Django项目实战：数据库事务处理与支付宝支付集成

from django.db import transaction
@transaction.atomic
def viewfunc(request):
  # 这些代码会在一个事务中执行
  ...
from django.db import transaction
def viewfunc(request):
  # 这部分代码不在事务中，会被Django自动提交
  ...
  with transaction.atomic():
    # 这部分代码会在事务中执行
    ...　 

from django.db import transaction
# 创建保存点
save_id = transaction.savepoint() 
# 回滚到保存点
transaction.savepoint_rollback(save_id)
# 提交从保存点到当前状态的所有数据库事务操作
transaction.savepoint_commit(save_id)

def create(self, validated_data): """ 保存订单 """ # 获取当前下单用户 user = self.context['request'].user # 组织订单编号 20170903153611+user.id # timezone.now() -> datetime order_id = timezone.now().strftime('%Y%m%d%H%M%S') + ('%09d' % user.id) address = validated_data['address'] pay_method = validated_data['pay_method'] # 生成订单 with transaction.atomic(): # 创建一个保存点 save_id = transaction.savepoint() try: # 创建订单信息 order = OrderInfo.objects.create( order_id=order_id, user=user, address=address, total_count=0, total_amount=Decimal(0), freight=Decimal(10), pay_method=pay_method, status=OrderInfo.ORDER_STATUS_ENUM['UNSEND'] if pay_method == OrderInfo.PAY_METHODS_ENUM['CASH'] else OrderInfo.ORDER_STATUS_ENUM['UNPAID'] ) # 获取购物车信息 redis_conn = get_redis_connection("cart") redis_cart = redis_conn.hgetall("cart_%s" % user.id) cart_selected = redis_conn.smembers('cart_selected_%s' % user.id) # 将bytes类型转换为int类型 cart = {} for sku_id in cart_selected: cart[int(sku_id)] = int(redis_cart[sku_id]) # # 一次查询出所有商品数据 # skus = SKU.objects.filter(id__in=cart.keys()) # 处理订单商品 sku_id_list = cart.keys() for sku_id in sku_id_list: while True: sku = SKU.objects.get(id=sku_id) sku_count = cart[sku.id] # 判断库存 origin_stock = sku.stock # 原始库存 origin_sales = sku.sales # 原始销量 if sku_count > origin_stock: transaction.savepoint_rollback(save_id) raise serializers.ValidationError('商品库存不足') # 用于演示并发下单 # import time # time.sleep(5) # 减少库存 # sku.stock -= sku_count # sku.sales += sku_count # sku.save() new_stock = origin_stock - sku_count new_sales = origin_sales + sku_count # 根据原始库存条件更新，返回更新的条目数，乐观锁 ret = SKU.objects.filter(id=sku.id, stock=origin_stock).update(stock=new_stock, sales=new_sales) if ret == 0: continue # 累计商品的SPU 销量信息 sku.goods.sales += sku_count sku.goods.save() # 累计订单基本信息的数据 order.total_count += sku_count # 累计总金额 order.total_amount += (sku.price * sku_count) # 累计总额 # 保存订单商品 OrderGoods.objects.create( order=order, sku=sku, count=sku_count, price=sku.price, ) # 更新成功 break # 更新订单的金额数量信息 order.total_amount += order.freight order.save() except serializers.ValidationError: raise except Exception as e: logger.error(e) transaction.savepoint_rollback(save_id) raise # 提交事务 transaction.savepoint_commit(save_id) # 更新redis中保存的购物车数据 pl = redis_conn.pipeline() pl.hdel('cart_%s' % user.id, *cart_selected) pl.srem('cart_selected_%s' % user.id, *cart_selected) pl.execute() return order

OpenSSL> genrsa -out app_private_key.pem  2048 # 私钥 OpenSSL> rsa -in app_private_key.pem -pubout -out app_public_key.pem # 导出公钥 OpenSSL> exit

class PaymentView(APIView):
  """
  支付
  """
  permission_classes = (IsAuthenticated,)
  def get(self, request, order_id):
    """
    获取支付链接
    """
    # 判断订单信息是否正确
    try:
      order = OrderInfo.objects.get(order_id=order_id, user=request.user,
                     pay_method=OrderInfo.PAY_METHODS_ENUM["ALIPAY"],
                     status=OrderInfo.ORDER_STATUS_ENUM["UNPAID"])
    except OrderInfo.DoesNotExist:
      return Response({'message': '订单信息有误'}, status=status.HTTP_400_BAD_REQUEST)
    # 构造支付宝支付链接地址
    alipay = AliPay(
      appid=settings.ALIPAY_APPID,
      app_notify_url=None, # 默认回调url
      app_private_key_path=os.path.join(os.path.dirname(os.path.abspath(__file__)), "keys/app_private_key.pem"),
      alipay_public_key_path=os.path.join(os.path.dirname(os.path.abspath(__file__)), "keys/alipay_public_key.pem"), # 支付宝的公钥，验证支付宝回传消息使用，不是你自己的公钥,
      sign_type="RSA2", # RSA 或者 RSA2
      debug=settings.ALIPAY_DEBUG # 默认False
    )
    order_string = alipay.api_alipay_trade_page_pay(
      out_trade_no=order_id,
      total_amount=str(order.total_amount),
      subject="美多商城%s" % order_id,
      return_url="http://www.meiduo.site:8080/pay_success.html", 
    )
    # 需要跳转到https://openapi.alipay.com/gateway.do? + order_string
    # 拼接链接返回前端
    alipay_url = settings.ALIPAY_URL + "?" + order_string
    return Response({'alipay_url': alipay_url})