Maintainable + Extensible = Clean ... yes, Code!

AntonioPerić-Mažar

29.10.2016-#sfcampua

Maintainable+Extensible=Clean...yes,Code!

@antonioperic

Aboutme

• AntonioPerić-Mažar,mag.ing.comp.

• CEO,Co-Founder@Locastic

• Co-Founder@ShiftConference

• Softwaredeveloper,Symfony2

• OpenSourceContributor

• SFUGCRO

• w:www.locastic.com

• m:[email protected]

• t:@antonioperic

@antonioperic

Locastic

• Wehelpclientscreateamazingwebandmobileapps(since2011)

• designanddevelopmentagency

• mobiledevelopment

• webdevelopment

• UX/UI

• TrainingandConsulting

• ShiftConference,SymfonyCroatia

• www.locastic.com

• t:@locastic

http://www.locastic.com

@antonioperic

Locastic

@antonioperic

Questions?

• Whothinksheisproducinggoodcode?

• Whatisbadcode?

• Whatisgoodcode?

• Doyouknowhowtomeasurecodequality?

@antonioperic

@antonioperic

Note:whenweaskedforthiscodewegotitinzipfile!!!NoVCSatall!

@antonioperic

@antonioperic

ThiswasonehugeWTFnproject!

@antonioperic

@antonioperic

CodeSmell!!!(BadCode)

• Useglobals

• Anythinghardcoded(url,ip,etc)

• Longclassesormethods

• Deepstructures

• Longandbadnames

• Lackofformatting

• Lackofstandard

@antonioperic


• Overuseofpublicstatic

• Toomanyparameters

• Weirdorderofparameters

• GODObject(hecandoeverythingandheknowseverything)

• Noinputvalidation

• Nocomments

@antonioperic


• Takes1-2sentencestoexplain

• Copy-pasted-repetitivecode

• Neverusedinheritance,interfaceorcomposition

• notreadable

• nottestable

@antonioperic


• hardtounderstand

• hardtomaintain

• givesaheadache

• youdon’twon’ttoworkon/withit

@antonioperic

@antonioperic

AvoidbeingSTUPID

Singleton

Tightcoupling

Untestability

Prematureoptimization

Indescriptivenaming

Duplication

@antonioperic

@antonioperic

Butwhywestilldoingit…

• Wearelazy

• Shortdeadlines

• Baddecisions

• Fast-good-cheap

• Wearealwaysthebestdeveloperever:)

@antonioperic

Codehasexpirationdate!

@antonioperic

Yesterday!

@antonioperic

Gooddevelopersareshipping!balance shipping vs good code

@antonioperic

Developersareevolving!

@antonioperic

@antonioperic

Languageisevolving

• Frameworks(Symfony<3)

• Packagemanagers(composer)

• Standards

• PHP7

@antonioperic

“Anyfoolcanwritecodethatacomputercanunderstand.Goodprogrammerswritecodethathumanscanunderstand.“

Martin Fowler

@antonioperic

CODE

@antonioperic

@antonioperic

Cleancode

• Codethatdoesn’texist

• KISS

• DRY

• SOLID

• Don’treinventthewheel

• DesignPatterns

• Testable->Tested

@antonioperic

Cleancode

• Flexible

• Maintainable

• Easytorefactor

• Readable

@antonioperic

Cleancodeiseasytounderstand,easytochangeandreusable.

@antonioperic

@antonioperic

Whyweshouldcare…

• Someoneelsewillusethatcode

• Youwillusethatcode

• Badcodedoesalotofthingsbutnonewell

• Youdon’twritecodejusttobethere

• Maintainingshouldbeeasy

• Goodcodesavemoneyandtime

@antonioperic

@antonioperic

Iftechnicaldebtisnotrepaid,itcanaccumulate'interest',makingithardertoimplementchangeslateron.

@antonioperic

@antonioperic

Guidanceforbetter(clean)code

@antonioperic

#1Namingmatters

• Don’tabbreviate

• $string->b=false;

• $string->bold=false;

• Makecodereadable

• Meaningfulnames

• Improvesreadability

• Goodcodeshouldbetalkingtoyou

• Youshouldreaditlikeabook,whitespaceisimportant

@antonioperic

#1Namingmatters

• Twoworldwordsvariablename

• $data,$data2

• $total,$total2,$total3

@antonioperic

#1Namingmatters

@antonioperic

#1Namingmatters

• Don’tbesilly!

@antonioperic

#1Namingmatters

• Goodnameshouldexplain

• whyitexist

• whatitdoes

• howtouseit

• Ifyouneedcommentforexplainit,itisbadname

• Classshoulduseanoun,methodaverb

@antonioperic

#2Codestandard

• Don’tmixstylesinproject,usewhitespace

• Easiertonavigateinsideproject

• Lesstimeforboardingnewdeveloper

• PHP-FIG

• StickwithPSR

• PSR-0autoloading

• PSR-1basingcodestyle

• PSR-2detailedcodingstyle

@antonioperic

#2Codestandard

• SymfonyfollowsthestandardsdefinedinthePSR-0,PSR-1,PSR-2andPSR-4documents.

• http://symfony.com/doc/current/contributing/code/standards.html

http://symfony.com/doc/current/contributing/code/standards.html

http://symfony.com/doc/current/contributing/code/standards.html

@antonioperic

#3Useonlyonelevelofindentationpermethod• {{{}}}trytoavoidthis

• forcesingleresponsibility

• small,simple,easiertounderstand

• ourmindmodelisimportant

• separatelogicblocksandcomplexlevelofindentationintomethods

@antonioperic

#4Don’tuseelse

• reducecodecomplexity

• earlyreturns

• useExceptions

• itreducecomplexofourmindmodel

• methodshouldnotdomorethenonething

• don’tuseintermediatevariable

• usepolymorphism,switchissignalforpolymorphism

• don’tabusepolymorphism

@antonioperic

#4Don’tuseelse

@antonioperic

#5Keepyourclasses/methodssmall• easiertotest

• doonething,anddoonethingwell

• allfunctionsshouldreturnsomethingandavoidreturningNULL

• keepmethodssmall(max.20linesofcode)

• avoidside-effects

• avoidglobalstate

@antonioperic

#6UseExceptions

• Usethem

• Makesuretocatchthem

• Specifythenatureoftheerror

• thrownewInvalidArgumentException();

• Don’tusespecialerrorcodes

@antonioperic

#7Designpatterns

• usethem,theygiveyousolutionforsomewellknownproblems

@antonioperic

#8UseSPL

• TheStandardPHPLibrary(SPL)isacollectionofinterfacesandclassesthataremeanttosolvecommonproblems.

• SPLprovidesasetofstandarddatastructure,asetofiteratorstotraverseoverobjects,asetofinterfaces,asetofstandardExceptions,anumberofclassestoworkwithfilesanditprovidesasetoffunctionslikespl_autoload_register()

@antonioperic

#8UseSPL

• Datastructures

• SplDoublyLinkedList—TheSplDoublyLinkedListclass

• SplStack—TheSplStackclass

• SplQueue—TheSplQueueclass

• SplHeap—TheSplHeapclass

• SplMaxHeap—TheSplMaxHeapclass

• SplMinHeap—TheSplMinHeapclass

• SplPriorityQueue—TheSplPriorityQueueclass

• SplFixedArray—TheSplFixedArrayclass

• SplObjectStorage—TheSplObjectStorageclass

@antonioperic

#8UseSPL

• Iterators

• AppendIterator—TheAppendIteratorclass

• ArrayIterator—TheArrayIteratorclass

• CachingIterator—TheCachingIteratorclass

• CallbackFilterIterator—TheCallbackFilterIteratorclass

• DirectoryIterator—TheDirectoryIteratorclass

• EmptyIterator—TheEmptyIteratorclass

• FilesystemIterator—TheFilesystemIteratorclass

• FilterIterator—TheFilterIteratorclass

• GlobIterator—TheGlobIteratorclass

• InfiniteIterator—TheInfiniteIteratorclass

• …

@antonioperic

#8UseSPL

• Interfaces• Countable—TheCountableinterface

• OuterIterator—TheOuterIteratorinterface• RecursiveIterator—TheRecursiveIteratorinterface

• SeekableIterator—TheSeekableIterator

@antonioperic

#8UseSPL

• Exceptions

• BadFunctionCallException—TheBadFunctionCallExceptionclass

• BadMethodCallException—TheBadMethodCallExceptionclass

• DomainException—TheDomainExceptionclass

• InvalidArgumentException—TheInvalidArgumentExceptionclass

• LengthException—TheLengthExceptionclass

• LogicException—TheLogicExceptionclass

• OutOfBoundsException—TheOutOfBoundsException

• OutOfRangeException—TheOutOfRangeException

• OverflowException—TheOverflowException

• RangeException—TheRangeException

• RuntimeException—TheRuntimeException

• UnderflowException—TheUnderflowException

• UnexpectedValueException—TheUnexpectedValueExceptionclass

@antonioperic

#9Lawofdemeter(LoD)

• Eachunitshouldhaveonlylimitedknowledgeaboutotherunits:onlyunits"closely"relatedtothecurrentunit.

• Eachunitshouldonlytalktoitsfriends;don'ttalktostrangers.

• Onlytalktoyourimmediatefriends

• Helpyoubuildcodethatiseasiertotest

@antonioperic

#9Lawofdemeter

@antonioperic

#9LawofDemeter

@antonioperic

#9Lawofdemeter(LoD)

• Benefits:

• Keepobjectinstantionsimple

• Easiertomockobjects

• Simplifydependencygraph

@antonioperic

#10Comments

• Goodcomments

• Badcomments

• PHPDoc

• Don’tusecommentsfortrackinghistoryofchanges

@antonioperic

#11Usetools

• PHPCS

• PHP-CS-Fixer

• pDepend(performsstaticcodeanalysis)

• PHPLOC(AtoolforquicklymeasuringthesizeofaPHPproject)

• SensioLabsInsight

• phpmd(messdetector)

• PHPCPD(copypastedetector)

• PHPDCP(deadcodedetector)

• learnmoreaboutyourIDE(PHPStormisamazingtool)

@antonioperic

#12improveyourself

• readalotofcode

• http://www.livecoding.tv/

• workinpairs• doopensource-youwillgetalotoffreereviews

fromamazingdevelopers

• showyourcodetootherdevelopers

• gotoconferences

• beresponsiveforyourcode

@antonioperic

“Iliveandbreathemycodeandmycodeismostlythefunstuff.Youknowthelogic,thestuffthatmakescoolapplications,right?.“

Misko Havery

@antonioperic

#11Boy-scoutrule

@antonioperic

#12Boyscoutrule

• Alwayscheckamoduleincleanerthanwhenyoucheckeditout.

• Alwaysleavecodeinbettershapethenyoufoundit

@antonioperic

Conclusion

• Cleancodeis:

• structured

• simple

• consistent

• Useboyscoutrule

• Dosmallsteps

• Thereisnosilverbulletonlyhardwork

@antonioperic

References

• https://cleancoders.com/• CleanCode:AHandbookofAgileSoftwareCraftsmanship,RobertC.

Martin

• DottingYourI’sandCrossingYourT7s,JulietteReindersFolmer,IPCSprint2015

• Yourcodesucks,let'sfixit-ByRafaelDohms

• CleanCode,TobiasSchlitt,WebSummerCamp2016

• GoogleTechTalks,CleanCode• https://www.youtube.com/watch?v=HZJxjlvBbVA,CleanCode,

DavidDonahue

• PlentyofothertalksatYoutube

https://cleancoders.com/

https://www.youtube.com/playlist?list=PL693EFD059797C21E

https://www.youtube.com/watch?v=HZJxjlvBbVA

@antonioperic

Thankyou!

www.locastic.com [email protected]

@antonioperic

Maintainable + Extensible = Clean ... yes, Code!

Education

Transcript of Maintainable + Extensible = Clean ... yes, Code!