drf序列化器与反序列化

什么是序列化与反序列化

"""
序列化：对象转换为字符串用于传输
反序列化：字符串转换为对象用于使用
"""

drf序列化与反序列化

"""
序列化：Model类对象转换为字符串用于传输
反序列化：字符串转换为Model类对象用于使用
"""

Model类

创建数据库：终端

>: mysql -uroot -p密码
>: create database 数据库名 charset=utf8

配置数据库：settings.py

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': '数据库名',
        'USER': 'root',
        'PASSWORD': '密码'
    }
}

修改操作数据库的模块：项目init文件

import pymysql
pymysql.install_as_MySQLdb()

创建model类：models.py

from django.db import models
class User(models.Model):
    CHOICE_SEX = (
        (0, '男'),
        (1, '女')
    )
    name = models.CharField(max_length=32, verbose_name='姓名')
    password = models.CharField(max_length=64, verbose_name='密码')
    sex = models.SmallIntegerField(choices=CHOICE_SEX, default=0)
    create_time = models.DateTimeField(auto_now_add=True, blank=True)
<span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Meta</span>:</span>
    <span class="hljs-comment"># 自定义创建的表名</span>
    db_table = <span class="hljs-string">'o_user'</span>
    <span class="hljs-comment"># admin界面中显示的表面与表名复数形式</span>
    verbose_name = <span class="hljs-string">'用户'</span>
    verbose_name_plural = verbose_name

<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">__str__</span><span class="hljs-params">(self)</span>:</span>
    <span class="hljs-keyword">return</span> self.name</code></pre>

注册model类：admin.py
from django.contrib import admin
from api.models import User
admin.site.register(User)
数据库迁移：在项目目录下的终端
>: python3 manage.py makemigrations
>: python3 manage.py migrate
注册超级用户：在项目目录下的终端
>: python3 manage.py createsuperuser
登陆admin页面添加数据：浏览器
http://localhost:8000/admin/
路由分发
项目urls.py
from django.conf.urls import url, include
from django.contrib import admin

urlpatterns = [

url(r'^admin/', admin.site.urls),

url(r'^api/', include('api.urls'))

]

api应用urls.py
from django.conf.urls import url
urlpatterns = [

]

获取多资源 接口
序列化类：serializers.py
from rest_framework import serializers

# 为每一个Model类至少配一个Serializer类

class UserSerializer(serializers.Serializer):

# 序列化一个Model类对象，其实就是序列化该类的每一个属性

name = serializers.CharField()

password = serializers.CharField()

sex = serializers.IntegerField()

create_time = serializers.DateTimeField()

视图类：views.py
from rest_framework.views import APIView
from rest_framework.response import Response
from .models import User
from .serializers import UserSerializer

# 对应路由：/users/

# 功能：get获取所有 | post新增一个 | put修改一个 | delete删除一个

class UsersAPIView(APIView):

def get(self, request, *args, **kwargs):

user_list = User.objects.all()
    <span class="hljs-comment"># instance存放的是queryset对象，many需要设置为True</span>
    user_data = UserSerializer(instance=user_list, many=<span class="hljs-keyword">True</span>).data
    <span class="hljs-keyword">return</span> Response(
        {
            <span class="hljs-string">'status'</span>: <span class="hljs-number">0</span>,
            <span class="hljs-string">'msg'</span>: <span class="hljs-string">'ok'</span>,
            <span class="hljs-string">'results'</span>: user_data
        }
    )</code></pre>

序列化字段操作（自定义字段）
序列化类修订：serializers.py
from rest_framework import serializers

# 为每一个Model类至少配一个Serializer类

class UserSerializer(serializers.Serializer):

# 序列化一个Model类对象，其实就是序列化该类的每一个属性

# 注意1：Model类与Serializer类是通过属性名建立关联的 - 属性名必须依照

name = serializers.CharField()

password = serializers.CharField()

# sex = serializers.IntegerField()

# 注意2：不需要通过给前台的数据，不需要提供该属性的序列化

# create_time = serializers.DateTimeField()
<span class="hljs-comment"># 注意3：serializers.SerializerMethodField()可以产生自定义序列化属性(不需要和Model类属性同步)，</span>
<span class="hljs-comment">#       但要为其绑定一个提供值的函数，函数名为 get_属性(self, obj) (obj为参与序列化的Model类对象)</span>
gender = serializers.SerializerMethodField()
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">get_gender</span><span class="hljs-params">(self, obj)</span>:</span>
    <span class="hljs-comment"># 该函数的返回值就作为对应自定义数据序列化后的值</span>
    <span class="hljs-keyword">return</span> obj.get_sex_display()</code></pre>

新增单资源 接口
序列化类(反序列化类)：serializers.py
from rest_framework import serializers
from .models import User

class UserDeserializer(serializers.Serializer):

name = serializers.CharField(label='姓名', max_length=32, min_length=3, error_messages={

'max_length': '姓名太长',

'min_length': '姓名太短'

})

password = serializers.CharField(label='密码', max_length=64, min_length=3, error_messages={

'max_length': '密码太长',

'min_length': '密码太短'

})

sex = serializers.IntegerField()

# required=False该字段前台可以不用传(不参与校验)

create_time = serializers.DateTimeField(required=False)
<span class="hljs-comment"># 完成ORM的操作</span>
<span class="hljs-comment"># def save(self):  # 不能直接重写save，因为系统的save可以完成新增或修改</span>
<span class="hljs-comment">#     # print(self.validated_data)</span>
<span class="hljs-comment">#     User.objects.create(**self.validated_data)</span>

<span class="hljs-comment"># 为post接口提供新增Model类对象的功能</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">create</span><span class="hljs-params">(self, validated_data)</span>:</span>
    <span class="hljs-comment"># 返回值：Model类要新增的对象</span>
    <span class="hljs-keyword">return</span> User.objects.create(**validated_data)</code></pre>

视图类：views.py
from rest_framework.views import APIView
from rest_framework.response import Response
from .models import User
from .serializers import UserSerializer

# 对应路由：/users/

# 功能：get获取所有 | post新增一个 | put修改一个 | delete删除一个

class UsersAPIView(APIView):

# 新增一个资源

def post(self, request, *args, **kwargs):

user_deser = UserDeserializer(data=request.data)

# raise_exception值为True，当校验失败，直接返回校验失败的错误信息

# result = user_deser.is_valid(raise_exception=True)

result = user_deser.is_valid()

if result:

new_user_obj = user_deser.save()

return Response({

'status': 0,

'msg': 'success',

'result': UserSerializer(new_user_obj).data

})

else:

return Response({

'status': 1,

'msg': 'failed',

'results': user_deser.errors

})


更新单资源 接口
序列化类(反序列化类)：serializers.py
from rest_framework import serializers
from .models import User

class UserDeserializer(serializers.Serializer):

name = serializers.CharField(label='姓名', max_length=32, min_length=3, error_messages={

'max_length': '姓名太长',

'min_length': '姓名太短'

})

password = serializers.CharField(label='密码', max_length=64, min_length=3, error_messages={

'max_length': '密码太长',

'min_length': '密码太短'

})

sex = serializers.IntegerField()

# required=False该字段前台可以不用传(不参与校验)

create_time = serializers.DateTimeField(required=False)
<span class="hljs-comment"># 完成ORM的操作</span>
<span class="hljs-comment"># def save(self):  # 不能直接重写save，因为系统的save可以完成新增或修改</span>
<span class="hljs-comment">#     # print(self.validated_data)</span>
<span class="hljs-comment">#     User.objects.create(**self.validated_data)</span>

<span class="hljs-comment"># 为post接口提供新增Model类对象的功能</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">create</span><span class="hljs-params">(self, validated_data)</span>:</span>
    <span class="hljs-comment"># 返回值：Model类要新增的对象</span>
    <span class="hljs-keyword">return</span> User.objects.create(**validated_data)

<span class="hljs-comment"># 为put接口提供更新Model类对象的功能</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">update</span><span class="hljs-params">(self, instance, validated_data)</span>:</span>
    <span class="hljs-comment"># 操作model对象</span>
    <span class="hljs-comment"># instance.name = validated_data.get('name')</span>
    <span class="hljs-comment"># instance.password = validated_data.get('password')</span>
    <span class="hljs-comment"># instance.sex = validated_data.get('sex')</span>
    <span class="hljs-comment"># instance.save()</span>
    <span class="hljs-comment"># 操作queryset对象</span>
    instance.update(**validated_data)
    <span class="hljs-keyword">return</span> instance</code></pre>

视图类：views.py
from rest_framework.views import APIView
from rest_framework.response import Response
from .models import User
from .serializers import UserSerializer

# 对应路由：/users/

# 功能：get获取所有 | post新增一个 | put修改一个 | delete删除一个

class UsersAPIView(APIView):

# 更新一个资源

def put(self, request, *args, **kwargs):

# 要更新的资源的主键

pk = kwargs.get('pk')
    <span class="hljs-comment"># 操作更新时可以选择操作 queryset对象 或 model对象</span>
    <span class="hljs-comment"># 操作model对象</span>
    <span class="hljs-comment"># old_user_obj = User.objects.get(pk=pk)</span>
    <span class="hljs-comment"># user_deser = UserDeserializer(instance=old_user_obj, data=request.data)</span>

    <span class="hljs-comment"># 操作queryset对象</span>
    old_user_query = User.objects.filter(pk=pk)
    user_deser = UserDeserializer(instance=old_user_query, data=request.data)

    <span class="hljs-comment"># raise_exception值为True，当校验失败，直接返回校验失败的错误信息</span>
    <span class="hljs-comment"># result = user_deser.is_valid(raise_exception=True)</span>
    result = user_deser.is_valid()
    <span class="hljs-keyword">if</span> result:
        <span class="hljs-comment"># new_user_obj = user_deser.save()  # 操作model对象</span>
        new_user_query = user_deser.save()  <span class="hljs-comment"># 操作queryset对象</span>
        new_user_obj = new_user_query.first()
        <span class="hljs-keyword">return</span> Response({
            <span class="hljs-string">'status'</span>: <span class="hljs-number">0</span>,
            <span class="hljs-string">'msg'</span>: <span class="hljs-string">'success'</span>,
            <span class="hljs-string">'result'</span>: UserSerializer(new_user_obj).data
        })
    <span class="hljs-keyword">else</span>:
        <span class="hljs-keyword">return</span> Response({
            <span class="hljs-string">'status'</span>: <span class="hljs-number">1</span>,
            <span class="hljs-string">'msg'</span>: <span class="hljs-string">'failed'</span>,
            <span class="hljs-string">'results'</span>: user_deser.errors
        })</code></pre>

删除单资源 接口
重构Model新增字段：models.py
class User(models.Model):
    CHOICE_SEX = (
        (0, '男'),
        (1, '女')
    )
    name = models.CharField(max_length=32, verbose_name='姓名')
    password = models.CharField(max_length=64, verbose_name='密码')
    sex = models.SmallIntegerField(choices=CHOICE_SEX, default=0)
    create_time = models.DateTimeField(auto_now_add=True, blank=True)
    # 新增：数据删除不是从数据库删除记录，而是修改记录状态，标示为已删除即可
    is_delete = models.BooleanField(default=False)
<span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Meta</span>:</span>
    <span class="hljs-comment"># 自定义创建的表名</span>
    db_table = <span class="hljs-string">'o_user'</span>
    <span class="hljs-comment"># admin界面中显示的表面与表名复数形式</span>
    verbose_name = <span class="hljs-string">'用户'</span>
    verbose_name_plural = verbose_name

<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">__str__</span><span class="hljs-params">(self)</span>:</span>
    <span class="hljs-keyword">return</span> self.name</code></pre>

数据库迁移：在项目目录下的终端
>: python3 manage.py makemigrations
>: python3 manage.py migrate
视图类接口：views.py
from rest_framework.views import APIView
from rest_framework.response import Response
from .models import User
from .serializers import UserSerializer

# 对应路由：/users/

# 功能：get获取所有 | post新增一个 | put修改一个 | delete删除一个

class UsersAPIView(APIView):

# 删除一个资源

def delete(self, request, *args, **kwargs):

pk = kwargs.get('pk')

try:

delete_user_obj = User.objects.get(pk=pk, is_delete=False)

# 完成删除信息的更新

delete_user_obj.is_delete = True

delete_user_obj.save()

return Response()

except:

return Response({

'status': 1,

'msg': '数据删除失败'

})

获取单资源 接口
序列化类：serializers.py
from rest_framework import serializers

# 为每一个Model类至少配一个Serializer类

class UserSerializer(serializers.Serializer):

# 序列化一个Model类对象，其实就是序列化该类的每一个属性

name = serializers.CharField()

password = serializers.CharField()

sex = serializers.IntegerField()

create_time = serializers.DateTimeField()

视图类：views.py
from rest_framework.views import APIView
from rest_framework.response import Response
from .models import User
from .serializers import UserSerializer

# 对应路由：/users/

# 功能：get获取所有 | post新增一个 | put修改一个 | delete删除一个

class UsersAPIView(APIView):

def get(self, request, *args, **kwargs):

pk = kwargs.get('pk', None)
    <span class="hljs-keyword">if</span> <span class="hljs-keyword">not</span> pk:
        user_query = User.objects.filter(is_delete=<span class="hljs-keyword">False</span>).all()
    <span class="hljs-keyword">else</span>:
        user_query = User.objects.filter(is_delete=<span class="hljs-keyword">False</span>, pk=pk)
        <span class="hljs-comment"># 如果只操作一个对象，many参数需要为False(默认值)</span>
        <span class="hljs-comment"># user_obj = User.objects.filter(is_delete=False, pk=pk).first()</span>
        <span class="hljs-comment"># user_data = UserSerializer(instance=user_obj, many=False).data</span>

    user_data = UserSerializer(instance=user_query, many=<span class="hljs-keyword">True</span>).data
    <span class="hljs-keyword">return</span> Response(
        {
            <span class="hljs-string">'status'</span>: <span class="hljs-number">0</span>,
            <span class="hljs-string">'msg'</span>: <span class="hljs-string">'ok'</span>,
            <span class="hljs-string">'results'</span>: user_data
        }
    )</code></pre>

序列化基础：重点内容
模型类：models.py
from django.db import models

# Create your models here.

class User(models.Model):

CHOICE_SEX = (

(0, '男'),

(1, '女')

)

name = models.CharField(max_length=32, verbose_name='姓名')

password = models.CharField(max_length=64, verbose_name='密码')

sex = models.SmallIntegerField(choices=CHOICE_SEX, default=0)

create_time = models.DateTimeField(auto_now_add=True, blank=True)

# 数据删除不是从数据库删除记录，而是修改记录状态，标示为已删除即可

is_delete = models.BooleanField(default=False)
<span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Meta</span>:</span>
    <span class="hljs-comment"># 自定义创建的表名</span>
    db_table = <span class="hljs-string">'o_user'</span>
    <span class="hljs-comment"># admin界面中显示的表面与表名复数形式</span>
    verbose_name = <span class="hljs-string">'用户'</span>
    verbose_name_plural = verbose_name

<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">__str__</span><span class="hljs-params">(self)</span>:</span>
    <span class="hljs-keyword">return</span> self.name</code></pre>

序列化类：
from rest_framework import serializers
from .models import User

class UserSerializer(serializers.Serializer):

# 序列化和反序列化都可以使用

name = serializers.CharField(label='姓名', max_length=32, min_length=3, error_messages={

'max_length': '姓名太长',

'min_length': '姓名太短'

})

password = serializers.CharField(label='密码', max_length=64, min_length=3, error_messages={

'max_length': '密码太长',

'min_length': '密码太短'

})

# 只有反序列化使用 - 用 write_only=True 标示只参与反序列化

sex = serializers.IntegerField(write_only=True)

# 只有序列化使用 - 自定义字段 - 用 read_only=True 标示只参与序列化

gender = serializers.SerializerMethodField(read_only=True)

def get_gender(self, obj):

return obj.get_sex_display()

# 序列化与反序列化都不使用 - 1）注释 | 2）required=False, write_only=True

create_time = serializers.DateTimeField(required=False, write_only=True)
<span class="hljs-comment"># 为全局校验钩子新增校验字段</span>
re_password = serializers.CharField(label=<span class="hljs-string">'确认密码'</span>, max_length=<span class="hljs-number">64</span>, min_length=<span class="hljs-number">3</span>, write_only=<span class="hljs-keyword">True</span>, error_messages={
    <span class="hljs-string">'max_length'</span>: <span class="hljs-string">'确认密码太长'</span>,
    <span class="hljs-string">'min_length'</span>: <span class="hljs-string">'确认密码太短'</span>
})

<span class="hljs-comment"># 反序列化两大方法重写 - 新增create | 更新update</span>
<span class="hljs-comment"># 为post接口提供新增Model类对象的功能</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">create</span><span class="hljs-params">(self, validated_data)</span>:</span>
    <span class="hljs-comment"># 返回值：Model类要新增的对象</span>
    <span class="hljs-keyword">return</span> User.objects.create(**validated_data)

<span class="hljs-comment"># 为put接口提供更新Model类对象的功能</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">update</span><span class="hljs-params">(self, instance, validated_data)</span>:</span>
    instance.update(**validated_data)
    <span class="hljs-comment"># 返回更新后的instance</span>
    <span class="hljs-keyword">return</span> instance

<span class="hljs-comment"># 局部钩子</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">validate_sex</span><span class="hljs-params">(self, value)</span>:</span>
    <span class="hljs-keyword">if</span> value <span class="hljs-keyword">not</span> <span class="hljs-keyword">in</span> (<span class="hljs-number">0</span>, <span class="hljs-number">1</span>):
        <span class="hljs-keyword">raise</span> serializers.ValidationError(<span class="hljs-string">'未知性别'</span>)
    <span class="hljs-keyword">return</span> value

<span class="hljs-comment"># 全局钩子</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">validate</span><span class="hljs-params">(self, attrs)</span>:</span>
    re_password = attrs.pop(<span class="hljs-string">'re_password'</span>)
    password = attrs.get(<span class="hljs-string">'password'</span>)
    <span class="hljs-keyword">if</span> re_password != password:
        <span class="hljs-keyword">raise</span> serializers.ValidationError(<span class="hljs-string">'二次密码不一致'</span>)
    <span class="hljs-keyword">return</span> attrs</code></pre>

视图类：
from rest_framework.views import APIView
from rest_framework.response import Response
from .models import User
from .serializers import UserSerializer

# 对应路由：/users/ | /users/pk/

# 功能：get获取所有 | post新增一个 | put修改一个 | delete删除一个 | get获取一个

class UsersAPIView(APIView):

# 获取所有资源 | 单个资源

def get(self, request, *args, **kwargs):

# 单个资源的主键

pk = kwargs.get('pk', None)

if not pk:

user_query = User.objects.filter(is_delete=False).all()

else:

user_query = User.objects.filter(is_delete=False, pk=pk)
    user_data = UserSerializer(instance=user_query, many=<span class="hljs-keyword">True</span>).data
    <span class="hljs-keyword">return</span> Response(
        {
            <span class="hljs-string">'status'</span>: <span class="hljs-number">0</span>,
            <span class="hljs-string">'msg'</span>: <span class="hljs-string">'ok'</span>,
            <span class="hljs-string">'results'</span>: user_data
        }
    )

<span class="hljs-comment"># 新增一个资源</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">post</span><span class="hljs-params">(self, request, *args, **kwargs)</span>:</span>
    user_deser = UserSerializer(data=request.data)

    <span class="hljs-comment"># raise_exception值为True，当校验失败，直接返回校验失败的错误信息</span>
    <span class="hljs-comment"># result = user_deser.is_valid(raise_exception=True)</span>
    result = user_deser.is_valid()
    <span class="hljs-keyword">if</span> result:
        new_user_obj = user_deser.save()
        <span class="hljs-keyword">return</span> Response({
            <span class="hljs-string">'status'</span>: <span class="hljs-number">0</span>,
            <span class="hljs-string">'msg'</span>: <span class="hljs-string">'success'</span>,
            <span class="hljs-string">'result'</span>: UserSerializer(new_user_obj).data
        })
    <span class="hljs-keyword">else</span>:
        <span class="hljs-keyword">return</span> Response({
            <span class="hljs-string">'status'</span>: <span class="hljs-number">1</span>,
            <span class="hljs-string">'msg'</span>: <span class="hljs-string">'failed'</span>,
            <span class="hljs-string">'results'</span>: user_deser.errors
        })

<span class="hljs-comment"># 更新一个资源</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">put</span><span class="hljs-params">(self, request, *args, **kwargs)</span>:</span>
    pk = kwargs.get(<span class="hljs-string">'pk'</span>)
    old_user_query = User.objects.filter(pk=pk, is_delete=<span class="hljs-keyword">False</span>)
    <span class="hljs-comment"># 没有数据</span>
    <span class="hljs-keyword">if</span> <span class="hljs-keyword">not</span> old_user_query:
        <span class="hljs-keyword">return</span> Response({
            <span class="hljs-string">'status'</span>: <span class="hljs-number">1</span>,
            <span class="hljs-string">'msg'</span>: <span class="hljs-string">'update failed'</span>,
        })

    user_deser = UserSerializer(instance=old_user_query, data=request.data)
    result = user_deser.is_valid()
    <span class="hljs-keyword">if</span> result:
        new_user_query = user_deser.save()
        new_user_obj = new_user_query.first()
        <span class="hljs-keyword">return</span> Response({
            <span class="hljs-string">'status'</span>: <span class="hljs-number">0</span>,
            <span class="hljs-string">'msg'</span>: <span class="hljs-string">'success'</span>,
            <span class="hljs-string">'result'</span>: UserSerializer(new_user_obj).data
        })
    <span class="hljs-keyword">else</span>:
        <span class="hljs-keyword">return</span> Response({
            <span class="hljs-string">'status'</span>: <span class="hljs-number">1</span>,
            <span class="hljs-string">'msg'</span>: <span class="hljs-string">'failed'</span>,
            <span class="hljs-string">'results'</span>: user_deser.errors
        })

<span class="hljs-comment"># 删除一个资源</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">delete</span><span class="hljs-params">(self, request, *args, **kwargs)</span>:</span>
    pk = kwargs.get(<span class="hljs-string">'pk'</span>)
    <span class="hljs-keyword">try</span>:
        delete_user_obj = User.objects.get(pk=pk, is_delete=<span class="hljs-keyword">False</span>)
        <span class="hljs-comment"># 完成删除信息的更新</span>
        delete_user_obj.is_delete = <span class="hljs-keyword">True</span>
        delete_user_obj.save()
        <span class="hljs-keyword">return</span> Response()
    <span class="hljs-keyword">except</span>:
        <span class="hljs-keyword">return</span> Response({
            <span class="hljs-string">'status'</span>: <span class="hljs-number">1</span>,
            <span class="hljs-string">'msg'</span>: <span class="hljs-string">'数据删除失败'</span>
        })</code></pre>