 rocks for unit and functional testing Dependency Injection, core classes have interfaces (easy mocking) No base classes, no static dependencies, no ActiveRecord Client fakes "real" requests for functional testing (BrowserKit component) Functional Testing Pros: tests configuration, tests API not implementation Unit Testing Pros: pinpoints issues, very directed testing http://www.slideshare.net/avalanche123/clean-code-5609451 Recommendation: Functional testing is recommended for controller actions Symfony2 provides WebTestCase and BrowserKit Unit testing for complex algorithms, third party API's too hard to mock Use Liip\FunctionalTesting to load fixtures, validate HTML5
32. Deployment Debian style (aka Liip Debian Packager) Write a manifest in YAML Build Debian packages with MAKE Install with apt-get install Server specific settings are asked during install, change later with dpkg-reconfigure Maintain a global overview of all application dependencies in case of (security) updates Watch Lukas' unconference talk later today! Fabric (used at OpenSky) Repository managed with git-flow Clone tagged release branch, init submodules Fix permissions (e.g. cache, log), delete dev/test controllers Replace password/API-key placeholders with prod values in config files Upload in parallel to production nodes, swap "current" symlink
33. 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 @weaverryan Ryan Weaver 27 Dec http://twitter.com/weaverryan/status/19565706752299009
34. Third Party Bundles Many vendors have already published bundles: FriendsOfSymfony (http://github.com/friendsofsymfony) UserBundle (forked from knplabs' DoctrineUserBundle) FacebookBundle (forked from kriswallsmith) Liip (http://github.com/liip) FunctionalTestBundle ViewBundle 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/
35. Third Party Bundles Bundles should follow the best practices No version-tagging or official package manager (yet) Use bundles by adding git submodules to your project Maintain your own fork and "own" what you use Not all bundles are equally maintained Symfony2 API changes => broken bundles If you track symfony/symfony, learn to migrate bundles Avoid rewriting a bundle's services/parameters directly The bundle's DI extension should allow for such configuration; if not, submit a pull request If absolutely necessary, a CompilerPass is cleaner
36. Contributing to Third Party Bundles Similar to Symfony2's own patch guidlines Fork and add remote repository Merge regularly to keep up-to-date Avoid committing directly to your master Merges from upstream should be fast-forwards Once upstream changes are stable, bump your project's submodule pointer
37. Contributing to Third Party Bundles Create branches for patches and new features Can'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 cleanly Create feature branch based on upstream's master Rebase or merge upstream's master when finished
38. 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 master Delete your feature branch Update your project's submodule to point to master
39. Resources If you want to jump in and contribute: http://docs.symfony-reloaded.org/master/contributing/community/other. html If you are still fuzzy on Dependency Injection: http://fabien.potencier.org/article/11/what-is-dependency-injection If you keep up with Symfony2 repository on github: http://docs.symfony-reloaded.org/master/
41. Application Using Dependency Injection
42. Circular Dependency Example
43. Dependency Injection All objects are instantiated in one of two ways: Using the "new" operator Using an object factory All objects get collaborators in one of two ways Passed to object constructor Set using a setter