Django“类型”对象不可迭代

Question

我使用 Django Rest Framework 制作了一个简单的 API，列出了学生们所尊敬的大学。列出数据的 url 是http://127.0.0.1:8000/api/v1/students/。尝试API后，我收到以下错误

TypeError at /api/v1/students/
'type' object is not iterable

Internal Server Error: /api/v1/students/
Traceback (most recent call last):
  File "/Users/gilangramadhanilhami/Desktop/88sparses/shipment/tracking/lib/python3.6/site-packages/django/core/handlers/exception.py", line 35, in inner
    response = get_response(request)
  File "/Users/gilangramadhanilhami/Desktop/88sparses/shipment/tracking/lib/python3.6/site-packages/django/core/handlers/base.py", line 128, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/Users/gilangramadhanilhami/Desktop/88sparses/shipment/tracking/lib/python3.6/site-packages/django/core/handlers/base.py", line 126, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/Users/gilangramadhanilhami/Desktop/88sparses/shipment/tracking/lib/python3.6/site-packages/django/views/decorators/csrf.py", line 54, in wrapped_view
    return view_func(*args, **kwargs)
  File "/Users/gilangramadhanilhami/Desktop/88sparses/shipment/tracking/lib/python3.6/site-packages/django/views/generic/base.py", line 69, in view
    return self.dispatch(request, *args, **kwargs)
  File "/Users/gilangramadhanilhami/Desktop/88sparses/shipment/tracking/lib/python3.6/site-packages/rest_framework/views.py", line 477, in dispatch
    request = self.initialize_request(request, *args, **kwargs)
  File "/Users/gilangramadhanilhami/Desktop/88sparses/shipment/tracking/lib/python3.6/site-packages/rest_framework/views.py", line 379, in initialize_request
    authenticators=self.get_authenticators(),
  File "/Users/gilangramadhanilhami/Desktop/88sparses/shipment/tracking/lib/python3.6/site-packages/rest_framework/views.py", line 273, in get_authenticators
    return [auth() for auth in self.authentication_classes]
TypeError: 'type' object is not iterable

我在 StackOverflow 上找到了一些解决方案，但找到解决方案的运气并不好。我正在文件APIView中使用views.py，我想了解为什么在我使用时会发生这种情况APIView（使用时也会出现此问题Viewset）。

我尝试过更改权限并没有帮助。同样设置many=True为“False”也没有解决问题。

有人有什么想法吗？提前致谢。

这是其他文件，以便更好地理解这个问题

模型.py

from django.db import models

class University(models.Model):
    name = models.CharField(max_length=50)
    url = models.URLField(unique=True)

    class Meta:
        verbose_name = "University"
        verbose_name_plural = "Universities"

    def __str__(self):
        return self.name

class Student(models.Model):
    first_name = models.CharField(max_length=50)
    last_name = models.CharField(max_length=50)
    university = models.ForeignKey(University, on_delete=models.CASCADE,)

    class Meta:
        verbose_name = "Student"
        verbose_name_plural = "Students"


    def __str__(self):
        return '%s %s' % (self.first_name, self.last_name)

序列化器.py

from rest_framework import serializers

from . import models

class StudentSerializer(serializers.ModelSerializer):
    class Meta:
        fields = (
            'id',
            'first_name',
            'last_name',
            'university'
        )
        model = models.Student

class UniversitySerializer(serializers.ModelSerializer):
    class Meta:
        fields = (
            'id',
            'name',
            'url'
        )
        model = models.University

视图.py

from rest_framework.views import APIView
from rest_framework.response import Response

from . import models
from . import serializers

class ListStudent(APIView):
    def list(self, request, format=None):
        students = models.Student.objects.all()
        serializer = serializers.StudentSerializer(students, many=True)
        return Response(serializer.data)

学生/urls.py

from django.urls import path

from . import views

urlpatterns = [
    path('', views.ListStudent.as_view(), name='student_list')
]

urls.py

from django.contrib import admin
from django.urls import path, include

urlpatterns = [
    path('admin/', admin.site.urls),
    path('api-auth/', include('rest_framework.urls', namespace='rest_framework')),
    path('api/v1/students/', include(('students.urls','students'), namespace='students')),
]

Answer 1

我认为这是一个小错误。我的'DEFAULT_AUTHENTICATION_CLASSES'样子是这样的

REST_FRAMEWORK = {
    'DEFAULT_AUTHENTICATION_CLASSES': (
        'rest_framework.authentication.SessionAuthentication'

    ),
    'DEFAULT_PERMISSION_CLASSES': (
        'rest_framework.permissions.IsAuthenticatedOrReadOnly'
    ),
}

我这里缺少的是一个简单的,. 应该是这样的

REST_FRAMEWORK = {
    'DEFAULT_AUTHENTICATION_CLASSES': (
        'rest_framework.authentication.SessionAuthentication',

    ),
    'DEFAULT_PERMISSION_CLASSES': (
        'rest_framework.permissions.IsAuthenticatedOrReadOnly',
    ),
}

我明白了“可迭代”这个词的含义。希望这可以帮助。