Django Rest Framework 3.0 to_representation未實現

Question

我正在使用Django 1.7.1和Python 2.7從Django Rest Framework 2.4升級到3.0.1，並且無法通過以下錯誤：

File "/Users/bjacobel/.virtualenvs/hey/lib/python2.7/site-packages/rest_framework/fields.py", line 375, in to_representation
    raise NotImplementedError('to_representation() must be implemented.')

我正在使用的代碼在2.4下運行得很好，我很難找到關於我正在使用的DRF類中發生了什么變化的任何文檔。 除了我的一個端點（為django.contrib.auth.models.User提供CRUD的那個端點之外，我注釋掉了所有端點，但我仍然得到錯誤。

serializers.py ：

from django.contrib.auth.models import User
from rest_framework import serializers

class UserSerializer(serializers.ModelSerializer):
    class Meta:
        model = User
        fields = ('id', 'first_name', 'last_name', 'email', 'username')

views.py ：

from django.contrib.auth.models import User
from hey.apps.api import serializers
from rest_framework import viewsets, permissions, filters

class User(viewsets.ModelViewSet):
    queryset = User.objects.all()
    serializer_class = serializers.UserSerializer
    permission_classes = (permissions.IsAuthenticated,)
    filter_backends = (filters.OrderingFilter,)

urls.py ：

from django.conf.urls import patterns, url, include
from hey.apps.api import views
from rest_framework.routers import SimpleRouter

router = SimpleRouter()


router.register(r'user', views.User)

urlpatterns = patterns('',
    url(r'^', include(router.urls)),
)

pagination.py

from rest_framework import pagination
from rest_framework import serializers

class LinksSerializer(serializers.Serializer):
    next = pagination.NextPageField(source='*')
    prev = pagination.PreviousPageField(source='*')

class CustomPaginationSerializer(pagination.BasePaginationSerializer):
    links = LinksSerializer(source='*')  # Takes the page object as the source
    total_results = serializers.Field(source='paginator.count')

    results_field = 'objects'

settings.py

REST_FRAMEWORK = {
    'DEFAULT_PAGINATION_SERIALIZER_CLASS': 'hey.apps.api.pagination.CustomPaginationSerializer',
    'PAGINATE_BY': 20,                  # Default to 20
    'PAGINATE_BY_PARAM': 'limit',       # Allow client to override, using `?limit=xxx`.
    'MAX_PAGINATE_BY': 100,             # Maximum limit allowed when using `?limit=xxx`.
    'TEST_REQUEST_DEFAULT_FORMAT': 'json',
    'DEFAULT_AUTHENTICATION_CLASSES': (
        'rest_framework.authentication.BasicAuthentication',
        'rest_framework.authentication.TokenAuthentication',
        'rest_framework.authentication.SessionAuthentication',
    )
}

謝謝。

Answer 1

問題出現在你的分頁序列化程序中，因為你正在使用serializers.Field ，它現在是Django REST Framework 3.0中的serializers.ReadOnlyField 。 這是一個微妙的變化，雖然它在發布公告中被提及，但對於那些超越分頁序列化器的人來說，這是最明顯的。

更新的默認分頁序列化程序使用ReadOnlyField作為count字段。 您應該可以通過交換字段來修復序列化程序。

class CustomPaginationSerializer(pagination.BasePaginationSerializer):
    links = LinksSerializer(source='*')  # Takes the page object as the source
    total_results = serializers.ReadOnlyField(source='paginator.count')

    results_field = 'objects'