DRF分阶段序列化细化实例

DRF是分两阶段进行的。

如果是API接收数据，则是先进行Parser，将外界接收的bytes数据分析成python数据类型，其间涉及encoding操作，再进行序列化，将python数据类型保存进数据库。

如果是从API获取数据，则是先进行反序列化，将数据库中的数据转成python数据类型，再进行renderer，将python数据类型渲染成可用于网络传输的byte类型。

实践的代码如下：

models.py

from django.db import models

# Create your models here.

class Toy(models.Model):
    created = models.DateTimeField(auto_now_add=True)
    name = models.CharField(max_length=150, blank=False, default='')
    description = models.CharField(max_length=250, blank=True, default='')
    toy_category = models.CharField(max_length=200, blank=False, default='')
    release_date = models.DateTimeField()
    was_included_in_home = models.BooleanField(default=False)

    class Meta:
        ordering = ('name', )

serializers.py

from rest_framework import serializers
from toys.models import Toy

class ToySerializer(serializers.Serializer):
    pk = serializers.ImageField(read_only=True)
    name = serializers.CharField(max_length=150)
    description = serializers.CharField(max_length=250)
    toy_category = serializers.CharField(max_length=200)
    release_date = serializers.DateTimeField()
    was_included_in_home = serializers.BooleanField(required=False)

    def create(self, validated_data):
        return Toy.objects.create(**validated_data)

    def update(self, instance, validated_data):
        instance.name = validated_data('name', instance.name)
        instance.description = validated_data('description', instance.description)
        instance.toy_category = validated_data('toy_category', instance.toy_category)
        instance.release_date = validated_data('release_date', instance.release_date)
        instance.was_included_in_home = validated_data('was_included_in_home', instance.was_included_in_home)
        instance.save()
        return instance

python manage.py shell实践。

from datetime import datetime
from django.utils import timezone
from django.utils.six import BytesIO
from rest_framework.renderers import JSONRenderer
from rest_framework.parsers import JSONParser
from toys.models import Toy
from toys.serializers import ToySerializer

toy_release_date = timezone.make_aware(datetime.now(), timezone.get_current_timezone())
toy1 = Toy(name='Snoopy talking action figure', description='Snoopy speaks five languages', release_date=toy_release_date, toy_category='Action figures', was_included_in_home=False)
toy1.save()
toy2 = Toy(name='Hawaiian Barbie', description='Barbie loves Hawaii', release_date=toy_release_date, toy_category='Dolls', was_included_in_home=True)
toy2.save()

serializer_for_toy1 = ToySerializer(toy1)
print(serializer_for_toy1.data)

serializer_for_toy2 = ToySerializer(toy2)
print(serializer_for_toy2.data)

json_renderer = JSONRenderer()
toy1_rendered_into_json = json_renderer.render(serializer_for_toy1.data)
toy2_rendered_into_json = json_renderer.render(serializer_for_toy2.data)
print(toy1_rendered_into_json)
print(toy2_rendered_into_json)

json_string_for_new_toy = '{"name":"Clash Royale play set","description":"6 figures from Clash Royale", "release_date":"2017-10-09T12:10:00.776594Z","toy_category":"Playset","was_included_in_home":false}'
json_bytes_for_new_toy = bytes(json_string_for_new_toy, encoding="UTF-8")
stream_for_new_toy = BytesIO(json_bytes_for_new_toy)
parser = JSONParser()
parsed_new_toy = parser.parse(stream_for_new_toy)
print(parsed_new_toy)

new_toy_serializer = ToySerializer(data=parsed_new_toy)
if new_toy_serializer.is_valid():
toy3 = new_toy_serializer.save()
print(toy3.name)