I am trying to implement a token swap of my custom ERC20 token via UniswapV3
I use Rinkeby Ethereum network.
I deployed the token under address: 0x4646CB39EA04d4763BED770F80F0e0dE8efcdF0f
I added the liquidity to Uniswap for this token and ETH.
Now, I try to execute swap in my contract, but it doesn't work. I get the error:
Gas estimation errored with the following message (see below). The transaction execution will likely fail. Do you want to force sending?
execution reverted
My Swap.sol contract takes an address of the token to swap with ETH as a constructor parameter. When I deploy it using DAI token address, the swap works just fine.
I assume this is a Uniswap liquidity related problem, but I added liquidity manually and I can swap my token inside their app.
Contract code:
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.10;
pragma abicoder v2;
import "#uniswap/v3-periphery/contracts/libraries/TransferHelper.sol";
import "#uniswap/v3-periphery/contracts/interfaces/ISwapRouter.sol";
import "#uniswap/v3-periphery/contracts/interfaces/IQuoter.sol";
contract Swap {
address private constant SWAP_ROUTER =
0xE592427A0AEce92De3Edee1F18E0157C05861564;
address private constant WETH = 0xc778417E063141139Fce010982780140Aa0cD5Ab;
address public tokenAddress;
address public immutable _owner;
ISwapRouter public immutable swapRouter;
constructor(address token) {
_owner = msg.sender;
swapRouter = ISwapRouter(SWAP_ROUTER);
tokenAddress = token;
}
function swapExactInputSingle() external payable {
require(msg.value > 0, "Must pass non 0 ETH amount");
ISwapRouter.ExactInputSingleParams memory params = ISwapRouter
.ExactInputSingleParams({
tokenIn: WETH,
tokenOut: tokenAddress,
fee: 3000,
recipient: msg.sender,
deadline: block.timestamp,
amountIn: msg.value,
amountOutMinimum: 1,
sqrtPriceLimitX96: 0
});
swapRouter.exactInputSingle{value: msg.value}(params);
}
receive() external payable {}
}
I had the same issue with the swapExactInputMultihop function on uniswap. For each pools/paths you're going through, you need to make sure you've got the correct pool fee set.
You can checkout the swap fees on the uniswap website: V3-overview/fees
or on a video tutorial, going through the whole process:
Blockchain With Wisdom on YouTube
Managed to fix it.
I set the fee: 3000 in contract, but I created liquidity with 1% fee, so I had to change it to fee: 10000 according to docs: fee The fee tier of the pool, used to determine the correct pool contract in which to execute the swap
Related
While attempting to fund me contract is tell me it encountered an error without specifying the error. I attempted to fund 0.1 eth through the fund function, and in the terminal it says:
[block:8404521 txIndex:12]
from: 0x8a9...e4303
to: FundMe.fund() 0x542...E109C
value: 100000000000000000 wei
data: 0xb60...d4288
logs: 0
hash: 0x29a...97939
and in the etherscan it says:status fail :
Contract 0x5422f3458be343e378e7a399e16fff548e7e109c
Warning! Error encountered during contract execution [execution reverted]
I tried looking for problems with my code and found none.
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.6 <0.9.0;
import "#chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol";
//import "#chainlink/contracts/src/v0.8/vendor/SafeMathChainlink.sol"; won't need in later complier versions.
contract FundMe {
mapping(address => uint256) public addressToAmountFunded;
function fund() public payable {
uint256 minimumUSD = 50 * 10 ** 18;
require( getConversionRate(msg.value) >= minimumUSD,"You need to send more Eth");
addressToAmountFunded[msg.sender] += msg.value;
}
function getVersion() public view returns (uint256){
AggregatorV3Interface priceFeed = AggregatorV3Interface(0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419);
return priceFeed.version();
}
function getPrice() public view returns (uint256){
AggregatorV3Interface priceFeed = AggregatorV3Interface(0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419);
(,int256 answer,,,)=priceFeed.latestRoundData();
return uint256(answer * 10000000000);
}
//10000000000 = Gwei which is why we added 10 zeros to getPrice(answer) to convert it to Wei amount
function getConversionRate(uint256 ethAmount) public view returns (uint256){
uint256 ethPrice = getPrice();
uint256 ethAmountInUsd = (ethPrice * ethAmount)/ 1000000000000000000; //divide 2x because we added 10*((getPrice)answer))
return ethAmountInUsd;
}
}
Aggregator contract address "0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419" belongs to mainnet
From here get the ETH/USD goerli testnet address:"0xD4a33860578De61DBAbDc8BFdb98FD742fA7028e"
Now in order to call chainlink oracle you have to have LINK token in your contract. Get some link token to your conract address from the faucet
Import the token in metamask. you will see the amount
send link token from your metamask to your contract
deploy your contract. if you are using Remix IDE chose the injected provider to connect to metamask. Because chainlink contract is on goerli, so you need to be on Goerli testnet. Once deployment goes through you can call the fund function.
Since the fund function has no argument, you need to send the value alongside the transaction. That is why inside the function you have msg.value to access to the sent amount.
In Remix ide, under "GAS LIMITinput there isVALUEinput. you need to pass the amount in there before you call thefund` function.
I want to make a smart contract that deposits UST on the eth anchor protocol, by using the deposit function. Here you can find the docs of this function I try to call. https://docs.anchorprotocol.com/ethanchor/ethanchor-contracts/router . The function gets called trough a proxy contract. I found the implementation address by reading the proxy contract on etherscan.
TestContracts on Ropsten testnet:
proxy: 0x7537aC093cE1315BCE08bBF0bf6f9b86B7475008
etherscan: https://ropsten.etherscan.io/address/0x7537aC093cE1315BCE08bBF0bf6f9b86B7475008
implementation (ROUTERV2): 0x2ba0010394eb3e41454c7d79c0fb6e0deb67284b
etherscan: https://ropsten.etherscan.io/address/0x2ba0010394eb3e41454c7d79c0fb6e0deb67284b
I imported the ROUTERV2 contract for calling the proxy with the abi of the implementation.
my execution order is:
deploying the contract
approving the contract for spending the tokens from the sender using ethers.
approveUST function on smart contract (I am not sure if this is necessary)
calling the depositStable function.
I get the following error when calling the depositStale function UNPREDICTABLE_GAS_LIMIT;
Below You see the contract I try to make. It should take the UST of the user and deposit it on eth anchor.
Here is a github link to the hardhat repo of the contract so you can simulate the bug and hopefully help me solving this issue.
https://github.com/tijgersoftware/Terra-anchor
I thank you for taking the time to read my question!
contract Anchor {
address public proxy;
address public operator;
address public USTAddress;
constructor(
address proxy_,
address operator_,
address USTAddress_
) public {
proxy = proxy_;
operator = operator_;
USTAddress = USTAddress_;
}
function approveUST() public {
ERC20(USTAddress).approve(
address(this),
0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
);
}
function initDepositStable(uint256 amount) public {
RouterV2(proxy).initDepositStable(amount);
}
function depositUST(uint256 amount) public {
// InterfaceOfImplementationContract(proxyAddress).MethodBeingCalled(
// parameter,
// parameter,
// parameter
// );
ERC20(USTAddress).approve(
address(this),
0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
);
RouterV2(proxy).depositStable(operator, amount);
}
}
tags: solidity, smart contracts, ethereum, anchor protocol, terra, brdige trasfer.
I'm trying to transfer an ERC721 token, but I'm getting the error ERC721: transfer caller is not owner nor approved for the transferToken method.
Main.sol
import "./ERC721.sol";
import "./Counters.sol";
contract Main is ERC721 {
using Counters for Counters.Counter;
Counters.Counter internal _tokenIds;
address payable internal admin;
constructor() ERC721("MyToken", "TOKEN") {
admin = payable(msg.sender);
}
}
Auction.sol
import "./Main.sol";
contract Auction is Main {
struct AuctionInfo {
uint256 tokenId;
address highestBidder;
uint highestBid;
}
mapping(string => AuctionInfo) private _auctionInfo;
function createAuction(string memory id) public {
_tokenIds.increment();
uint256 newTokenId = _tokenIds.current();
_mint(msg.sender, newTokenId);
_auctionInfo[id].tokenId = newTokenId;
}
function transferToken(string memory id) public {
require(msg.sender == _auctionInfo[id].highestBidder, "You are not the highest bidder");
safeTransferFrom(address(this), _auctionInfo[id].highestBidder, _auctionInfo[id].tokenId);
}
// other methods...
}
The minting contract is this and the owner of the token is the msg.sender of the minting method if I'm not mistaken. Am I to use the approve (or setApprovalForAll) for this each time before transferring? I've tried this, payable(this), and address(this) for the safeTransferFrom method, but none seem to be working.
For example, I tried the following, but get the same revert message:
approve(address(this), _auctionInfo[id].tokenId);
this.safeTransferFrom(address(this), _auctionInfo[id].highestBidder, _auctionInfo[id].tokenId);
The main principle behind any Blockchain is that nobody on the blockchain network should be trusted, and still the transactions should happen fool proof, with no possibility of any cheating being done (barring of course of some hacking).
If you invoke the approve method from the Auction contract, then the msg.sender for the approve function in the ERC721 token contract is your auction contract address. So, in other words, your Auction Contract is trying to approve itself to sell someone else's NFTs, which is not very trustworthy.
What should really happen is that owner of the NFT should invoke the approve method of the ERC721 contract - i.e. the transaction that you send for the approve function call, should be signed by the NFT owner wallet address. This way, the msg.sender for the approve function in the ERC721 contract will be the owner of the NFT. As per the ERC721 standards, the owner of the NFT can approve anyone they want, to sell their NFT(s), as the no-trust in the network is still maintained (At least I should be able to trust myself). The approve method should be invoked from within your DAPP, before the transferToken function is invoked from the DAPP.
Hope that explains why you are unable to transfer your ERC721 tokens.
Because of the internal visibility of the ERC721._approve() function, you can effectively perform the approval for the user.
Then you'll be able to execute the safeTransferFrom(tokenOwner, receiver, tokenId) from your contract, because your contract address is approved to operate this specific token even though it belongs to the tokenOwner.
This snippet mints the token, assigning the ownership to the msg.sender. But then it also calls the _approve() function that doesn't contain any validations and simply assigns the approval of the token to the Auction address.
pragma solidity ^0.8;
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC721/ERC721.sol";
contract Auction is ERC721 {
constructor() ERC721("CollectionName", "Symbol") {}
function createAuction() public {
uint256 newTokenId = 1;
_mint(msg.sender, newTokenId);
_approve(address(this), newTokenId);
}
}
You can see from the screenshot that the owner is 0x5B... (the user address) and that the token is approved for 0xd9... (the contract address).
Note: The _approve() function is internal - it can be called from the ERC721 contract and contracts deriving from it (in your case Main and Auction), but it can't be called from external contracts or end user addresses.
I have created a basic ERC20 token by implementing OpenZeppelin as follow in ERC20.sol file:
pragma solidity ^0.6.4;
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v3.4.0/contracts/token/ERC20/ERC20.sol";
contract Token is ERC20 {
constructor(string memory _name, string memory _symbol)
public
ERC20(_name, _symbol)
{
_mint(msg.sender, 10000000000000000000000000000);
}
}
Then implement another contract Contract.sol as follow:
import "./ERC20.sol";
pragma solidity ^0.6.4;
contract SimpleBank{
Token tokenContract;
constructor(Token _tokenContract) public {
tokenContract = _tokenContract;
}
function deposit(uint amt) public returns (bool) {
require(amt != 0 , "deposit amount cannot be zero");
tokenContract.transfer(address(this),amt);
return true;
}
}
As, I have deployed both contract from the address 0xAb8483F64d9C6d1EcF9b849Ae677dD3315835cb2 so, it holds 10000000000000000000000000000 tokens.
But when I call deposit function from same address I got the following error:
transact to SimpleBank.deposit errored: VM error: revert. revert The
transaction has been reverted to the initial state. Reason provided by
the contract: "ERC20: transfer amount exceeds balance". Debug the
transaction to get more information.
So, what is the proper way to interact with the deployed ERC20 token so that the deploy function works.
The user address 0xAb8483... sends a transaction executing SimpleBank's function deposit(), which makes 0xAb8483... the value of msg.sender in SimpleBank.
But then SimpleBank sends an internal transaction executing Token's function transfer(). Which makes SimpleBank address (not the 0xAb8483...) the value of msg.sender in Token.
So the snippet tokenContract.transfer(address(this),amt); within SimpleBank is trying to send SimpleBank's tokens. Not the user's (0xAb8483...) tokens.
This transfer of tokens (from point 2) reverts, because SimpleBank doesn't own any tokens. Which makes the top-level transaction (from point 1) revert as well.
If you want SimpleBank to be able to transfer 0xAb8483...'s tokens, 0xAb8483... needs to approve() the tokens first to be spent by SimpleBank. Directly from their address, so that they are msg.sender in the Token contract.
Only then SimpleBank can execute transferFrom(0xAb8483..., address(this), amt) (from, to, amount).
TLDR: Your contract can't spend tokens that it doesn't own, unless the owner has manually approved your contract to spend them.
If it could spend someone else's tokens without approval, it would be very easy to steal from people who can't/don't verify your source code (by spending their USDT, WETH and other widely-used tokens).
I am relatively new to Solidity, I am trying to fetch the price of a pair with the following contract:
contract Uniswap {
constructor () public payable {
}
function getBalance() public view returns (uint) {
return address(this).balance;
}
// calculate price based on pair reserves
function getTokenPrice(address pairAddress, uint amount) public payable returns(uint)
{
IUniswapV2Pair pair = IUniswapV2Pair(pairAddress);
IERC20 token1 = IERC20(pair.token1());
(uint Res0, uint Res1,) = pair.getReserves();
// decimals
uint res0 = Res0*(10**token1.decimals());
return((amount*res0)/Res1); // return amount of token0 needed to buy token1
}
}
but when I try to run on Remix the getTokenPriceit returns me the following error message:
The transaction has been reverted to the initial state. Note: The called function should be payable if you send value and the value you send should be less than your current balance. Debug the transaction to get more information.
Any idea why? I am trying to fetch the price of ETH/USDT so the using this website (https://v2.info.uniswap.org/pair/0x0d4a11d5eeaac28ec3f61d100daf4d40471f1852) and with the pair address at the end of the URL. Thanks for the help!
When you deploy a contract in Remix, it deploys to a local network. (By default. You can change it and deploy to mainnet as well, if you inject a production Infura provider for example.)
The Uniswap pair contract 0x0d4a11... does not exist on the local network.
The easiest solution is to deploy your contract on the mainnet (where the 0x0d4a11... Uniswap pair contract exists).
Or you can find another Uniswap pair on a public testnet (well-known are Rinkeby, Ropsten, Goerli, and Kovan), and deploy your contract on the same testnet. Don't forget to change the testnet address of the uniswap pair that you pass to your getTokenPrice() function.
Or you can deploy the Uniswap pair contract and all of its dependencies and change the dependencies addreses (which is a lot of work - my guess is that it's dependend on the Uniswap router contract, the actual token contracts of the pair, maybe they are dependend on some other contract, ...) to your local network. From here it's the same - deploy your contract to the local network, and call the getTokenPrice() with the correct pair address.
You may also invoke uniswap's Subgraph using javascript