model.py 文件源码

def _most_recent_property(
            cls, name, property_name, default_value=None, serialize=lambda x: x, deserialize=lambda x: x, ttl=120):

        cache_key = CrashReport.recent_crash_property_key(name, property_name)
        most_recent_value = memcache.get(cache_key)
        if most_recent_value is None:
            most_recent = 0
            most_recent_value = default_value

            q = CrashReport.all()
            q.filter('name = ', name)
            for entity in q.run():
                in_millis = to_milliseconds(entity.date_time)
                if most_recent <= in_millis:
                    most_recent = in_millis
                    most_recent_value = serialize(entity.__getattribute__(property_name))
            memcache.set(cache_key, most_recent_value, ttl)
        to_return = deserialize(most_recent_value)
        return to_return