Django序列化组件Serializers使用详解

from django.db import models

# Create your models here.


class Book(models.Model):
    id = models.IntegerField(primary_key=True)
    title = models.CharField(max_length=255)
    desc = models.CharField(max_length=255)
    is_deleted = models.IntegerField(choices=[(1, "删除"), (0, "未删除")])
    author = models.CharField(max_length=255)

from rest_framework.serializers import Serializer
from rest_framework import serializers


class BookSerializer(Serializer):
    id = serializers.IntegerField()
    title = serializers.CharField()
    desc = serializers.CharField()
    is_deleted = serializers.ChoiceField(choices=[(1, "删除"), (0, "未删除")], source="get_is_deleted_display")
    author = serializers.CharField()

from app01.models import Book
from app01.serializer import BookSerializer
from django.http import HttpResponse, JsonResponse

# Create your views here.


def get_books(request):
    books = Book.objects.all()
    se = BookSerializer(books, many=True)
    return JsonResponse(se.data, safe=False)

serializer = CommentSerializer(data={'email': 'foobar', 'content': 'baz'})
serializer.is_valid()
# False
serializer.errors
# {'email': ['Enter a valid e-mail address.'], 'created': ['This field is required.']}

def multiple_of_ten(value):
    if value % 10 != 0:
        raise serializers.ValidationError('Not a multiple of ten')

class GameRecord(serializers.Serializer):
    score = IntegerField(validators=[multiple_of_ten])

from rest_framework import serializers

class BlogPostSerializer(serializers.Serializer):
    title = serializers.CharField(max_length=100)
    content = serializers.CharField()

    def validate_title(self, value):
        """
        Check that the blog post is about Django.
        """
        if 'django' not in value.lower():
            raise serializers.ValidationError("Blog post is not about Django")
        return value

from rest_framework import serializers

class EventSerializer(serializers.Serializer):
    description = serializers.CharField(max_length=100)
    start = serializers.DateTimeField()
    finish = serializers.DateTimeField()

    def validate(self, data):
        """
        Check that start is before finish.
        """
        if data['start'] > data['finish']:
            raise serializers.ValidationError("finish must occur after start")
        return data

class CommentSerializer(serializers.Serializer):
    email = serializers.EmailField()
    content = serializers.CharField(max_length=200)
    created = serializers.DateTimeField()
　　 def create(self, validated_data):
        return Comment.objects.create(**validated_data)

    def update(self, instance, validated_data):
        instance.email = validated_data.get('email', instance.email)
        instance.content = validated_data.get('content', instance.content)
        instance.created = validated_data.get('created', instance.created)
        instance.save()
        return instance

# .save() will create a new instance.
serializer = CommentSerializer(data=data)
serializer.save()
# .save() will update the existing `comment` instance.
 serializer = CommentSerializer(comment, data=data)

serializer.save()

serializer.save(owner=request.user)

class AccountSerializer(serializers.ModelSerializer):
    class Meta:
        model = Account
        fields = ['id', 'account_name', 'users', 'created']

from res_framework import serializers

#这个类用于被实例化，多对多字段这么写
class AuthorSerializer(serializers.Serializer):
    id = serializers.Charfield()
    name = serializers.Charfield()
    age = serializers.Charfield()

#传给views.py的主类
class BookSerializer(serializers.Serializer):
    name = serializers.Charfield()
    #source 可以指定字段 ,  id是要序列化的表名。
    id  = serializers.CharField(source='nid') 
    #，source后字段用.的方式可以跨表查询。
    publish = serializer.CharField(source='publish.email')
    ''' 
    如果在models.py的book类中定义一个test方法。
    def test(self): 
        return str(self.price)+self.name
   '''
   # 返回的结果就会有xx字段，souce不但可以指定表模型字段，还可以指定模型表方法，并且赋值给xx变量
   xx = serializers.Charfield(source='test')
   
   
   #外键的实现方法：
   #一对多字段
   #如果要通过外键字段返回出版社的所有信息，包括id,name,email...
   #obj是当前循环序列化到的数据对象
    publish = serializers.SerializerMethodField()
    def get_publish(self,obj):
        return {'id‘:obj.publish.pk,'name':obj.publish.name}
   
   #多对多字段
   #所有作者的详情，也展示出来
    authors = serializers.SerializermethodFiled()
    def get_authors(self,obj):
        author_list  = obj.authors.all()
        author_ser = AuthorSerializer(author_list,many=True)
        return author_ser.data

from rest_framework.views import APIView
from rest_framework.response import Response
from app01 import models

class BookView(APIview):
    def get(self,request,*args,**kwargs)：
            #获取所有图书数据
        response = {'status':100,'msg':'获取成功'}
        book_list = models.Book.objects.all()
        #实例化BookSerializer类，把要序列化的数据book_list传入
        #如果要序列化querySet对象，一定要加many = True
        book_ser = BookSerializer(book_list,many=True)
        #把序列化后的数据book_ser.data 拿出来放到response字典中返回给客户端
        response['data'] = book_ser.data 
        return Response(response)

from app01 import models
class PublishSerializer(serializers.ModelSerializer): 
    class Meta: #固定写法
    # 指定要序列化Book表
    model = models.Book
    #指定要序列化的字段
    fields = ['nid','name']
    #序列化所有字段
    fileds ='__all__‘ 
    #要排除的字段（不能与fileds连用）
    # exclude = ['name','price'] 
    #深度判定
    depth = 1 
    #如果要不按照父类的来，想要自己定义显示的字段的话,自己定义一个，覆盖掉父类的字段属性。
    publish = serializers.SerializerMethodField()  #一对多字段
    def get_publish(self,obj):
        return {'id‘:obj.publish.pk,'name':obj.publish.name}

def to_representation(self, instance):
    """Convert `username` to lowercase."""
    ret = super().to_representation(instance)
    ret['username'] = ret['username'].lower()
    return ret

def to_internal_value(self, value):
    if value == None:
        return 0
    return value