The front end Dapp to interact with this contract can be found here pricelock.
It runs on Ethereum and serves to lock funds until a target price has been reached or a user-defined period of time has elapsed. The smart contract uses the Tellor Price Oracle to determine if the target price has been reached.
The contract can be used with geth as follows:
Start geth via
geth console
Since this will keep synchronyzing the blockchain and produce a lot of output open a second geth session for working and testing without lots of background information:
geth attach
Compile the sourcode of the smart contract via Remix and copy-paste the Web3 deploy output into a textfile that we call w3script.sh. You find that output in the Contract tab (top right) in Remix after clicking Create you can open the additional information Contract details (bytecode, interface etc.) and from there copy the output listed as Web3 deploy into the textfile. This output is by default assuming you are deploying from account web3.eth.accounts[0], if you want to choose a different account, change the account number accordingly. Before deploying the contract (which is broadcasted as a transaction), we need to unlock the account via web3.personal.unlockAccount(web3.eth.accounts[0]). Now we are ready to deploy the running the following command inside the geth web3 console:
loadScript('w3script.sh')
var contract = web3.eth.contract(compiled.priceLock.info.abiDefinition)
Deploy an instance of this contract to the blockchain. First the corresponding account needs to be unlocked (in our case account number 0):
web3.personal.unlockAccount(web3.eth.accounts[0])
var contractInstance = contract.new({from:web3.eth.accounts[0], data: compiled.priceLock.code, gas: 1000000})
Should you already have this contract on the blockchain (and kept a copy of the ABI definition) you can create an instance of that already deployed contract. In that case you also save gas for deploying the contract and do not spam the blockchain with endless contract re-creations. Replace ABI and address in the code snipped below with values which you obtained during the initial contract deployment:
var contract = web3.eth.contract(ABI);
var contractInstance = contract.at(address);
This contract has to get mined which might take up to a minute (you can watch your primary geth session to watch for incoming blocks), it has been mined once we see an address:
contractInstance.address
The contract is ready and we check its existence on some Ethereum blockchain explorer. Before we lock some funds from it within the contract, check the balance of account number 0:
web3.eth.getBalance(web3.eth.accounts[0])
Interaction with the contract happens via transactions, here we are locking 0.001 Wei from account 0 for 1 day (86400 seconds) or until the ETH/USD price crosses $350:
contractInstance.payIn.sendTransaction(86400, 350000000, {from: web3.eth.accounts[0], value:1000000000000000})
Checking the balance again should show a difference in value, note that not only the 0.001 Eth but also the gas to run this contract were subtracted from the balance of this account:
web3.eth.getBalance(web3.eth.accounts[0])
Also, the amount locked in the contract can be checked:
contractInstance.getMyLockedFunds()
The funds can be unlocked if either one of 2 conditions is met.
Condition 1. After the ETH/USD price crosses the specified threshold
Condition 2. After waiting the initially specified lock time (here 1 day [86400 seconds])
contractInstance.payOut.sendTransaction({from: web3.eth.accounts[0], gas: 1000000})
Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.