import basehashclass Hasher:    """    对数据库ID进行散列化计算    """    base36 = basehash.base62(11)    @classmethod    def from_model(cls, obj):        if obj.pk is None:            return None        return cls.make_hash(obj.pk)    @classmethod    def make_hash(cls, object_pk):        return cls.base36.hash('%(object_pk)d' % {            'object_pk': object_pk        })    @classmethod    def to_object_pk(cls, obj_hash):        unhashed = '%d' % cls.base36.unhash(obj_hash)        object_pk = int(unhashed)        return object_pk

class BaseModel(models.Model):    """自定义Model基类"""    create_at = models.DateTimeField(auto_now_add=True, verbose_name='创建时间')    update_at = models.DateTimeField(auto_now=True, verbose_name='更新时间')    delete_at = models.DateTimeField(null=True, blank=True, default=None, verbose_name='删除时间')    class Meta:        abstract = True    @property    def hash(self):        return Hasher.from_model(self)

class HashRetrieveViewSetMixin(GenericViewSet):    """使用Hash检索对象的ViewSet基类"""    def get_object(self):        queryset = self.filter_queryset(self.get_queryset())        obj = self.get_obj_from_hash(self.kwargs['pk'], queryset)        self.check_object_permissions(self.request, obj)        return obj    def get_obj_from_hash(self, hash_id, queryset):        """根据hash_id获取obj对象"""        pk = self.hash_to_pk(hash_id)        obj = get_object_or_404(queryset, pk=pk)        return obj    @staticmethod    def hash_to_pk(hash_id):        """Hash 转 id"""        try:            pk = Hasher.to_object_pk(hash_id)        except ValueError:            raise ParseError('parse error')        return pk