Stop being Rails developer

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WHY LIFE WITH RUBY ON RAILS BECOMES SO HARD AFTER FEW MONTHS OF DEVELOPMENT? IVAN NEMYTCHENKO

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IVAN NEMYTCHENKO > 14 years in IT > cofounded 2 IT-companies > occasional speaker > coorganized 2 HappyDev conferences > worked in a startup > worked as project-manager > working with Rails since 2006 > author of RailsHurts.com > internship for ruby junior developers: SkillGrid > twitter: @inem

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WHAT IS WRONG WITH RAILS?

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SAME PATTERN

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RAILSHURTS.COM/MESS

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RAILS-WAY IS NOT ENOUGH

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RAILS WORLD is so cool that we don't even have whole class of problems millions of java programmers struggring every day

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THESE THINGS MIGHT HELP YOU > SOLID principles > Design Patterns > Refactoring techniques > Architecture types > Code smells identification > Best practices of testing

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PRINCIPLES. MISUNDERSTOOD. APPLIED.

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DRY «DON'T REPEAT YOURSELF» RAILSHURTS.COM/_DRY

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JUST AVOID DUPLICATION, RIGHT?

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EVERYTHING HAS ITS PRICE

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PRICE: MORE RELATIONS

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«Duplication is far cheaper that wrong abstraction» — Sandi Metz

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KISS «KEEP IT SIMPLE, STUPID» RAILSHURTS.COM/_KISS

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RAILS IS SIMPLE, RIGHT?

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ACTIVERECORD class User < ActiveRecord::Base end

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ACTIVERECORD

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ACTIVERECORD > input data coercion > setting default values > input data validation > interaction with the database > handling nested structures > callbacks (before_save, etc...)

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- WHY SHOULD I CARE?

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Polymorphic STI model which belongs to another polymorphic model through third model, which also has some valuable JSON data stored in Postgres using hstore.

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WHAT ARE YOU GONNA DO? > reorganize associations > become Rails core contributor

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IT IS GOING TO BE PAINFUL

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PAINFUL BECAUSE OF THE COMPLEXITY

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RAILS IS NOT SIMPLE. IT IS CONVENIENT.

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FAT MODEL, SKINNY CONTROLLER RAILSHURTS.COM/_SKINNY

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RIGHT PROBLEM IDENTIFIED

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BUT IT IS ONLY PART OF THE PROBLEM

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YOU SHOULD HAVE NO FAT CLASSES AT ALL

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*HINT: PROPER SOLUTION REQUIRES THINKING OUT OF MVC BOX

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RAILS IS NOT YOUR APPLICATION RAILSHURTS.COM/_APP

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It just doesn't make sense. Here's my Rails application. Here's app folder. What's wrong?

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RAILSHURTS.COM/_CLEAN

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HEXXAGONAL ARCHITECTURE RAILSHURTS.COM/_HEXX

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YAGNI «YOU AREN'T GONNA NEED IT» RAILSHURTS.COM/_YAGNI

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WHAT IF YOUR APP DOESN'T NEED PERSISTANCE YET?

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WHAT IF YOUR APP CORE DOESN'T NEED WEB FRAMEWORK YET?

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«Question everything generally thought to be obvious» — Dieter Rams

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THREE RULES FOR DEVELOPERS WHO ARE NOT SURE OF ONE'S STRENGTH > Do not apply DRY principle too early > Remember about Single Responsibility Principle > Learn how to apply Design Patterns

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LET'S GET OUR HANDS DIRTY!

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FEATURE #1: USERS REGISTRATION

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FEATURE #1: USERS REGISTRATION

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SINGLE TABLE INHERITANCE ! CONDITIONAL VALIDATIONS !

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BOTH STI AND CONDITIONAL VALIDATIONS ARE JUST WORKAROUNDS THE PROBLEM IS DEEPER!

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SINGE RESPONSIBILITY PRINCIPLE: A CLASS SHOULD HAVE ONLY ONE REASON TO CHANGE

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OUR MODEL KNOWS ABOUT HOW.. > admin form is validated > org_user form is validated > guest_user form is validated > user data is saved

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FORM OBJECT !

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COOKING FORM OBJECT (STEP 1) class Person attr_accessor :first_name, :last_name def initialize(first_name, last_name) @first_name, @last_name = first_name, last_name end end

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COOKING FORM OBJECT (STEP 2) class Person attr_accessor :first_name, :last_name def initialize(first_name, last_name) @first_name, @last_name = first_name, last_name end include ActiveModel::Validations validates_presence_of :first_name, :last_name end

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COOKING FORM OBJECT (STEP 3) class Person include Virtus.model attribute :first_name, String attribute :last_name, String include ActiveModel::Validations validates_presence_of :first_name, :last_name end

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FORM OBJECT class OrgUserInput include Virtus.model include ActiveModel::Validations attribute :login, String attribute :password, String attribute :password_confirmation, String attribute :organization_id, Integer validates_presence_of :login, :password, :password_confirmation validates_numericality_of :organization_id end

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USING FORM OBJECT def create input = OrgUserInput.new(params) if input.valid? @user = User.create(input.to_hash) else #... end end

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FOUR SIMPLE OBJECTS INSTEAD OF ONE COMPLEX

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FEATURE #2: BONUSCODE REDEEM

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def redeem unless bonuscode = Bonuscode.find_by_hash(params[:code]) render json: {error: 'Bonuscode not found'}, status: 404 and return end if bonuscode.used? render json: {error: 'Bonuscode is already used'}, status: 404 and return end unless recipient = User.find_by_id(params[:receptor_id]) render json: {error: 'Recipient not found'}, status: 404 and return end ActiveRecord::Base.transaction do amount = bonuscode.mark_as_used!(params[:receptor_id]) recipient.increase_balance!(amount) if recipient.save && bonuscode.save render json: {balance: recipient.balance}, status: 200 else render json: {error: 'Error during transaction'}, status: 500 end end end

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SINGLE RESPONSIBILITY PRINCIPLE

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bonuscode.redeem_by(user) OR user.redeem_bonus(code) ?

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SERVICE OBJECT! (USE CASE, INTERACTOR)

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COOKING SERVICE OBJECT (STEP 1) class RedeemBonuscode def redeem unless bonuscode = Bonuscode.find_by_hash(params[:code]) render json: {error: 'Bonuscode not found'}, status: 404 and return end if bonuscode.used? render json: {error: 'Bonuscode is already used'}, status: 404 and return end unless recipient = User.find_by_id(params[:receptor_id]) render json: {error: 'Recipient not found'}, status: 404 and return end ActiveRecord::Base.transaction do amount = bonuscode.mark_as_used!(params[:receptor_id]) recipient.increase_balance!(amount) if recipient.save && bonuscode.save render json: {balance: recipient.balance}, status: 200 else render json: {error: 'Error during transaction'}, status: 500 end end end end

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COOKING SERVICE OBJECT (STEP 2) class RedeemBonuscode def run!(params) unless bonuscode = Bonuscode.find_by_hash(params[:code]) raise BonuscodeNotFound.new end if bonuscode.used? raise BonuscodeIsAlreadyUsed.new end unless recipient = User.find_by_id(params[:receptor_id]) raise RecipientNotFound.new end ActiveRecord::Base.transaction do amount = bonuscode.mark_as_used!(params[:receptor_id]) recipient.increase_balance!(amount) recipient.save! && bonuscode.save! end recipient.balance end end

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COOKING SERVICE OBJECT (STEP 3) def redeem use_case = RedeemBonuscode.new begin recipient_balance = use_case.run!(params) rescue BonuscodeNotFound, BonuscodeIsAlreadyUsed, RecipientNotFound => ex render json: {error: ex.message}, status: 404 and return rescue TransactionError => ex render json: {error: ex.message}, status: 500 and return end render json: {balance: recipient_balance} end

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BUSINESS LOGIC / CONTROLLER SEPARATION

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7 Patterns to Refactor Fat ActiveRecord Models railshurts.com/_7ways * * * Arkency railshurts.com/_arkency * * * Adam Hawkins railshurts.com/_hawkins