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rails_controller.rb
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This guide applies to a Ruby on Rails Controller class. It is part of Jo Hund’s Software Engineering Guide.

 

      		
    

    

      
        

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class ProjectsController < ApplicationController
  

      		
    

    

      
        

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Configuration

      		
      
        

      		
    

    

      
        

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 First we include other modules. They add new behavior to the controller. We want to know about
 this right away.

      		
      
        
  include Canable::Permissions
  

      		
    

    

      
        

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 Then we define any filters. Order is important here as an earlier before_filter that halts the
 filter_chain will prevent subsequent filters from being run.



 If using caches_action, it is critical to have before_filters declared before the cache directive.
 Action cache uses around filters. If your before_filters are further down the filter_chain than
 the cache around filter, the before filter might bever get executed (e.g. to check permissions to
 a resource).

      		
      
        
  before_filter :load_client
  before_filter :require_login
  

      		
    

    

      
        

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 Then we provide cache directives

      		
      
        
  caches_action :index
  

      		
    

    

      
        

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Controller Actions



 We keep the order of actions as generated by scaffolding. Makes it easy to find things.

      		
      
        
  

      		
    

    

      
        

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 Index action



    

  1. Check for permissions. Do it before instantiating in this action.
    2. 

  2. Instantiate collection
    3. 

  3. Response block
    4. 


      		
      
        
  def index
    enforce_list_permission(Project)
    @projects = Project.all

    respond_to do |format|
      format.html
      format.js
    end
  end
  

      		
    

    

      
        

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 Show action



    

  1. Instantiate object. If possible, scope the collection by the current_user to help
keeping your data secure.
    2. 

  2. Check for permissions.
    3. 

  3. Response block.
    4. 


      		
      
        
  def show
    @project = current_user.projects.all
    enforce_view_permission(@project)

    respond_to do |format|
      format.html
      format.js
    end
  end
  

      		
    

    

      
        

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 New action



    

  1. Instantiate object.
    2. 

  2. Check for permissions.
    3. 

  3. Response block.
    4. 


      		
      
        
  def new
    @project = current_user.projects.build
    enforce_create_permission(@project)

    respond_to do |format|
      format.html
      format.js
    end
  end
  
  def edit
  end
  

      		
    

    

      
        

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 Create action



    

  1. Instantiate object.
    2. 

  2. Check for permissions.
    3. 

  3. Persist new object.
    4. 

  4. Response block, conditional on success.
    5. 


      		
      
        
  def create
    @project = current_user.projects.build
    enforce_create_permission(@project)
    
    respond_to do |format|
      if @project.save
        flash[:notice] = 'Project was successfully created.'
        format.html { redirect_to(@project) }
        format.js
      else
        format.html { render :action => "new" }
        format.js
      end
    end
  end
  

      		
    

    

      
        

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 Update action



    

  1. Instantiate object.
    2. 

  2. Check for permissions.
    3. 

  3. Update and persist object.
    4. 

  4. Response block, conditional on success.
    5. 

  5. Redirect after successful update (http://en.wikipedia.org/wiki/Post/Redirect/Get)
    6. 


      		
      
        
  def update
    @project = current_user.projects.find(params[:id])
    enforce_update_permission(@project)

    respond_to do |format|
      if @project.update_attributes(params[:project])
        flash[:notice] = 'Project was successfully updated.'
        format.html { redirect_to(@project) }
        format.js
      else
        format.html { render :action => "edit" }
        format.js
      end
    end
  end
  

      		
    

    

      
        

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 Destroy action



    

  1. Instantiate object.
    2. 

  2. Check for permissions.
    3. 

  3. Destroy object.
    4. 

  4. Response block.
    5. 


      		
      
        
  def destroy
    @project = current_user.projectsfind(params[:id])
    enforce_destroy_permission(@project)
    @project.destroy

    respond_to do |format|
      format.html { redirect_to(projects_path) }
      format.js
    end
  end
  

      		
    

    

      
        

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 Next are protected actions. The protected keyword is not indented.

      		
      
        
protected

  def a_protected_method
  end
  

      		
    

    

      
        

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 And finally are private actions. The private keyword is not indented.


      		
      
        
private

  def a_private_method
  end

end