rewards-transfer-strategies.md

Transfer Strategies

Introduction

Transfer Strategies are isolated contracts to manage and support different reward systems. Currently there is StakedTokenStrategy to support StkAave rewards, and PullRewardsStrategy to support common ERC20 incentives pulled from a external vault. The RewardsController performs external calls to the transfer strategy contracts. The Transfer Strategies has one main mandatory function:

• performTransfer(address to, address reward, uint256 amount) The performTransfer function hook is called at claimRewards, and holds the custom logic to transfer the rewards from the source of the reward to the destination.

Due they are inmmutable contracts, the transfer strategy contracts contains an ERC20 recovery method in case of a transfer mistake to the contracts.

Supported Transfer Strategies

Pull Rewards Transfer Strategy

The strategy contract allows to integrate any ERC20 token that want to incentivize deposits or borrows at Aave markets. At the deployment you must provide the "vault" address where to pull rewards at the moment of claim.

At transfer hook, does a external call transferFrom to the ERC20 token, from the vault address to the claimer address.

The vault must perform an ERC20 approval to the PullRewardsTransferStrategy contract to transfer the rewards on behalf of the strategy contract at performTransfer hook.

Staked Token Transfer Strategy

The strategy contract allows to integrate the Staked Aave token as rewards. The strategy needs AAVE to be deposited at the Staked Token Transfer Strategy contract. At the deployment you must provide the Stake Aave token address.

At transfer hook, stakes the AAVE rewards while transferring the obtained stkAAVE to the desired user.