Oracle

A simple oracle with a minimal governance system. It allows multiple owners to post data and allows a majority of the current owners to add more owners or to remove owners.

Setting Up

Install Foundry. Then:

npm install

Building and Testing

forge build
forge test
forge coverage

Linting

Pre-configured solhint and prettier-plugin-solidity. Can be run by

npm run solhint
npm run prettier

Using this Oracle

Known Deployments of this Oracle

This oracle has been deployed to the following blockchains:

• Milkomeda-C1 Testnet:

  • Oracle Address: 0x47a7d67e89E5714456b9af39703C1dc62203002A
  • Data provided: latest price of 1 USD in ADA multiplied by 10^18
    • For example: the result 2875000000000000000 means that 1 USD costs 2.875 ADA.

• Milkomeda-C1:

  • Oracle Address: 0x49484Ae8646C12A8A68DfE2c978E9d4Fa5b01D16
  • Data provided: latest price of 1 USD in ADA multiplied by 10^18
  • Usage of this oracle is subject to these terms of service.

How to read data from this Oracle from a Smart Contract

The following sample contract shows how to read data from the oracle. Note that it is necessary to accept the terms of service first.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

interface IOracle {
    function readData() external view returns (uint256);
    function acceptTermsOfService() external;
}

contract SampleOracleDataConsumer {
    IOracle public oracle = IOracle(0xc531410f61FA22e19048D406EDE3361b3de5c386);
    // using the address of the oracle in Milkomeda-C1 as an example.
 
    constructor() {
        oracle.acceptTermsOfService();
    }

    function sampleFunctionUsingTheOracle() {
        data = oracle.readData();
        // then do something with the data...
    }
}

How to read data from this Oracle from a Web App

To read data from the oracle using web3.js, do the following:

import oracleArtifact from "../artifacts/SimpleOracle.json";

const oracleAddress = "0xc531410f61FA22e19048D406EDE3361b3de5c386"; 
// using the address of the oracle in Milkomeda-C1 as an example.

const oracle = new web3.eth.Contract(
    oracleArtifact.abi, 
    oracleAddress, 
    {from: authorizedAddress}
);

const data = await web3Promise(oracle, "readData");

Ensure that SimpleOracle.json is in your web app's ../artifacts/ folder.

The address authorizedAddress can be any address that has already called the oracle's acceptTermsOfService function. Because the oracle's readData function is a view function, this address does not need to belong to you. You do not need to possess the private key of this address.