Restful API serialize相关

官网：https://www.django-rest-framework.org/tutorial/1-serialization/

总结如下：

一、序列化

定义model

class Snippet(models.Model):
    created = models.DateTimeField(auto_now_add=True)
    title = models.CharField(max_length=100, blank=True, default='')

定义对应的Serializer

class SnippetSerializer(serializers.Serializer):
    id = serializers.IntegerField(read_only=True)
    title = serializers.CharField(required=False, allow_blank=True, max_length=100)
    code = serializers.CharField(style={'base_template': 'textarea.html'})

from rest_framework.renderers import JSONRenderer
from rest_framework.parsers import JSONParser

snippet = Snippet(code='foo = "bar"
')
snippet.save()

snippet = Snippet(code='print("hello, world")
')
snippet.save()

序列化过程

#序列化
serializer = SnippetSerializer(snippet)
#把序列化对象换成 python 原生类型string
serializer.data
# {'id': 2, 'title': '', 'code': 'print("hello, world")
', 'linenos': False, 'language': 'python', 'style': 'friendly'}

#把原生类型string，转换成json，可以输出到页面
content = JSONRenderer().render(serializer.data)
content
# b'{"id": 2, "title": "", "code": "print(\"hello, world\")\n", "linenos": false, "language": "python", "style": "friendly"}'

                                                                                                                                                                                                                                 

二、反序列化

把byte转化成原生string,再pase成

import io
#读入json数据流，
stream = io.BytesIO(content)

#转换成python原生string
data = JSONParser().parse(stream)

#原生string赋值给serialzer对象
serializer = SnippetSerializer(data=data)
serializer.is_valid()
# True
serializer.validated_data
# OrderedDict([('title', ''), ('code', 'print("hello, world")
'), ('linenos', False), ('language', 'python'), ('style', 'friendly')])

#保存成django的model对象。
serializer.save()
# <Snippet: Snippet object>

文件或流读入读出的参考：BytesIOfile

https://www.jianshu.com/p/b74a83e0f9fc

https://www.cnblogs.com/yqpy/p/8556090.html

三、简洁（常规）的写法 

1、model简化

#类似于modelForm,自动引入field，还默认有 create() and update() 操作。
class SnippetSerializer(serializers.ModelSerializer):
    class Meta:
        model = Snippet
        fields = ['id', 'title', 'code', 'linenos', 'language', 'style']

#类似于普通Form
class SnippetSerializer(serializers.Serializer):
    code = serializers.CharField(style={'base_template': 'textarea.html'})

 2、用drf的request,response简化

django ：request.POST  # Only handles form data.  Only works for 'POST' method.
drf  ：request.data  # Handles arbitrary data.  Works for 'POST', 'PUT' and 'PATCH' methods.

return Response(data)

@api_view(['GET', 'POST'])
def singer_list(request):
    """
    List all code snippets, or create a new snippet.
    """

    if request.method == 'GET':
        snippets = Snippet.objects.all()
        serializer = SnippetSerializer(snippets, many=True)
        return Response(serializer.data)
　　　　　　　　　　　　　　　　　　　　#用Response输出到终端，代替《 JSONRenderer().render(serializer.data) 》，简洁省事。

     elif request.method == 'POST': serializer = SnippetSerializer(data=request.data)
                                  #request.data 接收提交的json，转换成原生string

        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data, status=status.HTTP_201_CREATED)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

rest api的方法