使用redis 解决美多商城超卖的问题

import redis

r = redis.Redis(host='localhost', port=6379)

#定义过载

def limit_handler():

"""

return True: 允许; False: 拒绝

"""

amount_limit = 3  # 限制数量

keyname = 'limit123'  # redis key name

incr_amount = 1  # 每次增加数量

# 判断key是否存在

if not r.exists(keyname):

# 为了方便测试，这里设置默认初始值为95

# setnx可以防止并发时多次设置key

r.setnx(keyname, 0)

# 数据插入后再判断是否大于限制数

if r.incrby(keyname, incr_amount) <= amount_limit:

return True

return False

#定义秒杀接口

def miaosha(request):

res_one = News.objects.get(pk=1)

if limit_handler():

#if res_one.pd > 0:

time.sleep(5)

# res_one.pd = res_one.pd - 1

# res_one.save()

with connection.cursor() as c:

c.execute(' update news set pd = pd - 1 where id = 1 ')

return HttpResponse('ok')

else:

return HttpResponse('没有了')