Question

说，有两种模型：

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context="com.example.android.time.MainActivity">


    <include layout="@layout/app_bar_main"
        android:layout_height="match_parent"
        android:layout_width="match_parent" />

    <android.support.design.widget.NavigationView
        android:id="@+id/navigation_view"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:fitsSystemWindows="true"
        app:theme="@style/ThemeOverlay.AppCompat.navTheme"
        app:headerLayout="@layout/nav_drawer_header"
        app:menu="@menu/nav_drawer"/>
</android.support.v4.widget.DrawerLayout>

序列化器是：

class Model1(models.Model):
    r = models.CharField(max_length=200)

class Model2(models.Model):
    p = models.CharField(max_length=200)
    m = models.ForeignKey(Model1,on_delete=models.CASCADE)

给定的Model1序列化器将输出返回为： { “ id”：1 “ r”：“ r_value” }

，模型2序列化器输出为： { “ id”：1， “ p：” p_value“， “ m”：1 }

问题是我也希望在model2序列化器输出中使用r值。该怎么做？

Answer 1

您需要使用正确的source指定新字段-您可以在docs中阅读更多内容。

选项1：具有类序列化器：

class Model2Serializer(serializers.Serializer):
    id = serializers.IntegerField()
    p = serializers.CharField()
    r = serializers.CharField(source='m.r')

    class Meta:
         model = Model2
         fields = '__all__'

输出：{'p': u'pppp', 'r': u'rrrrr', 'id': 1}

选项2：使用类 ModelSerializer ：

class Model2Serializer(serializers.ModelSerializer):
    r = serializers.CharField(source='m.r')

    class Meta:
         model = Model2
         fields = '__all__'

输出：{'p': u'pppp', 'r': u'rrrrr', 'm': 1L, u'id': 1}

选项3：包括整个 Model1 ：

class Model1Serializer(serializers.ModelSerializer):
    class Meta:
        model = Model1
        fields = '__all__'

class Model2Serializer(serializers.Serializer):
    m = Model1Serializer()

    class Meta:
        model = Model2
        fields = '__all__'

输出：{'m': OrderedDict([(u'id', 1), ('r', u'rrrrr')])}

Answer 2

尝试

class Model1Serializer(serializers.Serializer):
   class Meta:
      model = Model1
      fields = '__all__'

class Model2Serializer(serializers.Serializer):
  r = Model1Serializer(many=True, source="model1_set")
  class Meta:
     model = Model2
     fields = '__all__'

Answer 3

如果您已经拥有Model1的Model1Serializer，则DRF非常容易：

class Model2Serializer(serializers.Serializer):
    m = Model1Serializer()
    class Meta:
         model = Model2
         fields = '__all__'

应该的。

Answer 4

1。如果您想将r设为m的属性

定义特定关系字段的序列化器类


class Model2Serializer(serializers.ModelSerializer):
    m = Model1Serializer()
    class Meta:
        model = Model2
        fields = '__all__'

输出：


[
    {
        "id": 1,
        "m": {
            "id": 1,
            "r": "RED"
        },
        "p": "Light RED"
    },
    {
        "id": 2,
        "m": {
            "id": 1,
            "r": "RED"
        },
        "p": "Dark RED"
    }
]

2。如果您只想使用ReadOnlyField

您可以使用ReadOnlyField


class Model2Serializer(serializers.ModelSerializer):
    r = serializers.ReadOnlyField(source='m.r')

    class Meta:
        model = Model2
        fields = '__all__'

输出：

[
    {
        "id": 1,
        "r": "RED",
        "p": "Light RED",
        "m": 1
    },
    {
        "id": 2,
        "r": "RED",
        "p": "Dark RED",
        "m": 1
    }
]

3。如果只想使用SerializerMethodField（）

您也可以SerializerMethodField和ist只读


class Model2Serializer(serializers.ModelSerializer):
    r = serializers.SerializerMethodField()

    class Meta:
        model = Model2
        fields = '__all__'

    def get_r(self, instance):
        return instance.m.r

输出：

[
    {
        "id": 1,
        "r": "RED",
        "p": "Light RED",
        "m": 1
    },
    {
        "id": 2,
        "r": "RED",
        "p": "Dark RED",
        "m": 1
    }
]

Answer 5

只需在序列化器Meta中使用depth=1。像这样：

class Model2Serializer(serializers.Serializer):
    class Meta:
         model = Model2
         fields = '__all__'
         depth = 1

此模型中确实存在的外键的级别为1。（顺便说一句，我不建议将其用于大型机型。但这完全适合您的情况）

如何从子序列化器获取特定字段？

5 个答案: