Error handling for API serving Rails apps

gistfile1.rb

class ApplicationController < ActionController::Base
 
  rescue_from PermissionDenied { |e| http_status_code(:forbidden, e) }
  rescue_from AccountExpired   { |e| http_status_code(:payment_required, e) }
 
  def http_status_code(status, exception)
    respond_to do |format|
      self.response.headers["X-Exception"] = @exception = exception
      format.html { render :template => "shared/status_#{status.to_s}", :status => status }
      format.any  { head status }
    end
  end
 
end