Pull Payment Upgradeable

Simple implementation of a https://consensys.github.io/smart-contract-best-practices/recommendations/#favor-pull-over-push-for-external-calls[pull-payment] strategy, where the paying contract doesn't interact directly with the receiver account, which must withdraw its payments itself. Pull-payments are often considered the best practice when it comes to sending Ether, security-wise. It prevents recipients from blocking execution, and eliminates reentrancy concerns. TIP: If you would like to learn more about reentrancy and alternative ways to protect against it, check out our blog post https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul]. To use, derive from the PullPayment contract, and use {_asyncTransfer} instead of Solidity's transfer function. Payees can query their due payments with {payments}, and retrieve them with {withdrawPayments}.

Methods

payments

function payments(address dest) external view returns (uint256)

Returns the payments owed to an address.

Parameters

Name	Type	Description
dest	address	The creditor's address.

Returns

Name	Type	Description
_0	uint256	undefined

withdrawPayments

function withdrawPayments(address payable payee) external nonpayable

Withdraw accumulated payments, forwarding all gas to the recipient. Note that any account can call this function, not just the payee. This means that contracts unaware of the PullPayment protocol can still receive funds this way, by having a separate account call {withdrawPayments}. WARNING: Forwarding all gas opens the door to reentrancy vulnerabilities. Make sure you trust the recipient, or are either following the checks-effects-interactions pattern or using {ReentrancyGuard}.

Parameters

Name	Type	Description
payee	address payable	Whose payments will be withdrawn.