英文:
DjangoRestFramework, how to add optional field not coming from model to serializer
问题
class CamperSerializer(serializers.ModelSerializer):
camper_id = serializers.IntegerField(source='id')
weather = serializers.SerializerMethodField('get_weather', read_only=True)
def get_weather(self, instance):
# Add your logic to fetch weather here
lat = instance.location.y
lon = instance.location.x
return getWeatherFromLatLon(lat, lon)
class Meta:
model = Camper
fields = ('camper_id', 'name', 'location', 'weather')
英文:
I have a model like this:
class Camper(models.Model):
location = models.PointField()
name = models.CharField(max_length=255)
and a viewset like this:
class CamperViewSet(viewsets.ModelViewSet):
...
def retrieve(self, request, *args, **kwargs):
"""Retrieve a Camper instance."""
show_weather = request.query_params.get('showWeather', False)
instance = self.get_object()
if show_weather:
lat = instance.location.y
lon = instance.location.x
instance.weather = getWeatherFromLatLon(lat, lon)
serializer = self.get_serializer(instance)
return Response(serializer.data)
So when I request /api/campers/8?showWeather=true I make another request in my view to get the weather from the current position.
How do I add it to my serializer ? It's an optional field so I need to manage this and it's only used in /campers/id so it will not be used in list/create/put/etc
My serializer looks like this:
class CamperSerializer(serializers.ModelSerializer):
camper_id = serializers.IntegerField(source='id')
class Meta:
model = Camper
fields = ('camper_id', 'name', 'location')
</details>
# 答案1
**得分**: 1
你可以为`retrive`操作添加`custom serializer`。我称之为`CamperRetriveSerializer`。
在`CamperRetriveSerializer`内，你可以使用`SerializerMethodField`来定义数据库中不存在的字段。
并且，你想要检查请求中的参数`show_weather`，最好是将其值传递到`context`中，并在序列化器中获取它。
像这样：
```python
class CamperRetriveSerializer(serializers.ModelSerializer):
weather = serializers.SerializerMethodField()
camper_id = serializers.IntegerField(source='id')
def get_weather(self, obj):
show_weather = self.context.get('show_weather')
if show_weather:
lat = obj.location.y
lon = obj.location.x
return getWeatherFromLatLon(lat, lon)
# 如果在请求中没有show_weather，则定义默认值
return ''
class Meta:
model = Camper
fields = ('camper_id', 'name', 'location', 'weather')
class CamperViewSet(viewsets.ModelViewSet):
...
def retrieve(self, request, *args, **kwargs):
"""Retrieve a Camper instance."""
instance = self.get_object()
show_weather = self.request.query_params.get('showWeather', False)
context = {
'show_weather': show_weather
}
serializer = CamperRetriveSerializer(instance, context=context)
return Response(serializer.data)
英文:
you can add custom serializer for retrive only todo it. I called CamperRetriveSerializer.
Inside CamperRetriveSerializer, you can use SerializerMethodField for define field not have in database.
And you want check param show_weather from request, best is pass value of it to context and get it in serializer.
Like this:
class CamperRetriveSerializer(serializers.ModelSerializer):
weather = serializers.SerializerMethodField()
camper_id = serializers.IntegerField(source='id')
def get_weather(self, obj):
show_weather = self.context.get('show_weather')
if show_weather:
lat = obj.location.y
lon = obj.location.x
return getWeatherFromLatLon(lat, lon)
# define default value if not show_weather in this
return ''
class Meta:
model = Camper
fields = ('camper_id', 'name', 'location', 'weather')
class CamperViewSet(viewsets.ModelViewSet):
...
def retrieve(self, request, *args, **kwargs):
"""Retrieve a Camper instance."""
instance = self.get_object()
show_weather = self.request.query_params.get('showWeather', False)
context = {
'show_weather': show_weather
}
serializer = CamperRetriveSerializer(instance, context=context)
return Response(serializer.data)
答案2
得分: 0
你可以为此使用两种不同的序列化器。
class CamperViewSet(viewsets.ModelViewSet):
serializer_class = CamperSerializer
def get_serializer_class(self):
serializer_class = self.serialzier_class
if self.request.method == 'GET':
serializer_class = CamperSerializerGet
return serializer_class
# 用于GET请求的序列化器
class CamperSerializerGet(serializers.ModelSerializer):
weather = serialziers.SerializerMethodField()
camper_id = serializers.IntegerField(source='id')
def get_weather(self, obj):
return obj.weather
class Meta:
model = Camper
fields = ('camper_id', 'name', 'location', 'weather')
# 用于其他请求的序列化器
class CamperSerializer(serializers.ModelSerializer):
camper_id = serializers.IntegerField(source='id')
class Meta:
model = Camper
fields = ('camper_id', 'name', 'location')
英文:
You can use two different serializers for this.
class CamperViewSet(viewsets.ModelViewSet):
serializer_class = CamperSerializer
def get_serializer_class(self):
serializer_class = self.serialzier_class
if self.request.method == 'GET':
serializer_class = CamperSerializerGet
return serializer_class
#Serializer for GET request
class CamperSerializerGet(serializers.ModelSerializer):
weather = serialziers.SerializerMethodField()
camper_id = serializers.IntegerField(source='id')
def get_weather(self, obj):
return obj.weather
class Meta:
model = Camper
fields = ('camper_id', 'name', 'location', 'weather')
#For other requests call this
class CamperSerializer(serializers.ModelSerializer):
camper_id = serializers.IntegerField(source='id')
class Meta:
model = Camper
fields = ('camper_id', 'name', 'location')
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
评论