Price Data

With Solidity: 0x148A40DDb8cb3edd76319E81Be3fE6C072853b2a

Multi-signature update record: 0x27159bb4400AC976B167Ed5E3835E5028Fbd97c7

We have implemented a new StdReference interface contract to allow whitelisted users to query data from our Standard Dataset.

To query prices from HebeSwap Oracle, a smart contract should reference HebeSwap Oracle StdReference contract, specifically the getReferenceData and getReferenceDatabulk methods.

getReferenceData

getReferenceData takes two strings (the base and quote symbol) as the inputs, respectively. It then queries the StdReference contract for the latest rates for those two tokens, and returns a ReferenceData struct, shown below.

Input

• The base symbol as type string
• The quote symbol as type string

Output

The base quote pair result as type ReferenceData

struct ReferenceData {
    uint256 rate;
    uint256 lastUpdatedBase;
    uint256 lastUpdatedQuote;
}

The ReferenceData struct has the following elements:

• Rate: the exchange rate in terms of base/quote. The value returned is multiplied by 1e18
• Last updated base: the last time when the base price was updated (since UNIX epoch)
• Last updated quote: the last time when the quoted price was updated (since UNIX epoch)

Example

For example, if we wanted to query the price of ETC/USDT, the demo contract below shows how this can be done.

import interfaces/IStdReference.sol

contract Demo {
    IStdReference public ref;

    constructor(IStdReference _ref) public {
        ref = _ref;
    }

    function demo() external view returns (IStdReference.ReferenceData memory) {
        return ref.getReferenceData("ETC", "USDT");
    }
}

The result from Demo() would yield:

ReferenceData(17640000000, 1691936304, 1692022704)

Where the results can be interpreted as:

{
    rate: 17640000000, // 17.64 of ETC/USDT
    lastUpdatedBase: 1691936304, // 2023-08-13 22:18:24
    lastUpdatedQuote: 1692022704 // 2023-08-14 22:18:24
}

getReferenceDatabulk

The second function, getReferenceDataBulk, takes information as data arrays. For example, if you pass in ['ETC','BTC','ETH'] as base and ['USDT','USDT','USDT'] as quote, the ReferenceDatareturned array contains the information regarding the following pairs:

• ETC/USDT
• BTC/USDT
• ETH/USDT

Input

• An array of base symbols as type string[]
• An array of quote symbol as type string[]

Output

• An array of the base quote pair results as type ReferenceData[]

Example Contract

The following smart contract code provides some simple examples of the StdReference contract and the getReferenceData function - these are not meant for production. The IStdReference.sol interface defines ReferenceData structure and the functions available to make the queries.

pragma solidity 0.6.11;
pragma experimental ABIEncoderV2;

interface IStdReference {
    /// A structure returned whenever someone requests for standard reference data.
    struct ReferenceData {
        uint256 rate; // base/quote exchange rate, multiplied by 1e18.
        uint256 lastUpdatedBase; // UNIX epoch of the last time when base price gets updated.
        uint256 lastUpdatedQuote; // UNIX epoch of the last time when quote price gets updated.
    }

    /// Returns the price data for the given base/quote pair. Revert if not available.
    function getReferenceData(string memory _base, string memory _quote)
        external
        view
        returns (ReferenceData memory);

    /// Similar to getReferenceData, but with multiple base/quote pairs at once.
    function getReferenceDataBulk(string[] memory _bases, string[] memory _quotes)
        external
        view
        returns (ReferenceData[] memory);
}

contract DemoOracle {
    IStdReference ref;

    uint256 public price;

    constructor(IStdReference _ref) public {
        ref = _ref;
    }

    function getPrice() external view returns (uint256){
        IStdReference.ReferenceData memory data = ref.getReferenceData("ETC","USD");
        return data.rate;
    }

    function getMultiPrices() external view returns (uint256[] memory){
        string[] memory baseSymbols = new string[](2);
        baseSymbols[0] = "ETC";
        baseSymbols[1] = "BTC";

        string[] memory quoteSymbols = new string[](2);
        quoteSymbols[0] = "USD";
        quoteSymbols[1] = "ETC";
        IStdReference.ReferenceData[] memory data = ref.getReferenceDataBulk(baseSymbols,quoteSymbols);

        uint256[] memory prices = new uint256[](2);
        prices[0] = data[0].rate;
        prices[1] = data[1].rate;

        return prices;
    }

    function savePrice(string memory base, string memory quote) external {
        IStdReference.ReferenceData memory data = ref.getReferenceData(base,quote);
        price = data.rate;
    }
}