Polygon Chainlink Oracle Scaffold

Built with scaffold-eth ❤️

is everything you need to get started building decentralized applications powered by smart contracts using Chainlink price feeds and vrf

---

quickstart

git clone https://github.com/Polygon-Academy/oraclescaffold

cd oraclescaffold

yarn install

yarn start

in a second terminal window:

cd oraclescaffold
yarn chain

in a third terminal window:

cd oraclescaffold
yarn deploy

🔏 Web3 Providers:

The frontend has three different providers that provide different levels of access to different chains:

mainnetProvider: (read only) Infura connection to main Ethereum network (and contracts already deployed like DAI or Uniswap).

localProvider: local HardHat accounts, used to read from your contracts (.env file points you at testnet or mainnet)

injectedProvider: your personal MetaMask, WalletConnect via Argent, or other injected wallet (generates burner-provider on page load)

---

🐜 Ant.design is the UI library with components like the grids, menus, dates, times, buttons, etc.

---

⛑ Helpers:

Transactor: The transactor returns a tx() function to make running and tracking transactions as simple and standardized as possible. We will bring in BlockNative's Notify library to track our testnet and mainnet transactions.

const tx = Transactor(props.injectedProvider, props.gasPrice);

Then you can use the tx() function to send funds and write to your smart contracts:

tx({
  to: readContracts[contractName].address,
  value: parseEther("0.001"),
});

tx(writeContracts["SmartContractWallet"].updateOwner(newOwner));

☢️ Warning: You will need to update the configuration for react-app/src/helpers/Transactor.js to use your BlockNative dappId

---

🖇 Hooks:

Commonly used Ethereum hooks located in packages/react-app/src/:

usePoller(fn, delay): runs a function on app load and then on a custom interval

usePoller(() => {
  //do something cool at start and then every three seconds
}, 3000);

useBalance(address, provider, [pollTime]): poll for the balance of an address from a provider

const localBalance = useBalance(address, localProvider);

useBlockNumber(provider,[pollTime]): get current block number from a provider

const blockNumber = useBlockNumber(props.provider);

useGasPrice([speed]): gets current "fast" price from ethgasstation

const gasPrice = useGasPrice();

useExchangePrice(mainnetProvider, [pollTime]): gets current price of Ethereum on the Uniswap exchange

const price = useExchangePrice(mainnetProvider);

useContractLoader(provider): loads your smart contract interface

const readContracts = useContractLoader(localProvider);
const writeContracts = useContractLoader(injectedProvider);

useContractReader(contracts, contractName, variableName, [pollTime]): reads a variable from your contract and keeps it in the state

const title = useContractReader(props.readContracts, contractName, "title");
const owner = useContractReader(props.readContracts, contractName, "owner");

useEventListener(contracts, contractName, eventName, [provider], [startBlock]): listens for events from a smart contract and keeps them in the state

const ownerUpdates = useEventListener(
  readContracts,
  contractName,
  "UpdateOwner",
  props.localProvider,
  1
);

---

📦 Components:

Your commonly used React Ethereum components located in packages/react-app/src/:

📬 <Address />: A simple display for an Ethereum address that uses a Blockie, lets you copy, and links to Etherescan.

  <Address value={address} />
  <Address value={address} size="short" />
  <Address value={address} size="long" blockexplorer="https://blockscout.com/poa/xdai/address/"/>
  <Address value={address} ensProvider={mainnetProvider}/>

🖋 <AddressInput />: An input box you control with useState for an Ethereum address that uses a Blockie and ENS lookup/display.

  const [ address, setAddress ] = useState("")
  <AddressInput
    value={address}
    ensProvider={props.ensProvider}
    onChange={(address)=>{
      setAddress(address)
    }}
  />

TODO GIF

💵 <Balance />: Displays the balance of an address in either dollars or decimal.

<Balance
  address={address}
  provider={injectedProvider}
  dollarMultiplier={price}
/>

👤 <Account />: Allows your users to start with an Ethereum address on page load but upgrade to a more secure, injected provider, using Web3Modal. It will track your address and localProvider in your app's state:

const [address, setAddress] = useState();
const [injectedProvider, setInjectedProvider] = useState();
const price = useExchangePrice(mainnetProvider);

<Account
  address={address}
  setAddress={setAddress}
  localProvider={localProvider}
  injectedProvider={injectedProvider}
  setInjectedProvider={setInjectedProvider}
  dollarMultiplier={price}
/>

💡 Notice: the <Account /> component will call setAddress and setInjectedProvider for you.

☢️ Warning: You will need to update the configuration for Web3Modal to use your Infura Id

📡 <Provider />: You can choose to display the provider connection status to your users with:

<Provider name={"mainnet"} provider={mainnetProvider} />
<Provider name={"local"} provider={localProvider} />
<Provider name={"injected"} provider={injectedProvider} />

💡 Notice: you will need to check the network id of your injectedProvider compared to your localProvider or mainnetProvider and alert your users if they are on the wrong network!

---

📄 Smart Contract Wallet:

📝 Edit your smart contract SmartContractWallet.sol in packages/hardhat/contracts

📝 Then edit the SmartContractWallet.js React component in packages/react-app/src

▶️ Run yarn run compile and yarn run deploy or just yarn run watch

🛠 Run this eth.build with your contract address to ask it who its owner is.

---

📚 OpenZeppelin Contracts -- TODO

You can import any of the OpenZeppelin contracts:

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

---

🛰 The Graph -- 🎥 speed run tutorial video

⛽️ GSN -- See Nifty.ink!

---

📤 Save to your Git

Create a new repo with the same name as this project and then:

git remote add origin https://github.com/**YOUR_GITHUB_USERNAME**/**YOUR_COOL_PROJECT_NAME**.git
git push -u origin master

---

🛳 Ship it!

You can deploy your static site and your dapp can go live:

yarn run build

# ship it!

yarn run surge

OR

yarn run s3

OR

yarn run ipfs