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Principles of Package Design (PHPCon Poland 2015)
The document discusses principles of package design, highlighting concepts such as the Release Reuse Equivalence Principle, Common Reuse Principle, and Acyclic Dependencies Principle. It emphasizes how packages should be structured for stability and cohesion, advocating for packages to change together and avoid cyclic dependencies. The principles aim to guide developers toward creating efficient and maintainable software packages.
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Principles of Package Design (PHPCon Poland 2015)
- 1. Principles of PackageDesign How to create cohesive, stable packages Matthias Noback
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- 3. A Year WithSymfony leanpub.com/a-year-with-symfony
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- 9. Principles of PackageDesign leanpub.com/principles-of-package-design
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- 12. A - Cohesionprinciples Perspective: the package in isolation
- 13. ! 1 - TheRelease Reuse Equivalence Principle The granule of reuse is the granule of release
- 14. 1 - TheRelease Reuse Equivalence Principle • Version control and hosting • Composer package definition • Meta-files • Auto-loading ! • Semantic versioning • Branches • Tags • Backward compatibility • Quality control
- 15. 1 - TheRelease Reuse Equivalence Principle The Rule of Three blog.codinghorror.com/rule-of-three/
- 16. 1 - TheRelease Reuse Equivalence Principle If you don't have the time to turn your reusable code into a proper package... ! Don't release it.
- 17. 2- The CommonReuse Principle Classes that are used together are packaged together If you use one class of a package, you will use all its other classes too.
- 18. 2- The CommonReuse Principle Smell: Feature strata
- 19. 2- The CommonReuse Principle Example of feature strata: the Symfony Security Component
- 20. 2- The CommonReuse Principle Smell: Classes with different dependencies
- 21. 2- The CommonReuse Principle Example of different dependencies: Gaufrette
- 22. 2- The CommonReuse Principle Different dependencies: Gaufrette { "name": "knplabs/gaufrette", ... "suggest": { "knplabs/knp-gaufrette-bundle": "to use with Symfony2", "dropbox-php/dropbox-php": "to use the Dropbox adapter", "rackspace/php-opencloud" : "to use Opencloud adapter", "herzult/php-ssh": "to use SFtp adapter", "phpseclib/phpseclib": "to use PhpseclibSftp adapter", "aws/aws-sdk-php": "to use the Amazon S3 adapter", "amazonwebservices/aws-sdk-for-php": "to use the legacy Amazon S "doctrine/dbal": "to use the Doctrine DBAL adapter", "microsoft/windowsazure": "to use Microsoft Azure Blob Storage a "ext-zip": "to use the Zip adapter", "ext-apc": "to use the APC adapter", ... },
- 23. 2 - TheCommon Reuse Principle Leszek Prabucki's response
- 24. 3 - TheCommon Closure Principle Classes that change together are packaged together
- 25. 3 - TheCommon Closure Principle Reasons for change • The application's features change • The business rules change • The web framework's best practices change • The persistence library's configuration changes • ...
- 26. 3 - TheCommon Closure Principle Smell: code for multiple application layers • Web User Interface • Command-line interface • Model • Infrastructure services
- 27. B - Couplingprinciples Perspective: the package in relation to other packages
- 28. 4 - TheAcyclic Dependencies Principle The dependency graph of packages must have no cycles
- 29. 4 - TheAcyclic Dependencies Principle
- 30. Stability Something is stableif it's resistant to change.
- 31. 5 - TheStable Dependencies Principle An irresponsible package
- 32. 5 - TheStable Dependencies Principle A dependent package
- 33. 5 - TheStable Dependencies Principle An instable package: irresponsible and dependent
- 34. 5 - TheStable Dependencies Principle A responsible package
- 35. 5 - TheStable Dependencies Principle An independent package
- 36. 5 - TheStable Dependencies Principle A stable package: responsible and independent
- 37. 5 - TheStable Dependencies Principle Depend in the direction of stability
- 38. 5 - TheStable Dependencies Principle Counter example
- 39. 6 - TheStable Abstractions Principle What is more likely to change? ! • Something concrete or something abstract? • A class or an interface?
- 40. 6 - TheStable Abstractions Principle Abstractness should increase with stability
- 41. Summary Reuse/release equivalence principle Reuseonly code that you can release as a product. Common reuse principle All code in a package is reused at the same time. Common closure principle Code in a package only changes for a few reasons. Acyclic dependencies principle No cycles in the dependency graph. Stable dependencies principle Only depend on more stable packages. Stable abstractions principle More stable packages are also more abstract.
- 42. Word of advice Youcan't maximize them all at the same time. ! Keep them in mind while you are working on a package.
- 43. Principles of PackageDesign leanpub.com/principles-of-package-design/c/phpconpl
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- 45. Images • http://cleancoders.com/ • https://github.com/ •https://bitbucket.org/ • https://packagist.org/ • http://martinfowler.com/eaaCatalog/ • http://butunclebob.com/ArticleS.UncleBob.PrinciplesOfOod • http://blog.8thlight.com/uncle-bob/2014/05/14/ TheLittleMocker.html