Django操作views（一）

views的作用

接收请求，响应请求。前后端不分离，返回的是页面；前后端分离，返回的是数据。

前后端不分离

操作之前，请确保应用已经注册到项目中，可以先看我的博客：
https://blog.csdn.net/weixin_43431593/article/details/106872257
https://blog.csdn.net/weixin_43431593/article/details/106876828

现在操作views，即通过views与数据库、前端打交道。"接收到响应"的中间过程，就是操作数据库的过程，因此，views需要导入模型。

models.py：

class students(models.Model):
    loginname = models.CharField(max_length=20)
    nickname = models.CharField(max_length=10)
    sex = models.BooleanField(default=True)

views.py:

from django.shortcuts import render
from django.http import HttpResponse
from .models import students

# Create your views here.

def studentsDetails(request):
    return HttpResponse("欢迎来到django学习基地")

配置主路由（项目文件的urls.py）：

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

urlpatterns = [
    # path('admin/', admin.site.urls),
    path('studyapp/', include('studyapp.urls')),
]

配置子路由（应用程序的urls.py）：

from django.urls import path
from studyapp.views import studentsDetails

urlpatterns = [
    path('studentsDetails/', studentsDetails),
]

命令行启动服务：

python manage.py runserver

输入子路由的路径：

http://127.0.0.1:8000/studyapp/studentsDetails/

即可获得页面响应，我们这里使用了HttpResponse(“欢迎来到django学习基地”)直接响应页面，这种方式，叫前后端不分离。

前后端分离

修改views文件：

from django.shortcuts import render
from django.http import HttpResponse, JsonResponse
from .models import students

# Create your views here.

# def studentsDetails(request):
#     return HttpResponse("欢迎来到django学习基地")

def studentsDetails(request):
    return JsonResponse({"info":"欢迎来到django学习基地"}, safe=False, json_dumps_params={'ensure_ascii':False})

刷新页面后，展示如下：

现在我们增加一个接口，获取数据库students表所有数据：

from django.shortcuts import render
from django.http import HttpResponse, JsonResponse
import json
from django.views.decorators.csrf import csrf_exempt
from django.core import serializers
from django.views.decorators.http import require_http_methods

# Create your views here.

from .models import students

# def studentsDetails(request):
#     return HttpResponse("欢迎来到django学习基地")

def studentsDetails(request):
    return JsonResponse({"info":"欢迎来到django学习基地"}, safe=False, json_dumps_params={'ensure_ascii':False})

@require_http_methods(["GET"])
@csrf_exempt
def getstudents(request):
    response = {}
    try:
        studentList = students.objects.filter()
        response['list'] = json.loads(serializers.serialize("json", studentList))
        response['msg'] = 'success'
        response['error_num'] = 0
    except  Exception as e:
        response['msg'] = str(e)
        response['error_num'] = 1
    return JsonResponse(response)

rest_framework接口规范

上面我们说到了前后端分离，并且写了一个接口，但不一定很规范，现在我们说django前后端分离的框架rest_framework。

安装配置先看看我的另一篇博客：

https://blog.csdn.net/weixin_43431593/article/details/107134506

应用目录添加serializers.py文件：

from .models import students
from rest_framework import serializers


class studentsSerializer(serializers.Serializer):
    msg = serializers.CharField(max_length=20)

更改views：

from django.shortcuts import render
from django.http import HttpResponse, JsonResponse
import json
from django.views.decorators.csrf import csrf_exempt
from django.core import serializers
from django.views.decorators.http import require_http_methods
from .serializers import studentsSerializer

# Create your views here.

from .models import students

# def studentsDetails(request):
#     return HttpResponse("欢迎来到django学习基地")

def studentsDetails(request):
    return JsonResponse({"info":"欢迎来到django学习基地"}, safe=False, json_dumps_params={'ensure_ascii':False})

@require_http_methods(["GET"])
@csrf_exempt
def getstudents(request):
    response = {}
    try:
        studentList = students.objects.filter()
        response['list'] = json.loads(serializers.serialize("json", studentList))
        response['msg'] = 'success'
        response['error_num'] = 0
    except  Exception as e:
        response['msg'] = str(e)
        response['error_num'] = 1

    serializers_obj = studentsSerializer(instance=response)
    response = serializers_obj.data

    return JsonResponse(response)

如上，首先导入模块“from .serializers import studentsSerializer”，接着引用：
“
serializers_obj = studentsSerializer(instance=response)
response = serializers_obj.data
”
因为有了序列器的作用，可以给前端返回想要的数据，这里只返回了“msg”。