Question

Hello Guy我是Django的新手。我使用Rest API与Django与我的Android应用程序进行交互。 我有变量任务所需的数据。由于有多个问题我使用过滤器而不是get。

这是我的Views.py：

class MapertablesViewSet(viewsets.ModelViewSet):
    """
    API endpoint that allows groups to be viewed or edited.
    """
    queryset = Mapertables.objects.all()
    serializer_class = MapertablesSerializer
    lookup_field = 'category_id'

    def get_queryset(self):
        #print self.kwargs['category_id']
        maps = Mapertables.objects.filter(category_id=self.kwargs['category_id'])
        #queryset = list(maps)
        #queryset =  serializers.serialize('json',maps)
        #print "AAAA ",queryset
        i = 0
        #quest ={}
        queryset = []
        queslist = []
        for question in maps:
            quest = {}
            quest['question'] = question.question_id
            #print 'qqqq  ',question.question_id
            #queryset =  serializers.serialize('json',[question,])
            choices = Choice.objects.filter(question=question.question_id)
            print choices
            #aaa = chain(question,choices)
            #print aaa
            #queryset =  serializers.serialize('json',[question,choices,])
            j = 0
            for option in choices:
                quest[j] = option.choice_text
                j += 1
            print 'data Here ',quest
            #data Here  {0: u'Highbury', 1: u'Selhurst Park', 2: u'The Dell', 3: u'Old Trafford', 'question': <Question: At which ground did Eric Cantona commit his "Kung Fu" kick ?>}
            serializer_class = CoustomeSerializer(queryset, many=True)
            print serializer_class.data
            #[]
            json = JSONRenderer().render(serializer_class.data)
            print 'JSON',json
            #[]
            i += 1

        queryset = queslist
        serializer_class = CoustomeSerializer(queryset,many=True)
        return queryset
        #print "questions",queslist
        #print "Ser ",ser.data

这是我的serializers.py：

class  MapertablesSerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        model =  Mapertables
        fields = ('question_id','category_id')


class CoustomeSerializer(serializers.HyperlinkedModelSerializer):
    #questions =  MapertablesSerializer(source='question_id')
    #choices = ChoiceSerializer(source='choice_text')
    class Meta:
        model = Question,Choice,Category
        fields = ('choice_text','choice_text','choice_text','choice_text','question_id')

定义为显示的网址： http://127.0.0.1:8000/mapers/ 异常类型：KeyError 例外值：'category_id'

当我查询特定类别时，它返回： http://127.0.0.1:8000/mapers/2/ { “细节”：“没找到。” }

Model.py文件如下：

from django.db import models

# Create your models here.
class Category(models.Model):
    category_name = models.CharField(max_length=200,default='1')
    def __str__(self):
        return self.category_name


class Question(models.Model):
    question_text = models.CharField(max_length=200)
    #category_name = models.ForeignKey(Category)
    pub_date = models.DateTimeField('date published')
    def was_published_recently(self):
        return self.pub_date >= timezone.now() - datetime.timedelta(days=1)
    was_published_recently.admin_order_field = 'pub_date'
    was_published_recently.boolean = True
    was_published_recently.short_description = 'Published recently?'
    def __str__(self):
        return self.question_text


class Mapertables(models.Model):
    category_id = models.ForeignKey(Category)
    question_id = models.ForeignKey(Question)


class Choice(models.Model):
    question = models.ForeignKey(Question)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0)
    def __str__(self):
        return self.choice_text

我想获得与类别相关的所有问题，并且选择模块中的选项可以解释为什么get_queryset中的所有内容。

请告诉我如何在MapertablesViewSet类中获取我所需的所有数据

如果您希望我发送完整项目，请提前告知我，我会提前打印并将其上传到驱动器或其他内容。

Answer 1

@Kevin Brown是对的你不应该担心序列化程序，或者在get_queryset方法上渲染任何内容，但我在get_queryset方法中注意到的一点是你不附加任何项目到列表queryset和querylist。我在下面给你一个想法：

    def get_queryset(self):
        #print self.kwargs['category_id']
        maps = Mapertables.objects.filter(category_id=self.kwargs['category_id'])
        i = 0
        queryset = []
        for question in maps:
            quest = {}
            quest['question'] = question.question_id
            choices = Choice.objects.filter(question=question.question_id)
            print choices

            j = 0
            for option in choices:
                quest[j] = option.choice_text
                j += 1
            print 'data Here ',quest
            # Adding items to queryset list
            queryset.append(quest)
            i += 1

        # You should have values here on queryset list
        print queryset

        return queryset

对于URL，请确保将category_id作为参数传递给URL模式。类似于url(r'^mapers/(?P<category_id>\d+)/?'的内容，如果你没有使用routers。如果您在此处粘贴您的网址定义，那就太棒了。好吧，我希望它可以帮助你更好地了解如何继续。

Answer 2

您正在从get_queryset方法返回一个空列表，因此列表视图中没有返回任何对象，pk无法检索到特定对象。

您似乎在get_queryset方法中做了很多不相关的事情，他们可能会对此问题做出贡献。您不应该在那里进行任何序列化，DRF将在以后为您处理。你应该在filter_queryset方法中进行过滤，或者将其传递给DRF来做。您也无法从该方法返回任何响应，只返回查询集。

Django序列化返回一个空列表

2 个答案: