Talk at Deccan RubyConf 2017, Pune, India

1. Sanity on Rails
Michael Kohl
Deccan RubyConf 2017

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

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The problem

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The problem
• Recurring problems
• Dependencies
• Framework entanglement
• Implicit code
• Good news: easily avoidable

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Dependencies

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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• Easily get outdated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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Dependencies
• Be selective about dependencies
• Look for actively maintained gems
• Use gems for common tasks
• Prefer developers with vested interest

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Dependencies

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Dependencies

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Framework entanglement

11. "A basic conceptional structure
(as of ideas)"
– Merriam Webster
"A basic structure underlying a
system, concept, or text." –
Oxford English dictionary
Deccan RubyConf 2017locksteplabs.com
Frameworks

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Frameworks - Controllers
• Abstracting HTTP communication
• Authentication
• Authorization
• Sessions / cookies
• Param validation / transformation
• Redirection / rendering

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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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Frameworks - Models
• Wrapper around datastore
• ActiveRecord configuration
• Associations
• Validations
• Finders / scopes
• Simple accessors / mutation methods

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

17. Deccan RubyConf 2017locksteplabs.com
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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Frameworks - Models
Credit: Code Climate

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

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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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Implicit code

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

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.
Deccan RubyConf 2017locksteplabs.com
Summary

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
Deccan RubyConf 2017locksteplabs.com
Resources

28. Deccan RubyConf 2017locksteplabs.com
Thank you!