'Handles GET requests, if the response is cached it returns it'

def default_open(self, request):

    if (request.get_method() != 'GET'):
        return None
    if exists_in_cache(self.cache_location, request.get_full_url(), self.max_age):
        return CachedResponse(self.cache_location, request.get_full_url(), set_cache_header=True)
    else:
        return None
