小实践：实现用户登录、注销及ORM管理功能、事务开启小实践
models.py
class Books(models.Model):
id = models.CharField(primary_key=True,max_length=20,verbose_name="图书ID")
name = models.CharField(max_length=20,verbose_name='图书名称')
status = models.BooleanField(default=False,verbose_name='是否出借',blank=True)
class Meta:
db_table = 'books'
verbose_name = '图书表'
def __str__(self):
return self.name
class Record(models.Model):
book = models.ForeignKey('Books',on_delete=models.CASCADE,verbose_name="图书")
name = models.CharField(max_length=20,verbose_name='借书姓名')
s_time = models.DateTimeField(auto_created=True,verbose_name='借书时间',auto_now=True) # auto_created 自动创建当前时间
e_time = models.DateTimeField(auto_created=True,verbose_name='还书时间',auto_now=True) # auto_now 任意一个字段变更都会自动更新时间
state = models.BooleanField(default=False,verbose_name='是否归还',blank=True)
class Meta:
db_table = 'records'
verbose_name = '图书记录'urls.py[注意：路由结尾要记得加$符号，负责会匹配其他的视图函数]
from django.contrib import admin
from django.urls import path,re_path,include
from news import views
urlpatterns = [
path('admin/', admin.site.urls),
re_path(r'^news/',include('news.urls')),
re_path(r'logout/$',views.LogoutView.as_view()),
re_path(r'login/$',views.LoginView.as_view()),
re_path(r'book/$',views.BookView.as_view()),
re_path(r'book/hanlde/$',views.RecordView.as_view())
]
用户登录注销：
from django.http import HttpResponse,JsonResponse
from django.views import View
from django.contrib.auth import authenticate,logout,login
class LogoutView(View):
def get(self,request):
logout(request)
return JsonResponse({'code':200,'message':'已退出登录'},status=200)
class LoginView(View):
def post(self,request):
username = request.POST.get('username')
password = request.POST.get('password')
user = authenticate(request,username=username,password=password)
if user is not None:
login(request,user)
return JsonResponse({'code':200,'message':'登录成功'})
else:
return JsonResponse({'code':400,'message':'登录失败'})admin.py 可后台查看数据
from .models import Books,Record
class BookAdmin(admin.ModelAdmin):
list_display = ['id','name','status']
class RecordAdmin(admin.ModelAdmin):
list_display = ['id','book','name','s_time','e_time','state']
admin.site.register(Books,BookAdmin)
admin.site.register(Record,RecordAdmin)ORM功能的增删改成实现
class BookView(View):
def get(self,request):
if not request.user.is_authenticated:
return JsonResponse({'code':2002,'messages':"认证失败你没有权限访问，请重新登录"})
bs= Books.objects.all()
result = []
for i in bs:
item = dict(id=i.id,name=i.name,status=i.status)
result.append(item)
return JsonResponse({'code':200,'data':result,'message':'ok'},safe=False)
def post(self,request):
pass
import json
# param =request.POST if len(request.POST)> 0 else json.loads(request.body.decode())
id = request.POST.get('id')
name = request.POST.get('name')
try:
Books.objects.create(id=id,name=name)
except Exception as e:
return JsonResponse({'code':2001,'message':'书籍编号已存在,异常：{}'.format(e)},safe=False)
else:
return JsonResponse({'code':1001,'message':'添加成功'},safe=False)
def delete(self,request):
id = request.POST.get('id')
if not id:
return JsonResponse({'code':1001,'message':'删除失败'})
try:
book = Books.objects.get(id=id)
except Exception as e:
return JsonResponse({'code': 1001, 'message': '删除失败:{}'.format(e)})
else:
book.delete()
return JsonResponse({'code': 200, 'message': '删除成功'})应用结果：
事务实现：
class RecordView(View):
def get(self, request):
pass
def post(self, request):
book_id = request.POST.get('id')
name = request.POST.get('name')
try:
book = Books.objects.get(id=book_id)
except Exception as e:
return JsonResponse({'code': 2001, 'messages': "{}".format(e)})
if book.status:
return JsonResponse({'code': 2001, 'messages': "该书籍已借书，请确认书籍的状态是否已出借"})
with transaction.atomic():
# update status
book.status = True
book.save()
# add record
Record.objects.create(name=name, book=book)
return JsonResponse({'code': 1000, 'messages': "出借成功"})
