Refactoring the third commandment
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The document discusses the importance of refactoring in software development, emphasizing its benefits such as cleaner code, improved maintainability, and faster development. It outlines specific scenarios for when to refactor, as well as common code smells to watch for, such as bloaters and change preventers. Additionally, it provides practical tools and principles to implement effective refactoring practices.
![Nicola Pietroluongo @niklongstone
Primitive Obsession
Use object instead
class Authentication
{
const ROLE_GUEST = 0;
const ROLE_MEMBER = 1;
const ROLE_ADMIN = 2;
const USER_ROLE = role;
public function getRole($user)
{
$role = $user[self::USER_ROLE];
// other operations
}](https://image.slidesharecdn.com/refactor-phpbenelux2018-180126211110/85/Refactoring-the-third-commandment-17-320.jpg)
Refactoring the third commandment
- 1. Nicola Pietroluongo @niklongstone REFACTORING THE THIRD COMMANDMENT
- 3. Nicola Pietroluongo @niklongstone Nicola Pietroluongo @niklongstone Lead developer/Solution architect Tech article writer Open Source contributor Author of Learning PHP7 by Packt Publishing +10y of PHP programming Amazon Alexa skill challenge award winner
- 4. Nicola Pietroluongo @niklongstone Refactoring the 3rd commandment Sections Introduction Code smells Summary and tools
- 5. Nicola Pietroluongo @niklongstone Its a process of restructuring an existing code, altering its internal structure without changing its external behavior.
- 6. Nicola Pietroluongo @niklongstone Why should you refactor? Benefits Your code: will look clean easy to understand easy to edit/maintain You: will code faster will spot bug easier
- 8. Nicola Pietroluongo @niklongstone When should you refactor? Rule of three two Everytime you add a feature Everytime you fix a bug During the review process
- 9. Nicola Pietroluongo @niklongstone When Shouldn't You Refactor? It depends Spaghetti code Extremely coupled Code too buggy Close to deadline
- 10. Nicola Pietroluongo @niklongstone What do I tell to the business?
- 12. Nicola Pietroluongo @niklongstone What to do before? Starting steps Announce it to your teammate Use a VCS Remember coding standard Remember OO and SOLID principles Write or improve the test
- 13. Nicola Pietroluongo @niklongstone Code smells Warning signs in your code
- 14. Nicola Pietroluongo @niklongstone Code smells If it stinks change it Bloaters Object-Orientation Abusers Change Preventers Unneeded Couplers
- 16. Nicola Pietroluongo @niklongstone Method / Class Size Long method Large class Long parameter list
- 17. Nicola Pietroluongo @niklongstone Primitive Obsession Use object instead class Authentication { const ROLE_GUEST = 0; const ROLE_MEMBER = 1; const ROLE_ADMIN = 2; const USER_ROLE = role; public function getRole($user) { $role = $user[self::USER_ROLE]; // other operations }
- 18. Nicola Pietroluongo @niklongstone Data Clumps Use object instead public function createPermission($user, $pass, $read, $write) { // other operations } public function updatePermission($user, $pass, $read, $write) { // other operations }
- 20. Nicola Pietroluongo @niklongstone Switch Statement Use object instead switch ($city) { case 'Brussels': return getWinterClothes(); case 'Miami': return getSummerClothes(); case 'Lisbon': return getNormalClothes(); }
- 21. Nicola Pietroluongo @niklongstone Switch Statement Use object instead interface City { public function getClothes(); } class Brussels implements City { function getClothes() { return 'normalClothes'; } } class Miami implements City{ //code...} $cityClothes = new $city(); // i.e. $city = Brussels; $cityClothes->getClothes();
- 22. Nicola Pietroluongo @niklongstone Refuse Badquest A subclass uses only some methods interface Animal { public function fly(); public function swim(); public function eat(); } class Fish implements Animal { public function swim() { // } public function fly() { //trow Exception } //
- 23. Nicola Pietroluongo @niklongstone I exists...
- 24. Nicola Pietroluongo @niklongstone Refuse Badquest A subclass uses only some methods interface GenericAnimal { public function eat() } interface SeaAnimal { public function swim() } class Fish implements GenericAnimal, SeaAnimal
- 25. Nicola Pietroluongo @niklongstone Change Preventers
- 26. Nicola Pietroluongo @niklongstone Change Preventers When you make many changes in other places 10101101010 10101101010 10101101010
- 27. Nicola Pietroluongo @niklongstone Change Preventers How to avoid Keep the class hierarchy small Avoid classes with same behaviour Enforce the Single responsibility principle
- 29. Nicola Pietroluongo @niklongstone Unneeded You can live without that Comments Dead code Future code not in use
- 31. Nicola Pietroluongo @niklongstone Couplers You spend too much time together... Message Chain Feature Envy Inappropriate Intimacy Middle Man Traits freak
- 32. Nicola Pietroluongo @niklongstone Message chain You can live without that CLIENT EMPLOYEE getOffice() returns class Office OFFICE getManager() $manager = $employee->getOffice()->getManager();
- 33. Nicola Pietroluongo @niklongstone Message chain You can live without that CLIENT EMPLOYEE getManager() OFFICE $manager = $employee->getManager();
- 34. Nicola Pietroluongo @niklongstone Traits freak Be careful
- 35. Nicola Pietroluongo @niklongstone I am a trait
- 36. Nicola Pietroluongo @niklongstone Traits freak Bad
- 37. Nicola Pietroluongo @niklongstone Traits freak ...
- 38. Nicola Pietroluongo @niklongstone More examples PHP Code smells https://github.com/niklongstone/php-refactoring
- 39. Nicola Pietroluongo @niklongstone Summary How to prevent code smells in PHP
- 40. Nicola Pietroluongo @niklongstone How to improve Part of your development process Short methods and classes Avoid duplications (DRY) SOLID principle Composition over inheritance Objects over simple structures declare(strict_types=1); Share your findings
- 41. Nicola Pietroluongo @niklongstone Tools Tools and automation
- 46. Nicola Pietroluongo @niklongstone PHPMD $ ./phpmd.phar filesOrDir reportFormat rules $ ./phpmd.phar fileA.php,fileB.php text cleancode,codesize
- 47. Nicola Pietroluongo @niklongstone Git diff $ git diff --name-only --diff-filter=d master src/CinemaBundle/Controller/CinemaController.php src/CinemaBundle/Entity/Screening.php src/CinemaBundle/Entity/ScreeningVenue.php src/CinemaBundle/Entity/Showing.php
- 48. Nicola Pietroluongo @niklongstone Sed $ sed ':a; $!N; s/n/,/; ta' :a creates a pattern $!N appends lines to the pattern if not last line s/n/,/ replaces new line with comma ta repeat the a
- 49. Nicola Pietroluongo @niklongstone Pull it together *All in one line ./phpmd.phar $(git diff --name-only --diff-filter=d master | sed ':a; $!N; s/n/,/; ta') text cleancode,codesize
- 50. Nicola Pietroluongo @niklongstone To improve yourself, Improve your code.