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Luca Guidi March 22nd, 2013 A Rails Criticism how i learned to stop worrying about the Golden Path

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AGENDA intro

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Luca Guidi Senior Developer at Litmus @jodosha - http//lucaguidi.com

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litmus Beautiful Email previews Campaign analytics Spam filter tests HTML code analysis And many other..

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Why Rails has revolutionized web development? (IMHO)

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Why Rails has revolutionized web development? (IMHO) Convention Over Configuration :)

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Why Rails has revolutionized web development? (IMHO) Convention Over Configuration Dynamic and innovative ecosystem :)

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Why Rails has revolutionized web development? (IMHO) Convention Over Configuration Dynamic and innovative ecosystem Productivity and Developer Happiness :)

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..but The Framework is almost ten years old

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..but The Framework is almost ten years old A Lot of Legacy Code is around

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..but The Framework is almost ten years old A Lot of Legacy Code is around Upgrades to a major release are *painful*

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AGENDA intro problems

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Active Record Active Record

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Models != Records Active Record

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Encapsulation violations Active Record 1 if article.state != 'published' 2 article.update_attribute(state: 'published') 3 end 1 unless article.published? 2 article.publish! 3 end 4 # not completely right...

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Encapsulation violations Active Record 1 if article.state != 'published' 2 article.update_attribute(state: 'published') 3 end 1 unless article.published? 2 article.publish! 3 end 4 # not completely right...

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Encapsulation violations Active Record 1 if article.state != 'published' 2 article.update_attribute(state: 'published') 3 end 1 unless article.published? 2 article.publish! 3 end 4 # not completely right...

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Tell, Don’t Ask violations Active Record 1 unless article.published? 2 article.publish! 3 end 4 # not completely right... 1 article.publish! 2 # push the implementation 3 # into the model

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Tell, Don’t Ask violations Active Record 1 unless article.published? 2 article.publish! 3 end 4 # not completely right... 1 article.publish! 2 # push the implementation 3 # into the model

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Tell, Don’t Ask violations Active Record 1 unless article.published? 2 article.publish! 3 end 4 # not completely right... 1 article.publish! 2 # push the implementation 3 # into the model

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Implicit vs Explicit API Active Record 1 Post.where(state:'published'). 2 order('created_at DESC'). 3 limit(5) 1 Post.most_recent_published 1 class Post < ActiveRecord::Base 2 def self.most_recent_published(limit = 5) 3 published.recent(limit).order('created_at DESC') 4 end 5 6 private 7 scope :published, ->() { where(state: 'published') } 8 scope :recent, ->(n) { limit(n) } 9 end

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Implicit vs Explicit API Active Record 1 Post.where(state:'published'). 2 order('created_at DESC'). 3 limit(5) 1 Post.most_recent_published 1 class Post < ActiveRecord::Base 2 def self.most_recent_published(limit = 5) 3 published.recent(limit).order('created_at DESC') 4 end 5 6 private 7 scope :published, ->() { where(state: 'published') } 8 scope :recent, ->(n) { limit(n) } 9 end

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Implicit vs Explicit API Active Record 1 Post.where(state:'published'). 2 order('created_at DESC'). 3 limit(5) 1 Post.most_recent_published 1 class Post < ActiveRecord::Base 2 def self.most_recent_published(limit = 5) 3 published.recent(limit).order('created_at DESC') 4 end 5 6 private 7 scope :published, ->() { where(state: 'published') } 8 scope :recent, ->(n) { limit(n) } 9 end

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Implicit vs Explicit API Active Record 1 Post.where(state:'published'). 2 order('created_at DESC'). 3 limit(5) 1 Post.most_recent_published 1 class Post < ActiveRecord::Base 2 def self.most_recent_published(limit = 5) 3 published.recent(limit).order('created_at DESC') 4 end 5 6 private 7 scope :published, ->() { where(state: 'published') } 8 scope :recent, ->(n) { limit(n) } 9 end

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Callbacks abuse Active Record Non-persistence logic is tight to the persistence life cycle. Eg. Sending emails

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Testability issues Active Record Micheal Feathers

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Testability issues Active Record A test is not a unit test if it talks to a database. Micheal Feathers

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Action Controller Action Controller It doesn’t affect too much your architecture, but it has strange OOP design.

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Frankenstein Controllers Action Controller 1 class PostsController < ApplicationController 2 before_filter :authenticate 3 4 def new 5 end 6 7 def create 8 @post = Post.new(params[:post]) 9 10 if @post.save 11 redirect_to post_url(@post), notice: 'Yay!' 12 else 13 render :new 14 end 15 end 16 end !& !! !& "! !& !%! #! " %"!

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Frankenstein Controllers Action Controller 1 class PostsController < ApplicationController 2 before_filter :authenticate 3 4 def new 5 end 6 7 def create 8 @post = Post.new(params[:post]) 9 10 if @post.save 11 redirect_to post_url(@post), notice: 'Yay!' 12 else 13 render :new 14 end 15 end 16 end !& !! !& "! !& !%! #! " %"!

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Frankenstein Controllers Action Controller 1 class PostsController < ApplicationController 2 before_filter :authenticate 3 4 def new 5 end 6 7 def create 8 @post = Post.new(params[:post]) 9 10 if @post.save 11 redirect_to post_url(@post), notice: 'Yay!' 12 else 13 render :new 14 end 15 end 16 end !& !! !& "! !& !%! #! " %"!

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Frankenstein Controllers Action Controller 1 class PostsController < ApplicationController 2 before_filter :authenticate 3 4 def new 5 end 6 7 def create 8 @post = Post.new(params[:post]) 9 10 if @post.save 11 redirect_to post_url(@post), notice: 'Yay!' 12 else 13 render :new 14 end 15 end 16 end !& !! !& "! !& !%! #! " %"!

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Frankenstein Controllers Action Controller 1 class PostsController < ApplicationController 2 before_filter :authenticate 3 4 def new 5 end 6 7 def create 8 @post = Post.new(params[:post]) 9 10 if @post.save 11 redirect_to post_url(@post), notice: 'Yay!' 12 else 13 render :new 14 end 15 end 16 end !& !! !& "! !& !%! #! " %"!

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Frankenstein Controllers Action Controller 1 class PostsController < ApplicationController 2 before_filter :authenticate 3 4 def new 5 end 6 7 def create 8 @post = Post.new(params[:post]) 9 10 if @post.save 11 redirect_to post_url(@post), notice: 'Yay!' 12 else 13 render :new 14 end 15 end 16 end !& !! !& "! !& !%! #! " %"!

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1 class PostsController < ApplicationController 2 # ... 3 4 def create 5 @post = Post.new(params[:post]) 6 7 if @post.save 8 # ... 9 else 10 # ... 11 end 12 end 13 end Odd classes Action Controller $!! ! "&! " %"&!!% !!!! $!!! %

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1 class PostsController < ApplicationController 2 # ... 3 4 def create 5 @post = Post.new(params[:post]) 6 7 if @post.save 8 # ... 9 else 10 # ... 11 end 12 end 13 end Odd classes Action Controller $!! ! "&! " %"&!!% !!!! $!!! %

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1 class PostsController < ApplicationController 2 # ... 3 4 def create 5 @post = Post.new(params[:post]) 6 7 if @post.save 8 # ... 9 else 10 # ... 11 end 12 end 13 end Odd classes Action Controller $!! ! "&! " %"&!!% !!!! $!!! %

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1 class PostsController < ApplicationController 2 # ... 3 4 def create 5 @post = Post.new(params[:post]) 6 7 if @post.save 8 # ... 9 else 10 # ... 11 end 12 end 13 end Odd classes Action Controller $!! ! "&! " %"&!!% !!!! $!!! %

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1 class PostsController < ApplicationController 2 # ... 3 4 def create 5 @post = Post.new(params[:post]) 6 # ... 7 end 8 end Encapsulation violations Action Controller $!! ! #$!! ! #$

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1 class PostsController < ApplicationController 2 # ... 3 4 def create 5 @post = Post.new(params[:post]) 6 # ... 7 end 8 end Encapsulation violations Action Controller $!! ! #$!! ! #$

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1 describe PostsController do 2 it 'assigns @posts' do 3 Post.should_receive(:most_recent_published). 4 and_return(posts = [mock]) 5 get :index 6 7 expect(assigns(:posts)).to eq(posts) 8 end 9 end Testability issues Action Controller !!! ! &!!! % $ !"!! !!! !!' ! ( ! !!!!

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1 describe PostsController do 2 it 'assigns @posts' do 3 Post.should_receive(:most_recent_published). 4 and_return(posts = [mock]) 5 get :index 6 7 expect(assigns(:posts)).to eq(posts) 8 end 9 end Testability issues Action Controller !!! ! &!!! % $ !"!! !!! !!' ! ( ! !!!!

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1 describe PostsController do 2 it 'assigns @posts' do 3 Post.should_receive(:most_recent_published). 4 and_return(posts = [mock]) 5 get :index 6 7 expect(assigns(:posts)).to eq(posts) 8 end 9 end Testability issues Action Controller !!! ! &!!! % $ !"!! !!! !!' ! ( ! !!!!

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1 describe PostsController do 2 it 'assigns @posts' do 3 Post.should_receive(:most_recent_published). 4 and_return(posts = [mock]) 5 get :index 6 7 expect(assigns(:posts)).to eq(posts) 8 end 9 end Testability issues Action Controller !!! ! &!!! % $ !"!! !!! !!' ! ( ! !!!!

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1 describe PostsController do 2 it 'assigns @posts' do 3 Post.should_receive(:most_recent_published). 4 and_return(posts = [mock]) 5 get :index 6 7 expect(assigns(:posts)).to eq(posts) 8 end 9 end Testability issues Action Controller !!! ! &!!! % $ !"!! !!! !!' ! ( ! !!!!

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1 describe PostsController do 2 it 'assigns @posts' do 3 Post.should_receive(:most_recent_published). 4 and_return(posts = [mock]) 5 get :index 6 7 expect(assigns(:posts)).to eq(posts) 8 end 9 end Testability issues Action Controller !!! ! &!!! % $ !"!! !!! !!' ! ( ! !!!!

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Action View Action View

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Views aren’t views Action View (but templates with logic) Without “real” views (or presenters), we’re tempted to push presentational methods into the models. In an ideal world we shouldn’t test our templates.

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Helpers are functional programming Action View 1 def user_full_name(user) 2 [ user.first_name, user.last_name ].join(' ') 3 end 4 5 url_for 6 # vs 7 Url.for 8 9 posts_url Half-assed way to solve presentational problems in ActionView.

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Helpers are functional programming Action View 1 def user_full_name(user) 2 [ user.first_name, user.last_name ].join(' ') 3 end 4 5 url_for 6 # vs 7 Url.for 8 9 posts_url Half-assed way to solve presentational problems in ActionView.

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Ruby on Rails Ruby on Rails

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Rails isn’t a framework, but an application template Ruby on Rails

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Rails is multi-paradigm as Ruby is. Ruby on Rails

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AGENDA intro problems solutions

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Decouple your logic from ActiveRecord as much as possible. Solutions AR is focused on data, but OOP is about behavior.

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Don’t think in ActiveRecord terms. Solutions Database is a detail, forget about associations, scopes, validations..

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Let your public API to declare intents. Solutions Let your design to emerge via TDD.

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Keep methods and accessors private as much as possible. Solutions Public APIs are hard to maintain as the codebase and the team grows.

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Skinny controllers and skinny models. Solutions Use service objects or DCI, they are easier and faster to test.

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Don’t be afraid to extract ad-hoc classes for specific responsibilities. Solutions Inner classes are your friends, they help you with details, and aren’t part of your public API.

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Use DIY presenters Solutions They will help you to keep your models clean from presentational logic.

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Refactor, refactor, refactor. Solutions

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AGENDA intro problems solutions conclusion

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Q&A

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me@lucaguidi.com @jodosha https://speakerdeck.com/jodosha/a-rails-criticism Except where otherwise noted, this work is licensed under: http://creativecommons.org/licenses/by-nc-sa/3.0/

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