Handling 404, 401 and 500 exceptions on Rails

gistfile1.rb

class ApplicationController < ActionController::Base  
  unless Rails.application.config.consider_all_requests_local
    	#rescue_from Exception, with: :render_500
  		rescue_from ActionController::RoutingError, with: :render_canvas_404
  		rescue_from ActionController::UnknownController, with: :render_404
  		rescue_from AbstractController::ActionNotFound, with: :render_404
  		rescue_from ActiveRecord::RecordNotFound, with: :render_404
  		rescue_from ActiveResource::ForbiddenAccess, with: :render_403
  	end
  
  def render_404(exception)
  
    	backtrace = exception.respond_to?(:backtrace) ? exception.backtrace : String.new
  
  	    logger.warn "**** NOT FOUND backtrace: #{exception.backtrace.slice(0,10).join("\n")} ******"
  	    
  	    @gallery_link = true
  
  	    respond_to do |format|
  	    	format.html { render 'errors/error_404', :layout => "application", :status => 404 }
  		    format.xml  { head 404 }
  		    format.any  { head 404 }
  	  	end
  	end
  
  	def render_canvas_404(exception)
  	    @not_found_path = exception.message
  	    @gallery_link = true
  
  	    respond_to do |format|
  	    	format.html { render 'errors/error_404', :layout => "application", :status => 404 }
  		    format.xml  { head 404 }
  		    format.any  { head 404 }
  	  	end
  	end
  
  	def render_500(exception)
  		@error = exception
  		
  		respond_to do |format|
  	    	format.html { render 'errors/error_500', :layout => "application", :status => 500 }
  		    format.xml  { head 500 }
  		    format.any  { head 500 }
  	  	end
  	end
  
  	def render_403(exception)
  		respond_to do |format|
  	    	format.html { render 'errors/error_403.html.erb', :layout => "application", :status => 403 }
  		    format.xml  { head 403 }
  		    format.any  { head 403 }
  	  	end
  	end
end