backend - rest-framework设置自定义返回

转自https://blog.csdn.net/yyy72999/article/details/84287243

这里我需要自定义返回的json的格式，主要是因为我需要返回状态码code，返回信息msg，以及原始数据data

我在工程目录下的backend app中，新建了一个文件夹utils
并创建文件

custom_json_response.py

from django.utils import six
from rest_framework.response import Response
from rest_framework.serializers import Serializer


class JsonResponse(Response):
    """
    An HttpResponse that allows its data to be rendered into
    arbitrary media types.
    """

    def __init__(self, data=None, code=None, msg=None,
                 status=None,
                 template_name=None, headers=None,
                 exception=False, content_type=None):
        """
        Alters the init arguments slightly.
        For example, drop 'template_name', and instead use 'data'.
        Setting 'renderer' and 'media_type' will typically be deferred,
        For example being set automatically by the `APIView`.
        """
        super(Response, self).__init__(None, status=status)

        if isinstance(data, Serializer):
            msg = (
                'You passed a Serializer instance as data, but '
                'probably meant to pass serialized `.data` or '
                '`.error`. representation.'
            )
            raise AssertionError(msg)

        self.data = {"code": code, "message": msg, "data": data}
        self.template_name = template_name
        self.exception = exception
        self.content_type = content_type

        if headers:
            for name, value in six.iteritems(headers):
                self[name] = value

这个类是用来包装返回rest-framework返回的json数据，可以看到它继承自rest_framework.response.Response

那么如何引用这个自定义返回呢，我们需要重写rest-framework的viewset类

custom_viewset_base.py

from rest_framework import status
from rest_framework import viewsets
from backend.utils.json_response import JsonResponse
from rest_framework import filters
from django_filters import rest_framework


class CustomViewBase(viewsets.ModelViewSet):
    # pagination_class = LargeResultsSetPagination
    # filter_class = ServerFilter
    queryset = ''
    serializer_class = ''
    permission_classes = ()
    filter_fields = ()
    search_fields = ()
    filter_backends = (rest_framework.DjangoFilterBackend, filters.SearchFilter, filters.OrderingFilter,)

    def create(self, request, *args, **kwargs):
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        self.perform_create(serializer)
        headers = self.get_success_headers(serializer.data)
        return JsonResponse(data=serializer.data, msg="success", code=201,
                            status=status.HTTP_201_CREATED, headers=headers)

    def list(self, request, *args, **kwargs):
        queryset = self.filter_queryset(self.get_queryset())
        page = self.paginate_queryset(queryset)
        if page is not None:
            serializer = self.get_serializer(page, many=True)
            return self.get_paginated_response(serializer.data)

        serializer = self.get_serializer(queryset, many=True)
        return JsonResponse(data=serializer.data, code=200, msg="success", status=status.HTTP_200_OK)

    def retrieve(self, request, *args, **kwargs):
        instance = self.get_object()
        serializer = self.get_serializer(instance)
        return JsonResponse(data=serializer.data, code=200, msg="success", status=status.HTTP_200_OK)

    def update(self, request, *args, **kwargs):
        partial = kwargs.pop('partial', False)
        instance = self.get_object()
        serializer = self.get_serializer(instance, data=request.data, partial=partial)
        serializer.is_valid(raise_exception=True)
        self.perform_update(serializer)

        if getattr(instance, '_prefetched_objects_cache', None):
            # If 'prefetch_related' has been applied to a queryset, we need to
            # forcibly invalidate the prefetch cache on the instance.
            instance._prefetched_objects_cache = {}

        return JsonResponse(data=serializer.data, msg="success", code=200, status=status.HTTP_200_OK)

    def destroy(self, request, *args, **kwargs):
        instance = self.get_object()
        self.perform_destroy(instance)
        return JsonResponse(data=[], code=204, msg="delete resource success", status=status.HTTP_204_NO_CONTENT)

可以看到每一个方法都返回了刚才定义的JsonResponse

分页器也需要重新定义

custom_pagination.py

from rest_framework.pagination import PageNumberPagination, LimitOffsetPagination
from collections import OrderedDict
from rest_framework.response import Response


class LargeResultsSetPagination(LimitOffsetPagination):
    page_size = 10
    page_size_query_param = 'page_size'
    max_page_size = 10000

    def get_paginated_response(self, data):
        code = 200
        msg = 'success'
        if not data:
            code = 404
            msg = "Data Not Found"

        return Response(OrderedDict([
            ('code', code),
            ('msg', msg),
            ('count', self.count),
            ('next', self.get_next_link()),
            ('previous', self.get_previous_link()),
            ('data', data),
        ]))

并自定错误处理

custom_exception.py

from rest_framework.views import exception_handler


def custom_exception_handler(exc, context):
    # Call REST framework's default exception handler first,
    # to get the standard error response.
    response = exception_handler(exc, context)

    # Now add the HTTP status code to the response.
    if response is not None:
        print(response.data)
        print(response)
        response.data.clear()
        response.data['code'] = response.status_code
        response.data['data'] = []

        if response.status_code == 404:
            try:
                response.data['message'] = response.data.pop('detail')
                response.data['message'] = "Not found"
            except KeyError:
                response.data['message'] = "Not found"

        if response.status_code == 400:
            response.data['message'] = 'Input error'

        elif response.status_code == 401:
            response.data['message'] = "Auth failed"

        elif response.status_code >= 500:
            response.data['message'] = "Internal service errors"

        elif response.status_code == 403:
            response.data['message'] = "Access denied"

        elif response.status_code == 405:
            response.data['message'] = 'Request method error'
        response.code = response.status_code
        response.status_code = 200
    return response

上述的分页器和错误处理函数，需要在setting.py中引用

REST_FRAMEWORK = {
    'DEFAULT_PAGINATION_CLASS': 'backend.utils.custom_pagination.LargeResultsSetPagination',
    'PAGE_SIZE': 10,
    'EXCEPTION_HANDLER': 'backend.utils.custom_exception_handler.custom_exception_handler',
}

最后一步，我们之前写好的View中的类，不再继承自rest_framework.viewsets，而是继承自我们自己定义的custom_viewset_base

如，user.py

from django.contrib.auth.models import User
from backend.utils.viewset_base import CustomViewBase
from backend.serializers.user import UserSerializer


class UserViewSet(CustomViewBase):
    """
    API endpoint that allows users to be viewed or edited.
    """
    queryset = User.objects.all().order_by('-date_joined')
    serializer_class = UserSerializer

运行后，可以看到json返回增加了code字段和message字段

另：为了增强的filter，可以安装'django_filters'并在django中引用

INSTALLED_APPS = [
   ...
    'django_filters',
]