Dynamic APY Adjuster for Staking Solidity, JavaScript
👤 Sharing: AI
Okay, let's create a simplified example of a dynamic APY (Annual Percentage Yield) adjuster for a staking contract using Solidity for the smart contract and JavaScript for a rudimentary frontend to interact with it. This will be a conceptual illustration.
**Solidity Contract (DynamicAPY.sol)**
```solidity
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
contract DynamicAPY {
uint256 public totalStaked;
uint256 public baseAPY = 10; // Base APY (10%) in percentage form
uint256 public maxAPY = 25; // Maximum APY (25%)
uint256 public minAPY = 5; // Minimum APY (5%)
uint256 public targetStaked = 10000; // Target Total Stake to influence APY
uint256 public lastUpdated;
mapping(address => uint256) public stakedBalances;
event Staked(address indexed user, uint256 amount);
event Unstaked(address indexed user, uint256 amount);
constructor() {
lastUpdated = block.timestamp;
}
function stake(uint256 _amount) public {
require(_amount > 0, "Amount must be greater than zero.");
stakedBalances[msg.sender] += _amount;
totalStaked += _amount;
emit Staked(msg.sender, _amount);
lastUpdated = block.timestamp; // Update timestamp on stake
}
function unstake(uint256 _amount) public {
require(_amount > 0, "Amount must be greater than zero.");
require(stakedBalances[msg.sender] >= _amount, "Insufficient balance.");
stakedBalances[msg.sender] -= _amount;
totalStaked -= _amount;
payable(msg.sender).transfer(_amount);
emit Unstaked(msg.sender, _amount);
lastUpdated = block.timestamp; // Update timestamp on unstake
}
function calculateAPY() public view returns (uint256) {
// APY is adjusted based on how close totalStaked is to targetStaked
uint256 apy;
if (totalStaked > targetStaked) {
// If total staked exceeds the target, reduce the APY
apy = baseAPY - (baseAPY - minAPY) * (totalStaked - targetStaked) / targetStaked;
//Ensure it doesnt go lower than the minimum APY
if(apy < minAPY){
apy = minAPY;
}
} else {
// If total staked is less than the target, increase the APY
apy = baseAPY + (maxAPY - baseAPY) * (targetStaked - totalStaked) / targetStaked;
//Ensure it doesnt go above the maximum APY
if(apy > maxAPY){
apy = maxAPY;
}
}
return apy;
}
// Function to get the current stake of a user
function getStake(address _user) public view returns (uint256) {
return stakedBalances[_user];
}
// Function to update the targetStaked (only callable by owner in a real application)
function setTargetStaked(uint256 _newTarget) public {
targetStaked = _newTarget;
}
// Function to update the baseAPY (only callable by owner in a real application)
function setBaseAPY(uint256 _newAPY) public {
baseAPY = _newAPY;
}
// Function to update the maxAPY (only callable by owner in a real application)
function setMaxAPY(uint256 _newAPY) public {
maxAPY = _newAPY;
}
// Function to update the minAPY (only callable by owner in a real application)
function setMinAPY(uint256 _newAPY) public {
minAPY = _newAPY;
}
}
```
**Explanation of Solidity Code:**
1. **`pragma solidity ^0.8.0;`**: Specifies the Solidity compiler version.
2. **`contract DynamicAPY { ... }`**: Defines the smart contract named `DynamicAPY`.
3. **State Variables:**
* `totalStaked`: Total amount of tokens staked in the contract.
* `baseAPY`: The baseline Annual Percentage Yield (APY) when the target stake is met. Expressed as a percentage (e.g., 10 for 10%).
* `maxAPY`: The maximum allowed APY.
* `minAPY`: The minimum allowed APY.
* `targetStaked`: The target amount of total staked tokens that influences APY adjustments. When `totalStaked` is near `targetStaked`, the APY will be closer to the `baseAPY`.
* `stakedBalances`: A mapping (dictionary) that stores the staked balance for each user (address).
4. **Events:**
* `Staked`: Emitted when a user stakes tokens.
* `Unstaked`: Emitted when a user unstakes tokens.
5. **`constructor()`**: Initializes the `lastUpdated` timestamp.
6. **`stake(uint256 _amount)`**:
* Allows users to stake tokens.
* Increases the user's `stakedBalances` and `totalStaked`.
* Emits the `Staked` event.
* Updates the `lastUpdated` timestamp.
7. **`unstake(uint256 _amount)`**:
* Allows users to unstake tokens.
* Decreases the user's `stakedBalances` and `totalStaked`.
* Transfers the tokens to the user.
* Emits the `Unstaked` event.
* Updates the `lastUpdated` timestamp.
8. **`calculateAPY()`**:
* Calculates the current APY based on `totalStaked` relative to `targetStaked`.
* If `totalStaked` is greater than `targetStaked`, the APY decreases from `baseAPY` toward `minAPY`.
* If `totalStaked` is less than `targetStaked`, the APY increases from `baseAPY` toward `maxAPY`.
* Uses a linear interpolation formula to determine the APY adjustment.
9. **`getStake(address _user)`**: Returns the staked balance of a given user.
10. **`setTargetStaked(uint256 _newTarget)`**, **`setBaseAPY(uint256 _newAPY)`**, **`setMaxAPY(uint256 _newAPY)`**, **`setMinAPY(uint256 _newAPY)`**: Functions to update the target, base, max, and min APY values. In a real-world contract, these should be restricted to an owner or admin role using `onlyOwner` modifiers for security.
**JavaScript Frontend (index.html and app.js)**
This is a very basic frontend to demonstrate interaction. You'll need to install `ethers` or `web3.js` for this to work. I'll use `ethers`.
**index.html**
```html
<!DOCTYPE html>
<html>
<head>
<title>Dynamic APY Staking</title>
<script src="https://cdn.ethers.io/lib/ethers-5.6.umd.min.js" type="application/javascript"></script>
<script src="app.js"></script>
</head>
<body>
<h1>Dynamic APY Staking</h1>
<label for="stakeAmount">Stake Amount:</label>
<input type="number" id="stakeAmount">
<button onclick="stake()">Stake</button><br><br>
<label for="unstakeAmount">Unstake Amount:</label>
<input type="number" id="unstakeAmount">
<button onclick="unstake()">Unstake</button><br><br>
<button onclick="getAPY()">Get Current APY</button>
<p id="apyDisplay">APY: </p>
<button onclick="getStake()">Get My Stake</button>
<p id="stakeDisplay">My Stake: </p>
<br>
<label for="targetStaked">New Target Staked Amount</label>
<input type="number" id="targetStakedAmount">
<button onclick="setTarget()">Set Target Stake (Owner Only)</button><br><br>
<label for="baseAPY">New Base APY Amount</label>
<input type="number" id="baseAPYAmount">
<button onclick="setBase()">Set Base APY (Owner Only)</button><br><br>
<label for="maxAPY">New Max APY Amount</label>
<input type="number" id="maxAPYAmount">
<button onclick="setMax()">Set Max APY (Owner Only)</button><br><br>
<label for="minAPY">New Min APY Amount</label>
<input type="number" id="minAPYAmount">
<button onclick="setMin()">Set Min APY (Owner Only)</button><br><br>
</body>
</html>
```
**app.js**
```javascript
const contractAddress = "YOUR_CONTRACT_ADDRESS"; // Replace with your deployed contract address
const contractABI = [
{
"inputs": [],
"stateMutability": "nonpayable",
"type": "constructor"
},
{
"anonymous": false,
"inputs": [
{
"indexed": true,
"internalType": "address",
"name": "user",
"type": "address"
},
{
"indexed": false,
"internalType": "uint256",
"name": "amount",
"type": "uint256"
}
],
"name": "Staked",
"type": "event"
},
{
"anonymous": false,
"inputs": [
{
"indexed": true,
"internalType": "address",
"name": "user",
"type": "address"
},
{
"indexed": false,
"internalType": "uint256",
"name": "amount",
"type": "uint256"
}
],
"name": "Unstaked",
"type": "event"
},
{
"inputs": [],
"name": "baseAPY",
"outputs": [
{
"internalType": "uint256",
"name": "",
"type": "uint256"
}
],
"stateMutability": "view",
"type": "function"
},
{
"inputs": [],
"name": "calculateAPY",
"outputs": [
{
"internalType": "uint256",
"name": "",
"type": "uint256"
}
],
"stateMutability": "view",
"type": "function"
},
{
"inputs": [
{
"internalType": "address",
"name": "_user",
"type": "address"
}
],
"name": "getStake",
"outputs": [
{
"internalType": "uint256",
"name": "",
"type": "uint256"
}
],
"stateMutability": "view",
"type": "function"
},
{
"inputs": [],
"name": "lastUpdated",
"outputs": [
{
"internalType": "uint256",
"name": "",
"type": "uint256"
}
],
"stateMutability": "view",
"type": "function"
},
{
"inputs": [],
"name": "maxAPY",
"outputs": [
{
"internalType": "uint256",
"name": "",
"type": "uint256"
}
],
"stateMutability": "view",
"type": "function"
},
{
"inputs": [],
"name": "minAPY",
"outputs": [
{
"internalType": "uint256",
"name": "",
"type": "uint256"
}
],
"stateMutability": "view",
"type": "function"
},
{
"inputs": [
{
"internalType": "uint256",
"name": "_newAPY",
"type": "uint256"
}
],
"name": "setBaseAPY",
"outputs": [],
"stateMutability": "nonpayable",
"type": "function"
},
{
"inputs": [
{
"internalType": "uint256",
"name": "_newAPY",
"type": "uint256"
}
],
"name": "setMaxAPY",
"outputs": [],
"stateMutability": "nonpayable",
"type": "function"
},
{
"inputs": [
{
"internalType": "uint256",
"name": "_newAPY",
"type": "uint256"
}
],
"name": "setMinAPY",
"outputs": [],
"stateMutability": "nonpayable",
"type": "function"
},
{
"inputs": [
{
"internalType": "uint256",
"name": "_newTarget",
"type": "uint256"
}
],
"name": "setTargetStaked",
"outputs": [],
"stateMutability": "nonpayable",
"type": "function"
},
{
"inputs": [
{
"internalType": "uint256",
"name": "_amount",
"type": "uint256"
}
],
"name": "stake",
"outputs": [],
"stateMutability": "nonpayable",
"type": "function"
},
{
"inputs": [
{
"internalType": "uint256",
"name": "_amount",
"type": "uint256"
}
],
"name": "unstake",
"outputs": [],
"stateMutability": "payable",
"type": "function"
},
{
"inputs": [],
"name": "targetStaked",
"outputs": [
{
"internalType": "uint256",
"name": "",
"type": "uint256"
}
],
"stateMutability": "view",
"type": "function"
},
{
"inputs": [],
"name": "totalStaked",
"outputs": [
{
"internalType": "uint256",
"name": "",
"type": "uint256"
}
],
"stateMutability": "view",
"type": "function"
}
]; // Replace with your contract's ABI
let contract;
let signer;
async function connectWallet() {
if (typeof window.ethereum !== 'undefined') {
try {
await window.ethereum.request({ method: "eth_requestAccounts" });
const provider = new ethers.providers.Web3Provider(window.ethereum);
signer = provider.getSigner();
contract = new ethers.Contract(contractAddress, contractABI, signer);
console.log("Wallet connected");
// Optionally update the UI to reflect the connected state
} catch (error) {
console.error("Wallet connection error:", error);
}
} else {
console.log("Please install MetaMask or a compatible wallet!");
}
}
async function stake() {
await connectWallet(); //Ensure you've connected your wallet
const amount = document.getElementById("stakeAmount").value;
try {
const tx = await contract.stake(amount);
await tx.wait(); // Wait for the transaction to be mined
console.log("Staked successfully!");
} catch (error) {
console.error("Stake error:", error);
}
}
async function unstake() {
await connectWallet();
const amount = document.getElementById("unstakeAmount").value;
try {
const tx = await contract.unstake(amount);
await tx.wait();
console.log("Unstaked successfully!");
} catch (error) {
console.error("Unstake error:", error);
}
}
async function getAPY() {
await connectWallet();
try {
const apy = await contract.calculateAPY();
document.getElementById("apyDisplay").innerText = "APY: " + apy + "%";
} catch (error) {
console.error("Get APY error:", error);
}
}
async function getStake() {
await connectWallet();
try {
const stake = await contract.getStake(await signer.getAddress());
document.getElementById("stakeDisplay").innerText = "My Stake: " + stake;
} catch (error) {
console.error("Get Stake error:", error);
}
}
async function setTarget() {
await connectWallet();
const newTarget = document.getElementById("targetStakedAmount").value;
try {
const tx = await contract.setTargetStaked(newTarget);
await tx.wait();
console.log("Target Staked Updated!");
} catch (error) {
console.error("Set Target Staked error:", error);
}
}
async function setBase() {
await connectWallet();
const newBase = document.getElementById("baseAPYAmount").value;
try {
const tx = await contract.setBaseAPY(newBase);
await tx.wait();
console.log("Base APY Updated!");
} catch (error) {
console.error("Set Base APY error:", error);
}
}
async function setMax() {
await connectWallet();
const newMax = document.getElementById("maxAPYAmount").value;
try {
const tx = await contract.setMaxAPY(newMax);
await tx.wait();
console.log("Max APY Updated!");
} catch (error) {
console.error("Set Max APY error:", error);
}
}
async function setMin() {
await connectWallet();
const newMin = document.getElementById("minAPYAmount").value;
try {
const tx = await contract.setMinAPY(newMin);
await tx.wait();
console.log("Min APY Updated!");
} catch (error) {
console.error("Set Min APY error:", error);
}
}
```
**Explanation of JavaScript Code:**
1. **`contractAddress` and `contractABI`**: Replace these with the actual address of your deployed smart contract and the contract's ABI (Application Binary Interface). You get the ABI from the Solidity compiler output.
2. **`ethers` Library**: The code uses the `ethers` library to interact with the Ethereum blockchain.
3. **`connectWallet()`**: Connects to the user's Ethereum wallet (e.g., MetaMask) using `window.ethereum`. It gets the provider and signer.
4. **`stake()`, `unstake()`, `getAPY()`, `getStake()`, `setTarget()`, `setBase()`, `setMax()`, `setMin()`**: These functions are called when the corresponding buttons are clicked. They:
* Get the input values from the HTML form.
* Call the appropriate function on the smart contract using the `contract` instance.
* Wait for the transaction to be mined.
* Display the results in the HTML.
5. **Error Handling**: Includes basic `try...catch` blocks for error handling.
**How to Run:**
1. **Deploy the Solidity Contract:**
* Use Remix IDE (remix.ethereum.org) or Hardhat/Truffle to compile and deploy the `DynamicAPY.sol` contract to a test network (e.g., Ganache, Rinkeby, Goerli).
* Note the deployed contract address.
* Also copy the ABI of the contract (Remix provides a "Copy to Clipboard" button for the ABI).
2. **Set Up Your Environment:**
* Create an `index.html` and `app.js` file in the same directory.
* Paste the HTML and JavaScript code above into those files.
* Replace `YOUR_CONTRACT_ADDRESS` in `app.js` with the actual contract address you obtained during deployment.
* Replace `contractABI` with the ABI of your contract.
3. **Serve the HTML:**
* You can use a simple web server to serve the `index.html` file. For example, if you have Python installed, you can run `python -m http.server` in the directory.
4. **Open in Browser:** Open `http://localhost:8000` (or the address shown by your web server) in your browser.
5. **Interact:**
* Make sure you have MetaMask or a compatible Ethereum wallet installed and connected to the same test network where you deployed the contract.
* Connect your wallet.
* Enter amounts to stake or unstake, and click the buttons.
* Click "Get Current APY" to see the calculated APY.
**Important Considerations and Improvements:**
* **Security:** This is a simplified example and is *not* production-ready. It lacks proper security checks and could be vulnerable to attacks.
* **Token Handling:** This example doesn't deal with actual ERC-20 tokens. In a real-world scenario, you'd need to integrate with an ERC-20 token contract (users would need to approve the staking contract to spend their tokens).
* **Access Control:** The `setTargetStaked`, `setBaseAPY`, `setMaxAPY`, and `setMinAPY` functions should be restricted to an owner or admin role using `onlyOwner` modifiers.
* **Reentrancy:** Be aware of reentrancy vulnerabilities, especially when transferring tokens. Use the "Checks-Effects-Interactions" pattern.
* **Frontend Polish:** The frontend is very basic. Use a framework like React, Vue.js, or Angular to create a more user-friendly interface.
* **Gas Optimization:** Solidity code can be optimized to reduce gas costs.
* **Testing:** Write thorough unit tests for your smart contract.
* **Error Handling:** The JavaScript error handling is rudimentary. Provide more informative error messages to the user.
* **Display Precision**: Be careful about displaying APY. Solidity doesn't natively support floating-point numbers. Consider using a fixed-point representation (e.g., storing the APY multiplied by 100 or 1000) and then dividing by that factor in the frontend for display.
* **Time-Based Rewards**: Instead of just staking/unstaking, a real-world staking contract would also calculate and distribute rewards over time based on the APY. This would require tracking the time a user has staked and calculating their reward accrual.
* **Periodic APY Updates:** The APY is currently recalculated every time someone stakes or unstakes. You might want to make this happen periodically (e.g., every day) to reduce gas costs. A time-based update would also prevent rapid APY fluctuations due to small stake changes.
This example provides a foundational understanding of dynamic APY adjustment in a staking contract. Remember to thoroughly research, test, and audit your code before deploying it to a production environment.
👁️ Viewed: 9
Comments