Dual fee system

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Dual fee system
Switch fee token in Boba Network
Boba Network accepts BOBA and ETH as fee tokens. The fee choice is recorded in the Boba_GasPriceOracle contract. Users and developers can switch fee tokens by calling the Boba_GasPriceOracle contract.
For users and developers
You can switch to BOBA as the fee token calling the Boba_GasPriceOracle contract. Since MetaMask doesn't support dual fee tokens, you must have at least 3 BOBA and 0.002 ETH in your wallet before switching fee token from ETH to BOBA. 3 BOBA are enough for you to swap more BOBA and do more than two transactions.
import { ethers } from 'ethers'
const BobaGasPriceOracleInterface = new utils.Interface([
  'function useBobaAsFeeToken()',
  'function useETHAsFeeToken()',
  'function bobaFeeTokenUsers(address) view returns (bool)',
  'function priceRatio() view returns (uint256)'
])
const Proxy__Boba_GasPriceOracle = new Contract(
	Proxy__Boba_GasPriceOracleAddress,
	BobaGasPriceOracleInterface
	l2Wallet
)
await Boba_GasPriceOracle.useBobaAsFeeToken()
To avoid any accident, we only allow EOA accounts to use BOBA as the fee token.
The default fee token option is ETH. You can swith the fee token from BOBA to ETH calling the Boba_GasPriceOracle contract. Before switching to ETH, you have to have at least 0.002 ETH in your wallet. Otherwise, you will get stuck due to lack of ETH. We provide a meta transaction option for you to swap BOBA for a small amount of ETH. You can see this is option in the offical gateway.
import { ethers } from 'ethers'
const BobaGasPriceOracleInterface = new utils.Interface([
  'function useBobaAsFeeToken()',
  'function useETHAsFeeToken()',
  'function bobaFeeTokenUsers(address) view returns (bool)',
  'function priceRatio() view returns (uint256)'
])
const Proxy__Boba_GasPriceOracle = new Contract(
	Proxy__Boba_GasPriceOracleAddress,
	BobaGasPriceOracleInterface
	l2Wallet
)
await Boba_GasPriceOracle.useETHAsFeeToken()
For frontend and backend developers
We provide a simple script as a demo for you to switch fee tokens. Clone the repository, open it, and install nodejs packages with yarn:
$ git clone [email protected]:bobanetwork/boba.git
$ cd boba/boba_examples/boba-fee
$ yarn clean # only needed / will only work if you had it installed previously
$ yarn
Then, add .env in boba/boba_examples/boba-fee.
# Rinkeby
ADDRESS_MANAGER_ADDRESS=0x93A96D6A5beb1F661cf052722A1424CDDA3e9418
L1_NODE_WEB3_URL=https://rinkeby.infura.io/v3/KEY
L2_NODE_WEB3_URL=https://rinkeby.boba.network
PRIV_KEY=
​
​
# Mainnet
ADDRESS_MANAGER_ADDRESS=0x8376ac6C3f73a25Dd994E0b0669ca7ee0C02F089
L1_NODE_WEB3_URL=https://mainnet.infura.io/v3/KEY
L2_NODE_WEB3_URL=https://mainnet.boba.network
PRIV_KEY=
Finally, you can switch your fee token by running the following command:
# Use BOBA as the fee token
$ yarn use:boba 
​
# Use ETH as the fee token
$ yarn use:eth
Basic Operations
Contract Deployment Example
Last modified 3mo ago
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For users and developers
For frontend and backend developers