carwin_activity/util/default_key_constructor.py

# coding=utf-8
from rest_framework_extensions.key_constructor.bits import ListSqlQueryKeyBit, PaginationKeyBit, RetrieveSqlQueryKeyBit, \
    KeyBitBase
from rest_framework_extensions.key_constructor.constructors import DefaultKeyConstructor

from datetime import datetime
from django.core.cache import cache


class UpdatedAtKeyBit(KeyBitBase):
    key = "updated_at"

    def get_data(self, **kwargs):
        value = cache.get(self.key, None)
        if not value:
            value = datetime.utcnow()
            cache.set(self.key, value=value)
        return str(value)