I am trying to call following function from my solidity contract using web3js frontend.
function playerData(address player) public {
gameStatus[player] = false;
}
webjs calls this method using following line of code.
await myContract.methods.playerData(playerAddress)
.send(
{
from: playerAddress,
}
)
Now when this line is executed, metamask window opens up and waits for confirmation. As there is no token transfer involved in this method, I want to remove confirmation step of metamask.
Please help me understand if there is a way to call this method without confirmation popup from metamask.
Thanks!
If you are going to change the state of the blockchain ( modify a State variable ), you'll need to create a transaction, and since transactions are signed by a user you'll need a wallet ( in this case metamask ) to confirm that transaction.
Metamask is a wallet, a simple app ( be it browser extension or physical USB ) that allows someone to interact with a blockchain account using a private key, in this case you use the wallet to sign the transaction and paying for the gas fees.
If you are NOT changing any State variable, just make your functions view or pure and you won't get the pop-up for metamask.
Now, if you DO change a State variable, the only way you could do it without using metamask is by getting a web3js account object from a private key, and manually signing it with this account ( check out this ), now I heavily advise against this unless you know what you're doing, because if you publish your private key somewhere, anyone will be able to access your account.
Related
I have a ReactJS project that can communicate with my smart contract. However, in my smart contract I have used the Require function to check for certain conditions before proceeding to execute down stream code. However, I do not know how to access the error messages in the event that certain conditions are not met.
For example:
bool public isRed = false;
require(isRed, "The state is not red");
How would I be able to access the "The state is not red" from the front end I am currently using Alchemy web3 to communicate with the blockchain?
After I have deployed a contract, I'm able to interact with the setter functions, as well as with the getter functions. However, after a day goes by, when i try to interact with the same contract again, that is still open and loaded on my remix I get a "pending" message when I try to set and change some variables like a different address. When I try to call a get function also nothing happens. I don't know how to interact with my deployed contract again.
When I reload the contract using the contract address "at address", it properly loads the contract if I select the right smart contract (containing the getter and setter functions) from the dropdown menu in the "deploy and run" page. However, the same problem occurs, that is: when i try to set a variable the transaction is not mined (pending indefinetly), and the call functions also dont read the data.
In order for me to move forward with my project I need to be able to access and interact with the contract if I need to change a variable which currently doesn't work...
Anyone has an idea how to solve this (probably trivial) problem? Thanks!
My contract needs LINK token in order to function.
I want to let users fund LINK tokens to the contract via a function on the contract, and then do some logic for the user based on their funding.
How can i make this possible within the contract?
I've tried to do calls like this.
LINK.balanceOf(walletaddress) does work, (It gets the link amount that's in the wallet).
However, this function below does not work for some reason.
It goes through and all, but with like empty data.
Metamask shows differently when i do the same call from their front-end button. (I assume it does the same as remix does)
https://testnet.bscscan.com/token/0x84b9B910527Ad5C03A9Ca831909E21e236EA7b06#readContract
Here is how i try to get my contracts approval.
function approveTransfer(uint256 amount) public returns(string memory) {
uint256 approveAmt = amount * 10**18;
LINK.approve(_msgSender(),approveAmt);
approvedAmount = approveAmt;
}
Okay, so i kept searching and searching and searching....
Until i found something amazing on their discord channel. (It's most likely written somewhere else too).
Harry | Chainlink
The LINK token is an ERC677 with transferAndCall functionality. So
depending on how your smart contract function call that generates the
random number is made, you can change it to be a 'transferAndCall'
function instead of one that just does the VRF request, with the idea
being that it will transfer enough LINK to fulfill the VRF request.
Then in your consuming contract that does the VRF request, you
implement the 'onTokenTransfer' function which simply calls your other
function that does the VRF request. The end result of this is that
when the user transfers LINK to the contract, it automatically does a
VRF request all in the 1 single transaction.
So instead of the user pressing a button which calls the function in
your consuming contract to do the VRF request, they press a button
which does a 'transferAndCall' function from the LINK token contract,
which in turn transfer LINK to your consuming contract and calls the
'onTokenTransfer' function in your consuming contract, which then
calls your function to do the VRF request, which will be successfully
fulfilled because it just received LINK for the request
See an implementation of this in my previous hackathon entry "Link Gas Station"
https://github.com/pappas999/Link-Gas-Station/blob/master/contracts/WeatherCheck.sol
https://github.com/pappas999/Link-Gas-Station/blob/master/src/relayer/relayer.js
So in short, this is possible because my contract have the
function onTokenTransfer(address from, uint256 amount, bytes memory data) public {
receivedTokenTransfer = true;
lastDepositer = from;
lastDepositerAmountInLink = amount / 10**18;
}
I can therefor instead of sending LINK to my own contract, i can send LINK to LINK's contract address, with the data payload transferAndCall , MycontractAddress, and the amount of LINK my contract should receive.
Upon this payment is sent, chainlink will send my contract the payment and call the function called onTokenTransfer (On my contract). :)))
Ho0pe this helps someone in the future.
Not possible from within your contract, unless the external contract explicitly allows it or contains a security flaw using deprecated tx.origin instead of msg.sender.
See the last paragraph and code snippet in this answer to see how it could be misused if it were possible.
When your contract executes LINK's function, msg.sender in the LINK contract is now your contract - not the user.
Both transfer() and approve() (in order to call transferFrom() later) functions rely on msg.sender, which you need to be the user. But it's not - it's your contract.
When your contract delegates a call to LINK's function, the state changes are stored in your contract - not in the LINK.
But you'd need to store the state changes in the LINK contract, so this is not an option either.
I am studying how to make BEP-20 tokens. For this I copied the following contract in remix to be able to study it:
Contract in BscScan
If I copy the whole file and compile it in Remix, when I deploy it it doesn't show me any getters. No public view function appears. If I look at the contract displayed on the testnet, it doesn't have any supply of tokens either.
I separated the files and libraries for a better reading. And it is then, when I try to display it, that I get the following error:
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.
It gives me the feeling that this contract does not generate the tokens ... What am I wrong?
I managed to fix the problem. As I suspected, in order to deploy the contract I have to remove everything related to uniswap and cakeswap. This displays the contract correctly.
If you wanted to deploy the contract with the uniswap interfaces in injected web3, you would need the uniswap testnet.
I found a test address for cake here:
Binance Smart change tesnet
I'd like to remove a slack bot from a channel using slack's API.
I've tried channels.kick but ofcourse, a bot is not a user so it can't be deleted that way. I haven't found any solutions so far on the interwet or on Slacks API documentation.
You are not correct. You can remove a bot user from a public channel or private channel using API methods just fine. I just tested it on a private channel to confirm.
So there must be another reason why this does not work for you. Please check if any of these reasons below apply to your case. Also, please provide the error message you are getting from the API, as that would greatly help to identify the reason.
Here are some potential reasons why kicking a bot user might not work for you:
wrong method: channels.kick only works for public channel, use groups.kick for private channels.
wrong token: bot tokens can not use the kick methods. You need to use a user access token to invoke that API method. (you would get the user_is_bot error)
trying to remove oneself: a user can not kick himself. (you would get the cant_kick_self error)
not using channel IDs: the kick methods require you to provide a channel ID, the name will not work. (you would get the channel_not_found error)
Based on your question I would assume you are getting the user_is_bot error, which let you to assume (incorrectly) that you can't kick a bot. In that case the solution would be to use a user token (not a bot token) to execute the method.