Overview

• Rails Controllers + Instance Variables
• Decent Exposure Overview
• Decent Exposure Magic explained
• Configuration
• Customization
• Questions? Comments?

Rails Controllers + Instance Variables

• Instance variables are available to views via the controller

app/controllers/posts_controller.rb def show @post = Post.find(params[:id]) end

app/views/posts/show.html.erb <p> <strong>Title:</strong> <%= @post.title %> </p> <p> <strong>Text:</strong> <%= @post.text %> </p>

Rails Controllers + Instance Variables - Problems

• Breaks encapsulation
• Set in multiple places (helper, filter, action). Leads to: "where did this come from?" or "what is this?"

app/controllers/posts_controller.rb def show @post = Post.find(params[:id]) @text = @post.text end

app/views/posts/show.html.erb <p> <strong>Title:</strong> <%= @post.title %> </p> <p> <strong>Text:</strong> <%= @text %> </p>

• Hard to stub instance variables while testing

Decent Exposure Overview - Rails Scaffold

Rails default scaffold

class PeopleController < ApplicationController before_action :set_person, only: [:show, :edit, :update, :destroy] def index @people = Person.all end def show end def new @person = Person.new end def edit end def create @person = Person.new(person_params) if @person.save redirect_to @person, notice: 'Person was successfully created.' else render action: 'new' end end def update if @person.update(person_params) redirect_to @person, notice: 'Person was successfully updated.' else render action: 'edit' end end def destroy @person.destroy redirect_to people_url, notice: 'Person was successfully destroyed.' end private def set_person @person = Person.find(params[:id]) end def person_params params[:person] end end

Decent Exposure Overview - decent_exposure

class PeopleController < ApplicationController expose(:person) def create if person.save redirect_to(person) else render :new end end def update if person.save redirect_to(person) else render :edit end end private def person_params # example of strong parameters params.require(:person).permit(:name) end end

<p> <strong>Name:</strong> <%= person.name %> </p>

Decent Exposure - Magic explained

• Updates attributes, marks as dirty

class PeopleController expose(:person) def create if person.save redirect_to(person) else render :new end end end

person.attributes = params[:person] # update_attributes(params[:person])

Decent Exposure - Magic explained cont.

Decent Exposure - Magic explained cont.

Decent Exposure - Magic explained cont.

Configuration

Specify the model name:

expose(:company, model: :enterprisey_company)

Specify the parameter accessor method:

expose(:company, params: :company_params)

Specify the finder method (ie: reset password):

expose(:article, finder: :find_by_slug)

Specify the parameter key to use to fetch the object:

expose(:article, finder_parameter: :slug)

Off the beaten path (careful):

expose(:environment) { Rails.env }

Customization (Strategies)

• strong_parameters

class ApplicationController < ActionController::Base decent_configuration do strategy DecentExposure::StrongParametersStrategy end end

class PeopleController < ApplicationController expose(:person, attributes: :person_params) private def person_params params.require(:person).permit(:name) end end

• person_params will only be called on a PUT, POST or PATCH request.

Questions? Comments?

• Questions? Comments?
  
  
  
  
  

Refs

• https://github.com/voxdolo/decent_exposure
• http://decentexposure.info/