Abusing The Router (For Hexagonal Fun) - RoRoSyd December 12

A short overview of the Hexagonal Architecture style with some fun usages of the router to help us out.

Transcript

1. ABUSING
   THE ROUTER
   (FOR HEXAGONAL FUN)
   JON ROWE
   

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2. World.new.hello!
   Hi everybody. I’m Jon.
   

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3. World.new.hello!
   Hi everybody. I’m Jon.
   Freelance Rubyist.
   

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4. World.new.hello!
   Hi everybody. I’m Jon.
   Freelance Rubyist.
   Why is the rum gone?
   

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5. ABUSING
   THE ROUTER
   (FOR HEXAGONAL FUN)
   JON ROWE
   

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6. HEXAWAT?
   

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7. HEXAGONAL
   Hexagonal Architecture
   

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8. HEXAGONAL
   Hexagonal Architecture
   Describes the structure of an app
   

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9. HISTORY
   

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10. HISTORY
    Originally by Alistair Cockburn
    

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11. Application
    

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12. HISTORY
    Originally by Alistair Cockburn
    Also called “Ports and Adaptors”
    

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13. HEXAGONAL
    

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14. HEXAGONAL
    Decouple the application
    

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15. HEXAGONAL
    Decouple the application
    Make the business logic the focus
    

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16. HEXAGONAL
    Decouple the application
    Make the business logic the focus
    Provide adaptors for technology
    

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17. HEXAGONAL
    Decouple the application
    Make the business logic the focus
    Provide adaptors for technology
    Provide adaptors for I/O
    

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18. HEXAGONAL RAILS
    

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19. HEXAGONAL RAILS
    Describes structure of application
    

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20. HEXAGONAL RAILS
    Describes structure of application
    but... Rails is not the application
    

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21. HEXAGONAL RAILS
    Describes structure of application
    but... Rails is not the application
    ... Rails is the HTTP Adaptor
    

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22. HEXAGONAL RAILS
    Describes structure of application
    but... Rails is not the application
    ... Rails is the HTTP Adaptor
    Describes building apps *with* Rails
    

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23. Application
    

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24. RAILS
    DB
    LOGGING
    CMD LINE
    Application
    

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25. WHY?
    

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26. WHY?
    Separate responsibilities
    

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27. WHY?
    Separate responsibilities
    Push dependencies inwards
    

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28. WHY?
    Separate responsibilities
    Push dependencies inwards
    Make things more explicit
    

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29. WHY?
    

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30. WHY?
    Modular code
    

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31. WHY?
    Modular code
    Isolated / Testable code
    

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32. WHY?
    Modular code
    Isolated / Testable code
    Cleaner code
    

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33. HOW?
    

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34. HOW?
    Dependency Injection / Inversion
    

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35. HOW?
    Dependency Injection / Inversion
    Pure Ruby service classes
    

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36. HOW?
    Dependency Injection / Inversion
    Pure Ruby service classes
    Response Objects
    

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37. HOW?
    Dependency Injection / Inversion
    Pure Ruby service classes
    Response Objects
    Define an API
    

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38. BUT WAIT...
    WASN’T THIS TALK ABOUT THE ROUTER?
    

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39. Pushing Inwards
    

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40. Pushing Inwards
    Dependency Inversion
    

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41. Pushing Inwards
    Dependency Inversion
    Push things down into the app
    

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42. Pushing Inwards
    Dependency Inversion
    Push things down into the app
    Take decisions early
    

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43. Pushing Inwards
    Dependency Inversion
    Push things down into the app
    Take decisions early
    Tell don’t ask
    

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44. Rails
    

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45. Rails
    The router is top of the Rails stack
    

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46. Rails
    The router is top of the Rails stack
    Push inwards from there
    

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47. Rails
    The router is top of the Rails stack
    Push inwards from there
    Without an addition to the framework?
    

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48. Rails
    The router is top of the Rails stack
    Push inwards from there
    Without an addition to the framework?
    

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49. resources :one, controller: :generic, type: One
    resources :two, controller: :generic, type: Two
    controller GenericController
    def show
    params[:type].find params[:id]
    end
    #snip...
    end
    Router
    

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50. resources :listing
    class ListingController
    before_filter :ensure_admin!, except: :show
    #snip...
    end
    Router
    

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51. namespace :admin
    resources :listing, except: :show
    end
    resources :listing, only: :show
    Router
    

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52. constraint IsAdmin do
    resources :listing, except: :show
    end
    constraint IsUser do
    resources :listing, only: :show
    end
    Router
    

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53. Constraints
    class IsAdmin
    def self.matches? request
    request.env[‘warden.env’].user!.is_admin?
    end
    end
    class IsUser
    def self.matches? request
    request.env[‘warden.env’].user!
    end
    end
    

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54. Constraints
    constraint AllowedAccess.new(:beta) do
    resource :shiney_thing
    end
    class AllowedAccess < Struct.new(:feature)
    attr_reader :feature
    def matches? request
    unless Features.new(user).allow? feature
    throw :warden, Warden::Redirect...
    end
    end
    end
    

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55. Summary
    

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56. Summary
    Push things inwards
    

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57. Summary
    Push things inwards
    Isolate your business logic
    

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58. Summary
    Push things inwards
    Isolate your business logic
    Bend Rails to your application
    

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59. Summary
    Push things inwards
    Isolate your business logic
    Bend Rails to your application
    Have fun!
    

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60. THANKS
    @jonrowe (Twitter, GitHub, etc)
    http://jonrowe.co.uk
    P.S. I’m available...
    

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