rpc: 翻译成中文:远程过程调用[远程服务调用].

http://www.lufei.com/api

post请求

action=get_all_student&params=301&sex=1

restful: 翻译成中文: 资源状态转换.

把后端所有的数据/文件都看成资源.

那么接口请求数据,本质上来说就是对资源的操作了.

web项目中操作资源,无非就是增删查改.所以要求在地址栏中声明要操作的资源是什么,然后通过http请求动词来说明对资源进行哪一种操作.

POST http://www.lufei.com/api/students/ 添加学生数据

GET http://www.lufei.com/api/students/ 获取所有学生

DELETE http://www.lufei.com/api/students/<pk> 删除1个学生

GET http://www.lufei.com/api/students/<pk> 获取一个学生

- 提供了定义序列化器Serializer的方法，可以快速根据 Django ORM 或者其它库自动序列化/反序列化；
- 提供了丰富的类视图、Mixin扩展类，简化视图的编写；
- 丰富的定制层级：函数视图、类视图、视图集合到自动生成 API，满足各种需要；
- 多种身份认证和权限认证方式的支持；[jwt]
- 内置了限流系统；
- 直观的 API web 界面；
- 可扩展性，插件丰富

# mkvirtualenv drfdemo -p python3
# pip install django

pip install djangorestframework
pip install pymysql

cd ~/Desktop
django-admin startproject drfdemo

INSTALLED_APPS = [
    ...
    'rest_framework',
]

class Student(models.Model):
    # 模型字段
    name = models.CharField(max_length=100,verbose_name="姓名")
    sex = models.BooleanField(default=1,verbose_name="性别")
    age = models.IntegerField(verbose_name="年龄")
    class_null = models.CharField(max_length=5,verbose_name="班级编号")
    description = models.TextField(max_length=1000,verbose_name="个性签名")

    class Meta:
        db_table="tb_student"
        verbose_name = "学生"
        verbose_name_plural = verbose_name

create database students charset=utf8;

python manage.py startapp students

安装pymysql
pip install pymysql

import pymysql
pymysql.install_as_MySQLdb()

DATABASES = {
    # 'default': {
    #     'ENGINE': 'django.db.backends.sqlite3',
    #     'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
    # },
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': "students",
        "HOST": "127.0.0.1",
        "PORT": 3306,
        "USER": "root",
        "PASSWORD":"123",
    }
}

python manage.py makemigrations
python manage.py migrate

注释掉 backends/mysql/base.py中的35和36行代码。

# 创建序列化器类，回头会在试图中被调用
from rest_framework import serializers
from .models import Student

class StudentModelSerializer(serializers.ModelSerializer):
    class Meta:
        model = Student
        fields = "__all__"

from rest_framework.viewsets import ModelViewSet
from .models import Student
from .serializers import StudentModelSerializer
# Create your views here.
class StudentViewSet(ModelViewSet):
    queryset = Student.objects.all()
    serializer_class = StudentModelSerializer

from . import views
from rest_framework.routers import DefaultRouter

# 路由列表
urlpatterns = []

router = DefaultRouter()  # 可以处理视图的路由器
router.register('students', views.StudentViewSet)  # 向路由器中注册视图集

urlpatterns += router.urls  # 将路由器中的所以路由信息追到到django的路由列表中

from django.contrib import admin
from django.urls import path,include

urlpatterns = [
    path('admin/', admin.site.urls),
    path("stu/",include("students.urls")),
]

python manage.py runserver

1. 序列化,序列化器会把模型对象转换成字典,经过response以后变成json字符串
2. 反序列化,把客户端发送过来的数据,经过request以后变成字典,序列化器可以把字典转成模型
3. 反序列化,完成数据校验功能

python manage.py startapp ser

from rest_framework import serializers

# 声明序列化器，所有的序列化器都要直接或者间接继承于 Serializer
# 其中，ModelSerializer是Serializer的子类，ModelSerializer在Serializer的基础上进行了代码简化
class StudentSerializer(serializers.Serializer):
    """学生信息序列化器"""
    # 1. 需要进行数据转换的字段
    id = serializers.IntegerField()
    name = serializers.CharField()
    age = serializers.IntegerField()
    sex = serializers.BooleanField()
    description = serializers.CharField()

    # 2. 如果序列化器集成的是ModelSerializer，则需要声明调用的模型信息

    # 3. 验证代码

    # 4. 编写添加和更新模型的代码

from rest_framework import serializers
class BookSerializer(serializers.Serializer): #序列化器 Serializer

Serializer(instance=None, data=empty, **kwarg)

serializer = StudentSerializer(instance, context={'request': request})

from students.models import Student

student = Student.objects.get(id=3)

from .serializers import StudentSerializer

serializer = StudentSerializer(instance=student)

serializer.data
# {'id': 4, 'name': '小张', 'age': 18, 'sex': True, 'description': '猴赛雷'}

from django.views import View
from students.models import Student
from .serializers import StudentSerializer
from django.http.response import JsonResponse
class StudentRetrieveView(View):
    """使用序列化器序列化转换单个模型数据"""
    def get(self,request,pk):
        # 获取数据
        student = Student.objects.get(pk=pk)
        # 数据转换[序列化过程]
        serializer = StudentSerializer(instance=student)
        print(serializer.data)
        # 响应数据
        return JsonResponse(serializer.data)

class StudentView(View):    
    """使用序列化器序列化转换多个模型数据"""
    def get(self,request):
        # 获取数据
        student_list = Student.objects.all()

        # 转换数据[序列化过程]
        # 如果转换多个模型对象数据，则需要加上many=True
        serializer = StudentSerializer(instance=student_list,many=True)
        print( serializer.data ) # 序列化器转换后的数据

        # 响应数据给客户端
        # 返回的json数据，如果是列表，则需要声明safe=False
        return JsonResponse(serializer.data,safe=False)
    
    
    # 访问结果：
    # [OrderedDict([('id', 1), ('name', 'xiaoming'), ('age', 20), ('sex', True), ('description', '测试')]), OrderedDict([('id', 2), ('name', 'xiaohui'), ('age', 22), ('sex', True), ('description', '后面来的测试')]), OrderedDict([('id', 4), ('name', '小张'), ('age', 18), ('sex', True), ('description', '猴赛雷')])]

python manage.py startapp books

INSTALLED_APPS = [
    # ...
    'ser',
    'unser',
]

python manage.py makemigrations
python manage.py migrate

from rest_framework import serializers

# 外部函数设置为验证函数
def check_title(data):
    if data == "django入门":
        raise serializers.ValidationError("这本书，我定了，你不能叫")

class BookSerializer(serializers.Serializer):
    # 字段声明
    # 字段 = serializers.字段类型(验证选项)
    title = serializers.CharField(required=True, max_length=20,validators=[check_title])
    pub_date = serializers.DateField(required=True)
    read = serializers.IntegerField(default=0,min_value=0, error_messages={"min_value":"对不起，当前字段必须大于或等于0"})
    comment = serializers.IntegerField(allow_null=True)

    # 自定义方法设置校验方法
    # validate_字段(字段值)    用于验证指定字段
    # validate(客户端提交的所有数据)  用于验证多个字段[联合验证]
    def validate_title(self, data):
        if("oldboy" in data):
            # 跑出错误
            raise serializers.ValidationError("对不起，图书名不能包含oldboy！")

        # 必须在校验完成以后，返回结果
        return data

    def validate(self, data):
        read = data.get("read")
        comment = data.get("comment")

        if(comment>read):
            raise serializers.ValidationError("对不起，阅读量不能小于评论量，喷子！")

        return data

from book.serializers import BookSerializer
data = {'pub_date': 123}
serializer = BookSerializer(data=data)
serializer.is_valid()  # 返回False
serializer.errors
# {'title': [ErrorDetail(string='This field is required.', code='required')], 'pub_date': [ErrorDetail(string='Date has wrong format. Use one of these formats instead: YYYY[-MM[-DD]].', code='invalid')]}
serializer.validated_data  # {}

data = {'title': 'python'}
serializer = BookSerializer(data=data)
serializer.is_valid()  # True   验证结果返回值
serializer.errors  # {}  错误信息
serializer.validated_data  #  OrderedDict([('btitle', 'python')])

# Return a 400 response if the data was invalid.
serializer.is_valid(raise_exception=True)

class BookSerializer(serializers.Serializer):
    """图书数据序列化器"""
    ...

    def validate_title(self, value):
        if 'django' not in value.lower():
            raise serializers.ValidationError("图书不是关于Django的")
        return value

from book.serializers import BookSerializer
data = {'title': 'python'}
serializer = BookSerializer(data=data)
serializer.is_valid()  # False   
serializer.errors
#  {'title': [ErrorDetail(string='图书不是关于Django的', code='invalid')]}

class BookSerializer(serializers.Serializer):
    """图书序列化器"""
    ...

    def validate(self, attrs):
        read = attrs['read']
        comment = attrs['comment']
        if read < comment:
            raise serializers.ValidationError('阅读量小于评论量，不可以通过')
        return attrs

from book.serializers import BookSerializer
data = {'title': 'about django', 'read': 10, 'comment': 20}
s = BookSerializer(data=data)
s.is_valid()  # False
s.errors
#  {'non_field_errors': [ErrorDetail(string='阅读量小于评论量', code='invalid')]}

def about_django(value):
    if 'django' not in value.lower():
        raise serializers.ValidationError("图书不是关于Django的")

class BookSerializer(serializers.Serializer):
    """图书序列化器"""
    id = serializers.IntegerField(label='ID', read_only=True)
    title = serializers.CharField(label='名称', max_length=20, validators=[about_django])
    pub_date = serializers.DateField(label='发布日期', required=False)
    read = serializers.IntegerField(label='阅读量', required=False)
    comment = serializers.IntegerField(label='评论量', required=False)

from book.serializers import BookSerializer
data = {'title': 'python'}
serializer = BookSerializer(data=data)
serializer.is_valid()  # False   
serializer.errors
#  {'title': [ErrorDetail(string='图书不是关于Django的', code='invalid')]}

class BookSerializer(serializers.Serializer):
    """图书数据序列化器"""
    ...

　　def create(self, validated_data):
    　　"""添加数据"""
    　　instance = Book.objects.create(**validated_data)
    　　return instance

　　def update(self, instance, validated_data):
    　　"""修改数据"""
    　　instance.title = validated_data.get("title")
    　　instance.pub_date = validated_data.get("pub_date")
    　　instance.read = validated_data.get("read")
   　　 instance.comment = validated_data.get("comment")
   　　 # 下面的save是调用了ORM中提供给模型保存数据的save，不是序列化器中的save
   　　 instance.save()
  　　  return instance

from django.views import View
from django.http import JsonResponse
from .serializers import BookSerializer

class BookView(View):
    """使用序列化器完成反序列化和验证数据功能"""

　　# 新增
    def get2(self,request):
        """使用序列化器在反序列化时添加数据"""
        data_dict = {
            "title":"路飞项目实战1990",
            "pub_date":"2009-10-10",
            "read": 10000,
            "comment": 300
        }

        serializer = BookSerializer(data=data_dict)
        serializer.is_valid(raise_exception=True)
        # 调用序列化器内部保存数据的方法[自动调用create或者update]
        # 在源码save方法207行中，系统通过判断初始化序列化器时是否传递了instance参数作为判断依据，
        # 传递了instance，则save方法中调用update
        # 没有传递instance，则save方法中调用create
        serializer.save()


        return JsonResponse({"message":"ok"})
　　# 编辑
    def get(self,request):
        """使用图序列化器在反序列化时修改数据"""
        data_dict = {
            "title":"路飞项目实战2019",
            "pub_date":"2019-10-10",
            "read": 10000,
            "comment": 300
        }

        pk = 2　　　　# 编辑
        book = Book.objects.get(pk=pk)

        serializer = BookSerializer(instance=book, data=data_dict)
        serializer.is_valid(raise_exception=True)
        serializer.save()
        return JsonResponse(serializer.data) 

book = serializer.save()

from .serializers import BookSerializer
data = {'title': 'python入门指南'}
serializer = BookSerializer(data=data)
serializer.is_valid()  # True
serializer.save()  # <BookInfo: python入门指南>

from .models import Book
book = Book.objects.get(id=2)
data = {'title': 'django入门指南'}
serializer = BookSerializer(book, data=data)
serializer.is_valid()  # True
serializer.save()  # <BookInfo: django入门指南>
book.title  # 'django入门指南'

# request.user 是django中记录当前登录用户的模型对象
serializer.save(自定义字段名=request.user,自定义字段名2=xxx)

# Update `comment` with partial data
serializer = CommentSerializer(comment, data={'content': u'foo bar'}, partial=True)

from rest_framework import serializers
class BookModelSerializer(serializers.ModelSerializer): # ModelSerializer 模型序列化器

class BookModelSerializer(serializers.ModelSerializer):
    """图书数据序列化器"""
　　# 元类
    class Meta:
        model = Book           # 生命当前使用的模型类        
        fields = '__all__'     # 复制所有的字段声明   
        fields = ['id','title']# 选择字段
        exclude = ['read']     # 排除字段    

>>> from booktest.serializers import BookSerializer
>>> serializer = BookSerializer()
>>> serializer
BookSerializer():
    id = IntegerField(label='ID', read_only=True)
    title = CharField(label='名称', max_length=20)
    pub_date = DateField(allow_null=True, label='发布日期', required=False)
    read = IntegerField(label='阅读量', max_value=2147483647, min_value=-2147483648, required=False)
    comment = IntegerField(label='评论量', max_value=2147483647, min_value=-2147483648, required=False)

class BookSerializer(serializers.ModelSerializer):
    """图书数据序列化器"""
    class Meta:
        model = Book
        fields = "__all__"

class BookSerializer(serializers.ModelSerializer):
    """图书数据序列化器"""
    class Meta:
        model = Book
        exclude = ('pub_date',)

class BookSerializer(serializers.ModelSerializer):
    
    class Meta:
        model = Book
        fields = ('id', 'title', 'comment', 'read')

class BookSerializer(serializers.ModelSerializer):
    """图书序列化器"""
    class Meta:
        model = Book
        fields = ('id', 'title', 'pub_date'， 'read', 'comment')
        read_only_fields = ('id', 'read', 'comment')

class BookSerializer(serializers.ModelSerializer):
    """图书序列化器"""
    class Meta:
        model = Book
        fields = ('id', 'title', 'pub_date', 'read', 'comment')
        extra_kwargs = {
            'read': {'min_value': 0, 'required': True},
            'comment': {'min_value': 0, 'required': True},
        }

# BookSerializer():
#    id = IntegerField(label='ID', read_only=True)
#    title = CharField(label='名称', max_length=20)
#    pub_date = DateField(allow_null=True, label='发布日期', required=False)
#    read = IntegerField(label='阅读量', max_value=2147483647, min_value=0, required=True)
#    comment = IntegerField(label='评论量', max_value=2147483647, min_value=0, required=True)

"""使用模型类序列化器"""
from rest_framework import serializers
from .models import Book
class BookModelSerializer(serializers.ModelSerializer):
    """字段声明"""

    """元类"""
    class Meta:
        model = Book # 声明当前使用的模型类
        fields = "__all__" # 复制所有的字段声明过来

"""使用模型类序列化器"""
from .serializers import BookModelSerializer
from .models import Book
class BookView2(View):
    def get1(self,request):
        """使用模型类序列化器进行序列化"""

        """提供所有的图书信息"""
        book_list = Book.objects.all()
        serializer = BookModelSerializer(instance=book_list, many=True)
        return JsonResponse(serializer.data,safe=False)

"""使用模型类序列化器"""
from rest_framework import serializers
from .models import Book
class BookModelSerializer(serializers.ModelSerializer):
    """字段声明"""

    """元类"""
    class Meta:
        model = Book # 声明当前使用的模型类
        fields = "__all__" # 复制所有的字段声明过来
        # fields = ["id","title","read","pub_date"]
        # 额外的字段声明
        extra_kwargs = {
            "title":{
                "error_messages":{"max_length":"对不起，当前字段不能超过20个字符"}
            }
        }

    # 自定义方法设置校验方法
    def validate_title(self, data):
        if("oldboy" in data):
            # 跑出错误
            raise serializers.ValidationError("对不起，图书名不能包含oldboy！")

        # 必须在校验完成以后，返回结果
        return data

    def validate(self, data):
        read = data.get("read")
        comment = data.get("comment")

        if(comment>read):
            raise serializers.ValidationError("对不起，阅读量不能小于评论量，喷子！")

        return data

"""使用模型类序列化器"""
from .serializers import BookModelSerializer
from .models import Book
class BookView2(View):
    def get(self,request):
        data_dict = {
            "title":"django入门3333",
            "pub_date":"2009-10-10",
            # "read": -10000, # 模拟失败的情况
            "read": 100,
            "comment": 30
        }
        serializer = BookModelSerializer(data=data_dict)

        serializer.is_valid(raise_exception=True)

        print(serializer.errors)

        serializer.save()

        return JsonResponse(serializer.validated_data, safe=False)