call

# File actionpack/lib/action_dispatch/middleware/show_exceptions.rb, line 31
    def call(env)
      @app.call(env)
    rescue Exception => exception
      request = ActionDispatch::Request.new env
      backtrace_cleaner = request.get_header("action_dispatch.backtrace_cleaner")
      wrapper = ExceptionWrapper.new(backtrace_cleaner, exception)
      request.set_header "action_dispatch.exception", wrapper.unwrapped_exception
      request.set_header "action_dispatch.report_exception", !wrapper.rescue_response?

      if wrapper.show?(request)
        render_exception(request.dup, wrapper)
      else
        raise exception
      end
    end