class ActionDispatch::ActionableExceptions

def actionable_request?(request)
  request.get_header("action_dispatch.show_detailed_exceptions") && request.post? && request.path == endpoint
end

def call(env)
  request = ActionDispatch::Request.new(env)
  return @app.call(env) unless actionable_request?(request)
  ActiveSupport::ActionableError.dispatch(request.params[:error].to_s.safe_constantize, request.params[:action])
  redirect_to request.params[:location]
end

def initialize(app)
  @app = app
end

def redirect_to(location)
  uri = URI.parse location
  if uri.relative? || uri.scheme == "http" || uri.scheme == "https"
    body = ""
  else
    return [400, { Rack::CONTENT_TYPE => "text/plain; charset=utf-8" }, ["Invalid redirection URI"]]
  end
  [302, {
    Rack::CONTENT_TYPE => "text/html; charset=#{Response.default_charset}",
    Rack::CONTENT_LENGTH => body.bytesize.to_s,
    ActionDispatch::Constants::LOCATION => location,
  }, [body]]
end