开发实践8_REST

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 models


class 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

    @classmethod
    def get_all(cls):
        return cls.objects.all()

admin //

from django.contrib import admin

from rest_app.models import Students


admin.site.register(
    Students
)

app下serializer.py //

from rest_framework import serializers

from rest_app.models import Students


class StudentSerializer(serializers.ModelSerializer):  # 自定义一个用于序列化student模型的序列化类
    class Meta:
        model = Students
        fields = (
            "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 Response

from 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_name

    def __str__(self):
        return self.class_name

    @classmethod
    def get_all(cls):
        return cls.objects.all()

admin //

from django.contrib import admin

from rest_app.models import Students, StudentsCla

models = [
    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 = StudentsCla
        fields = (
            "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_c
    serializer_class = StudentsClaSerializer
    pass

total urls //

from rest_framework import routers

from rest_app.views import ListStudentsClaViewSet

router = 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

注册

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")

    @classmethod
    def 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):
        pass
        return 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):
        pass
        return render(self.request, "", locals())

    def put(self, request):
        pass

    def 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 models


class Stu(models.Model):
    name = models.CharField(max_length=32, verbose_name="name")
    gpa = models.IntegerField(verbose_name="gpa")

    @classmethod
    def 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 = Stu
        fields = (
            "name",
            "gpa",
        )

views //

class ListALLStudentsView(ListCreateAPIView):
    queryset = Stu.get_all()
    serializer_class = StuSerializer


class SingleStu(RetrieveUpdateDestroyAPIView):
    queryset = Stu.get_all()
    serializer_class = StuSerializer
    lookup_url_kwarg = "name"