Withdrawable

v0.4.3

A contract API and example implementation to provision point to point pull payments from contract to contract or contract to external account using a withdraw paradigm rather than transfer.

Ether differs significantly from other value mechanisms such as ERC20 tokens in that it is intrinsically transferrable between accounts rather than addresses being registered against tokens existing only in a contract. While ERC20 offers transfer() and transferFrom() which have inspired 'wrapped ether' for token like transfers of ether within a contract, the nature of ether differs enough from tokens for ether to warrent a dedicated API standard for moving money between contracts and addresses to which destinations and values are internally defined but caller need not be.

Payment channels, for example, might have a single internally defined recipient so there is no need to permission the caller of withdrawAll() so as to allow any address to call it and move the money to that recipient. This makes contract to contract transfers and clearing house operations simpler.

The minimal API defines withdrawAll() along with events Deposit() and Withdrawal() with all other state variables and functions in the extended API being optional.

Yank

To facilitate economical clearing house transactions, a stateless singleton contract called Yank can be supplied arrays of withdrawable contract addresses and respective recipient addresses with which to pull money through a chain or group of contracts to exit addresses.

WithdrawableMinAbstract

ABI

[{"constant":false,"inputs":[],"name":"withdrawAll","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"anonymous":false,"inputs":[{"indexed":true,"name":"_from","type":"address"},{"indexed":false,"name":"_value","type":"uint256"}],"name":"Deposit","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"_from","type":"address"},{"indexed":true,"name":"_to","type":"address"},{"indexed":false,"name":"_value","type":"uint256"}],"name":"Withdrawal","type":"event"}]

withdrawAll

function withdrawAll() public returns (bool);

Withdraws entire balance to the sender or other internally specified address.

Returns success boolean

Events

event Deposit(address indexed _from, uint _value)

Logged upon receiving a deposit.

_from The sender address

_value The value of ether recieved

event Withdrawal(address indexed _from, address indexed _to, uint _value)

Logged upon a withdrawal.

_from The address account by the contract to have owned the ether

_to The addres to which funds were sent

_value The value of ether sent

WithdrawableAbstract

ABI

[{"constant":true,"inputs":[{"name":"_addr","type":"address"}],"name":"etherBalanceOf","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"_to","type":"address"},{"name":"_value","type":"uint256"}],"name":"withdrawTo","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"_value","type":"uint256"}],"name":"withdraw","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[],"name":"withdrawAll","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"_from","type":"address"},{"name":"_value","type":"uint256"}],"name":"withdrawFrom","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"_addrs","type":"address[]"},{"name":"_values","type":"uint256[]"}],"name":"withdrawFor","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"_addrs","type":"address[]"}],"name":"withdrawAllFor","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"_from","type":"address"}],"name":"withdrawAllFrom","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"anonymous":false,"inputs":[{"indexed":true,"name":"_from","type":"address"},{"indexed":false,"name":"_value","type":"uint256"}],"name":"Deposit","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"_from","type":"address"},{"indexed":true,"name":"_to","type":"address"},{"indexed":false,"name":"_value","type":"uint256"}],"name":"Withdrawal","type":"event"}]

etherBalanceOf

function etherBalanceOf(address _addr) public view returns (uint)

Recommended

Returns the balance of ether held in the contract for _addr

_addr An ethereum address

withdrawAll

function withdrawAll() public returns (bool);

Required

Withdraws entire balance of sender to the sender or other internally specified address.

Returns success boolean

withdraw

function withdraw(uint _value) public returns (bool)

Optional

Withdraws a value of ether from the contract. Returns success boolean.

_value the value to withdraw

withdrawTo

function withdrawTo(address _to, uint _value) public returns (bool)

Optional

Withdraws a value of ether from the contract sending it to a thirdparty address.

_to a recipient address

_value the value to withdraw

Returns success boolean

withdrawAllFor

function withdrawAllFor(address[] _addrs) public returns (bool)

Sends entire balance of the supplied address to the supplied address

_addr a holder address in the contract

Returns success boolean

withdrawFor

function withdrawFor(address[] _addrs, uint[] _values) public returns (bool)

Optional

Sends a value of ether held for an address to that address.

_addr a holder address in the contract

_value the value to withdraw

Return success boolean

withdrawAllFrom

function withdrawAllFrom(address _kAddr) public returns (bool)

Optional

Withdraws all awarded ether from an external Withdrawable contract in which the current contract address may hold value. This function calls the withdrawAll() function of the thirdparty contract.

_kAddr The address of a third party Withdrawable contract.'

_value The value to withdraw into the current contract.

Returns success boolean

withdrawFrom

function withdrawFrom(address _kAddr, uint _value) public returns (bool)

Optional

Withdraws a value of ether from an external Withdrawable contract in which the current contract address may hold value. This function calls the withdraw(value) function of the thirdparty contract.

_kAddr The address of a third party Withdrawable contract.'

_value The value to withdraw into the current contract.

Returns success boolean

Events

event Deposit(address indexed _from, uint _value)

Logged upon receiving a deposit.

_from The sender address

_value The value of ether recieved

event Withdrawal(address indexed _from, address indexed _to, uint _value)

Logged upon a withdrawal.

_from The address account by the contract to have owned the ether

_to The addres to which funds were sent

_value The value of ether sent

Yank

ABI

[{"constant":false,"inputs":[{"name":"_kAddrs","type":"address[]"},{"name":"_addrs","type":"address[]"}],"name":"yank","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"regName","outputs":[{"name":"","type":"bytes32"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"VERSION","outputs":[{"name":"","type":"bytes32"}],"payable":false,"stateMutability":"view","type":"function"},{"anonymous":false,"inputs":[{"indexed":true,"name":"_kAddr","type":"address"}],"name":"WithdrawnAll","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"_kAddr","type":"address"},{"indexed":true,"name":"_for","type":"address"}],"name":"WithdrawnAllFor","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"_kAddr","type":"address"},{"indexed":true,"name":"_for","type":"address"}],"name":"Failed","type":"event"}]

VERSION

function VERSION() public constant returns (bytes32)

Returns the UTF8 encoded version as a bytes32

regName

function regName() public constant returns (bytes32)

Returns 'yank' as a bytes32 type for registration with the SandalStraps framework

yank

function yank(address[] _kAddrs, address[] _addrs) public returns (bool);

Performs clearing house pull payments across an array of withdrawable contracts by by calling withdrawAll() and withdrawAllFor(). Chained contracts should be ordered furtherest to closest. Any throws in the chain will revert the transaction. _kAddrs and _addrs must be of equal length with _addrs values being 0x0 where no recipient address is required. Ether that may have accumulated in the Yank contract itself is sent to msg.sender at the end of the call.

_kAddrs[] An array of withdrawable contracts

_addrs[] An array of recipient addresses

Events

event WithdrawnAll(address indexed _kAddr);

Logged when a call to WithdrawlAll is made

event WithdrawnAllFor(address indexed _kAddr, address indexed _for);

Logged when a call to WithdrawAllFor is made

event Failed(address indexed _kAddr, address indexed _for);

Logged when a withdraw fails and does not revert the transaction.