Repository containing a gas cost effective standard for meta transaction to be used by any contract to enable native meta transaction feature on any function. The approach support signed typed messages so that while signing the data on client side user see a human readable message instead of scary hex string.
You can see the LIVE DEMO Here(works on Kovan)
The standard is the result of initiative by metamask here https://medium.com/metamask/announcing-a-generalized-metatransaction-contest-abd4f321470b
Biconomy was selected as one of the finalist in the hackathon. Read here
- Inherit EIP712MetaTransaction contract
- Use msgSender() method where ever you were using msg.sender
userAddress => externally owned address of the user eg the user address in his metamask wallet
sigR => 32 bytes r part of the signature
sigS => 32 bytes s part of the signature
sigV => integer v part of the signature
r,s,v can be calculated using ethers.js utility method.
Since this standard supports EIP-712 so signature parameters should be generated using eth_signTypedData_v3 or eth_signTypedData_v4 JSON RPC method.
NOTE: Make sure you have nodejs version > 12.0.0
- Run
npm install
command to install all the dependencies - At last, Run
npm run test
to run all the test cases.