开发实践8_REST-编程知识

一、Django REST Framework, Django View & APIView

MTV模式实现前后端分离。Representational State Transfer 表现层状态转化。Representation 资源（Resource a specific info. on net.）具体呈现形式。ST 修改服务端的数据。修改数据 == POST请求。实现: 安装依赖 pip install djangorestframework / 序列化 / 视图装饰器 / 视图集

pip install djangorestframework

pip install httpie

python manage.py startapp rest_app

setting注册

path('rest_app/', include('rest_app.urls', namespace='rest')),

models //

from django.db import modelsclass Students(models.Model):name = models.CharField(max_length=32, verbose_name="NAME")age = models.IntegerField(verbose_name="AAAAGE")gender = models.CharField(max_length=2, verbose_name="GENDER")gpa = models.FloatField(verbose_name="BASIS")class Meta:verbose_name = "Students"verbose_name_plural = verbose_name + 'S'def __str__(self):return self.name@classmethoddef get_all(cls):return cls.objects.all()

admin //

from django.contrib import adminfrom rest_app.models import Studentsadmin.site.register(Students
)

app下serializer.py //

from rest_framework import serializersfrom rest_app.models import Studentsclass StudentSerializer(serializers.ModelSerializer):  # 自定义一个用于序列化student模型的序列化类class Meta:model = Studentsfields = ("id","name","age","gender","gpa",)

# 序列化：继承djangorestframework中的serialize。str(a dict), 是一个jason字符串。

views //

from rest_framework.decorators import api_view
from rest_framework.response import Responsefrom rest_app.models import Students
from rest_app.serializer import StudentSerializer@api_view(["GET"])
def students_view(request):# 用不着render了，前端也不存在query set，所以需要序列化类students = Students.get_all()ser = StudentSerializer(students, many=True)return Response(ser.data)

# 视图装饰器。能接收什么样的请求。api_view。

urls //

from django.urls import path
from .views import *app_name = 'rest'urlpatterns = [path('stuview/', students_view, name="stuview"),
]

# 用httpie来检测。

http get http://127.0.0.1:8000/rest/stuview

or postman.

Django rest post请求 put delete请求

views //

@api_view(["GET", "POST"])
def students_view(request):# 用不着render了，前端也不存在query set，所以需要序列化类if request.method == "GET":students = Students.get_all()ser = StudentSerializer(students, many=True)return Response(ser.data)if request.method == "POST":ser = StudentSerializer(data=request.data)if ser.is_valid():ser.save()return Response(ser.data, status=status.HTTP_201_CREATED)else:return Response(status=status.HTTP_400_BAD_REQUEST)

# id是自增的，所以不创建也可。建了也白建。但其他关键字在创建时不可省略。

postman:

post raw json

@api_view(["GET", "PUT", "DELETE"])
def student_detail_view(request, sid):try:student = Students.get_one(sid)except Students.DoesNotExist:return Response(status=status.HTTP_404_NOT_FOUND)if request.method == "GET":ser = StudentSerializer(student)return Response(ser.data)if request.method == "PUT":ser = StudentSerializer(student, data=request.data)if ser.is_valid():ser.save()return Response(ser.data)else:return Response(status=status.HTTP_400_BAD_REQUEST)if request.method == "DELETE":student.delete()return Response(status=status.HTTP_204_NO_CONTENT)

put 即使只修改一个字段也要写入所有字段

delete 不需要传，只需要send

二、Django REST 视图集

models //

class StudentsCla(models.Model):class_name = models.CharField(max_length=32, verbose_name="NAMECLA")mentor = models.CharField(max_length=32, verbose_name="HEADTEACHER")class Meta:verbose_name = "CLA"verbose_name_plural = verbose_namedef __str__(self):return self.class_name@classmethoddef get_all(cls):return cls.objects.all()

admin //

from django.contrib import adminfrom rest_app.models import Students, StudentsClamodels = [Students,StudentsCla
]admin.site.register(models)

serializer //

class StudentsClaSerializer(serializers.ModelSerializer):  # 自定义一个用于序列化student模型的序列化类class Meta:model = StudentsClafields = ("class_name","mentor",)

views //

class ListStudentsClaViewSet(ModelViewSet):queryset = StudentsCla.get_all()  # 使用模型视图集需要指定queryset的值和s_cserializer_class = StudentsClaSerializerpass

total urls //

from rest_framework import routersfrom rest_app.views import ListStudentsClaViewSetrouter = routers.DefaultRouter()
router.register('student_class', ListStudentsClaViewSet)

path('', include(router.urls))

视图集是将一个视图函数转换成一个类，并继承ViewSet。结果的这个类即类视图。

三、VIEW & API VIEW 类视图

常分三类。View类视图（django原生有的），APIView类视图（支持前后端分离），通用类视图。

View类视图：①继承View类，编写对应的请求方法，处理不同请求状态。②配置路由，使用as_view()。

演示：

python manage.py startapp view_app

path('view/', include('view_app.urls', namespace="view")),

models //

class Stu(models.Model):name = models.CharField(max_length=32, verbose_name="name")gpa = models.CharField(verbose_name="gpa")@classmethoddef get_all(cls):return cls.objects.all()

views //

class ListStuView(View):def get(self, request):stus = Stu.get_all()return render(self.request, "", locals())def post(self, request):passreturn render(self.request, "", locals())class ListStuAPIView(APIView):def get(self, request):stus = Stu.get_all()return Response(status=status.HTTP_200_OK)def post(self, request):passreturn render(self.request, "", locals())def put(self, request):passdef delete(self, request):pass

sub urls //

urlpatterns = [path('view/', ListStuView.as_view(), name="list"),
]

通用类视图

Django Restful

①操作所有的model。继承ListCreateAPIView类，并添加queryset和serializer_class两个类属性

②操作单个model。继承RetrieveUpdateDestroyAPIView类，并添加queryset和serializer_class两个类属性

总路由 //

path('view/', include('view_app.urls', namespace="view")),

models //

from django.db import modelsclass Stu(models.Model):name = models.CharField(max_length=32, verbose_name="name")gpa = models.IntegerField(verbose_name="gpa")@classmethoddef get_all(cls):return cls.objects.all()

url //

app_name = "view"urlpatterns = [path('view/', ListStuView.as_view(), name="list"),path('detail/<name>/', SingleStu.as_view()),
]

视图集不用写路由，但是类视图要写。

serializer //

class StuSerializer(serializers.ModelSerializer):  # 自定义一个用于序列化student模型的序列化类class Meta:model = Stufields = ("name","gpa",)

views //

class ListALLStudentsView(ListCreateAPIView):queryset = Stu.get_all()serializer_class = StuSerializerclass SingleStu(RetrieveUpdateDestroyAPIView):queryset = Stu.get_all()serializer_class = StuSerializerlookup_url_kwarg = "name"