Remix

Consuming Oracle Data

An example contract named OracleReader.sol allows you to consume Oracle data and can be quickly deployed on Remix. Remix is a web-based integrated development environment (IDE) for creating, running, and debugging smart contracts directly in your browser.

info

Addresses in this contract are hardcoded for the Sepolia testnet. For other supported networks, please check the Dashboard.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.16;

/**
 * @title OracleReader
 * @notice A simple contract to read from Chronicle oracles
 * @dev To see the full repository, visit https://github.com/chronicleprotocol/OracleReader-Example.
 * @dev Addresses in this contract are hardcoded for the Sepolia testnet.
 * For other supported networks, check the https://chroniclelabs.org/dashboard/oracles.
 */
contract OracleReader {
    /**
    * @notice The Chronicle oracle to read from.
    * Chronicle_ETH_USD_3:0xdd6D76262Fd7BdDe428dcfCd94386EbAe0151603
    * Network: Sepolia
    */

    IChronicle public chronicle = IChronicle(address(0xdd6D76262Fd7BdDe428dcfCd94386EbAe0151603));

    /** 
    * @notice The SelfKisser granting access to Chronicle oracles.
    * SelfKisser_1:0x0Dcc19657007713483A5cA76e6A7bbe5f56EA37d
    * Network: Sepolia
    */
    ISelfKisser public selfKisser = ISelfKisser(address(0x0Dcc19657007713483A5cA76e6A7bbe5f56EA37d));

    constructor() {
        // Note to add address(this) to chronicle oracle's whitelist.
        // This allows the contract to read from the chronicle oracle.
        selfKisser.selfKiss(address(chronicle));
    }

    /** 
    * @notice Function to read the latest data from the Chronicle oracle.
    * @return val The current value returned by the oracle.
    * @return age The timestamp of the last update from the oracle.
    */
    function read() external view returns (uint256 val, uint256 age) {
        (val, age) = chronicle.readWithAge();
    }
}

// Copied from [chronicle-std](https://github.com/chronicleprotocol/chronicle-std/blob/main/src/IChronicle.sol).
interface IChronicle {
    /** 
    * @notice Returns the oracle's current value.
    * @dev Reverts if no value set.
    * @return value The oracle's current value.
    */
    function read() external view returns (uint256 value);

    /** 
    * @notice Returns the oracle's current value and its age.
    * @dev Reverts if no value set.
    * @return value The oracle's current value using 18 decimals places.
    * @return age The value's age as a Unix Timestamp .
    * */
    function readWithAge() external view returns (uint256 value, uint256 age);
}

// Copied from [self-kisser](https://github.com/chronicleprotocol/self-kisser/blob/main/src/ISelfKisser.sol).
interface ISelfKisser {
    /// @notice Kisses caller on oracle `oracle`.
    function selfKiss(address oracle) external;
}

Ensure your environment is set to Remix VM - Sepolia Fork (since this example is hardcoded for Sepolia).

Deploy the OracleReader.sol contract and you should see the following:

• chronicle: returns 0xdd6D76262Fd7BdDe428dcfCd94386EbAe0151603, which is the address of the Chronicle_ETH_USD_3 Oracle
• read: returns the current price (3533995000000000000000) and its age (1718091840) at the moment of calling.

Note: the price uses 18 decimals, meaning that the actual price is 3533.995. Age uses Unix Timestamp, meaning that 1718091840 corresponds to 'Tue Jun 11 2024 07:44:00 GMT'.

• selfKisser: returns the address of the SelfKisser 0x0Dcc19657007713483A5cA76e6A7bbe5f56EA37d