Download - Dancing about architecture
The idiomatic approach embodied in Railsenables rapid development.
• Built in discrete layers• Models, views, and controllers• Controllers implement CRUD• Routes are RESTful• /lib = whatever doesn’t fit MVC
IdiomaticRails
But rapid development comes at a cost.
• Business logic leaking through the layers
• Raw SQL in models
• Complex object dependencies
• Conditional logic everywhere
• Controllers with non-CRUD methods
• Route exceptions become the norm
• Slow test suite execution
• /lib overflow
symptoms of a mature rails application
“Most software eventually degrades to the point where someone will declare the design to be unsound.”-- Uncle Bob
• Rigidity
• Fragility
• Immobility
• Feature friction
warning signs of adegraded design
Bad design happens one line of code at a time.
• Duplicated code
• Long methods
• God objects
• Feature envy
• Class intimacy
• Contrived complexity
• Übercallbacks
commoncode smells
• Reek
• Flog
• RSpec
• Bug reports
• Feature requests
• Intuition
refactoringtoolkit
• TDD until it doesn’t hurt anymore
• Build the interface you want to have
• Hexagonal architecture
• Verbs as nouns
refactoringpatterns
• Let the test suite tell you where the pain points are
• Test only what you’re testing
• Stub everything else
• If you can’t stub it, it’s supposed to be a method
• Avoid factories
• Refactor until your methods are shorter than your tests
test-drivendevelopment
• Build a new object
• Add the methods you wish you had
• Wrap the methods that you do have
• Refactor until it’s symmetrical
interface-drivendesign
• Layered architectures are a convenient metaphor but break down quickly in a real app
• Build a Ruby application and integrate it with Rails, not the other way around
• Allow your application to be driven by users, programs, automated tests, batch scripts, ...
• Don't think in layers, think in ports
• Everything is an API
hexagonalarchitecture
hexagonalarchitecture
WebBrowser
RakeTask
APIClient
TestingFramework
APIServer
Database
Mocks
iOSApplication
CommandLine
Domain ObjectsPersistence
HTTP
Com
man
d Lin
eM
essaging
DefaultLogger
ExternalMonitoring
Service
EmailService
• Classes don’t have to represent business objects
• Classes can represent processes
• Classes can represent interactions
• Classes can represent workflows
• Do you need a run method, or a running class?
gerunds:the verb-as-noun
Agile development has democratized architecture.
.: we are all architects.
Be the best architect you can be.
