Sample Masquerades Controller

application_controller.rb

class ApplicationController < ActionController::Base
  
  helper_method :masquerading?, :current_unit_measure
  
protected
  
  def masquerading?
    session[:masked_id].present?
  end

end

index.html.haml

.page-header
  %h1
    %i.icon-eye-open
    Who would you like to spy?
  %blockquote Be careful...


%h3 Select a user:
%table.table.table-striped
  %thead
    %th #
    %th First name
    %th Last name
    %th Email
    %th Actions

  %tbody
    - @users.each do |user|
      - if current_user.id != user.id
        %tr
          %td= user.id
          %td= user.first_name
          %td= user.last_name
          %td= mail_to user.email
          %td
            = link_to new_masquerade_path(masquerade_user_id: user.id), class: 'btn btn-danger' do
              %i.icon-eye-open
              Masquerade!

  %thead
    %th #
    %th First name
    %th Last name
    %th Email
    %th Actions

masquerades_controller.rb

class MasqueradesController < ApplicationController

  before_filter :authenticate_user!
  before_filter :authorize_super_admin!

  def index
    @users = User.all

    respond_to do |format|
      format.html
    end
  end

  def new
    user = User.find(params[:masquerade_user_id])
    session[:masked_id] = current_user.id
    sign_in(user)

    redirect_to root_path, notice: "Now masquerading as #{user.full_name}"
  end

  def escape
    if (user = User.find(session[:masked_id])) && session[:masked_id].present?
      sign_in(user)
    end
    session[:masked_id] = nil

    redirect_to root_path, notice: "Stopped masquerading"
  end

protected

  def authorize_super_admin!
    redirect_to root_path, notice: "Unatorized" unless current_user.super_admin? || masquerading?
  end

end

routes.rb

SampleApp::Application.routes.draw do
  ###
  # Masquerade!!!
  resources :masquerades, only: [:index, :new] do
    collection do
      get :escape
    end
  end
end