@donz283213342_twitter - you will keep getting that same error, because the _result that's being returned is currently an empty string due to an ongoing issue on our end.
The other suggestion was simply to add in a check to handle such an eventuality accordingly by checking for an emptry string in your smart-contract's __callback
as a quick note, it affects the random ds specifically.
Another note about your contract, you should be using the onlyProvable(or onlyProvable depending on API) modifier instead, instead of manually trying to check the cbAddress, as that doesn't actually return an address, but instead a bool as to whether the sender and tx orginator are in fact the same and a provable callback address
@bertolo1988 best case the contract doesn't work properly, worst case, its funds become exploitable. The code change is minimal work, but has a major footprint potential.
It utilizes a long deployed contract (several years) called the OracleAddressResolver whose address is hardcoded, which simply contains the address of the latest Provable Connector and, which is essentially the on-chain logic or class. All the underlying mechanisms are open-sourced for this
Another note about your contract, you should be using the onlyProvable(or onlyProvable depending on API) modifier instead, instead of manually trying to check the cbAddress, as that doesn't actually return an address, but instead a bool as to whether the sender and tx orginator are in fact the same and a provable callback address
Are you saying this line doesn't work? if (msg.sender != provable_cbAddress()) revert();
Hi @marcos-iov - nope, you have it correctly, though now in our github examples we drop the explicit if & revert() in favour of the neater require(msg.sender == provable_cbAddress());.
You can see them all here: github.com/provable-things/ethereum-examples
@oraclize-support
And changed my callback to:
function __callback( bytes32 _queryId, string memory _result, bytes memory _proof ) public {
emit logDebugString(msg.sender, 'here1');
require(msg.sender == provable_cbAddress());
emit logDebugString(msg.sender, 'here2');
require(ongoingBets[_queryId].sender != address(0x0) , 'query does not exist');
emit logDebugString(msg.sender, 'here3');
if(provable_randomDS_proofVerify__returnCode( _queryId, _result, _proof) != 0){
emit logDebugString(msg.sender, 'here4');
revert();
} else {
emit logDebugString(msg.sender, 'here5');
uint ceiling = (MAX_INT_FROM_BYTE ** NUM_RANDOM_BYTES_REQUESTED) - 1;
emit logDebugString(msg.sender, 'here6');
uint randomNumber = uint(keccak256(abi.encodePacked(_result))) % ceiling;
uint spin = (randomNumber % 100) + 1;
emit logDebugString(msg.sender, 'here6');
Bet memory bet = ongoingBets[_queryId];
if(spin < bet.spinUnder){
addAmountToUser(bet.sender, bet.prize);
}
emit logBetSuccess(bet.sender, spin, bet.spinUnder, bet.stake, bet.prize, bet.payout, balances[bet.sender]);
delete ongoingBets[_queryId];
}
}