linea-ccip-gateway

Adapted from EVM gateway for fetching data on Linea along with Sparse Merkle Proofs and return it to the L1 callback function.

Start dev env

cp .env.example .env
pnpm i
pnpm build
pnpm start

Build

pnpm build

Tests

pnpm i
pnpm compile
pnpm test

Example of how to use CCIP-Read using EtherJs

This example demonstrates how to use CCIP-Read using EtherJs to call a contract that implements the protocol.

Interacting with the TestL1 Contract Using CCIP-Read

To interact with the TestL1 contract using the CCIP-Read protocol, follow these steps:

Prerequisites

Before running the script, ensure that you have the necessary environment variables set up in your .env file:

• INFURA_API_KEY: Your Infura project ID, which allows you to connect to the Ethereum network via Infura.

Adding the Script

Create a new script file in your project directory at scripts/testL1.ts and add the following code:

import { ethers } from "ethers";
import "dotenv/config";

// Define the ABI for the getLatest function
const getLatestABI = [
  {
    inputs: [],
    name: "getLatest",
    outputs: [
      {
        internalType: "uint256",
        name: "",
        type: "uint256",
      },
    ],
    stateMutability: "view",
    type: "function",
  },
];

async function main() {
  /* 
  Address of the deployed TestL1 contract on the Sepolia testnet.
  You can view the contract on Etherscan using the following link:
  https://sepolia.etherscan.io/address/0xb12038acce44e39dd5b2f59f0f68bbfaac35dd16
  */

  const testL1Address = "0xB12038acCE44e39dd5B2f59F0f68bbfAaC35dd16";

  const provider = new ethers.JsonRpcProvider(
    `https://sepolia.infura.io/v3/${process.env.INFURA_API_KEY}`
  );

  const testL1Contract = new ethers.Contract(
    testL1Address,
    getLatestABI,
    provider
  );

  try {
    // Call the getLatest function with CCIP read enabled
    const result = await testL1Contract.getLatest({ enableCcipRead: true });
    console.log({ result });
  } catch (error) {
    console.error({ error });
  }
}

main().catch((error) => {
  console.error("Error in main execution:", error);
  process.exitCode = 1;
});

This script connects to the Sepolia testnet and calls the getLatest function of the TestL1 contract, demonstrating how to enable and use the CCIP-Read functionality.

Running the Script

To execute the script, follow these steps:

1. Open a terminal and navigate to the root directory of your project.

2. Run the script using Hardhat with the following command:

npx hardhat run scripts/testL1.ts --network sepolia

• This command will launch the testL1.ts script, which interacts with the TestL1 contract deployed on the Sepolia network.
• The script demonstrates the usage of Chainlink's CCIP-Read protocol to fetch and verify off-chain data using a Sparse Merkle Proof.

What the Script Does

• Connects to the Sepolia Network: Utilizes Infura as the provider to connect to the Ethereum Sepolia testnet.
• Interacts with the Contract: Calls the getLatest function on the TestL1 contract, showcasing how to enable and leverage CCIP-Read capabilities.
• Handles Off-Chain Data: Demonstrates the retrieval and verification of off-chain data, integrating it back into the on-chain environment using CCIP.

This example provides a practical demonstration of how to set up and utilize the CCIP-Read protocol within a dApp, highlighting the benefits of off-chain data fetching and proof verification.