Django Rest框架—如何在ModelSerializer中添加自定义字段

I created a ModelSerializer and want to add a custom field which is not part of my model.

我创建了一个ModelSerializer，并希望添加一个不属于模型的自定义字段。

I found a description to add extra fields here and I tried the following:

我在这里找到了添加额外字段的描述，我尝试了以下方法:

customField = CharField(source='my_field')

When I add this field and call my validate() function then this field is not part of the attr dict. attr contains all model fields specified except the extra fields. So I cannot access this field in my overwritten validation, can I?

当我添加这个字段并调用我的validate()函数时，这个字段不是attr命令的一部分。所以我不能在重写的验证中访问这个字段，对吗?

When I add this field to the field list like this:

当我将这个字段添加到字段列表中时:

class Meta:
    model = Account
    fields = ('myfield1', 'myfield2', 'customField')

then I get an error because customField is not part of my model - what is correct because I want to add it just for this serializer.

然后我得到一个错误，因为customField不是我模型的一部分——正确的是什么，因为我想为这个序列化器添加它。

Is there any way to add a custom field?

有办法添加自定义字段吗?

6 个解决方案

#1

You're doing the right thing, except that CharField (and the other typed fields) are for writable fields.

您正在做正确的事情，除了CharField(和其他类型的字段)是用于可写字段的。

In this case you just want a simple read-only field, so instead just use:

在本例中，您只需要一个简单的只读字段，因此只需使用:

customField = Field(source='get_absolute_url')

#2

In fact there a solution without touching at all the model. You can use SerializerMethodField which allow you to plug any method to your serializer.

事实上，有一种解决方案，完全不触及模型。您可以使用SerializerMethodField，它允许您将任何方法插入到序列化器中。

class FooSerializer(ModelSerializer):
    foo = serializers.SerializerMethodField()

    def get_foo(self, obj):
        return "Foo id: %i" % obj.pk

#3

...for clarity, if you have a Model Method defined in the following way:

…为了清晰起见，如果您有以下方式定义的模型方法:

class MyModel(models.Model):
    ...

    def model_method(self):
        return "some_calculated_result"

You can add the result of calling said method to your serializer like so:

可以将调用上述方法的结果添加到序列化器中，如下所示:

class MyModelSerializer(serializers.ModelSerializer):
    model_method_field = serializers.CharField(source='model_method')

p.s. Since the custom field isn't really a field in your model, you'll usually want to make it read-only, like so:

另外，由于自定义字段在您的模型中并不是一个字段，您通常希望它是只读的，如下所示:

class Meta:
    model = MyModel
    read_only_fields = (
        'model_method_field',
        )

#4

here answer for your question. you should add to your model Account:

这是你的问题的答案。您应该添加到您的模型帐户:

@property
def my_field(self):
    return None

now you can use:

现在您可以使用:

customField = CharField(source='my_field')

source: https://*.com/a/18396622/3220916

来源:https://*.com/a/18396622/3220916

#5

With the last version of Django Rest Framework, you need to create a method in your model with the name of the field you want to add.

对于Django Rest框架的最后一个版本，您需要在模型中创建一个方法，该方法的名称是您想要添加的字段。

class Foo(models.Model):
    . . .
    def foo(self):
        return 'stuff'
    . . .

class FooSerializer(ModelSerializer):
    foo = serializers.ReadOnlyField()

    class Meta:
        model = Foo
        fields = ('foo',)

#6

To show self.author.full_name, I got an error with Field. It worked with ReadOnlyField:

显示self.author。full_name，我有一个字段错误。它与ReadOnlyField合作:

class CommentSerializer(serializers.HyperlinkedModelSerializer):
    author_name = ReadOnlyField(source="author.full_name")
    class Meta:
        model = Comment
        fields = ('url', 'content', 'author_name', 'author')

#1