Rack error redirector

error_redirection.rb

# This rack engine redirects to external URLs when some error is thrown.
# How to use it?
# Just add the rack middleware in config/application.rb
#   require 'rack/error_redirection'
#   config.app_middleware.insert_before('ActionDispatch::ShowExceptions', 'Rack::ErrorRedirection')
# And fill the error_404_url and error500_url variables
module Rack
  class ErrorRedirection
    def initialize(app)
      @app = app
    end
    def call(env)
      response = @app.call(env)
      Rails.logger.debug response.inspect
      if response[0] == "404"
        ["302", { Location: error_404_url}, '']
      elsif response[0] == "500"
        ["302", { Location: error_500_url}, '']
      else
        response
      end
    end
  end
end