Gas Relay for a Secure Protocol for Native Meta Transactions
A secure and efficient Gas Relay implementation based on the ERC-2771 specification. This software enables meta-transactions by receiving signed requests from Transaction Signers, covering gas costs, and relaying transactions to a Trusted Forwarder.
Meta-transactions provide an elegant solution to this problem by allowing third parties to sponsor transaction costs on behalf of users. This shifts the gas payment burden from users to the service providers, enabling a more user-friendly and accessible dApp experience.
Despite the promise of meta-transactions, implementing them securely and efficiently remains a challenge for developers. Without a standardized approach, the risk of fragmented solutions, duplicated efforts, and potential security vulnerabilities increases.
Gas relay is built to interface with any EVM compatiable chain, it is all about a change in the config of the Relay server. It is important to not that all trusted forwarder across chain are deployed to that same address using create2.
These contract ar not upgradeable.
Components
- Gas Relay
- Handles incoming signed requests.
- Verifies signatures and validates nonces.
- Submits transactions via the Trusted Forwarder.
- Trusted Forwarder
- Forwards the transaction to the Recipient contract.
- Ensures the integrity of msg.sender for meta-transactions.
- Recipient Contract
- Implements the ERC-2771 interface to accept meta-transactions.
- Rust: Ensure you have Rust installed.
- Foundry: Required for running tests locally.
- Docker (optional): For containerized deployment.
git clone https://github.com/developeruche/gas-relay.git
cd gas-relay/server
cargo build --release
create a .config.toml file, adding these configs.
[server]
db_url = "host=localhost user=postgres"
# db_url ="host=xxxx.amazonaws.com port=5432 user=postgres password=xxxx dbname=postgres sslmode=disable" production-sample
server_url = "127.0.0.1:8010"
access_key = "0x4bbbf85ce3377467afe5d46f804f221813b2bb87f24d81f60f1fcdbf7cbf4356"
[[chains]]
name = "anvil"
rpc_url = "http://127.0.0.1:8545/"
chain_id = 1
accounts_private_keys = ["0x4bbbf85ce3377467afe5d46f804f221813b2bb87f24d81f60f1fcdbf7cbf4356", "0x4bbbf85ce3377467afe5d46f804f221813b2bb87f24d81f60f1fcdbf7cbf4356", "0x4bbbf85ce3377467afe5d46f804f221813b2bb87f24d81f60f1fcdbf7cbf4356", "0x4bbbf85ce3377467afe5d46f804f221813b2bb87f24d81f60f1fcdbf7cbf4356", "0x4bbbf85ce3377467afe5d46f804f221813b2bb87f24d81f60f1fcdbf7cbf4356", "0x4bbbf85ce3377467afe5d46f804f221813b2bb87f24d81f60f1fcdbf7cbf4356", "0x4bbbf85ce3377467afe5d46f804f221813b2bb87f24d81f60f1fcdbf7cbf4356", "0x4bbbf85ce3377467afe5d46f804f221813b2bb87f24d81f60f1fcdbf7cbf4356"]
trusted_forwarder = "0x5FbDB2315678afecb367f032d93F642f64180aa3"./target/release/relayer --config-path ./.config.toml - Node: Ensure the node runtime engine is installed.
- npm:
npm install @developeruche/gas-relay-sdk- yarn:
yarn add @developeruche/gas-relay-sdk- pnpm:
pnpm add @developeruche/gas-relay-sdkimport { prepRequest, gaslessRelay, batchedGaslessRelay, estimateGas } from '@developeruche/gas-relay-sdk';
import { ethers } from 'ethers';The prepRequest function prepares a gasless transaction request by signing the transaction with the user’s Ethereum signer and estimating the required gas.
const signer = new ethers.Wallet('your-private-key', provider);
const relayRequest = await prepRequest(
signer,
'0xRecipientAddress',
BigInt(0), // value in wei
'0xData', // transaction data
'0xTrustedForwarderAddress',
'ERC2771Forwarder', // Name of the trusted forwarder
BigInt(1), // Chain ID
'your-access-key'
);
console.log('Relay Request:', relayRequest);Once you have prepared a relay request, you can send it to the gas relay server using the gaslessRelay function.
const response = await gaslessRelay(relayRequest, 'http://relay-server-url/relay');
console.log('Relay Response:', response);If you need to send multiple relay requests, you can batch them using the batchedGaslessRelay function.
let re1 = await prepRequest(
signer,
'0xe7f1725E7734CE288F8367e1Bb143E90bb3F0512',
BigInt(0),
'0x3e6fec04',
'0x5FbDB2315678afecb367f032d93F642f64180aa3',
'ERC2771Forwarder',
BigInt(31337)
);
let re2 = await prepRequest(
signer,
'0xe7f1725E7734CE288F8367e1Bb143E90bb3F0512',
BigInt(0),
'0x3e6fec04',
'0x5FbDB2315678afecb367f032d93F642f64180aa3',
'ERC2771Forwarder',
BigInt(31337)
);
let payableAccount = '0x5FbDB2315678afecb367f032d93F642f64180aa3';
let res1 = await batchedGaslessRelay([re1, re2], payableAccount, 'http://127.0.0.1:8010/batch-relay');
console.log(res1);You can estimate the gas required for a transaction by using the estimateGas function.
const estimatedGas = await estimateGas(
'0xRecipientAddress',
'0xData',
'0xSenderAddress',
BigInt(0),
'0xTrustedForwarderAddress',
signer
);
console.log('Estimated Gas:', estimatedGas.toString());- Foundry: Required for running tests locally.
- npm:
npm install @developeruche/gas-relay-sdk- yarn:
yarn add @developeruche/gas-relay-sdk- pnpm:
pnpm add @developeruche/gas-relay-sdk- forge:
forge install OpenZeppelin/openzeppelin-contracts// SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;
import "@openzeppelin/contracts/metatx/ERC2771Context.sol";
contract StorageContract is ERC2771Context {
mapping(string => string) private storageMap;
constructor(address trustedForwarder) ERC2771Context(address(trustedForwarder)) {}
function setValue(string memory key, string memory value) public {
storageMap[key] = value;
}
function getValue(string memory key) public view returns (string memory) {
return storageMap[key];
}
}See CONTRIBUTING.md.
The Gas Relay library (i.e. all code outside of the bin directory) is licensed under the GNU General Public License v3.0.
The Gas Relay binaries (i.e. all code inside of the bin directory) is licensed under the GNU General Public License v3.0.
The Gas Relay SDKs is licensed under the GNU General Public License v3.0.