ccip-read-workshop

Simple example to fetch data from the Verax Registry on Linea using ccip-read

Link to repo

Links of interest

• Linea ccip-read doc: https://docs.linea.build/developers/tooling/cross-chain/ccip-read-gateway
• Linea ENS repo: https://github.com/Consensys/linea-ens
• NFT Resolver repo: https://github.com/Consensys/nft-resolver

CCIP Read flow for Linea's ENS integration

Quick start

Copy the .env.example file to .env and set the DEPLOYER_PRIVATE_KEY.
Optionally, set the ETHERSCAN_API_KEY if you want to verify the contracts on etherscan.

npm install
npx hardhat compile
npx hardhat ignition deploy ignition/modules/VeraxFetcher.ts --network sepolia

You should see the following output:

Deployed Addresses

VeraxFetcherModule#VeraxFetcher - 0xd25Cc85a1c87CeB1553e823e46e2890d0a70a33C

If you want to verify the contract on etherscan, you can use the following command:

npx hardhat verify --network sepolia [DEPLOYED_ADDRESS] 0x17289b2e80DcaB38249adb5a2Bd1a0cAF12361A0 0xDaf3C3632327343f7df0Baad2dc9144fa4e1001F

Copy the contract address as this will be the contract that you'll call from the UI to start the ccip-read flow.

Open the ui/demo.html file in your browser and set the Verax Fetcher Contract Address to the address you copied in the previous step.
You can also change the Attestation ID to the one you want to fetch.

When you click on the Get attestation button, the ccip-read flow will be triggered and if the attestation exists in the Verax Registry, its id will be displayed, otherwise an error will be shown.

Get the storage slot index in the queried contract

For this example, the storage slot queried is already known:
uint256 constant ATTESTATIONS_SLOT = 102;

To write your own fetcher contract that answers to your needs, you can use the hardhat-storage-layout plugin to have a list of the storage slots for a given contract.
Example for the Verax Registry contract:

cd contracts/L2
npx hardhat check