Solidity

There are two ways that you can access the oracle in your dApp. You can either declare an IDIAOracleV2 interface or import the solidity library.

Using DIAOracleV2 Interface

The following is an example of how to retrieve price value from a standard DIA oracle. For the purpose of this example, we will be using the following demo oracle on Ethereum: 0xCD5F...f3cB.

1. Access any DIA oracle smart contract.

2. Call getValue(pair_name) with pair_name being the full pair name such as BTC/USD. You can use the "Read" section on Etherscan to execute this call.

3. The response of the call contains four values:

   1. The current asset's price in USD with a fix-comma notation of 8 decimals.

   2. The UNIX timestamp of the last oracle update.

pragma solidity ^0.8.13;

interface IDIAOracleV2 {
    function getValue(string memory) external view returns (uint128, 
             uint128);
}

contract DIAOracleSample {

    address diaOracle;

    constructor(address _oracle) {
        diaOracle = _oracle;
    }

    function getPrice(string memory key) 
    external 
    view
    returns (
        uint128 latestPrice, 
        uint128 timestampOflatestPrice
    ) {
        (latestPrice, timestampOflatestPrice) =   
                 IDIAOracleV2(diaOracle).getValue(key); 
    }
}

Find the detailed description of the functions and how to run tests on our GitHub page:

GitHub - diadata-org/DIA-integration-sampleGitHub

Solidity integration example

Using Solidity Library

DIA has a dedicated Solidity library to facilitate the integration of DIA oracles in your own contracts. The library consists of two functions, getPrice and getPriceIfNotOlderThan.

Access the library

import { DIAOracleLib } from "./libraries/DIAOracleLib.sol";

Methods

getPrice

function getPrice(
        address oracle,
        string memory key
        )
        public
        view
        returns (uint128 latestPrice, uint128 timestampOflatestPrice);

Returns the price of a specified asset along with the update timestamp.

Parameters:

Name	Type	Description
oracle	address	Address of the oracle that we want to use
key	string	The asset that we want to use e.g. "ETH/USD"

Return Values:

Name	Type	Description
latestPrice	uint128	Price of the specified asset returned by the DIAOracle
timestampOflatestPrice	uint128	The update timestamp of the latest price

getPriceIfNotOlderThan

function getPriceIfNotOlderThan(
        address oracle,
        string memory key,
        uint128 maxTimePassed
        )
        public
        view
        returns (uint128 price, bool inTime)
    {

Checks if the oracle price is older than maxTimePassed

Parameters:

Name	Type	Description
oracle	address	Address of the oracle that we want to use
key	string	The asset that we want to use e.g. "ETH/USD"
maxTimePassed	uint128	The maximum acceptable time passed in seconds since the the price was updated

Return Values:

Name	Type	Description
Price	uint128	Price of the specified asset returned by the DIAOracle
inTime	uint128	A boolian that is true if the price was updated at most maxTimePassed seconds ago, otherwise false

Find a detailed integration example and how to run a test on our GitHub page:

GitHub - diadata-org/DIAOracleLibGitHub

Sample contract

pragma solidity ^0.8.13;

import { DIAOracleLib } from "./libraries/DIAOracleLib.sol";

contract DIAOracleSample {
    error PriceTooOld();

    address diaOracle;

    constructor(address _oracle) {
        diaOracle = _oracle;
    }

    function getPrice(
        string memory key
    ) external view returns (uint128 latestPrice) {
        (latestPrice, ) = DIAOracleLib.getPrice(diaOracle, key);
    }

    function checkPriceAge(
        string memory key,
        uint128 maxTimePassed
    ) external view returns (uint128 price) {
        bool inTime;
        (price, inTime) = DIAOracleLib.getPriceIfNotOlderThan(
            diaOracle,
            key,
            maxTimePassed
        );

        if (!inTime) revert PriceTooOld();
    }
}