django - 在 django-rest-framework 中使用 .to_representation() 和 .to_internal_value？

Question

.to_representation() 和 .to_internal_value 在序列化器中做什么？
如果我将数据传递给序列化器，数据是否首先抛出 to_representation() ？
这两个有什么用？

Answer 1

If you want to create a custom field, you'll need to subclass Field and then override either one or both of the .to_representation() and .to_internal_value() methods. These two methods are used to convert between the initial datatype, and a primitive, serializable datatype. Primitive datatypes will typically be any of a number, string, boolean, date/time/datetime or None. They may also be any list or dictionary like object that only contains other primitive objects. Other types might be supported, depending on the renderer that you are using.

The .to_representation() method is called to convert the initial datatype into a primitive, serializable datatype.

The to_internal_value() method is called to restore a primitive datatype into its internal python representation. This method should raise a serializers.ValidationError if the data is invalid.

Note that the WritableField class that was present in version 2.x no longer exists. You should subclass Field and override to_internal_value() if the field supports data input.

引用:

1. http://www.django-rest-framework.org/api-guide/fields/#custom-fields
2. https://github.com/tomchristie/django-rest-framework/blob/master/rest_framework/serializers.py#L417