Symfony4 Deep Dive

1. Symfony4 Deep Dive SensioLabs
2. License Symfony4 Deep Dive Copyright © 2017 SensioLabs – All Rights Reserved Contents are provided for strictly personal use. No part of these contents may be reproduced, stored in a retrieval system, publicly shared or transmitted in any form or by any means. Disclaimer Contents are distributed on an "as is" basis, without warranty. Although every precaution has been taken in the preparation of this work, neither the authors nor SensioLabs shall have any liability to any person or entity with respect to any loss or damage caused or alleged to be caused directly or indirectly by the information contained in this work.
3. • SSID: GT Conference • Username: SymfonyLive • Password: Berlin2017 Wifi
4. SensioLabs Introduction
5. The Symfony Release Cycle
6. We are here
7. • LTS release (3 years of support) • Symfony 3.3 + additional features + additional deprecations • release: November 2017 Symfony 3.4
8. • standard release (8 months of support) • Symfony 3.3 + additional features - deprecated features • release: November 2017 Symfony 4.0
9. Version Release date End of Maintenance End of Life 2.8 LTS 11/2015 11/2018 11/2019 3.3 05/2017 01/2018 07/2018 3.4 LTS 11/2017 11/2020 11/2021
10. Version Release date End of Maintenance End of Life 2.8 LTS 11/2015 11/2018 11/2019 3.3 05/2017 01/2018 07/2018 4.0 11/2017 07/2018 01/2019
11. The Symfony Standard Edition
12. Symfony 2.x/3.x applications were based on the Symfony Standard Edition. The Symfony SE is shipped with all Symfony components and different bundles. The Symfony Standard Edition
13. It ships with code that isn‘t used in all individual projects. The Symfony SE is often perceived as being „big“. Removing not needed functionality is a cumbersome task. The Symfony Standard Edition
14. Symfony Flex
15. • Flex prefers composition over inheritance. • New project start with almost no dependencies. • Only needed features are added by developers. What is Symfony Flex?
16. • hooks into the Composer workflow • automatically enables Symfony bundles • executes predefined recipes when packages are installed • recipes are removed when packages are uninstalled What is Symfony Flex?
17. Bootstrapping a Symfony application
18. Using Composer composer create-project \ symfony/framework- standard-edition:3.3.* \ my-app
19. Using the Symfony Installer symfony new my-app 3.3
20. Bootstrapping an application using Flex composer create-project \ symfony/skeleton my-app
21. Initial project size in comparison Symfony 3 Symfony 4
22. Symfony 3 Symfony 4 Basic directory structure in comparison
23. Hands on: User Group Radar
24. Initialize the project composer create-project \ symfony/skeleton:^3.4@beta \ meetup
25. https://goo.gl/PVGrzA Download example code
26. Recipes
27. • The Symfony SE came with ready-to-use bundles and a sensible default config. • Adding new components/bundles and configuring them can be a complicated task. • Flex will automatically enable a bundle in all environments. How to add functions to a Flex project?
28. • description of things to apply when a package is installed • maintained by the core team • stored in the symfony/recipes repository • automatically applied when the package is installed What is a recipe?
30. • automatically enable a bundle in some/all environments • provide a reasonable default config • set some environment variables • copy files and create directories A recipe can
31. Applying a recipe during installation $ composer require symfony/console Using version ^3.3 for symfony/console ./composer.json has been updated Loading composer repositories with package information Updating dependencies (including require-dev) Package operations: 1 install, 0 updates, 0 removals - Installing symfony/console (v3.3.10): Downloading (100%) Writing lock file Generating autoload files Symfony operations: 1 recipe - Configuring symfony/console (3.3): From github.com/symfony/recipes:master Executing script make cache-warmup [OK] Executing script assets:install --symlink --relative public [OK]
32. Applying a recipe during installation $ composer require symfony/console Using version ^3.3 for symfony/console ./composer.json has been updated Loading composer repositories with package information Updating dependencies (including require-dev) Package operations: 1 install, 0 updates, 0 removals - Installing symfony/console (v3.3.10): Downloading (100%) Writing lock file Generating autoload files Symfony operations: 1 recipe - Configuring symfony/console (3.3): From github.com/symfony/recipes:master Executing script make cache-warmup [OK] Executing script assets:install --symlink --relative public [OK]
33. Applying a recipe during installation $ composer require symfony/console Using version ^3.3 for symfony/console ./composer.json has been updated Loading composer repositories with package information Updating dependencies (including require-dev) Package operations: 1 install, 0 updates, 0 removals - Installing symfony/console (v3.3.10): Downloading (100%) Writing lock file Generating autoload files Symfony operations: 1 recipe - Configuring symfony/console (3.3): From github.com/symfony/recipes:master Executing script make cache-warmup [OK] Executing script assets:install --symlink --relative public [OK]
34. Aliases
35. For common problems, Flex decides which is the best package to use. Use the alias to let Flex make the choice for you (e.g. admin, orm, etc.). Alternatives can still be installed using their full package name. Flex makes choices for you
36. Aliases allow to reference packages from the Symfony namespace by their base name. Instead of symfony/foo you can just use foo (e.g. form instead of symfony/form). Aliases for Symfony components
37. Packs
38. What is a pack? Packs are groups of several packages which all contribute to solve common problems. Developers only need to install one package instead of lots of packages.
39. • Groups packages that are useful during development: • logging (Monolog) • profiling (WebProfilerBundle) • testing (PhpUnitBridge) Example: The debug pack
40. • symfony/monolog-bundle • easycorp/easy-log-handler • symfony/profiler-pack • symfony/phpunit-bridge • symfony/var-dumper Example: The debug pack
41. • debug-pack • profiler-pack • orm-pack • webpack-encore-pack • api-pack Popular packs
42. Contrib recipes
43. • the core recipes repository is restricted to a limited set of packages • maintainers of other bundles cannot add their own recipes • the selection is opionated and the choice is made by the core team • only for MIT licensed packages Limitation of core recipes
44. • are maintained by the community • can be created for MIT and Apache licensed packages • are not enabled by default Contrib recipes
45. Activating contrib recipes in composer.json { "extra": { "symfony": { "id": "01BX217DNRHSWETJFT83M3XDE9", "allow-contrib": false } } }
46. Activating contrib recipes in composer.json { "extra": { "symfony": { "id": "01BX217DNRHSWETJFT83M3XDE9", "allow-contrib": false } } }
47. Activating contrib recipes in composer.json { "extra": { "symfony": { "id": "01BX217DNRHSWETJFT83M3XDE9", "allow-contrib": true } } }
48. Interactive activation
49. SensioLabs
50. SensioLabs Improved Dependency Injection
51. • will be applied to all services configured in the same file • can be overriden per service Default options per file services: _defaults: autowire: true autoconfigure: true public: false
52. Autoconfiguration based on types Definitions can be modified based on parent classes/implemented interfaces. For example, bundles can add tags to definitions based on implemented interfaces.
53. • the class attribute is optional • if omitted, the id will be treated as the FQCN Class based service ids services: AppBundle\Service\ExampleService: ~ # is equivalent to AppBundle\Service\ExampleService: class: AppBundle\Service\ExampleService
54. • collects PHP classes based on glob patterns and PSR-4-compatible namespaces • some files/directories can be excluded PSR-4 based service configuration
55. PSR-4 based service configuration services: App\: resource: '../src/*' # you can exclude directories or files # but if a service is unused, it's removed anyway #exclude: '../src/{Entity,Migrations,Repository,Tests}' exclude: '../src/{Entity}' # refine service definitions AppBundle\Service\ExampleService: arguments: # bind arguments that cannot be autowired $someArgument: 'some_value'
56. Environment variables Warming up the application cache upfront requires all container parameters to be set. Some cloud hosting providers do not make these credentials available. Env var placeholders allow to inject and replace options at runtime.
57. Usage of environment variables # defining default values for env var placeholders parameters: env(DB): 'sqlite://../../var/data.db' doctrine: dbal: url: '%env(DB)%'
58. • strings may break type hints (e.g. a port number is expected to be an integer in PHP code) • to pass structured data (e.g. arrays) you need more env vars • reading from files for security reasons not possible Non-string environment variables
59. • „bool:“, „int:“, „float:“, „string:“: perform type castings • „resolve:“: resolves container parameters • „base64:“, „json:“: decode data • „file:“: reads data from files „const:“ parses PHP constants Supported operators
60. Full example parameters: # roughly equivalent to # "(int) getenv('DATABASE_PORT')" app.connection.port: '%env(int:DATABASE_PORT)%' project_dir: '/foo/bar' env(DB): 'sqlite://%%project_dir%%/var/data.db' db_dsn: '%env(resolve:DB)%' env(SECRETS_FILE): '/etc/secure/example.com/secrets.json' app.secrets: '%env(json:file:SECRETS_FILE)%' env(NUM_ITEMS): 'App\\Entity\\BlogPost::NUM_ITEMS' app.num_items: '%env(constant:NUM_ITEMS)%'
61. SensioLabs
62. SensioLabs The Cache Component
63. Compute some data structures can be a time or memory consuming task. However, recalculating them on every request may not always be necessary. Caches can be used to share the same result between requests to save resources. The Cache component
64. The PHP Framework Interoperability Group develops recommendations and interfaces for common problems that are solved by different frameworks. Standards are published as so-called PHP Standard Recommendations (PSRs). The PHP-FIG
65. PSR-6
66. PSR-6 specifies a standard for a cache implementation. It describes interfaces that represent the cache data and its metadata as well as how to store data into and retrieve from the cache. PSR-6
67. • encapsulates the data that should be cached • associates data with a key and expiration time • CacheItemInterface is specified by PSR-6 Cache items
68. • cache pools are the gateway to write cache items into the cache and get them back via their key • CacheItemPoolInterface is specified by PSR-6 Cache pools
69. • Cache adapters are Symfony‘s terminology for concrete cache backends. • They are never used directly be the end-user, but will only be configured once. • Developers only act with the cache through cache pools. Cache adapters
70. • APCu • Doctrine • Filesystem • Memcached • Pdo • Redis Built-in adapters
71. Configuring the default adapter framework: cache: app: cache.adapter.redis system: cache.adapter.apcu
72. The system cache pool is used internally by Symfony to cache framework related fragments (e.g. the serializer and validator caches). The system cache pool
73. The app cache pool is meant to store application related data. It is not used automatically by the framework. Application developers must make use of the cache.app service to store data into and retrieve data from the app cache. The app cache pool will be used for autowiring by default. The app cache pool
74. CacheItemInterface interface CacheItemInterface { public function getKey(); public function get(); public function isHit(); public function set($value); public function expiresAt($expiration); public function expiresAfter($time); }
75. CacheItemPoolInterface interface CacheItemPoolInterface { public function getItem($key); public function getItems(array $keys = array()); public function hasItem($key); public function clear(); public function deleteItem($key); public function deleteItems(array $keys); public function save(CacheItemInterface $item); public function saveDeferred(CacheItemInterface $item); public function commit(); }
76. Storing cache items public function computeAndCache(CacheItemPoolInterface $cache) { $item = $cache->getItem('cache_key'); // compute some $value $item->set($value); $cache->save($item); }
77. Retrieve cache items public function retrieveFromCache(CacheItemPoolInterface $cache): ?Value { $item = $cache->getItem('cache_key'); if ($item->isHit()) { return $item->get(); } return null; }
78. Full example public function computeAndCache(CacheItemPoolInterface $cache) { $item = $cache->getItem('cache_key'); // return the cached value if possible if ($item->isHit()) { return $item->get(); } // compute some $value $item->set($value); $cache->save($item) ; return $value; }
79. Custom cache pools framework: cache: pools: # the "api" cache pool will be # available as the cache.api service api: adapter: memcached
80. PSR-16
81. PSR-6 solves caching but is rather formal. It is more verbose than needed for many use cases. PSR-16 defines a streamlined interface for common cases. PSR-16
82. The CacheInterface interface CacheInterface { public function get($key, $default = null); public function set($key, $value, $ttl = null); public function delete($key); public function clear(); public function getMultiple($keys, $default = null); public function setMultiple($values, $ttl = null); public function deleteMultiple($keys); public function has($key); }
83. Full example public function computeAndCache(CacheInterface $cache) { if ($cache->has('cache_key')) { // return the cached value if possible return $cache->get('cache_key'); } // compute some $value $cache->set('cache_key', $value) ; return $value; }
84. Wrapping a PSR-6 adapter services: api_cache: class: Symfony\Component\Cache\Simple\Psr6Cache arguments: - '@cache.app'
85. SensioLabs
86. SensioLabs The Workflow Component
87. Introduction Workflows are processes in your application (for example, the publishing process of blog posts). They should be kept outside your code and be defined in your application config.
88. Terms 1/1 • Place the states a workflow can be in • Transition an action that brings the workflow from one place into another
89. Terms 2/2 • Definition the places of a workflow and the transitions to get from one place to another • Marking the current state of the workflow, stored in a MarkingStore
90. Workflow configuration framework: workflows: blog_publishing: type: 'workflow’ # or ‘state_machine’ # ...
91. Workflow configuration framework: workflows: blog_publishing: type: 'workflow' marking_store: type: 'multiple_state' # or 'single_state' arguments: - 'currentPlace' # ...
92. Workflow configuration framework: workflows: blog_publishing: type: 'workflow' marking_store: type: 'multiple_state' arguments: - 'currentPlace' supports: [AppBundle\Entity\BlogPost] # ...
93. Workflow configuration framework: workflows: blog_publishing: type: 'workflow' marking_store: type: 'multiple_state' arguments: - 'currentPlace' supports: [AppBundle\Entity\BlogPost] places: - draft # ...
94. Workflow configuration framework: workflows: blog_publishing: type: 'workflow' marking_store: type: 'multiple_state' arguments: - 'currentPlace' supports: [AppBundle\Entity\BlogPost] places: - draft # ... transitions: to_review: from: draft to: review # ...
95. • a definition will be created for each workflow • a workflow can be retrieved from the service container (workflow.<name>) • the service is an instance of Workflow Workflow configuration
96. • can() test if a transition can be applied • apply() applies a transition • getEnabledTransitions() returns all applyable transitions The Workflow class
97. Applying transitions public function publishIfPossible( Article $article, Workflow $workflow ) { if ($workflow->can($article, 'publish')) { $workflow->apply($article, 'publish'); } }
98. • several events are triggered throughout the lifecycle of a workflow • listeners can access the workflow through the passed event object Workflow events
99. • workflow.leave before a place is left • workflow.transition before a transition is applied • workflow.enter before a place is entered Workflow events
100. • workflow.entered after a place has been entered • workflow.completed after a transition was applied • workflow.announce announces all enabled transitions Workflow events
101. • transitions can be blocked by listeners of the workflow.guard event • an instance of GuardEvent will be passed • guard listeners are taken into account when can() is executed The guard event
102. The GuardEvent class GuardEvent extends Event { private $blocked = false; public function isBlocked() { return $this->blocked; } public function setBlocked($blocked) { $this->blocked = (bool) $blocked; } }
103. SensioLabs
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