Sanity on Rails — How to write maintainable Rails applications in 2017

Rails is not your application! Don’t overcomplicate your development life by trying to make everything fit within its MVC structure. A framework provides tools and abstractions, use them to build your business logic, don’t force your business logic to fit into them.

Transcript

1. Sanity on Rails
   Michael Kohl
   
   Deccan RubyConf 2017
   

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2. • Michael Kohl (@citizen428)
   
   • CTO @ Lockstep Labs
   
   • Based in Bangkok, Thailand
   
   • Ruby developer since ~2004
   
   • Former mentor at RubyLearning
   Deccan RubyConf 2017
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   Yours truly
   

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3. Deccan RubyConf 2017
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   The problem
   

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4. Deccan RubyConf 2017
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   The problem
   • Recurring problems
   
   • Dependencies
   
   • Framework entanglement
   
   • Implicit code
   
   • Good news: easily avoidable
   

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5. Deccan RubyConf 2017
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   Dependencies
   

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6. Deccan RubyConf 2017
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   Dependencies
   • Bootstrap the app faster
   
   • Prevent “not invented here syndrome”
   
   • Get peer reviewed
   
   • Easily get outdated
   
   • Memory footprint & startup times
   
   • Have more dependencies
   

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7. Deccan RubyConf 2017
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   Dependencies
   • Be selective about dependencies
   
   • Look for actively maintained gems
   
   • Use gems for common tasks
   
   • Prefer developers with vested interest
   

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8. Deccan RubyConf 2017
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   Dependencies
   

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9. Deccan RubyConf 2017
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   Dependencies
   

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10. Deccan RubyConf 2017
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    Framework entanglement
    

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11. "A basic conceptional structure
    
    (as of ideas)"
    
    – Merriam Webster
    
    "A basic structure underlying a
    system, concept, or text." –
    
    Oxford English dictionary
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    Frameworks
    

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12. Deccan RubyConf 2017
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    Frameworks - Controllers
    • Abstracting HTTP communication
    
    • Authentication
    
    • Authorization
    
    • Sessions / cookies
    
    • Param validation / transformation
    
    • Redirection / rendering
    

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13. Deccan RubyConf 2017
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    Frameworks - Controllers
    # Actions
    resources :actions, only: [:index]
    namespace :actions do
    resource :enqueue_cvs, only: [:create]
    resource :import_cvs, only: [:create]
    resource :generate_suggestions, only: [:create]
    resource :logs, only: [:destroy]
    end
    # Users
    resources :users, except: [:new, :edit, :show]
    namespace :users do
    resources :filters, only: [:create]
    resources :passwords, only: [:create, :edit, :update]
    end
    

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14. Deccan RubyConf 2017
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    Frameworks - Models
    • Wrapper around datastore
    
    • ActiveRecord configuration
    
    • Associations
    
    • Validations
    
    • Finders / scopes
    
    • Simple accessors / mutation methods
    

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15. Deccan RubyConf 2017
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    Frameworks - Models
    • Extract POROs
    
    • Various extraction patterns
    
    • Service objects
    
    • Form objects
    
    • Query objects
    
    • many more
    
    • Use namespacing
    

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16. Deccan RubyConf 2017
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    Frameworks - Models
    ! tree app/services/cv
    app/services/cv
    "## file_mover.rb
    "## importer.rb
    "## parser.rb
    "## repository.rb
    "## suggestion_handler.rb
    $## viewer.rb
    

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17. Deccan RubyConf 2017
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    Frameworks - Models
    require_dependency 'cv'
    class Cv
    # Class for importing CV files into ElasticSearch in a standardized way.
    class Importer
    attr_accessor :file_name, :content, :md5sum, :file_type, :attributes, :parse
    def self.import(file_name, content, attr = {})
    new(file_name, content, attr).import
    end
    def initialize(file_name, content, attr = {})
    self.file_name = File.basename(file_name)
    …
    parse_attributes(attr)
    end
    def import
    add_to_es
    extract_plaintext
    parse_cv if parse
    end
    

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18. Deccan RubyConf 2017
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    Frameworks - Models
    Credit: Code Climate
    

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19. Deccan RubyConf 2017
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    Frameworks - Models
    class AbandonedTrialQuery
    def initialize(relation = Account.scoped)
    @relation = relation
    end
    def find_each(&block)
    @relation.
    where(plan: nil, invites_count: 0).
    find_each(&block)
    end
    end
    Credit: Code Climate
    

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20. Deccan RubyConf 2017
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    Frameworks - Views
    • Response generation
    
    • Should be mostly logic free
    
    • Rails conflates view model & template
    
    • Helpers become dumping grounds
    

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21. Deccan RubyConf 2017
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    Frameworks - Views
    class UserView < ApplicationView
    include ActionView::Helpers::TagHelper
    forward :first_name, :last_name
    def formatted_full_name
    content_tag :strong, "#{first_name} #{last_name}"
    end
    end
    

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22. Deccan RubyConf 2017
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    Implicit code
    

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23. Deccan RubyConf 2017
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    Implicit code
    • “Convention over configuration”
    
    • Magic:
    
    • AR configuration
    
    • Instance variables in views
    
    • Implicit code:
    
    • AR callbacks
    
    • before_action/after_action
    

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24. Deccan RubyConf 2017
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    Implicit code
    • Hard for newcomers to understand
    
    • Hard to follow code flow
    
    • Easy, not simple
    
    • Doesn’t apply in all cases
    

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25. Deccan RubyConf 2017
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    Implicit code
    • Be more explicit!
    
    • Reading is more important than writing!
    
    • POROs to encapsulate processes
    
    • Don’t try to be too clever!
    

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26. • Be selective when adding gems
    
    • Build business logic on top of what Rails
    provides, don’t mix it with framework
    code
    
    • Explicit is often better than implicit
    
    • There are no silver bullets, all software
    development involves tradeoffs.
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    Summary
    

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27. • How DHH Organizes His Rails Controllers

    http://jeromedalbert.com/how-dhh-organizes-
    his-rails-controllers/
    
    • 7 Patterns to Refactor Fat ActiveRecord Models

    http://blog.codeclimate.com/blog/2012/10/17/7-
    ways-to-decompose-fat-activerecord-models/
    
    • Objects on Rails

    http://objectsonrails.com
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    Resources
    

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28. Deccan RubyConf 2017
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    Thank you!
    

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