realkinando
commented
4 years ago Took some time to do extra research before pushing :
- Events have been created taking into consideration the need to log meta transactions made via the system :
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Event ForwardedTx(address indexed from, uint256 indexed batchId,uint256 indexed batchNonce,...) is emitted after every Tx forwarded by BiconomyForwarder.sol. This event is inspired by the EIP 1776 contracts made by Ronan Sandford[1]. It returns all the req params + result of the call
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Event FeeCharged(address index from, uint256 indexed batchId, uint256 indexed batchNonce, uint256 feeCharged, address token) is emitted after every Tx forwarded by ERC20FeeProxy.sol. This specifically emits the fee charged, which is calculated and levied within ERC20FeeProxy.sol
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Events have been separated such that BiconomyForwarder.sol can produce useful information for data processing, without relayers being forced to use a fee proxy, if they want such data logged
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Address from, uint256 batchId & uint256 batchNonce, present in both events, can be combined to form a composite key. This is vital to be able to create ERC20Forwarder subgraph [2], or to present a table of transactions made (alongside the fees levied) within the Biconomy dApp dashboard
- EIP research, related reading :
- Our schema for ERC20 meta transactions is fixed. While this makes integration significantly simpler, it also means that if we want to integrate new features (such as scheduling, like with Ethereum Alarm Clock) we would need to migrate the forwarder and the fee proxies... My experiences in development have given me a desire to avoid EIP 2585 (not worth the additional effort IMHO)... Not sure about this...
References : 1 - https://github.com/wighawag/singleton-1776-meta-transaction/blob/master/contracts/src/GenericMetaTxProcessor.sol 2 - https://thegraph.com/docs/define-a-subgraph#writing-mappings 3 - https://github.com/ethereum/EIPs/issues/2585
fixed contract import errors, tests, personal sign, made helpers