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Slides for my talk at the Community Day of Laracon Europe 2014. Talk abstract With many great tools available for sharing packages of PHP code, it is now up to you as a developer to design these packages well. You have to decide what to put in a package, when to split a package and on what other packages you can safely depend. You will learn how to make good decisions about your package design and release reliable, highly usable and therefore highly esteemed packages of PHP code.
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Principles of PHP Package DesignObject oriented design for packages
Matthias Noback - Noback's OfficeLaracon Europe/Amsterdam - 8/28/2014
Matthias NobackNoback's Office
PHP developer, consultantWriter, speakerProud father
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Tight couplingCoupling to a framework
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Code
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Squiggly lines
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Code
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PackagesThere are many different kinds
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Class design
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Package designNothing?
butunclebob.com
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Principles of PHP Package Design
leanpub.com/principles-of-php-package-design
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Package designCohesion
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Package designCoupling
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A - Cohesion principlesPerspective: the package in isolation
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1 - The Release Reuse Equivalence PrincipleThe granule of reuse is the granule of release
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1 - The Release Reuse Equivalence Principle
Version control and hostingComposer package definitionMeta-filesAuto-loading
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Semantic versioning
Quality control
·BranchesTagsBackward compatibility
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1 - The Release Reuse Equivalence Principle
If you don't have the time to turn your reusable code into a proper package...
Don't release it.
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2- The Common Reuse PrincipleClasses that are used together are packaged together
If you use one class of a package,you will use all its other classes too.
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2- The Common Reuse PrincipleSmell: Feature strata
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2- The Common Reuse PrincipleExample of feature strata: the Symfony Security Component
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2- The Common Reuse PrincipleSmell: Classes with different dependencies
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2- The Common Reuse PrincipleExample of different dependencies: Gaufrette
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2- The Common Reuse PrincipleDifferent 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 S3 adapters", "doctrine/dbal": "to use the Doctrine DBAL adapter", "microsoft/windowsazure": "to use Microsoft Azure Blob Storage adapter", "ext-zip": "to use the Zip adapter", "ext-apc": "to use the APC adapter", ... }, ...} 24/50
2 - The Common Reuse PrincipleLeszek Prabucki's response
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3 - The Common Closure PrincipleClasses that change together are packaged together
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3 - The Common Closure PrincipleReasons for change
The application's features changeThe business rules changeThe web framework's best practices changeThe persistence library's configuration changes...
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3 - The Common Closure PrincipleSmell: code for multiple application layers
Web User InterfaceCommand-line interfaceModelInfrastructure services
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B - Coupling principlesPerspective: the package in relation to other packages
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4 - The Acyclic Dependencies PrincipleThe dependency graph of packages must have no cycles
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4 - The Acyclic Dependencies Principle
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Stability
Something is stable if it's resistant to change.
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5 - The Stable Dependencies PrincipleAn irresponsible package
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5 - The Stable Dependencies PrincipleA dependent package
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5 - The Stable Dependencies PrincipleAn instable package: irresponsible and dependent
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5 - The Stable Dependencies PrincipleA responsible package
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5 - The Stable Dependencies PrincipleAn independent package
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5 - The Stable Dependencies PrincipleA stable package: responsible and independent
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5 - The Stable Dependencies PrincipleDepend in the direction of stability
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5 - The Stable Dependencies PrincipleCounter example
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6 - The Stable Abstractions PrincipleWhat is more likely to change?
Something concrete or something abstract?A class or an interface?
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6 - The Stable Abstractions PrincipleAbstractness should increase with stability
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SummaryReuse/release equivalence principle
Common reuse principle
Common closure principle
Acyclic dependencies principle
Stable dependencies principle
Stable abstractions principle
·Reuse only code that you can release as a product.-
·All code in a package is reused at the same time.-
·Code in a package only changes for a few reasons.-
·No cycles in the dependency graph.-
·Only depend on more stable packages.-
·More stable packages are also more abstract.-
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Word of advice
You can't maximize them all at the same time.
Keep them in mind while you are working on a package.
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Principles of PHP Package Design
leanpub.com/principles-of-php-package-design
I'm impressed. — Robert C. Martin
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Principles of PHP Package Design
Get a 10 dollar discount:
http://leanpub.com/principles-of-php-package-design/c/laracon
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Questions?
feedback joind.in/11685
twitter @matthiasnoback
leanpub leanpub.com/principles-of-php-package-design
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Image courtesyClean CodersGitHubBitBucketPackagistPoEAABut Uncle BobRobert Martin
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