Consuming Oracle Data

Chronicle oracles are read-protected by a whitelist, meaning you won't be able to read them on-chain without your address being added to the whitelist.

info

On Testnet, the SelfKisser contract allows users to whitelist themselves, whimsically termed 'kiss' themselves.

On Mainnet, to get access to production Oracles, please open a ticket on Discord via the 🆘 ｜ support channel.

Testnet Network	SelfKisser Address
Ethereum Sepolia	0x0Dcc19657007713483A5cA76e6A7bbe5f56EA37d
Base Sepolia	0x70E58b7A1c884fFFE7dbce5249337603a28b8422
Arbitrum Sepolia	0xc0fe3a070Bc98b4a45d735A52a1AFDd134E0283f
Polygon zkEVM Testnet Cardona	0xCce64A8127c051E784ba7D84af86B2e6F53d1a09
Gnosis Mainnet	0x0Dcc19657007713483A5cA76e6A7bbe5f56EA37d
Mantle Testnet	0x9ee0DC1f7cF1a5c083914e3de197Fd1F484E0578
Scroll Sepolia	0x0Dcc19657007713483A5cA76e6A7bbe5f56EA37d
zkSync Sepolia	0x25f594edde4f58A14970b2ef6616badBa4B1CdDD
Optimism Sepolia	0xfF619a90cDa4020897808D74557ce3b648922C37
Berachain Bartio	0x2FFCAfF4BcF6D425c424f303eff66954Aa3A27Fd
Superseed Sepolia	0x371A53bB4203Ad5D7e60e220BaC1876FF3Ddda5B
Corn Sepolia	0x8CA2E3a09c79233127dC21955e28A6b9C4bf166E

Consuming Oracle Data (Remix)

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.

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Addresses in this contract are hardcoded for the Sepolia testnet. For other supported networks, please check the Dashboard. By toggling the <dev mode> option located in the top right corner, you can find the Oracles' addresses for different chains on Testnet. In the table above you can find the address of the SelfKisser on different chains.

// 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