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