Django 序列化

一、注

关于Django中的序列化主要应用在将数据库中检索的数据返回给客户端用户，特别的Ajax请求一般返回的为Json格式。

二、实例

1、serializers

from django.core import serializers
 
ret = models.BookType.objects.all()
 
data = serializers.serialize("json", ret)

2、json.dumps

import json
 
#ret = models.BookType.objects.all().values('caption')
ret = models.BookType.objects.all().values_list('caption')
 
ret=list(ret)
 
result = json.dumps(ret)

由于json.dumps时无法处理datetime日期，所以可以通过自定义处理器来做扩展，如：

import json 
from datetime import date 
from datetime import datetime 
   
class JsonCustomEncoder(json.JSONEncoder): 
    
    def default(self, field): 
     
        if isinstance(field, datetime): 
            return o.strftime('%Y-%m-%d %H:%M:%S') 
        elif isinstance(field, date): 
            return o.strftime('%Y-%m-%d') 
        else: 
            return json.JSONEncoder.default(self, field) 
   
   
# ds = json.dumps(d, cls=JsonCustomEncoder) 

djangorestframework 序列化：

作用：

1. 对用户请求数据进行验证

2. 获取数据进行序列化

a. 自定义字段

from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework import serializers
from .. import models


class PasswordValidator(object):
    def __init__(self, base):
        self.base = base

    def __call__(self, value):
        if value != self.base:
            message = 'This field must be %s.' % self.base
            raise serializers.ValidationError(message)

    def set_context(self, serializer_field):
        """
        This hook is called by the serializer instance,
        prior to the validation call being made.
        """
        # 执行验证之前调用,serializer_fields是当前字段对象
        pass


class UserSerializer(serializers.Serializer):
    ut_title = serializers.CharField(source='ut.title')
    user = serializers.CharField(min_length=6)
    pwd = serializers.CharField(error_messages={'required': '密码不能为空'}, validators=[PasswordValidator('666')])


class TestView(APIView):
    def get(self, request, *args, **kwargs):

        # 序列化，将数据库查询字段序列化为字典
        data_list = models.UserInfo.objects.all()
        ser = UserSerializer(instance=data_list, many=True)
        # 或
        # obj = models.UserInfo.objects.all().first()
        # ser = UserSerializer(instance=obj, many=False)
        return Response(ser.data)

    def post(self, request, *args, **kwargs):
        # 验证，对请求发来的数据进行验证
        ser = UserSerializer(data=request.data)
        if ser.is_valid():
            print(ser.validated_data)
        else:
            print(ser.errors)

        return Response('POST请求，响应内容')

b. 基于Model自动生成字段

from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework import serializers
from .. import models


class PasswordValidator(object):
    def __init__(self, base):
        self.base = str(base)

    def __call__(self, value):
        if value != self.base:
            message = 'This field must be %s.' % self.base
            raise serializers.ValidationError(message)

    def set_context(self, serializer_field):
        """
        This hook is called by the serializer instance,
        prior to the validation call being made.
        """
        # 执行验证之前调用,serializer_fields是当前字段对象
        pass

class ModelUserSerializer(serializers.ModelSerializer):

    user = serializers.CharField(max_length=32)

    class Meta:
        model = models.UserInfo
        fields = "__all__"
        # fields = ['user', 'pwd', 'ut']
        depth = 2
        extra_kwargs = {'user': {'min_length': 6}, 'pwd': {'validators': [PasswordValidator(666), ]}}
        # read_only_fields = ['user']


class TestView(APIView):
    def get(self, request, *args, **kwargs):

        # 序列化，将数据库查询字段序列化为字典
        data_list = models.UserInfo.objects.all()
        ser = ModelUserSerializer(instance=data_list, many=True)
        # 或
        # obj = models.UserInfo.objects.all().first()
        # ser = UserSerializer(instance=obj, many=False)
        return Response(ser.data)

    def post(self, request, *args, **kwargs):
        # 验证，对请求发来的数据进行验证
        print(request.data)
        ser = ModelUserSerializer(data=request.data)
        if ser.is_valid():
            print(ser.validated_data)
        else:
            print(ser.errors)

        return Response('POST请求，响应内容')

c. 生成URL

from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework import serializers
from .. import models


class PasswordValidator(object):
    def __init__(self, base):
        self.base = str(base)

    def __call__(self, value):
        if value != self.base:
            message = 'This field must be %s.' % self.base
            raise serializers.ValidationError(message)

    def set_context(self, serializer_field):
        """
        This hook is called by the serializer instance,
        prior to the validation call being made.
        """
        # 执行验证之前调用,serializer_fields是当前字段对象
        pass


class ModelUserSerializer(serializers.ModelSerializer):
    ut = serializers.HyperlinkedIdentityField(view_name='detail')
    class Meta:
        model = models.UserInfo
        fields = "__all__"

        extra_kwargs = {
            'user': {'min_length': 6},
            'pwd': {'validators': [PasswordValidator(666),]},
        }



class TestView(APIView):
    def get(self, request, *args, **kwargs):

        # 序列化，将数据库查询字段序列化为字典
        data_list = models.UserInfo.objects.all()
        ser = ModelUserSerializer(instance=data_list, many=True, context={'request': request})
        # 或
        # obj = models.UserInfo.objects.all().first()
        # ser = UserSerializer(instance=obj, many=False)
        return Response(ser.data)

    def post(self, request, *args, **kwargs):
        # 验证，对请求发来的数据进行验证
        print(request.data)
        ser = ModelUserSerializer(data=request.data)
        if ser.is_valid():
            print(ser.validated_data)
        else:
            print(ser.errors)

        return Response('POST请求，响应内容')

d. 自动生成URL

from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework import serializers
from .. import models


class PasswordValidator(object):
    def __init__(self, base):
        self.base = str(base)

    def __call__(self, value):
        if value != self.base:
            message = 'This field must be %s.' % self.base
            raise serializers.ValidationError(message)

    def set_context(self, serializer_field):
        """
        This hook is called by the serializer instance,
        prior to the validation call being made.
        """
        # 执行验证之前调用,serializer_fields是当前字段对象
        pass


class ModelUserSerializer(serializers.HyperlinkedModelSerializer):
    ll = serializers.HyperlinkedIdentityField(view_name='xxxx')
    tt = serializers.CharField(required=False)

    class Meta:
        model = models.UserInfo
        fields = "__all__"
        list_serializer_class = serializers.ListSerializer

        extra_kwargs = {
            'user': {'min_length': 6},
            'pwd': {'validators': [PasswordValidator(666), ]},
            'url': {'view_name': 'xxxx'},
            'ut': {'view_name': 'xxxx'},
        }


class TestView(APIView):
    def get(self, request, *args, **kwargs):
        # # 序列化，将数据库查询字段序列化为字典
        data_list = models.UserInfo.objects.all()
        ser = ModelUserSerializer(instance=data_list, many=True, context={'request': request})
        # # 如果Many=True
        # # 或
        # # obj = models.UserInfo.objects.all().first()
        # # ser = UserSerializer(instance=obj, many=False)
        return Response(ser.data)

    def post(self, request, *args, **kwargs):
        # 验证，对请求发来的数据进行验证
        print(request.data)
        ser = ModelUserSerializer(data=request.data)
        if ser.is_valid():
            print(ser.validated_data)
        else:
            print(ser.errors)

        return Response('POST请求，响应内容')

说明：

对于choices，用source='get_xxx_display'

对于manytomany，如 课程 与 教师表：

class CourseSerialize(serializers.Serializer):
    name = serializers.CharField(max_length=32)
    teachers = serializers.SerializerMethodField()
    def get_teachers(self, obj):
        teachers = obj.teachers.all()
        return teachers.values('age')