So basically I make a new address for each user, but it's just 1 of many addresses in the hot wallet?
Yes. At Just-Dice I used bitcoind, and simply did getAddressesByAccount() to see if there was already an address associated with a userid, and getAccountAddress() to get one if there wasn't. Then you can listAccounts() to see the balance for each account with the required number of confirmations and move() to move the funds from a player's 'account' to the main hot wallet account so you don't count it twice.
Recently I heard Gavin saying that the 'accounts' feature in bitcoind is likely to be removed soon, so I guess this isn't a good idea to use any more.
I would advise against the account feature, it isn't meant to be a database, like you are using it. I usually just keep a database table that links addresses to users, I think this system is more robust than using the account feature.
And to be honest I have written dice games in javaEE, which is actually really strong.
How do you get live updates from new deposits. Do I have to check for new deposits for every possible deposit address once per minute? What do you recommend to run so that when a deposit happens there is a event that says "Hey, you got a new deposit" and how do you link this to the site?
So the flow I did for javaEE, is a couple of checks. One was a cronjob, in tomcat they are not called that, this runs every 5 mins (remember I wait for 1 confirmations anyway, so I don't have to run every 5-10 secs which is probably what you would do for non-confirmed transactions). For my next check, I always run bitcoind in -tx=1 mode so I have access to the entire bitcoin blockchain, and don't have to use a blockchain api. Then using netcat and java socket server, I would have bitcoind send any wallet transactions to the socket server, and put in a queue (any first in first out data structure would work). Remember take this with a grain of salt this transaction, it is usually a non-confirmed transaction, and it can be subject to many attacks. This just alerts my application that a transaction is possible waiting and to track it a bit.
Now that we verified that indeed we have a new balance, I use web sockets to push it to the user. JavaEE is amazing at writing this in a simple class. If you don't want to use websockets, or the the users can't get a good connection, then just simple javascript polling works as well. Then that updates the frontend accordingly. Remember to always check the balance before executing anything server side. This is just a view, and should never be trusted.
Pretty sure listreceivedbyaddress also protects against that.
I looked into it - I don't see any way to prevent it returning the entire list of addresses and transactions each time you call it.
That's a huge ever-growing amount of data to parse over and over again.
I'd much rather have bitcoind do all that grunt work for me and just tell me which account has a new confirmed deposit.
Yes it is a big list, but what I usually do with java, is just hold on to it in an array of objects and remove the the ones we have already processed already. I can always build that array at startup from the double entry database, incase of shutdown or restart.
but looking at the callbacks of bitcoind...