DjangoRestFramework，如何向序列化器添加不来自模型的可选字段

huangapple
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英文:

DjangoRestFramework, how to add optional field not coming from model to serializer

问题

  1. class CamperSerializer(serializers.ModelSerializer):
  3.     camper_id = serializers.IntegerField(source='id')
  4.     weather = serializers.SerializerMethodField('get_weather', read_only=True)
  6.     def get_weather(self, instance):
  7.         # Add your logic to fetch weather here
  8.         lat = instance.location.y
  9.         lon = instance.location.x
  10.         return getWeatherFromLatLon(lat, lon)
  12.     class Meta:
  13.         model = Camper
  14.         fields = ('camper_id', 'name', 'location', 'weather')
英文:

I have a model like this:

  1. class Camper(models.Model):
  2.     location = models.PointField()
  3.     name = models.CharField(max_length=255)

and a viewset like this:

  1. class CamperViewSet(viewsets.ModelViewSet):
  2. ...
  3.     def retrieve(self, request, *args, **kwargs):
  4.         """Retrieve a Camper instance."""
  5.         show_weather = request.query_params.get('showWeather', False)
  6.         instance = self.get_object()
  7.         if show_weather:
  8.             lat = instance.location.y
  9.             lon = instance.location.x
  10.             instance.weather = getWeatherFromLatLon(lat, lon)
  12.         serializer = self.get_serializer(instance)
  13.         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:

  1. class CamperSerializer(serializers.ModelSerializer):
  3.     camper_id = serializers.IntegerField(source='id')
  5.     class Meta:
  6.         model = Camper
  7.         fields = ('camper_id', 'name', 'location')
  10. </details>
  13. # 答案1
  14. **得分**: 1
  16. 你可以为`retrive`操作添加`custom serializer`。我称之为`CamperRetriveSerializer`。
  18. 在`CamperRetriveSerializer`内，你可以使用`SerializerMethodField`来定义数据库中不存在的字段。
  20. 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。
  22. 像这样：
  24. ```python
  25. class CamperRetriveSerializer(serializers.ModelSerializer):
  26.     
  27.     weather = serializers.SerializerMethodField()
  28.     camper_id = serializers.IntegerField(source='id')
  29.     
  30.     def get_weather(self, obj):
  31.         show_weather = self.context.get('show_weather')
  32.         if show_weather:
  33.             lat = obj.location.y
  34.             lon = obj.location.x
  35.             return getWeatherFromLatLon(lat, lon)
  37.         # 如果在请求中没有show_weather，则定义默认值
  38.         return ''
  40.     class Meta:
  41.         model = Camper
  42.         fields = ('camper_id', 'name', 'location', 'weather')
  45. class CamperViewSet(viewsets.ModelViewSet):
  46.     ...
  48.     def retrieve(self, request, *args, **kwargs):
  49.         """Retrieve a Camper instance."""
  50.         instance = self.get_object()
  51.         show_weather = self.request.query_params.get('showWeather', False)
  52.         context = {
  53.             'show_weather': show_weather
  54.         }
  55.         serializer = CamperRetriveSerializer(instance, context=context)
  56.         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:

  1.     class CamperRetriveSerializer(serializers.ModelSerializer):
  2.     
  3.         weather = serializers.SerializerMethodField()
  4.         camper_id = serializers.IntegerField(source=&#39;id&#39;)
  5.     
  6.         def get_weather(self, obj):
  7.             show_weather = self.context.get(&#39;show_weather&#39;)
  8.             if show_weather:
  9.                 lat = obj.location.y
  10.                 lon = obj.location.x
  11.                 return getWeatherFromLatLon(lat, lon)
  12.     
  13.             # define default value if not show_weather in this
  14.             return &#39;&#39;
  15.     
  16.         class Meta:
  17.             model = Camper
  18.             fields = (&#39;camper_id&#39;, &#39;name&#39;, &#39;location&#39;, &#39;weather&#39;)
  19.     
  20.     
  21.     
  22.     class CamperViewSet(viewsets.ModelViewSet):
  23.     ...
  24.     
  25.     
  26.         def retrieve(self, request, *args, **kwargs):
  27.             &quot;&quot;&quot;Retrieve a Camper instance.&quot;&quot;&quot;
  28.             instance = self.get_object()
  29.             show_weather = self.request.query_params.get(&#39;showWeather&#39;, False)
  30.             context = {
  31.                 &#39;show_weather&#39;: show_weather
  32.             }
  33.             serializer = CamperRetriveSerializer(instance, context=context)
  34.             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。

  1. class CamperViewSet(viewsets.ModelViewSet):
  2.     serializer_class = CamperSerializer
  4.     def get_serializer_class(self):
  5.         serializer_class = self.serialzier_class
  6.         if self.request.method == &#39;GET&#39;:
  7.             serializer_class = CamperSerializerGet
  8.         return serializer_class
  10. # 用于GET请求的序列化器
  11. class CamperSerializerGet(serializers.ModelSerializer):
  12.     weather = serialziers.SerializerMethodField()
  13.     camper_id = serializers.IntegerField(source=&#39;id&#39;)
  15.     def get_weather(self, obj):
  16.         return obj.weather    
  18.     class Meta:
  19.         model = Camper
  20.         fields = (&#39;camper_id&#39;, &#39;name&#39;, &#39;location&#39;, &#39;weather&#39;)
  22. # 用于其他请求的序列化器
  23. class CamperSerializer(serializers.ModelSerializer):
  24.     camper_id = serializers.IntegerField(source=&#39;id&#39;)
  26.     class Meta:
  27.         model = Camper
  28.         fields = (&#39;camper_id&#39;, &#39;name&#39;, &#39;location&#39;)
英文:

You can use two different serializers for this.

  1. class CamperViewSet(viewsets.ModelViewSet):
  2.     serializer_class = CamperSerializer
  4.     def get_serializer_class(self):
  5.         serializer_class = self.serialzier_class
  6.         if self.request.method == &#39;GET&#39;:
  7.             serializer_class = CamperSerializerGet
  8.         return serializer_class
  10. #Serializer for GET request
  11. class CamperSerializerGet(serializers.ModelSerializer):
  12.     weather = serialziers.SerializerMethodField()
  13.     camper_id = serializers.IntegerField(source=&#39;id&#39;)
  15.     def get_weather(self, obj):
  16.         return obj.weather    
  18.     class Meta:
  19.         model = Camper
  20.         fields = (&#39;camper_id&#39;, &#39;name&#39;, &#39;location&#39;, &#39;weather&#39;)
  22. #For other requests call this
  23. class CamperSerializer(serializers.ModelSerializer):
  25.     camper_id = serializers.IntegerField(source=&#39;id&#39;)
  27.     class Meta:
  28.         model = Camper
  29.         fields = (&#39;camper_id&#39;, &#39;name&#39;, &#39;location&#39;)

huangapple
  • 本文由 发表于 2023年2月14日 02:15:15
  • 转载请务必保留本文链接：https://go.coder-hub.com/75439749.html
  • django
  • django-rest-framework
  • optional-parameters
  • serialization
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