I want to send ether to token owner.
ownerOf returns address, so I set payable address inside of sendEther function.
However, error says 'Type address is not implicitly convertible to expected type address payable'.
Is there any way to set payable address inside function?
Could you give me any advise?
function sendEther(uint256 _tokenId) public payable {
address payable _tokenOwner = ownerOf(_tokenId);
_tokenOwner.transfer(msg.value);
}
ERC721.sol
function ownerOf(uint256 tokenId) public view returns (address) {
address owner = _tokenOwner[tokenId];
return owner;
}
You can't directly cast from address to address payable, but you can cast in two steps, through uint160:
address payable _tokenOwner = address(uint160(ownerOf(_tokenId)));
Related
I'm trying to send some Ether between contracts but I'm getting this error:
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.
My contract:
contract test {
address public owner;
address payable public receiverContract;
constructor(address payable _receiverContract) payable{
receiverContract = _receiverContract;
owner = msg.sender;
}
function sendEther() public payable {
receiverContract.transfer(msg.value);
}
receive() external payable {
}
}
The receiver contract also has a receive() external payable function and I'm getting the error when calling sendEther() with some Ethers and after seeding the test contract with some Ethers
The message indicate that you should add a requirement to test if the user actually have the Ether he is trying to send to the contract.
address public owner;
address payable public receiverContract;
constructor(address payable _receiverContract) payable{
receiverContract = _receiverContract;
owner = msg.sender;
}
function sendEther() public payable {
require(address(this).balance > msg.value, "Not enough funds" );
receiverContract.transfer(msg.value);
}
receive() external payable {
}
} ```
the withdraw function gets me an error and it shows send and transfer are only available for object of type address payable and not address...
Confusing!!
solidity
//SPDX-License-Identifier: MIT
//this line of code was created to fund account
//show the value of fund in the address
pragma solidity ^0.8.0;
// the fundMe contract should be able to accept payment
function withdraw()payable public {
msg.sender.transfer(address(this).balance);
}
}
In Solidity, there is a difference between a normal address and a payable address so the correct way to send Ether to the sender would be payable(msg.sender).transfer(address(this).balance); this converts the normal address to a payable address. For more details take a look at this
I think up until solidity ^0.8.0, msg.sender was payable. withdraw function should be called only by the owner of the contract and you do not need to make it payable.
address payable private owner;
// set the owner when the contract is created
constructor(){
owner=payable(msg.sender)
}
function withdraw() public {
require(msg.sender==owner,"only contract owner can call this");
owner.transfer(address(this).balance);
}
However, using transfer is not safe. Because .transfer() sends more gas than 2300. Thus making it possible for reentrancy. A better way would be:
function withdraw() public {
require(msg.sender==owner,"only contract owner can call this");
(bool success, ) = owner.call{value:address(this).balance}("");
// success should be true
require(success,"Withdraw failed")
}
What is the difference between msg.sender and address(this) in the below code?
**pragma solidity ^0.8.0;
contract Escrow{
address public payer;
address payable public payee;
address public lawyer;
uint public amount;
constructor(
address _payer,
address payable _payee,
uint _amount) {
payer = _payer;
payee = _payee;
lawyer = msg.sender;
amount = _amount;
}
function deposit() payable public {
require(msg.sender == payer, 'Sender must be the payer');
require(address(this).balance <= amount, 'Cant send more than escrow amount');
}
function release() public {
require(address(this).balance == amount, 'cannot release funds before full amount is sent');
require(msg.sender == lawyer, 'only lawyer can release funds');
payee.transfer(amount);
}
function balanceOf() view public returns(uint) {
return address(this).balance;
}
}**
msg.sender is the address of the contract caller.
address(this) is the address of the smart contract itself.
They are both addresses in Solidity, but there is a big difference between msg.sender and address(this).
Allow me to use a simplified Smart Contract below to highlight the difference. All screenshots are from the Remix-Ethereum IDE (click here).
pragma solidity ^0.8.0;
contract Escrow {
address public owner;
constructor() {
owner = msg.sender;
}
function depositNothing() public view {
require(msg.sender == owner, 'You are not the owner!');
}
function balanceOf() view public returns(uint) {
return address(this).balance;
}
}
msg.sender
We are talking about the ACCOUNT address from which the function in the Smart Contract was called. For example, suppose in the Remix Ethereum (IDE), the Escrow Smart Contract was deployed from the ACCOUNT address:
0x5B38Da6a701c568545dCfcB03FcB875f56beddC4
In that case, the State Variable owner will have the same address mentioned above. This is because the constructor function was called from that address.
Now, suppose we change the ACCOUNT address to:
0xAb8483F64d9C6d1EcF9b849Ae677dD3315835cb2
We then call the function depositNothing from the Smart Contract which was deployed earlier. You will get the following error, however:
This is because the msg.sender in the depositNothing function equates to the second ACCOUNT address. This obviously does not equate to the first ACCOUNT Address - owner. The second argument in the require function was therefore returned along with the error.
address(this)
This is not the same as the ACCOUNT Address discussed earlier. This strictly refers to the address given to the Smart Contract when it is deployed to the Ethereum blockchain.
This can be found here:
0xd8b934580fcE35a11B58C6D73aDeE468a2833fa8
Error message:
transact to Payment.deposit errored: VM error: revert.
revert 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.
contract Payment{
address Account2;
address Owner;
constructor() public{
Account2 = 0x583031D1113aD414F02576BD6afaBfb302140225;
Owner = msg.sender;
}
function deposit() payable public{
address(uint160(Account2)).transfer(1 ether);
}
If you don't want to use msg.value then it is compulsory that your contract should have enough balance.
So you can create a fallback function in order to deposit enough ether to your contract first and then you can call your deposit() function.
Your contract after adding fallback function
pragma solidity ^0.5.1;
contract Payment{
address Account2;
address Owner;
constructor() public{
Account2 = 0x583031D1113aD414F02576BD6afaBfb302140225;
Owner = msg.sender;
}
function () payable external{}
function deposit() payable public{
address(uint160(Account2)).transfer(1 ether);
}
function getContractBalance() public view returns(uint) {
return address(this).balance;
}
}
It works without error on my remix VM.
So make sure:
The contract has a balance greater than 1 ether
If Account2 is a contract's address, then it need to have a fallback function to receive ether
I have a problem which I'm trying to figure out for a week I think I'm 90% there.
If I deploy a contract MerchantA on a private blockchain and retrieve it's contract address and ABI through the solidity command line solc --abi MerchantA.sol and store it.
Where do I enter this ABI & Address in a brand new contract say inside SendMoneyContract method where calls one of the function of AnimalContract deployed at address 0xrandom.
The material I'm finding online has been to include both solidity source code in the same file but for my case, I can't do it. Reason being MerchantAContract is unique for each deployment [each merchant added gets a unique contract`.
So far, from my understanding, I need to include the MerchantA contract address and ABI. I have no idea how to do it inside the solidity function.
You do not do anything with the ABI.
Let's say you want to call the functionA function on MerchantA FROM MerchantB, all you do is take the interface from MerchantA, an example of an interface of an ERC20 token is:
contract Token {
function totalSupply() constant returns (uint256 supply) {}
function balanceOf(address _owner) constant returns (uint256 balance) {}
function transfer(address _to, uint256 _value) returns (bool success) {}
function transferFrom(address _from, address _to, uint256 _value) returns (bool success) {}
function approve(address _spender, uint256 _value) returns (bool success) {}
function allowance(address _owner, address _spender) constant returns (uint256 remaining) {}
event Transfer(address indexed _from, address indexed _to, uint256 _value);
event Approval(address indexed _owner, address indexed _spender, uint256 _value);
uint public decimals;
string public name;
}
On MerchantB, wherever you want to call functionA, you put the following code:
MerchantA merchantA = MerchantA(0x0000000000000000000000000000000000000000); //Replace 0x000000000000000000000000000000000000000 with the address of MerchantA
merchantA.functionA();
You will need to swap out the interface of MerchantA because you are not using an ERC20 token as well as what function you want to call.