Modernizing Legacy Code Step by Step

We’ll be taking a real PHP 5.2 codebase and migrating it to the latest and greatest PHP version. We’ll cover refactoring, adding components to handle routing, database access, as well as converting our HTML output to views. We’ll step through the entire process to demonstrate a repeatable solution for modernizing your legacy application!

Transcript

1. Modernizing Legacy Code Step By Step Joe Ferguson November 15th 2018
2. Who Am I? Joe Ferguson PHP Developer PHP Architect @ Ministry Brands Twitter: @JoePFerguson OSMI Board Member Drone Racing Pilot
3. For Further Reading leanpub.com/mlaphp leanpub.com/minimumviabletests
4. Legacy Applications
5. “There are no solutions, only trade offs” - Joe Ferguson - Paul M. Jones - Thomas Sowell
6. Taking stock of what we’re working with
10. Initial Project Overview Is there a framework? Is there a coding standard? Is there any autoloading? How are dependencies behind handled? Is there an ORM or how is the database being utilized? Is there a development environment?
11. Is there a framework?
12. Is there a framework?
13. Is there a coding standard?
15. Is there a coding standard?
16. No Standard? No problem!
17. Is there any autoloading?
19. Is there any autoloading?
20. There is a PSR for that…
21. How are dependencies handled?
23. Is there an ORM or how is the database being utilized?
25. Tools to help
26. PHP Coding Standards Fixer http://cs.sensiolabs.org/
27. PHP Coding Standards Fixer php-cs-fixer fix app --dry-run
28. PHP Mess Detector https://phpmd.org
29. PHP Mess Detector https://phpmd.org $ phpmd app html cleancode --reportfile report.html
30. Warning about Automating Code Changes
31. Composer https://getcomposer.org/doc/01-basic-usage.md
32. Triage Address any critical things found PHP Short Tags! PHP version issues Current server is 5.2 lets test 7.2 Fixing critical vulnerabilities
33. Get into Git!
34. Get into Git!
35. “We should just rewrite the app”
36. "This would be so much easier in framework _____________”
37. Why not rewrite? Progress halts entirely Business logic is rarely reused Most of the time is getting back to current functionality
38. Why you should refactor Progress continues Business logic reused Modernizing functionality instead of recreating
39. Existing Tests This is great! Review the tests to get an idea of coverage Passing tests become your control for any upcoming changes Confidence++
40. No Existing Tests Not the end of the world! Inspect the code base, was it written to be easily testable? Could you easily mock dependencies?
41. Untestable Code Not all code is testable If you can’t easily unit test the code base, consider alternatives Functional testing and Acceptance testing are valid options
42. Acceptance Testing NOT a replacement for Unit Testing Test large parts of your application at a time Can be harder to pinpoint error location Gives large code coverage in short amount of time
50. Digging into the Code Code Consolidation
51. Code Consolidation
52. Code Consolidation
53. _config_vars.php
54. _db_connect.php
55. composer require vlucas/phpdotenv
57. Database Class
58. Progress
59. header.php
60. Digging into the Code Code Consolidation Replace globals with DI
64. Digging into the Code Code Consolidation Replace globals with Dependency Injection Write tests
68. Digging into the Code Code Consolidation Replace globals with Dependency Injection Write tests Extract SQL (to ORM or other)
69. Digging into the Code Code Consolidation Replace globals with Dependency Injection Write tests Extract SQL (to ORM or other) Extract Business Logic (To domain logic)
72. _functions.php
73. Weather Class
74. Refactoring index.php
75. header.php
76. Digging into the Code Code Consolidation Replace globals with Dependency Injection Write tests Extract SQL (to ORM or other) Extract Business Logic (To domain logic) Extract Presentation Logic to Views (Twig, Blade, etc)
77. Digging into the Code Code Consolidation Replace globals with Dependency Injection Write tests Extract SQL (to ORM or other) Extract Business Logic (To domain logic) Extract Presentation Logic to Views (Twig, Blade, etc) Extract Action Logic (To Controllers)
78. Digging into the Code Code Consolidation Replace globals with Dependency Injection Write tests Extract SQL (to ORM or other) Extract Business Logic (To domain logic) Extract Presentation Logic to Views (Twig, Blade, etc) Extract Action Logic (To Controllers) Write (more) tests
79. Resources / Q & A Modernizing Legacy Applications In PHP - Paul M. Jones https://leanpub.com/mlaphp Minimum Viable Tests - Chris Hartjes https://leanpub.com/minimumviabletests Code Style https://github.com/FriendsOfPHP/PHP-CS-Fixer, http://editorconfig.org php mess detector https://phpmd.org Autoloading PSR-4 https://getcomposer.org/doc/01-basic-usage.md ORMs http://www.doctrine-project.org http://propelorm.org Docker https://leanpub.com/dockerfordevs, Vagrant https://puphpet.com
80. Joe Ferguson Twitter: @JoePFerguson Email: joe@joeferguson.me Freenode: joepferguson Contact Info: https://joind.in/talk/4e1b4