July 22, 2024 / All posts
Hello everyone, as you know, the Robonomics project operates on two networks simultaneously: Ethereum and Kusama. Currently, there is no way to transfer the XRT token between these networks. Therefore, we are closely following the Snowbridge project, which is being developed as a universal bridge between Ethereum and Polkadot: https://docs.snowbridge.network/
Over the last month, we successfully transferred ERC20 XRT tokens between the test networks Sepolia and Rococo Asset Hub following the instructions from Snowbridge:
https://docs.snowbridge.network/rococo-testnet/rococo-sepolia-token-transfers
First, the XRT contract was deployed on Sepolia:
https://sepolia.etherscan.io/address/0x9e216c3aF5F0c6cE70851B93ddDB62573380CfEf
Since we needed to test sending our own token, we had to register it. This step consists of two parts: checking the required fee and registering the token:
To check the required fee, we called the quoteRegisterTokenFee
method of the bridge contract (https://sepolia.etherscan.io/address/0x5b4909ce6ca82d2ce23bd46738953c7959e710cd#readProxyContract) and received the value 5000000500000000000
:
To register the token, we called the registerToken
method of the bridge contract (https://sepolia.etherscan.io/address/0x5b4909ce6ca82d2ce23bd46738953c7959e710cd#writeProxyContract), specifying the required fee and the address of the deployed token:
The registration process should take about 30 minutes, and the new token should appear in the foreignAssets in Rococo Asset Hub. This can be checked using a chain state query in Rococo Asset Hub (https://polkadot.js.org/apps/?rpc=wss%3A%2F%2Frococo-asset-hub-rpc.polkadot.io#/chainstate):
After successful registration, we received the following response:
{
owner: 5GjRnmh5o3usSYzVmsxBWzHEpvJyHK4tKNPhjpUR3ASrruBy
issuer: 5GjRnmh5o3usSYzVmsxBWzHEpvJyHK4tKNPhjpUR3ASrruBy
admin: 5GjRnmh5o3usSYzVmsxBWzHEpvJyHK4tKNPhjpUR3ASrruBy
freezer: 5GjRnmh5o3usSYzVmsxBWzHEpvJyHK4tKNPhjpUR3ASrruBy
supply: 0
deposit: 100,000,000,000
minBalance: 1
isSufficient: false
accounts: 1
sufficients: 0
approvals: 0
status: Live
}
The next step was sending the XRT token from Sepolia to Rococo Asset Hub. For this, we performed the following actions:
First, we allowed the bridge contract to use 15 XRT from the account:
https://sepolia.etherscan.io/address/0x9e216c3aF5F0c6cE70851B93ddDB62573380CfEf#writeContract
Initiated the transfer of XRT from Sepolia to Rococo Asset Hub following Snowbridge's instructions using the WETH example: https://docs.snowbridge.network/rococo-testnet/rococo-sepolia-token-transfers#id-5.-send-weth-to-polkadot
A critical note regarding the destinationAddress.data
field: its value needed to be enclosed in quotes (e.g. "0xb0fca9a0c5e03ab5b2294784fbbabea010295b3e1e48575cfe18dc2172ef657d").
At this stage, we encountered significant delays. Instead of the expected 30 minutes, the transaction took several days. Eventually, all our transfers were successfully completed. Example transaction: https://sepolia.etherscan.io/tx/0xec539cd89cb955ffea2ff65cae6685a8abb0966a2c1b76876a308cc036cd18fb
The XRT balance on the target account in Rococo Asset Hub can be checked by sending a foreignAssets.account()
request in chain state:
Sent a total of 15 XRT, so the balance in Rococo Asset Hub looked like this:
{
balance: 15,000,000,000
status: Liquid
reason: Consumer
extra: null
}
The final step was sending XRT from Rococo Asset Hub back to Sepolia. We performed the following extrinsic in Rococo Asset Hub:
This transaction can be viewed in the Rococo Asset Hub block explorer:
The corresponding transaction in Sepolia:
https://sepolia.etherscan.io/tx/0xe8a95dca350143a0c41891137e332962f2918351dcfc2612519e69c7a5c46772
This step was completed relatively quickly, within half an hour. As a result, 1 XRT was transferred back to Sepolia. The XRT balance in Rococo Asset Hub remained at 14 XRT:
{
balance: 14,000,000,000
status: Liquid
reason: Consumer
extra: null
}