rails.md

Rails

Programming

• Write DRY code during development any project.

• Order variables and methods alphabetically when possible.

• Use 2 space indentation.

• Do not make any spelling mistakes or grammar mistakes. Use proper english words.

• put space if needs. like- <% if current_user %>(correct) <%if current_user%>(wrong). Another example: "hello" (correct) " hello " (wrong)

• Use valid syntax. If you are using rails 5 version, then follow rails 5 syntax. Example: don't use => like- (:presence => true), use (presence: true)

• Do not repeat same code, write it inside helper. Example: suppose you are styling a button with some front-awesome style and this same button needs in more than one places, then write it inside a helper method and then call it from view and pass link path.

  # bad
  # index.html.erb
  <%= link_to ('<i class="fa fa-trash" title="Delete Details"></i> Delete').html_safe,
                employee_path(employee),
                method: :delete,
                data: { confirm: "Are you sure?" },
                class: 'btn btn-danger btn-sm' %>
  
  # show.html.erb
  <%= link_to ('<i class="fa fa-trash" title="Delete Details"></i> Delete').html_safe,
                employee_path(@employee),
                method: :delete,
                data: { confirm: "Are you sure?" },
                class: 'btn btn-danger btn-sm' %>
  
  # good
  # helper.rb
  def delete_link(path)
    link_to ('<i class="fa fa-trash" title="Delete Details"></i> Delete').html_safe,
              path,
              method: :delete,
              data: { confirm: "Are you sure?" },
              class: 'btn btn-danger btn-sm'
  end
  
  # index.html.erb
  <%= delete_link(employee_path(employee)) %>
  
  # show.html.erb
  <%= delete_link(employee_path(@employee)) %>

• Name of the helper(or variable/funcation/scope) should reflect its purpose.

• Try to avoid comment messages unless the code is too complicated

• Always use lastest syntax.

Bundler

• Put gems in alphabetical order in the Gemfile.

• Do not use any unnecessary gems in your project.

• Use only established gems in your projects. If you're contemplating on including some little-known gem you should do a careful review of its source code first.

• If your project needs different gems for different environments, then group it for that specific environment.

  group :development, :test do
    gem 'mysql2'   #mysql for development
    gem 'pry-rails', "~> 0.3.4"
  end
  
  group :production do
    gem 'pg'    #postgresql for production
  end

• Do not remove the Gemfile.lock from version control. This is not some randomly generated file - it makes sure that all of your team members get the same gem versions when they do a bundle install.

Migrations

• Keep the schema.rb under version control and arrange it well, so that it clearly understandable.

• Add database level validation as well model level validation

• Enforce foreign-key constraints.

• When writing constructive migrations (adding tables or columns), use the change method instead of up and down methods.

  # the old way
  class AddNameToPeople < ActiveRecord::Migration
    def up
      add_column :people, :name, :string
    end
  
    def down
      remove_column :people, :name
    end
  end
  
  # the new preferred way
  class AddNameToPeople < ActiveRecord::Migration
    def change
      add_column :people, :name, :string
    end
  end

• If you are writing something within up migration, write it in the reverse order within down migration if needed.

• After migrating a migration use rollback command to check whether the database can return to its previous state or not.

Routing

• When you need to add more actions use member and collection routes.

  # bad
  get 'subscriptions/:id/unsubscribe'
  resources :subscriptions
  
  # good
  resources :subscriptions do
    get 'unsubscribe', on: :member
  end
  
  # bad
  get 'photos/search'
  resources :photos
  
  # good
  resources :photos do
    get 'search', on: :collection
  end

• If you need to define multiple member/collection routes use the alternative block syntax.

  resources :items do
    member do
      get 'allocate'
      put 'reallocate'
      # more routes
    end
  end
  
  resources :photos do
    collection do
      get 'search'
      # more routes
    end
  end

• Use nested routes to express better the relationship between ActiveRecord models.

  class Post < ActiveRecord::Base
    has_many :comments
  end
  
  class Comments < ActiveRecord::Base
    belongs_to :post
  end
  
  # routes.rb
  resources :posts do
    resources :comments
  end

• Left unnecessary routes if those routes are not used. Use except/only for the purpose.

  resources :users, except: [:show]
  resources :employee, except: [:show, :edit, :update]

Controllers

• Keep the controllers skinny - they should only retrieve data for the view layer and shouldn't contain any business logic (all the business logic should naturally reside in the model).

• If more than one action in a controller contains same lines of code, then write it into seperate a method and use callback funcation to invoke it on those action.

  # bad
  # controller.rb
  def edit
    @category = Category.find(params[:id])  
  end
  
  def show
    @category = Category.find(params[:id])
    @category_items = @category.items.paginate(page: params[:page], per_page: 5)
  end
  
  #good
  # controller.rb
  before_action :get_category, only: [:edit, :show]
  def show
    @category_items = @category.items.paginate(page: params[:page], per_page: 5)
  end
  
  def get_category
    @category = Category.find(params[:id])
  end

• If current_user exists in browser, then don't need to hit database every time you need curent_user.

  #bad
  def current_user
    @current_user = User.find(session[:user_id]) if session[:user_id]
  end
  
  #good
  def current_user
    @current_user ||= User.find(session[:user_id]) if session[:user_id]
  end

• Remove n + 1 query problem from all places in your project.

• Your code should be precise. Like, use flash in single line.

  #bad
  redirect_to users_path
  flash[:notice] = "User successfully created."
  
  #good
  redirect_to users_path, flash: { success: "User successfully created." }

Model

• Write your model simple and well formated. Group same type of method. Follow this coding pattern for model.

  class Issue < ActiveRecord::Base
    enum priority: [:high, :medium, :low, :as_soon_as_possible]
  
    belongs_to :item, optional: true
    belongs_to :system, optional: true     
  
    has_many :resolution, optional: true    
  
    validates :title, presence: true       
    validate  :item_or_system_presence
    validate  :item_closed_at_limitation
    validate  :system_closed_at_limitation
  
    scope :order_desending, -> { order('created_at DESC') }
    scope :unclosed,        -> { where(closed_at: nil) }
  
    def item_or_system_presence
      unless [item, system].any?
        errors.add :base, 'Item / System must be present!'
      end
    end
  end

• Generate model from terminal. Do not create model.rb and migration your own, let rails to do it for you.

  rails generate model Item name:string description:text
  

• Choose a proper name for methods, scopes etc.

Views

• Please do not use inline style.

• Try to avoid html_safe. Instead of using this - link_to("Add".html_safe, new_user_path(@user), class: "btn") , we should use link_to block.

  <% link_to(new_user_path(@user), class: "btn") do %>
    <span>Add</span>
  <% end %>

• Try to use partial instead of writing same code multiple time.