CCIP Tutorial

A comprehensive tutorial demonstrating how to use Chainlink's Cross-Chain Interoperability Protocol (CCIP) to send messages between different blockchain networks.

Overview

This project contains two main smart contracts that showcase cross-chain messaging capabilities:

• Sender Contract: Sends string messages to other blockchain networks
• Receiver Contract: Receives and processes messages from other blockchain networks

Features

• ✅ Cross-chain string message transmission
• ✅ LINK token fee payment system
• ✅ Event emission for message tracking
• ✅ Owner-only access control for sending messages
• ✅ Gas limit configuration for destination chain execution
• ✅ Out-of-order execution support

Smart Contracts

Sender Contract (contracts/sender.sol)

The Sender contract enables sending string messages to other chains using CCIP.

Key Features:

• Inherits from OwnerIsCreator for access control
• Uses LINK tokens to pay for cross-chain fees
• Configurable gas limits and execution parameters
• Comprehensive error handling and event emission

Main Function:

function sendMessage(
    uint64 destinationChainSelector,
    address receiver,
    string calldata text
) external onlyOwner returns (bytes32 messageId)

Receiver Contract (contracts/Receiver.sol)

The Receiver contract processes incoming cross-chain messages.

Key Features:

• Inherits from CCIPReceiver base contract
• Stores the last received message details
• Emits events for message tracking
• Provides getter functions for message retrieval

Main Functions:

function _ccipReceive(Client.Any2EVMMessage memory any2EvmMessage) internal override
function getLastReceivedMessageDetails() external view returns (bytes32 messageId, string memory text)

Prerequisites

• Node.js and npm
• Hardhat or Foundry development environment
• LINK tokens for paying CCIP fees
• Access to supported blockchain networks

Supported Networks

CCIP supports various blockchain networks including:

• Ethereum
• Polygon
• Avalanche
• Arbitrum
• Optimism
• Base
• And more...

Installation

1. Clone the repository:

git clone https://github.com/marksantiago02/CCIP-tutorial.git
cd CCIP-tutorial

2. Install dependencies:

npm install

Usage

Deploying Contracts

1. Deploy the Receiver contract on the destination chain:

   • Provide the CCIP router address for that chain

2. Deploy the Sender contract on the source chain:

   • Provide the CCIP router address
   • Provide the LINK token address

3. Fund the Sender contract with LINK tokens to pay for fees

Sending Messages

Call the sendMessage function on the Sender contract with:

• destinationChainSelector: The chain selector ID for the target network
• receiver: Address of the Receiver contract on the destination chain
• text: The string message to send

Monitoring Messages

• Monitor the MessageSent event on the source chain
• Monitor the MessageReceived event on the destination chain
• Use the getLastReceivedMessageDetails() function to retrieve the last received message

Events

MessageSent

event MessageSent(
    bytes32 indexed messageId,
    uint64 indexed destinationChainSelector,
    address receiver,
    string text,
    address feeToken,
    uint256 fees
);

MessageReceived

event MessageReceived(
    bytes32 indexed messageId,
    uint64 indexed sourceChainSelector,
    address sender,
    string text
);

Security Considerations

⚠️ Important Notice: These contracts are for educational purposes only and contain hardcoded values for clarity. They use un-audited code and should NOT be used in production environments.

Best Practices

• Use dynamic extraArgs configuration instead of hardcoded values
• Implement proper access controls
• Add comprehensive error handling
• Monitor gas limits for destination chain execution
• Regularly update to latest CCIP versions

Resources

• Chainlink CCIP Documentation
• CCIP Best Practices
• Supported Networks

License

This project is licensed under the MIT License.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Support

For questions and support, please refer to the Chainlink Discord or Chainlink Documentation.