8.drf-序列化器

在序列化类中，如果想使用request,则可以通过self.context['request']获取

序列化器的主要由两大功能

- 对请求的数据进行校验（底层调用的是Django的Form和ModelForm）
- 对数据库查询的数据进行序列化

1.数据的校验

注意自定义的钩子函数中的参数value，对于FK或者M2M的字段，是一个对象而不是文本

1.1Serializer

基于Serializer类，类似Django中的Form

import re
from rest_framework.views import APIView
from rest_framework.views import Response
from rest_framework import serializers
from django.core.validators import EmailValidator


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

    def __call__(self, value):
        match_object = re.match(self.base, value)
        if not match_object:
            raise serializers.ValidationError('格式错误')


class UserSerializer(serializers.Serializer):
    username = serializers.CharField(label='姓名', min_length=6, max_length=32)
    age = serializers.IntegerField(label='年龄', min_value=0, max_value=200)
    level = serializers.ChoiceField(choices=((1, '董事长'), (2, '经理'), (3, '员工')))
    email1 = serializers.EmailField(label='邮箱1')
    email2 = serializers.CharField(label='邮箱2', validators=[EmailValidator, ])
    email3 = serializers.CharField(label='邮箱3')
    email4 = serializers.CharField(label='邮箱4', validators=[MyEmailValidator(r"^w+@\w+\.\w+$")])

    def validate_email3(self, value):
        "钩子函数"
        if not re.match(r"^w+@\w+\.\w+$", value):
            raise serializers.ValidationError('格式错误')
        return value


class User(APIView):
    def get(self, request):
        return Response({'code':0, 'data':'创建成功'})

    def post(self, request):
        ser = UserSerializer(data=request.data)
        if not ser.is_valid():
            return Response({'code':1006, 'data':ser.errors})
        print(ser.validated_data)
        return Response({'code':0, 'data':'创建成功'})

1.2 ModelSerializer

基于ModelSerializer类，类似Django中的ModelForm

import re
from rest_framework.views import APIView
from rest_framework.views import Response
from rest_framework import serializers


class UserModelSerializer(serializers.ModelSerializer):

    class Meta:
        model = UserInfo
        # fields = '__all__'
        fields = ['username', 'age', 'email', 'password', 'level', 'depart', 'roles']




class User(APIView):
    def get(self, request):
        return Response({'code': 0, 'data': '创建成功'})

    def post(self, request):
        ser = UserModelSerializer(data=request.data)
        if not ser.is_valid():
            return Response({'code': 1006, 'data': ser.errors})
        ser.save()
        print(ser.validated_data)
        return Response({'code': 0, 'data': '创建成功'})

2.序列化

通过ORM从数据库中获取QuerySet或者对象，然后序列化为json格式的数据

模型类

from django.db import models


# Create your models here.
class Role(models.Model):
    title = models.CharField(verbose_name='名称', max_length=32)


class Department(models.Model):
    title = models.CharField(verbose_name='名称', max_length=32)


class UserInfo(models.Model):
    level_choices = ((1, '普通会员'), (2, 'VIP'), (3, 'SVIP'))
    level = models.IntegerField(verbose_name='级别', choices=level_choices, default=1)

    username = models.CharField(verbose_name='用户名', max_length=32)
    password = models.CharField(verbose_name='密码', max_length=32)
    age = models.IntegerField(verbose_name='年龄', default=18)
    email = models.CharField(verbose_name='邮箱', max_length=64)
    token = models.CharField(verbose_name='TOKEN', max_length=64, null=True, blank=True)

    depart = models.ForeignKey(verbose_name='部门', to='Department', null=True, blank=True, on_delete=models.CASCADE)
    roles = models.ManyToManyField(verbose_name='角色', to="Role")

2.1 基本使用

序列化的是一个queryset，则many=True
序列化的是一个对象，则many=False

视图类

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

from web.models import UserInfo


class UserModelSerializer(serializers.ModelSerializer):
    class Meta:
        model = UserInfo
        fields = ['username', 'age', 'email']


class User(APIView):
    def get(self, request):
        """获取用户列表"""
        queryset = UserInfo.objects.all()
        ser = UserModelSerializer(instance=queryset, many=True)
        return Response({'code': 0, 'data': ser.data})

2.2 自定义字段

将数据库中的choice字段显示中文，如level_text
将ForeignKey字段显示，如depart
自定义字段，如extra,
如果类中自定义的字段名和数据库的一样，则覆盖掉数据库的字段，如depart

extra = serializers.SerializerMethodField()
def get_extra(self,obj):
        return 666

 1 from rest_framework.views import APIView
 2 from rest_framework.views import Response
 3 from rest_framework import serializers
 4 from django.core.validators import EmailValidator
 5 
 6 from web.models import UserInfo, Department, Role
 7 
 8 
 9 class UserModelSerializer(serializers.ModelSerializer):
10     level_text = serializers.CharField(source="get_level_display")
11     depart = serializers.CharField(source="depart.title")
12 
13 
14     extra = serializers.SerializerMethodField()
15     class Meta:
16         model = UserInfo
17         fields = ['username', 'age', 'email', 'level_text', 'depart', 'extra']
18 
19 
20     def get_extra(self,obj):
21         return 666
22 
23 
24 class User(APIView):
25     def get(self, request):
26         """获取用户列表"""
27 
28         queryset = UserInfo.objects.all()
29         ser = UserModelSerializer(instance=queryset, many=True)
30         return Response({'code': 0, 'data': ser.data})

2.3 序列化的嵌套

在一个序列化类中，可以嵌套另外一个序列化类

视图

import re
from rest_framework.views import APIView
from rest_framework.views import Response
from rest_framework import serializers
from django.core.validators import EmailValidator

from web.models import UserInfo, Department, Role

class DepartModelSerializer(serializers.ModelSerializer):
    class Meta:
        model = Department
        fields = '__all__'

class RoleModelSerializer(serializers.ModelSerializer):
    class Meta:
        model = Role
        fields = '__all__'



class UserModelSerializer(serializers.ModelSerializer):
    depart = DepartModelSerializer()
    roles = RoleModelSerializer(many=True)

    class Meta:
        model = UserInfo
        fields = ['username', 'age', 'email', 'depart', 'roles']



class User(APIView):
    def get(self, request):
        """获取用户列表"""

        queryset = UserInfo.objects.all()
        ser = UserModelSerializer(instance=queryset, many=True)
        return Response({'code': 0, 'data': ser.data})