I've wrote a simple code for fetching ETH price by using Chainlink interfaces as below:
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
import "#chainlink/contracts/src/v0.6/interfaces/AggregatorV3Interface.sol";
contract ABI {
AggregatorV3Interface internal priceFeed;
constructor() public {
priceFeed = AggregatorV3Interface(0xF4030086522a5bEEa4988F8cA5B36dbC97BeE88c);
}
function latestPrice() public view returns (int256) {
(, int256 answer,,,) = priceFeed.latestRoundData();
return answer;
}
}
The problem is when is being compiled by Remix, it has no problem but after execution it throws the error below:
call to ContractName.FunctionName errored: execution reverted
Do you think what the problem is?
Because your question didn't specify on which network you're running the script, I'm assuming that you're using the Remix VM emulator.
The specified Chainlink contract is available on Ethereum mainnet only. Any other network (including the emulator) does not have this contract deployed on this address.
To use the data feed contract in Remix, you can create a local fork of the mainnet, and then connect to the local network in the IDE.
Change ENVIRONMENT to Injected Web3 in Remix IDE and connect to metamask. For example, if you are using Kovan network use address as mentioned in the docs.
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;
import "#chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol";
contract PriceConsumerV3 {
AggregatorV3Interface internal priceFeed;
/**
* Network: Kovan
* Aggregator: ETH/USD
* Address: 0x9326BFA02ADD2366b30bacB125260Af641031331
*/
constructor() {
priceFeed = AggregatorV3Interface(0x9326BFA02ADD2366b30bacB125260Af641031331);
}
/**
* Returns the latest price
*/
function getLatestPrice() public view returns (int) {
(
/*uint80 roundID*/,
int price,
/*uint startedAt*/,
/*uint timeStamp*/,
/*uint80 answeredInRound*/
) = priceFeed.latestRoundData();
return price;
}
}
Related
Total beginner here apologies in advance.
I'm learning Solidity and using Hardhat and trying to figure out how to return the value of the Chainlink price feed in this tutorial contract after deployment. I know how to return the function output in remix but having trouble figuring out how to use console.log or another method in Hardhat. I am able to use console.log for built in functions like token address but can't figure out how to apply to other functions. This is using the Goerli Testnet btw.
// SPDX-License-Identifier: MIT
pragma solidity 0.8.0;
import "#chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol";
contract TestChainlink {
AggregatorV3Interface internal priceFeed;
constructor() {
// ETH / USD
priceFeed = AggregatorV3Interface(0xD4a33860578De61DBAbDc8BFdb98FD742fA7028e);
}
function getLatestPrice() public view returns (int) {
(
uint80 roundID,
int price,
uint startedAt,
uint timeStamp,
uint80 answeredInRound
) = priceFeed.latestRoundData();
// for ETH / USD price is scaled up by 10 ** 8
return price;
}
}
I tried emulating console.log usage that work for built in functions like token address to apply them to the Chainlink getLatestPrice() function.
const Token = await ethers.getContractFactory("TestChainlink");
const token = await Token.deploy();
console.log("Token address:", token.address);
i.e.
I tried a ton of different combinations this was the last one I will spare all the error messages since it probably isn't a complex solve for a non novice.
console.log("ETH Price:", getLatestPrice());
try
let price = await token.getLatestPrice();
console.log(`Eth price is: ${price}`);
I'm trying to wrap Eth from an smart contract as I want to swap weth later in uniswap but I don't know how to import the WETH code from goerli scan WETH = 0xB4FBF271143F4FBf7B91A5ded31805e42b2208d6;.
Following internet examples I accomplished wrapping Eth but all influencers just import a ERC20 library to create a new one. I don't understand why they are using this as they are not interacting with the right weth contract.
Here is the code I used but is just creating a new token. Can anyone give me some advice?
// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity ^0.8.0;
pragma abicoder v2;
import '#uniswap/v3-periphery/contracts/interfaces/ISwapRouter.sol';
import '#uniswap/v3-periphery/contracts/libraries/TransferHelper.sol';
import '#openzeppelin/contracts/token/ERC20/ERC20.sol';
contract SwapExamples is ERC20 {
// For the scope of these swap examples,
// we will detail the design considerations when using `exactInput`, `exactInputSingle`, `exactOutput`, and `exactOutputSingle`.
// It should be noted that for the sake of these examples we pass in the swap router as a constructor argument instead of inheriting it.
// More advanced example contracts will detail how to inherit the swap router safely.
// This example swaps DAI/WETH9 for single path swaps and DAI/USDC/WETH9 for multi path swaps.
ISwapRouter public immutable swapRouter;
address payable [] private s_Wallets;
uint256 public walletA = address(this).balance;
// Router = 0xE592427A0AEce92De3Edee1F18E0157C05861564
address public constant WETH = 0xB4FBF271143F4FBf7B91A5ded31805e42b2208d6; //0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
// For this example, we will set the pool fee to 0.3%.
uint24 public constant poolFee = 3000;
uint256 public UsdOut;
constructor(ISwapRouter _swapRouter) ERC20("Wrapped Ether", "WETH") {//ERC20("Wrapped Ether", "WETH")
swapRouter = _swapRouter;
}
function Deposit() public payable {
s_Wallets.push(payable(msg.sender));
}
function Mint() external payable {
_mint(address(this), address(this).balance);
}
}
You need not create a new ERC20 token.
Calling:
WETH.deposit.value(msg.value)();
helps you wrap your ETH and you don't need to import WETH code from anywhere.
After wrapping, you can then move on to swapping WETH for any other token on Uniswap like you said.
I've created a ERC20 contract in Remix:
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "#openzeppelin/contracts/token/ERC20/ERC20.sol";
contract MyToken is ERC20 {
constructor(string memory name, string memory symbol) ERC20(name, symbol) {
_mint(msg.sender, 1002000);
}
}
Then I deployed it:
But the balance of msg.sender is zero:
Does anyone know what's wrong?
I just tried your code and it works perfectly like intended.
It is important, that you compile the correct contract using Remix, see my attached picture. You need to choose the contract "MyToken". I guess you could have deployed the contract "ERC20 - #openzeppelin/contracts/token/ERC20/ERC20.sol" which would lead to the behaviour you mentioned.
compile "MyToken" in Remix
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.9.0 ;
interface AggregatorV3Interface {
function decimals() external view returns (uint8);
function description() external view returns (string memory);
function version() external view returns (uint256);
// getRoundData and latestRoundData should both raise "No data present"
// if they do not have data to report, instead of returning unset values
// which could be misinterpreted as actual reported values.
function getRoundData(uint80 _roundId)
external
view
returns (
uint80 roundId,
int256 answer,
uint256 startedAt,
uint256 updatedAt,
uint80 answeredInRound
);
function latestRoundData()
external
view
returns (
uint80 roundId,
int256 answer,
uint256 startedAt,
uint256 updatedAt,
uint80 answeredInRound
);
}
contract FundMe {
mapping (address => uint256) public addressTotalAmountFunded;
function fund() public payable {
addressTotalAmountFunded[msg.sender] += msg.value;
}
function getVersion() public view returns (uint256){
AggregatorV3Interface priceFeed = AggregatorV3Interface(0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419);
return priceFeed.version();
}
}
Hi I am trying to understand why I get this error when I want to check the version
Any thoughts?
The 0x5f4e... address hardcoded in your getVersion() function doesn't hold any smart contract on the Kovan testnet (link). Even though it has a contract deployed on the mainnet, these environments are separated.
When there's no smart contract on the address, there's nothing to send a response to the internal call. Your code expects an uint256 response from the version() call, so that it can return it from the getVersion().
When it doesn't receive the expected response, it throws an exception, effectively reverting the "main" call.
Make sure the address of the data feed is for the Testnet you are using (most likely Kovan) and not for Mainnet.
I experienced the same problem. The problem was with the network selection. You're requesting the price info from a wallet address/contract on Rinkby network. I tried the wallet address on the Kovan network instead and that worked for me.
This is the Kovan address I used 0x9326BFA02ADD2366b30bacB125260Af641031331
It worked find a returned the ETH/USD Price info.
So basically you can solve it in 2 ways:
Go to your metamask and change your network to Rinkby and use the rinkby ETH/USD address in your functions or
Keep your network on Kovan and use the Kovan ETH/USD address.
I am using ganache to create 10 ethereum accounts. I want to transfer ethereum from one account to a smart contract. I am doing this by writing two following smart contracts in solidity;
pragma solidity >=0.4.0 <0.6.0;
contract Ether_Transfer_To{
function () external payable { //fallback function
}
function get_balance() public returns(uint){
return address(this).balance;
}
}
contract Ether_Transfer_From{
Ether_Transfer_To private the_instance;
constructor() public{
//the_instance=Ether_Transfer_To(address(this));
the_instance=new Ether_Transfer_To();
}
function get_balance() public returns(uint){
return address(this).balance;
}
function get_balance_of_instance() public returns(uint){
//return address(the_instance).balance;
return the_instance.get_balance();
}
function () external payable {
// msg.sender.send(msg.value)
address(the_instance).send(msg.value);
}
}
When I deploy the contract Ether_Transfer_From smart contract then I get its three-member functions as follows in remix;
But when I sent one 1 Wei from account to smart contract by writing 1 in the text box and clicking on a (fallback) button, then I get the following error;
transact to Ether_Transfer_From. (fallback) errored: VM Exception while
processing transaction: out of gas
I followed the answer of the same question by installing Ganache-cli 7.0.0 beta.0 by using following command;
npm install -g ganache-cli#7.0.0-beta.0
But I still get the same error. I think I am using older Ganache cli instead of Ganache-cli 7.0.0 beta.0 as it goes to C drive and I installed ganache 2.1.1 in D drive previously.
I just want to send ethereum from one account to other but I am really stuck in this out of gas Error. If there is any way to remove this error or transfer ethereum from one account to another then please let me know.
So this is what I did for one of my projects.
This snippet, deploys the compiles the solidity file and then deploys it and gets the address of the deployed contract address
const input = fs.readFileSync('Migrations.sol');
const output = solc.compile(input.toString(), 1);
const bytecode = output.contracts[':Migrations']['bytecode'];
const abi = JSON.parse(output.contracts[':Migrations'].interface);
var contract = new web3.eth.Contract(abi);
contract.deploy({
data: '0x'+bytecode,
})
.send({
from: chairPerson,
gas: 5500000,
gasPrice: '2000000000000'
})
.on('receipt', (receipt) => {
add=receipt.contractAddress;
})
Now using contract's abi, I can call methods of the deployed contract and use the following code to transfer '1.5' ether from one address to another.
contract.methods.registerRequest(fromAddress,toAddress,requestNumber).send({from:fromAddress,value : web3.utils.toWei('1.5', 'ether')}).on('transactionHash', (hashResult) => {-- some code--})
And also make the method in the solidity as payable to allow it to transfer ether, like :
function registerRequest(address requestedBy,address requestedTo,uint requestNumber) payable public{}
Refer : https://web3js.readthedocs.io/en/v1.2.0/web3-eth-contract.html#id12
Basically I used web3 api itself to transfer ether from one account
to another by calling my solidity method.
Also, check the following things :
1. While deploying, are you deploying with enough gas ? I faced this error when I was deploying the contract with less gas quantity
2. Your method in solidity should be payable