Receiver.sol

// SPDX-License-Identifier: MIT
pragma solidity 0.8.19;

import {Client} from "@chainlink/contracts-ccip/src/v0.8/ccip/libraries/Client.sol";
import {CCIPReceiver} from "@chainlink/contracts-ccip/src/v0.8/ccip/applications/CCIPReceiver.sol";

/**
 * THIS IS AN EXAMPLE CONTRACT THAT USES HARDCODED VALUES FOR CLARITY.
 * THIS IS AN EXAMPLE CONTRACT THAT USES UN-AUDITED CODE.
 * DO NOT USE THIS CODE IN PRODUCTION.
 */

/// @title - A simple contract for receiving string data across chains.
contract Receiver is CCIPReceiver {
    // Event emitted when a message is received from another chain.
    event MessageReceived(
        bytes32 indexed messageId, // The unique ID of the message.
        uint64 indexed sourceChainSelector, // The chain selector of the source chain.
        address sender, // The address of the sender from the source chain.
        string text // The text that was received.
    );

    bytes32 private lastReceivedMessageId; // Store the last received messageId.
    string private lastReceivedText; // Store the last received text.

    /// @notice Constructor initializes the contract with the router address.
    /// @param router The address of the router contract.
    constructor(address router) CCIPReceiver(router) {}

    /// handle a received message
    function _ccipReceive(
        Client.Any2EVMMessage memory any2EvmMessage
    ) internal override {
        lastReceivedMessageId = any2EvmMessage.messageId; // fetch the messageId
        lastReceivedText = abi.decode(any2EvmMessage.data, (string)); // abi-decoding of the sent text

        emit MessageReceived(
            any2EvmMessage.messageId,
            any2EvmMessage.sourceChainSelector, // fetch the source chain identifier (aka selector)
            abi.decode(any2EvmMessage.sender, (address)), // abi-decoding of the sender address,
            abi.decode(any2EvmMessage.data, (string))
        );
    }

    /// @notice Fetches the details of the last received message.
    /// @return messageId The ID of the last received message.
    /// @return text The last received text.
    function getLastReceivedMessageDetails()
        external
        view
        returns (bytes32 messageId, string memory text)
    {
        return (lastReceivedMessageId, lastReceivedText);
    }
}