Namespaces / PSR-0 & PSR-4

Overview of Namespaces and PSR-0 and PSR-4

Transcript

1. Namespaces / PSR 0 & 4 Justin Yost Web Developer at Loadsys » twitter.com/jtyost2 » github.com/jtyost2 » lynda.com/justinyost » yostivanich.com CC BY-NC 4.0 Justin Yost 1
2. Definition » Namespaces encapsulate stuff CC BY-NC 4.0 Justin Yost 2
3. Problems » Solves collisions between files and class names » Ability to alias CC BY-NC 4.0 Justin Yost 3
4. Requirements » PHP 5.3+ CC BY-NC 4.0 Justin Yost 4
5. Example? CC BY-NC 4.0 Justin Yost 5
6. <?php namespace Awesome; class EmpireStrikesBack {} ?> <?php namespace Favorites; class EmpireStrikesBack {} ?> CC BY-NC 4.0 Justin Yost 6
7. Namespaces Let you create a space for your code to live without naming conflicts with other code. * Classes * Functions * CONST * Interfaces CC BY-NC 4.0 Justin Yost 7
8. Sub Namespaces? CC BY-NC 4.0 Justin Yost 8
9. <?php namespace Awesome\Totally; class EmpireStrikesBack {} ?> <?php namespace Favorites\Really; class EmpireStrikesBack {} ?> CC BY-NC 4.0 Justin Yost 9
10. Multiple Namespaces? CC BY-NC 4.0 Justin Yost 10
11. <?php namespace Awesome\Totally\Yep; class EmpireStrikesBack {} namespace Favorites\Really\Really; class EmpireStrikesBack {} ?> CC BY-NC 4.0 Justin Yost 11
12. Ok why do I care? Ever named a class? * User * Auth * Login * Table * Database * String * ... CC BY-NC 4.0 Justin Yost 12
13. How to use? » Declare namespaces » Reference classes by their namespaced name CC BY-NC 4.0 Justin Yost 13
14. Example CC BY-NC 4.0 Justin Yost 14
15. file1.php <?php namespace Awesome; class EmpireStrikesBack {} ?> CC BY-NC 4.0 Justin Yost 15
16. file2.php <?php namespace Favorites; include 'file1.php'; class EmpireStrikesBack {} new EmpireStrikesBack(); // \Favorites\EmpireStrikesBack() new Awesome\EmpireStrikesBack(); // \Favorites\Awesome\EmpireStrikesBack() new \Awesome\EmpireStrikesBack(); // \Awesome\EmpireStrikesBack() new \Exception(); // \Exception ?> CC BY-NC 4.0 Justin Yost 16
17. Aliasing/Importing » use imports a namespace » use also lets you alias a Namespaced object CC BY-NC 4.0 Justin Yost 17
18. Example CC BY-NC 4.0 Justin Yost 18
19. <?php namespace Favorites; use Awesome\EmpireStrikesBack as Something; use Awesome\LaptiNeck; class EmpireStrikesBack {} new EmpireStrikesBack(); // \Favorites\EmpireStrikesBack() new Awesome\EmpireStrikesBack(); // \Favorites\Awesome\EmpireStrikesBack() new \Awesome\EmpireStrikesBack(); // \Awesome\EmpireStrikesBack() new Something(); // \Awesome\EmpireStrikesBack() new LaptiNeck(); // \Awesome\LaptiNeck() new \Exception(); // \Exception ?> CC BY-NC 4.0 Justin Yost 19
20. Must I use Namespaces » Nope » But really, you should be CC BY-NC 4.0 Justin Yost 20
21. How to Use? » PSR-0 » Autoloading Standard CC BY-NC 4.0 Justin Yost 21
22. PSR-0 » Paths match the Namespace Path » And other stuff... \Doctrine\Common\IsolatedClassLoader => /path/to/project/lib/vendor/Doctrine/Common/IsolatedClassLoader.php CC BY-NC 4.0 Justin Yost 22
23. PSR-0 » Deprecated » Out with the old and all that » There were some issues » Composer, Underscores, etc CC BY-NC 4.0 Justin Yost 23
24. PSR-4 » \<NamespaceName>(\<SubNamespaceNames>)*\<ClassName> » Must include vendor Namespace » May include sub namespaces \Symfony\Core\Request => /path/to/project/lib/vendor/Symfony/Core/Request.php CC BY-NC 4.0 Justin Yost 24
25. PSR-4 » Focused on packages » Underscores have no meaning » Composer supports both PSR-4/0 CC BY-NC 4.0 Justin Yost 25
26. Composer briefly » Composer gives you a way of assigning dependencies » Includes an autoloader to load said dependencies » Pretty much every framework supports/requires composer » Composer includes pretty good information on using it without a framework CC BY-NC 4.0 Justin Yost 26
27. Autloading? » Include Composer's Autoloader File » And then just reference namespaced Composer Files CC BY-NC 4.0 Justin Yost 27
28. Example CC BY-NC 4.0 Justin Yost 28
29. <?php namespace Favorites; require __DIR__ . '/vendor/autoload.php'; use Awesome\LaptiNeck; class EmpireStrikesBack {} new EmpireStrikesBack(); // \Favorites\EmpireStrikesBack() new Awesome\EmpireStrikesBack(); // \Favorites\Awesome\EmpireStrikesBack() new \Awesome\EmpireStrikesBack(); // \Awesome\EmpireStrikesBack() new LaptiNeck(); // \Awesome\LaptiNeck() new \Exception(); // \Exception ?> CC BY-NC 4.0 Justin Yost 29
30. What Should I Have Taken Away » Namespaces solve a real problem » Namespaces are actually relatively easy » PSR-4 doesn't require a lot of work » Implement composer and you solve several problems CC BY-NC 4.0 Justin Yost 30
31. Questions? » twitter.com/jtyost2 » github.com/jtyost2 » lynda.com/justinyost » yostivanich.com CC BY-NC 4.0 Justin Yost 31