Question

我正在尝试遵循Django Rest Framework和VueJS的教程，以使它们一起工作。现在，在使用JSONRenderer render函数时，我遇到了以下问题：

AttributeError: 'ReturnList' object has no attribute 'get'

我的列表视图是：

from rest_framework import status
from rest_framework.generics import ListAPIView, RetrieveAPIView
from rest_framework.permissions import AllowAny
from rest_framework.response import Response
from .models import Cat
from .renderers import CatJSONRenderer
from .serializers import CatSerializer, CatListSerializer
class CatListApiView(ListAPIView):
    model = Cat
    queryset = Cat.objects.all()
    permissions_classes = (AllowAny, )
    renderer_classes = (CatJSONRenderer, )
    serializer_class = CatListSerializer

我的renderers.py是：

class CatJSONRenderer(JSONRenderer):
    charset = 'utf-8'
    def render(self, data, media_type=None, renderer_context=None):
        print(data)
        errors = data.get('errors', None)

        if errors is not None:
            return super(CatJSONRenderer, self).render(data)

        return json.dumps({'cats': data})

回溯是：

Traceback:

File "/home/ytsejam/.virtualenvs/londonyogavidya/lib/python3.7/site-packages/django/core/handlers/exception.py" in inner
  34.             response = get_response(request)

File "/home/ytsejam/.virtualenvs/londonyogavidya/lib/python3.7/site-packages/django/core/handlers/base.py" in _get_response
  156.                 response = self.process_exception_by_middleware(e, request)

File "/home/ytsejam/.virtualenvs/londonyogavidya/lib/python3.7/site-packages/django/core/handlers/base.py" in _get_response
  154.                 response = response.render()

File "/home/ytsejam/.virtualenvs/londonyogavidya/lib/python3.7/site-packages/django/template/response.py" in render
  106.             self.content = self.rendered_content

File "/home/ytsejam/.virtualenvs/londonyogavidya/lib/python3.7/site-packages/rest_framework/response.py" in rendered_content
  72.         ret = renderer.render(self.data, accepted_media_type, context)

File "/home/ytsejam/public_html/londoner/yogavidya/apps/cat/renderers.py" in render
  7.         errors = data.get('errors', None)

Exception Type: AttributeError at /api/cats/
Exception Value: 'ReturnList' object has no attribute 'get'

我该如何解决这个问题？谢谢

Answer 1

我可以通过安装from bokeh.io import show from bokeh.layouts import widgetbox from bokeh.models import ColumnDataSource, Slider, DataTable, TableColumn, CustomJS source = ColumnDataSource(dict(x = list(range(6)), y = [x ** 2 for x in range(6)])) columns = [TableColumn(field = "x", title = "x"), TableColumn(field = "y", title = "x**2")] table = DataTable(source = source, columns = columns, width = 320) slider = Slider(start = 1, end = 100, value = 6, step = 1, title = "i", width = 300) callback_code = """ i = slider.value; new_data = {"x": [1, 2, 3, 4, 5], "y": [1, 4, 9, 16, 25]} table.source.data = new_data table.width = 320 + i * 25; """ callback = CustomJS(args = dict(slider = slider, table = table), code = callback_code) slider.js_on_change('value', callback) show(widgetbox(slider, table))来解决此问题。如果有人遇到问题，这会将django-rest-framework-json-api.转换为dict。

Answer 2

这可能不是解决此问题的正确方法，但它或多或少是一种解决方法。我发现，在不分页资源的情况下，它会返回data类型的 <class 'rest_framework.utils.serializer_helpers.ReturnList'>。 render()类的renderer方法可以处理的实际期望输出为<class 'collections.OrderedDict'>。我所做的是在分页返回<class 'collections.OrderedDict'>时用资源实现分页。下面的代码段是我的代码示例，供求职者审查。

class CategoryList(MyListCreateAPIView): 
    #without the pagination implementation
    queryset = Category.objects.all()
    serializer_class = CategorySerializer
    ... # for brevity
    renderer_classes = (CategoryJSONRenderer,)

初始资源网址为http://localhost:8000/categories/

class CategoryList(MyListCreateAPIView):
    # with pagination implementation
    ... # for brevity
    pagination_class = StandardResultsSetPagination

资源网址现在看起来像http://localhost:8000/categories/?limit=5。分页资源可以解决整个问题。

Github comment制作的@jsenecal证明了整个解决方法。

DRF JSONRenderer'ReturnList'对象没有属性'get'

2 个答案: