WordPress’ minimum-supported version is still PHP 5.2 (gasp!) but that doesn’t mean you should let that hold you back from leveraging modern PHP features in your plugins and themes! In this talk, we’ll take a deep dive into ways you can start leveraging modern PHP features today to bring new life to that old plugin or theme. We’ll cover how to code partial plugin activation for old versions of PHP, use autoloaders and namespaces, setup group aliasing, use return type declarations, leverage traits, and much more.

1. WORDPRESS DEVELOPMENT
IN A MODERN PHP WORLD
DREW JAYNES

2. DREW JAYNES
SANDHILLS DEVELOPMENT

3. THIS TALK:
WHY VS HOW

4. THIS TALK
TALK STRUCTURE
▸ Basic benefits of each concept
▸ Why each is worth pursuing
▸ Pseudo-code examples
▸ Practical examples

5. Slides: http://drewf.us/wcphx19

6. WHAT DOES MODERN PHP
DEVELOPMENT REALLY MEAN?

7. WHAT DOES MODERN PHP DEVELOPMENT MEAN?
MODERN PHP DEVELOPMENT CONCEPTS
▸ Namespaces
▸ Autoloading
▸ Closures (anonymous functions)
▸ *Type hints (and return type
declarations)
▸ Late static binding
▸ Traits
▸ Generators
▸ Group aliasing
▸ *Exception-based error
handling
▸ libsodium and modern security

8. MODERN DOESN’T JUST
MEAN NEWER FEATURES

9. FOLLOW THE LEADER?

10. “AS FOR THE FUTURE, YOUR TASK IS
NOT TO FORESEE IT, BUT TO ENABLE IT."
Antoine De Saint-Exupéry
WORDPRESS DEVELOPMENT IN A MODERN PHP WORLD

11. Slides: http://drewf.us/wcphx19

12. THE CONCEPTS

13. REFACTORING
OLD CODE

14. BEST PRACTICES
REFACTORING APPROACHES
▸ All or nothing
▸ Rewrite
▸ Back-compat concerns
▸ Gradual iteration
▸ Partial activation
▸ Version-protected bootstrap

15. REFACTORING FOR THE
SAKE OF REFACTORING:
A cautionary tale

16. NAVIGATING NEW
SKILLS TAKES TIME

17. DO: DIVE IN
HEAD FIRST

18. DON’T: JAM UP
YOUR USERS

19. EMBRACE WHAT YOUR
USERS CAN SUPPORT

20. NAMESPACES

21. BEST PRACTICES
NAMESPACES
▸ Establishes baseline code ownership
▸ Simpler naming of allthethings
▸ Better code segregation
▸ Easier interoperability with other people’s code

22. NAMESPACES
EXAMPLES
▸ My_Verbose_Plugin_Class_Name
▸ My_PluginClass_Name
▸ My_PluginComponentClass_Name
▸ My_Pluginfunction_name()
▸ ThisTotallyWorksEvenThoughItsRidiculous

23. NAMESPACES
IN PRACTICE: BEFORE

24. NAMESPACES
IN PRACTICE: AFTER

25. WHY USE
NAMESPACES?

26. BEST PRACTICES
WHY USE NAMESPACES?
▸ Prevent naming collisions
▸ Code readability
▸ Promote better code organization
▸ Aliasing can help marry legacy with modern code

27. WITH GREAT ALIASING POWER
COMES GREAT RESPONSIBILITY

28. NAMESPACES
ALIASING EXAMPLES
▸ use Legacy_Verbose_Controller_Class as Standardized_Controller;
class Controller extends Standardized_Controller {}
▸ class_alias( ‘Legacy_Controller_Class’, ‘ComponentStandardized_Controller’ );
new ComponentStandardized_Controller( $collection );

29. NAMESPACES
ALIASING EXAMPLES
▸ use Legacy_Verbose_Controller_Class as Standardized_Controller;
class Controller extends Standardized_Controller {}
▸ class_alias( ‘Legacy_Controller_Class’, ‘ComponentStandardized_Controller’ );
new ComponentStandardized_Controller( $collection );

30. NAMESPACES
ALIASING IN PRACTICE: BEFORE

31. NAMESPACES
ALIASING IN PRACTICE: AFTER

32. NAMESPACES
ALIASING IN PRACTICE: AFTER

33. AUTOLOADING WHAT YOU
NEED WHEN YOU NEED IT

34. BEST PRACTICES
AUTOLOADING
▸ Automatic loading of classes etc. instead of manually requiring them
▸ Typically follows project organization
▸ Composer vs PSR-0 vs PSR-4 vs Rolling your own

35. AUTOLOADERS CONVERT
CLASS NAMES
INTO FILE NAMES

36. AUTOLOADING
AUTOLOADING IN PRACTICE

37. AUTOLOADING
RESOURCES
▸ Composer: https://getcomposer.org/
▸ PSR-0: https://www.php-fig.org/psr/psr-0/
▸ PSR-4: https://www.php-fig.org/psr/psr-4/
▸ Drew’s autoloader: https://gist.github.com/DrewAPicture/
b0f1c0e637b072a41e5dfec6a38a7808
▸ Tom McFarlin’s autoloader: https://github.com/tommcfarlin/simple-
autoloader-for-wordpress

38. HINTING AT MISTAKES
BEFORE YOU MAKE THEM

39. WORDPRESS DEVELOPMENT IN A MODERN PHP WORLD
TYPE HINTS
▸ Helps catch avoidable mistakes
▸ Defines expectations for what is accepted
▸ *Base support for class/interface name or self
▸ 5.1 added array, 5.4 added callable
▸ 7.0 added scalar type support,
e.g. string, bool, int, float (no aliases!)
▸ 7.1 added iterable, 7.2 added object
▸ Multiple types not supported

40. TYPE HINTS
EXAMPLES
▸ function feed_pet( Pet $pet )
▸ ex_update_collection( Collection $collection, array $atts );
▸ try {} catch( Marker_Interface $exception ) {}

41. TYPE HINTS
IN PRACTICE

42. TYPE HINTS
IN PRACTICE

43. NICE TO HAVES

44. AVOID RUNNING OVER YOUR USERS
IN THE PURSUIT OF SHINY THINGS

45. NICE TO HAVES
CLOSURES (5.3+)
▸ Anonymous functions
▸ One way to express simple one-time-use code
▸ Be careful using closures with hooks

46. CLOSURES
PANDORA’S ANONYMOUS BOX
▸ add_action( ‘some_hook’, function( $param1, $param2 ) {
// do stuff
}
▸ function feed_pet( callable $process ) {}
▸ feed_pet( function() {
echo ‘Pet is fed.’;
} );
▸ call_user_func_array( $callback, $args );

47. CLOSURES
PANDORA’S ANONYMOUS BOX
▸ add_action( ‘some_hook’, function( $param1, $param2 ) {
// do stuff
}
▸ function feed_pet( callable $message ) {}
▸ feed_pet( function() {
echo ‘My pet has been fed.’;
} );
▸ call_user_func_array( $callback, $args );

48. CLOSURES
PANDORA’S ANONYMOUS BOX
▸ add_action( ‘some_hook’, function( $param1, $param2 ) {
// do stuff
}
▸ function feed_pet( callable $process ) {}
▸ feed_pet( function() {
echo ‘Pet is fed.’;
} );
▸ call_user_func_array( $callback, $args );

49. CLOSURES
IN PRACTICE

50. CLOSURES
IN PRACTICE

51. CLOSURES CAN BE HANDY, BUT
SHOULD BE USED WITH CARE

52. FLIPPING OOP
ON ITS HEAD

53. NICE TO HAVES
LATE STATIC BINDING (5.3+)
▸ Allows parent/super classes to statically reference aspects
of the calling or sub-class
▸ Flips the OOP inheritance model on its head
▸ Leveraged via the static keyword vs self

54. LATE STATIC BINDING
EXAMPLES

55. LATE STATIC BINDING
EXAMPLES

56. RECYCLING CODE

57. NICE TO HAVES
TRAITS (5.4+)
▸ Makes reusing code across classes simpler
▸ Free of inheritance (horizontal use)
▸ Traits vs dependency injection
▸ Really powerful when combined with abstract methods
▸ Are traits really evil? (no)

58. TRAITS
IN PRACTICE: BEFORE

59. TRAITS
IN PRACTICE: BEFORE

60. TRAITS
IN PRACTICE: AFTER

61. EFFICIENT ALIASING

62. NICE TO HAVES
GROUP ALIASING (7+)
▸ Allows for aliasing multiple classes or functions at once
▸ Cuts down on top-heavy aliasing blocks
▸ Importing and aliasing functions, importing constants was added in 5.6

63. GROUP ALIASING
EXAMPLES

64. GROUP ALIASING
IN PRACTICE

65. BACK-COMPAT
GOTCHAS

66. GOTCHAS
BACK-IN-COMPAT TO LOOK OUT FOR
▸ Call-time pass by reference (warning 5.3, fatal 5.4)
▸ my_update_function( &$something ) // WRONG
▸ PHP4-style constructors deprecated (7.0+)
▸ Static calls to non-static methods (deprecated 7.0+)

67. “SOFTWARE IS A GREAT COMBINATION
BETWEEN ARTISTRY AND ENGINEERING.”
Bill Gates
WORDPRESS DEVELOPMENT IN A MODERN PHP WORLD

68. THANK YOU
Drew Jaynes | DrewAPicture
Slides: http://drewf.us/wcphx19