handle_redirect_loop_if_appears

handle_redirect_loop_if_appears.rb

class ApplicationController < ActionController::Base

  ...

  before_filter :handle_redirect_loop_if_appears
  ...
  after_filter :set_session_back_url
  ...

  def handle_redirect_loop_if_appears
    return session[:redirect_loop_count] = nil unless request_repeats?
    return session[:redirect_loop_count] = 1   unless session[:redirect_loop_count]

    max_observed_time_diff_betn_reqs_when_in_loop = 10000
    max_loop_count = 3

    session[:last_request_time] = Time.now.to_i

    session[:redirect_loop_count] += 1
    return if session[:redirect_loop_count] < max_loop_count

    if last_request_after < max_observed_time_diff_betn_reqs_when_in_loop
      session[:last_request_time]   = nil
      session[:redirect_loop_count] = nil

      redirect_to rescue_url and return
    end
  end

  def last_request_after
    return unless session[:last_request_time]

    time_diff = Time.now.to_i - session[:last_request_time].to_i
    time_diff = time_diff * (-1) if time_diff < 0
  end

  def rescue_url
    home_url
  end

  def home_url
    '/'
  end

  def request_repeats?
    session[:back_url] == request.fullpath
  end

  def set_session_back_url
    return unless request.get?
    return if request.xhr?

    session[:back_url] = request.fullpath
  end

  ...
end