def get(self,uid,itemID):
if (not self.user) or (str(self.user.key().id())!=uid):
self.redirect('/login')
return
item=Item.getByID(itemID)
latestBid=Bid.getLatestBidByItem(itemID)
myLatestBid=Bid.getLatestBidByItemAndUser(itemID,uid)
if not item or dt.datetime.now()+dt.timedelta(hours=8)>item.endDate:
self.redirect('/'+uid)
return
self.render("item.html",user=self.user,item=item,latestBid=latestBid,myLatestBid=myLatestBid)
def post(self,uid,itemID):
#currently do not need authentication
if (not self.user) or (str(self.user.key().id())!=uid):
self.redirect('/login')
return
item=Item.getByID(itemID)
if not item:
self.redirect('/'+uid)
return
customerBid=self.request.get("customerBidPost")
customerBid=float(customerBid)
#Lock Mechanism to prevent concurrent bidding
try:
#lock mechanism
#if lock then wait
lock=memcache.get("lock"+itemID)
count=0
while lock and count<=9:
memcache.set("sleep"+itemID+uid,0)
sleep=0
while sleep<=100:
memcache.incr("sleep"+itemID+uid)
sleep=memcache.get("sleep"+itemID+uid)
lock=memcache.get("lock"+itemID)
#set lock
memcache.set("lock"+itemID,True)
latestBid=Bid.getLatestBidByItem(itemID)
#check if the bidding info is valid
# if later than the end bid time or lower than the latest bid amount, invalid bidding
if item.endDate<(dt.datetime.now()+dt.timedelta(hours=8)) or (latestBid and customerBid<=latestBid.bidAmount):
raise Exception
outBidder=None
#expire old bid
if latestBid:
# to identify the identify of the outBidder
if latestBid.bidder!=uid:
outBidder=latestBid.bidder
latestBid.expire()
latestBid.save()
#insert the new bid
bid=Bid(bidder=uid,item=itemID,bidAmount=customerBid,timeStamp=dt.datetime.now()+dt.timedelta(hours=8),activeFlag=True)
bid.save()
#update bidder info
if itemID not in self.user.myBidItems:
self.user.myBidItems.append(itemID)
self.user.save()
#send an email on every bid
try:
send_bid_email(self.user,item)
except:
pass
#send email to the outBidder
if outBidder:
outBidder=Bidder.by_id(outBidder)
try:
send_outbid_email(outBidder,item)
except:
pass
self.redirect('/'+uid+'?result=success')
except:
error="Your Bid Is Invalid"
myLatestBid=Bid.getLatestBidByItemAndUser(itemID,uid)
self.render("item.html",user=self.user,item=item,latestBid=latestBid,myLatestBid=myLatestBid,error=error)
finally:
#release lock
success=memcache.delete("lock"+itemID)
count=0
while not success and count<10:
success=memcache.delete("lock"+itemID)
count+=1