Django Rest Framework 外键序列化

Question

我有以下型号：

class Geofence(models.Model):
    id = models.IntegerField(default=0, primary_key=True)
    name = models.CharField(max_length=200, default="Geofence", blank=False)
    lat = models.DecimalField(default=0, decimal_places=6, max_digits=10, blank=False)
    long = models.DecimalField(default=0, decimal_places=6, max_digits=10, blank=False)
    radius = models.IntegerField(default=10, blank=False)

    def __str__(self):
        return "Geofence: " + str(self.name);

class Checkpoint(models.Model):
    id = models.IntegerField(default=0, primary_key=True)
    name = models.CharField(max_length=200, default="Geofence", blank=False)
    geofence = models.ForeignKey(Geofence, related_name='geofence')
    lat = models.DecimalField(default=0, decimal_places=6, max_digits=10, blank=False)
    long = models.DecimalField(default=0, decimal_places=6, max_digits=10, blank=False)
    trip_id = models.IntegerField(default=0, blank=False)
    enter_time = models.DateTimeField("Enter Time", blank=False)
    start_time = models.DateTimeField("Start Time", blank = True, null=True)
    stop_time = models.DateTimeField("Stop Time", blank= True, null = True)

及其各自的序列化程序：

class GeofenceSerializer(serializers.ModelSerializer):
    id = serializers.IntegerField(min_value=0)
    name = serializers.CharField()
    lat = serializers.DecimalField(max_digits=10, decimal_places=6, coerce_to_string=False)
    long = serializers.DecimalField(max_digits=10, decimal_places=6, coerce_to_string=False)
    radius = serializers.IntegerField(min_value=0)
    class Meta:
        model = Geofence
        fields = ('id', 'name','lat', 'long', 'radius')

    def create(self, valid_data):
        return Geofence.objects.create(**valid_data)

    def update(self, instance, valid_data):
        instance.id = valid_data.get('id', instance.id)
        instance.name = valid_data.get('name', instance.name)
        instance.name = valid_data.get('lat', instance.lat)
        instance.long = valid_data.get('long', instance.long)
        instance.radius = valid_data.get('radius', instance.radius)
        instance.save()



class CheckpointSerializer(serializers.ModelSerializer):
    lat = serializers.DecimalField(max_digits=10, decimal_places=6, coerce_to_string=False)
    long = serializers.DecimalField(max_digits=10, decimal_places=6, coerce_to_string=False)
    enter_time = serializers.DateTimeField()
    start_time =serializers.DateTimeField()
    geofence = serializers.SlugRelatedField(many=False, slug_field="id", read_only=True)
    class Meta:
        model = Checkpoint
        fields = ('trip_id', 'geofence', 'start_time', 'stop_time', 'lat', 'long', 'enter_time')

我从滑块中获取日期时间并进行 ajax 调用以获取相关数据。服务器以 500 错误响应。具体来说，错误“KeyError: geofence”

这是被调用的视图：

class ResultsView(APIView):
    model = Checkpoint
    serializer_class = CheckpointSerializer
    def get(self, request, start, end):
        begin_date = parse_datetime(request.GET["start"]) 
        end_date = parse_datetime(request.GET["end"])
        ids = Checkpoint.objects.filter(start_time__range=(begin_date,end_date)).filter(stop_time__range=(begin_date,end_date)).distinct().values('trip_id', 'lat', 'long', 'enter_time')
        serializer = CheckpointSerializer(ids, many=True)
        return Response(serializer.data)

    def post(self, request, format=None):
        request.data["id"] = uuid.uuid4().int & (1<<8)-1
        serializer = CheckpointSerializer(data= request.data)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data)
        return Response(serializer.error)

和角度调用：

$http.get("http://127.0.0.1:8000/traffic/get/?end=" + $scope.endDateTime + "&format=json&search=Search&start=" + $scope.startDateTime)
  .then(function(response) {
     console.log("Response: " + response.data)
       $scope.data = response.data;
   });

我认为问题在于序列化程序中的外键：

geofence = serializers.SlugRelatedField(many=False, slug_field="id", read_only=True)

这是在 django rest 框架中序列化外键的正确方法吗？如果没有，有人能举个例子吗？

Answer 1

你是这个意思吗？ Specifying nested serialization

有一个简单的例子：

class AccountSerializer(serializers.ModelSerializer):
    class Meta:
        model = Account
        depth = 1 # You need only add this sentence.

结果是这样的：

[
  {
    "id": 1,
    "priority": 10,
    "role": {
      "id": 1,
      "department": "researcher"
    }
  }
]

但是，您可以获得 ForeignKey 的所有字段。 ForeignKey的一些字段我不知道怎么获取。

Answer 2

对于这个特定问题，我通过在字符字段中使用源参数来表示外键而不是相关字段来解决它。在这种情况下，正确的序列化程序条目是：

geofence = serializers.CharField(source='geofence.id', read_only=True)

class Meta:
    model = Checkpoint
    fields = ('geofence', 'start_time', 'lat', 'long', 'enter_time')

我在检查点表中使用了它，因为检查点是地理围栏，而不是在原始帖子中错误地将外键放入地理围栏表中。字段名称简单地列在类元中。类元是必要的，因为序列化器是模型序列化器。

Answer 3

我猜你必须做一些改变。您可以在 GeofenceSerializer 中引入许多 Checkpoint。这样：

class GeofenceSerializer(serializers.ModelSerializer):
      id = serializers.IntegerField(min_value=0)
      name = serializers.CharField()
      lat = serializers.DecimalField(max_digits=10, decimal_places=6,     coerce_to_string=False)
      long = serializers.DecimalField(max_digits=10, decimal_places=6, coerce_to_string=False)
      radius = serializers.IntegerField(min_value=0)
      checkpoint = serializers.PrimaryKeyRelatedField(many=True, read_only=True)
      class Meta:
           model = Geofence
          fields = ('id', 'name','lat', 'long', 'radius','checkpoint')

def create(self, valid_data):
    return Geofence.objects.create(**valid_data)

def update(self, instance, valid_data):
    instance.id = valid_data.get('id', instance.id)
    instance.name = valid_data.get('name', instance.name)
    instance.name = valid_data.get('lat', instance.lat)
    instance.long = valid_data.get('long', instance.long)
    instance.radius = valid_data.get('radius', instance.radius)
    instance.save()



class CheckpointSerializer(serializers.ModelSerializer):
      lat = serializers.DecimalField(max_digits=10, decimal_places=6, coerce_to_string=False)
      long = serializers.DecimalField(max_digits=10, decimal_places=6, coerce_to_string=False)
      enter_time = serializers.DateTimeField()
      start_time =serializers.DateTimeField()

      class Meta:
           model = Checkpoint
           fields = ('trip_id', 'start_time', 'stop_time', 'lat', 'long', 'enter_time')