from rest_framework.pagination import PageNumberPagination
from rest_framework.exceptions import ParseError

class MyPagination(PageNumberPagination):
    page_size = 10
    page_size_query_param = 'page_size'

    def paginate_queryset(self, queryset, request, view):
        if request.query_params.get('pageoff', None) or request.query_params.get('page', None)=='0':
            if queryset.count()<500:
                return None
            elif queryset.count()>=500:
                raise ParseError('单次请求数据量大,请分页获取')
        return super().paginate_queryset(queryset, request, view=view)