Build on the Chainlink Platform

import { cre } from "@chainlink/cre-sdk"

cre.handler(
  cron.trigger({ schedule: "0 */5 * * *" }), // Every 5 minutes
  (runtime) => {
    // Fetch data from API
    const price = httpClient.get(url).result()

    // Read from EVM blockchain
    const threshold = evmClient.read(contract).result()

    // Make any computation
    const shouldUpdate = price > threshold

    // Write result onchain
    return evmClient.write(contract, price).result()
  }
)

// SPDX-License-Identifier: MIT
pragma solidity 0.8.24;

import {IRouterClient} from "@chainlink/contracts-ccip/contracts/interfaces/IRouterClient.sol";

import {Client} from "@chainlink/contracts-ccip/contracts/libraries/Client.sol";
import {OwnerIsCreator} from "@chainlink/contracts@1.4.0/src/v0.8/shared/access/OwnerIsCreator.sol";
import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.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 transferring tokens across chains.
contract TokenTransferor is OwnerIsCreator {
  using SafeERC20 for IERC20;

  // Custom errors to provide more descriptive revert messages.
  error NotEnoughBalance(uint256 currentBalance, uint256 requiredBalance); // Used to make sure contract has enough
  // token balance
  error NothingToWithdraw(); // Used when trying to withdraw Ether but there's nothing to withdraw.
  error FailedToWithdrawEth(address owner, address target, uint256 value); // Used when the withdrawal of Ether fails.
  error DestinationChainNotAllowlisted(uint64 destinationChainSelector); // Used when the destination chain has not been
  // allowlisted by the contract owner.
  error InvalidReceiverAddress(); // Used when the receiver address is 0.
  // Event emitted when the tokens are transferred to an account on another chain.

  // The chain selector of the destination chain.
  // The address of the receiver on the destination chain.
  // The token address that was transferred.
  // The token amount that was transferred.
  // the token address used to pay CCIP fees.
  // The fees paid for sending the message.
  event TokensTransferred( // The unique ID of the message.
    bytes32 indexed messageId,
    uint64 indexed destinationChainSelector,
    address receiver,
    address token,
    uint256 tokenAmount,
    address feeToken,
    uint256 fees
  );

  // Mapping to keep track of allowlisted destination chains.
  mapping(uint64 => bool) public allowlistedChains;

  IRouterClient private s_router;

  IERC20 private s_linkToken;

  /// @notice Constructor initializes the contract with the router address.
  /// @param _router The address of the router contract.
  /// @param _link The address of the link contract.
  constructor(
    address _router,
    address _link
  ) {
    s_router = IRouterClient(_router);
    s_linkToken = IERC20(_link);
  }

  /// @dev Modifier that checks if the chain with the given destinationChainSelector is allowlisted.
  /// @param _destinationChainSelector The selector of the destination chain.
  modifier onlyAllowlistedChain(
    uint64 _destinationChainSelector
  ) {
    if (!allowlistedChains[_destinationChainSelector]) {
      revert DestinationChainNotAllowlisted(_destinationChainSelector);
    }
    _;
  }

  /// @dev Modifier that checks the receiver address is not 0.
  /// @param _receiver The receiver address.
  modifier validateReceiver(
    address _receiver
  ) {
    if (_receiver == address(0)) revert InvalidReceiverAddress();
    _;
  }

  /// @dev Updates the allowlist status of a destination chain for transactions.
  /// @notice This function can only be called by the owner.
  /// @param _destinationChainSelector The selector of the destination chain to be updated.
  /// @param allowed The allowlist status to be set for the destination chain.
  function allowlistDestinationChain(
    uint64 _destinationChainSelector,
    bool allowed
  ) external onlyOwner {
    allowlistedChains[_destinationChainSelector] = allowed;
  }

  /// @notice Transfer tokens to receiver on the destination chain.
  /// @notice pay in LINK.
  /// @notice the token must be in the list of supported tokens.
  /// @notice This function can only be called by the owner.
  /// @dev Assumes your contract has sufficient LINK tokens to pay for the fees.
  /// @param _destinationChainSelector The identifier (aka selector) for the destination blockchain.
  /// @param _receiver The address of the recipient on the destination blockchain.
  /// @param _token token address.
  /// @param _amount token amount.
  /// @return messageId The ID of the message that was sent.
  function transferTokensPayLINK(
    uint64 _destinationChainSelector,
    address _receiver,
    address _token,
    uint256 _amount
  )
    external
    onlyOwner
    onlyAllowlistedChain(_destinationChainSelector)
    validateReceiver(_receiver)
    returns (bytes32 messageId)
  {
    // Create an EVM2AnyMessage struct in memory with necessary information for sending a cross-chain message
    //  address(linkToken) means fees are paid in LINK
    Client.EVM2AnyMessage memory evm2AnyMessage = _buildCCIPMessage(_receiver, _token, _amount, address(s_linkToken));

    // Get the fee required to send the message
    uint256 fees = s_router.getFee(_destinationChainSelector, evm2AnyMessage);

    uint256 requiredLinkBalance;
    if (_token == address(s_linkToken)) {
      // Required LINK Balance is the sum of fees and amount to transfer, if the token to transfer is LINK
      requiredLinkBalance = fees + _amount;
    } else {
      requiredLinkBalance = fees;
    }

    uint256 linkBalance = s_linkToken.balanceOf(address(this));

    if (requiredLinkBalance > linkBalance) {
      revert NotEnoughBalance(linkBalance, requiredLinkBalance);
    }

    // approve the Router to transfer LINK tokens on contract's behalf. It will spend the requiredLinkBalance
    s_linkToken.approve(address(s_router), requiredLinkBalance);

    // If sending a token other than LINK, approve it separately
    if (_token != address(s_linkToken)) {
      uint256 tokenBalance = IERC20(_token).balanceOf(address(this));
      if (_amount > tokenBalance) {
        revert NotEnoughBalance(tokenBalance, _amount);
      }
      // approve the Router to spend tokens on contract's behalf. It will spend the amount of the given token
      IERC20(_token).approve(address(s_router), _amount);
    }

    // Send the message through the router and store the returned message ID
    messageId = s_router.ccipSend(_destinationChainSelector, evm2AnyMessage);

    // Emit an event with message details
    emit TokensTransferred(messageId, _destinationChainSelector, _receiver, _token, _amount, address(s_linkToken), fees);

    // Return the message ID
    return messageId;
  }

  /// @notice Transfer tokens to receiver on the destination chain.
  /// @notice Pay in native gas such as ETH on Ethereum or POL on Polygon.
  /// @notice the token must be in the list of supported tokens.
  /// @notice This function can only be called by the owner.
  /// @dev Assumes your contract has sufficient native gas like ETH on Ethereum or POL on Polygon.
  /// @param _destinationChainSelector The identifier (aka selector) for the destination blockchain.
  /// @param _receiver The address of the recipient on the destination blockchain.
  /// @param _token token address.
  /// @param _amount token amount.
  /// @return messageId The ID of the message that was sent.
  function transferTokensPayNative(
    uint64 _destinationChainSelector,
    address _receiver,
    address _token,
    uint256 _amount
  )
    external
    onlyOwner
    onlyAllowlistedChain(_destinationChainSelector)
    validateReceiver(_receiver)
    returns (bytes32 messageId)
  {
    // Create an EVM2AnyMessage struct in memory with necessary information for sending a cross-chain message
    // address(0) means fees are paid in native gas
    Client.EVM2AnyMessage memory evm2AnyMessage = _buildCCIPMessage(_receiver, _token, _amount, address(0));

    // Get the fee required to send the message
    uint256 fees = s_router.getFee(_destinationChainSelector, evm2AnyMessage);

    if (fees > address(this).balance) {
      revert NotEnoughBalance(address(this).balance, fees);
    }

    // approve the Router to spend tokens on contract's behalf. It will spend the amount of the given token
    IERC20(_token).approve(address(s_router), _amount);

    // Send the message through the router and store the returned message ID
    messageId = s_router.ccipSend{value: fees}(_destinationChainSelector, evm2AnyMessage);

    // Emit an event with message details
    emit TokensTransferred(messageId, _destinationChainSelector, _receiver, _token, _amount, address(0), fees);

    // Return the message ID
    return messageId;
  }

  /// @notice Construct a CCIP message.
  /// @dev This function will create an EVM2AnyMessage struct with all the necessary information for tokens transfer.
  /// @param _receiver The address of the receiver.
  /// @param _token The token to be transferred.
  /// @param _amount The amount of the token to be transferred.
  /// @param _feeTokenAddress The address of the token used for fees. Set address(0) for native gas.
  /// @return Client.EVM2AnyMessage Returns an EVM2AnyMessage struct which contains information for sending a CCIP
  /// message.
  function _buildCCIPMessage(
    address _receiver,
    address _token,
    uint256 _amount,
    address _feeTokenAddress
  ) private pure returns (Client.EVM2AnyMessage memory) {
    // Set the token amounts
    Client.EVMTokenAmount[] memory tokenAmounts = new Client.EVMTokenAmount[](1);
    tokenAmounts[0] = Client.EVMTokenAmount({token: _token, amount: _amount});

    // Create an EVM2AnyMessage struct in memory with necessary information for sending a cross-chain message
    return Client.EVM2AnyMessage({
      receiver: abi.encode(_receiver), // ABI-encoded receiver address
      data: "", // No data
      tokenAmounts: tokenAmounts, // The amount and type of token being transferred
      extraArgs: Client._argsToBytes(
        // Additional arguments, setting gas limit and allowing out-of-order execution.
        // Best Practice: For simplicity, the values are hardcoded. It is advisable to use a more dynamic approach
        // where you set the extra arguments off-chain. This allows adaptation depending on the lanes, messages,
        // and ensures compatibility with future CCIP upgrades. Read more about it here:
        // https://docs.chain.link/ccip/concepts/best-practices/evm#using-extraargs
        Client.GenericExtraArgsV2({
          gasLimit: 0, // Gas limit for the callback on the destination chain
          allowOutOfOrderExecution: true // Allows the message to be executed out of order relative to other messages
          // from
          // the same sender
        })
      ),
      // Set the feeToken to a feeTokenAddress, indicating specific asset will be used for fees
      feeToken: _feeTokenAddress
    });
  }

  /// @notice Fallback function to allow the contract to receive Ether.
  /// @dev This function has no function body, making it a default function for receiving Ether.
  /// It is automatically called when Ether is transferred to the contract without any data.
  receive() external payable {}

  /// @notice Allows the contract owner to withdraw the entire balance of Ether from the contract.
  /// @dev This function reverts if there are no funds to withdraw or if the transfer fails.
  /// It should only be callable by the owner of the contract.
  /// @param _beneficiary The address to which the Ether should be transferred.
  function withdraw(
    address _beneficiary
  ) public onlyOwner {
    // Retrieve the balance of this contract
    uint256 amount = address(this).balance;

    // Revert if there is nothing to withdraw
    if (amount == 0) revert NothingToWithdraw();

    // Attempt to send the funds, capturing the success status and discarding any return data
    (bool sent,) = _beneficiary.call{value: amount}("");

    // Revert if the send failed, with information about the attempted transfer
    if (!sent) revert FailedToWithdrawEth(msg.sender, _beneficiary, amount);
  }

  /// @notice Allows the owner of the contract to withdraw all tokens of a specific ERC20 token.
  /// @dev This function reverts with a 'NothingToWithdraw' error if there are no tokens to withdraw.
  /// @param _beneficiary The address to which the tokens will be sent.
  /// @param _token The contract address of the ERC20 token to be withdrawn.
  function withdrawToken(
    address _beneficiary,
    address _token
  ) public onlyOwner {
    // Retrieve the balance of this contract
    uint256 amount = IERC20(_token).balanceOf(address(this));

    // Revert if there is nothing to withdraw
    if (amount == 0) revert NothingToWithdraw();

    IERC20(_token).safeTransfer(_beneficiary, amount);
  }
}

import "@chainlink/contracts/src/v0.8/shared/interfaces/AggregatorV3Interface.sol";

contract SVRConsumer {
  AggregatorV3Interface internal svrFeed;

  constructor(
    address _svrFeedAddress
  ) {
    svrFeed = AggregatorV3Interface(_svrFeedAddress);
  }

  function getLatestPrice() public view returns (int256) {
    (, /* uint80 roundID */
      int256 price, /* uint256 startedAt */
      /* uint256 timeStamp */
      /* uint80 answeredInRound */,,
    ) = svrFeed.latestRoundData();
    return price;
  }
}

import { createClient, decodeReport, LogLevel, getReportVersion, formatReport } from "@chainlink/data-streams-sdk"
import "dotenv/config"

async function main() {
  if (process.argv.length < 3) {
    console.error("Please provide a feed ID as an argument")
    console.error("Example: npx tsx singleStream.ts 0x000359843a543ee2fe414dc14c7e7920ef10f4372990b79d6361cdc0dd1ba782")
    process.exit(1)
  }

  const feedId = process.argv[2]
  const version = getReportVersion(feedId)

  try {
    const config = {
      apiKey: process.env.API_KEY || "YOUR_API_KEY",
      userSecret: process.env.USER_SECRET || "YOUR_USER_SECRET",
      endpoint: "https://api.testnet-dataengine.chain.link",
      wsEndpoint: "wss://ws.testnet-dataengine.chain.link",
      // Comment to disable SDK logging:
      logging: {
        logger: console,
        logLevel: LogLevel.INFO,
      },
    }

    const client = createClient(config)
    console.log(`\nFetching latest report for feed ${feedId} (${version})...\n`)

    // Get raw report data
    const report = await client.getLatestReport(feedId)
    console.log(`Raw Report Blob: ${report.fullReport}`)

    // Decode the report
    const decodedData = decodeReport(report.fullReport, report.feedID)

    // Combine decoded data with report metadata
    const decodedReport = {
      ...decodedData,
      feedID: report.feedID,
      validFromTimestamp: report.validFromTimestamp,
      observationsTimestamp: report.observationsTimestamp,
    }
    console.log(formatReport(decodedReport, version))
  } catch (error) {
    if (error instanceof Error) {
      console.error("Error:", error.message)
    } else {
      console.error("Unknown error:", error)
    }
    process.exit(1)
  }
}

main()