I am deployed ERC-721 smart contract and sale was started and 3ETH in my contract
Now I am worried about how can I withdraw ETH from the contract to my wallet. How can I upgrade my contract with the withdrawal function?
Please help
Thanking in anticipation
If the contract is already deployed with no withdraw function, no proxie, without a delegatecall, is very hard or imposible to withdraw the ether
Related
I am developing a smart contract on solidity where user can deposit $CAKE in my pool and after depositing, the deposited $CAKE will be automatically redirected to some other pool. But I don't know how to write this! Can anyone help?
I don't have any clue on how to do this or even if it is possible?
I actually need a very simple smart contract using the following functions "transferfrom" and "approve".
I just need a smart contract that will be able to request approval to spend a token ( example -- bake ) from a wallet if the user calls the "approve" function.
It will also be able to withdraw the particular token from the user's wallet to the "address to" set by the contract's onwer, if the onwer calls the "transferfrom" function.
There's a design limitation of the ERC20 standard that disallows approval through a contract in between.
The user always needs to invoke the approve() function on the token contract directly - not through your contract.
I just start to learn solidity and I've finished a couple courses and I want some help to create my first working smart contract.
The smart contract I want to build will buy and sell tokens on the pancakeswap platform from a smart contract; it like my smart contract will start interacting with a pancakeswap contract to execute some trades, doing the same stuff as I'm using their website.
Any help will be appreciated
I have tried to add the interfaces I need to start the interaction between my contract and pancakeswap router contract to use the function
I'm new in solidity and erc20, so I read ERC20 description on the openzeppelin and find this function which isn't clear for me.
approve(spender, amount)
What's the purpose of allowing to the spender spend my token, instead of send my tokens to the spender directly?
You can change the approved amount or revoke it altogether (only the unspent amount). But you cannot take back an already sent transfer.
A common use case for the approve() function is trading on a DEX (decentralized exchange). You approve the DEX contract address to spend your USDT tokens for example. And when you want to buy an XYZ token (against USDT), the DEX simply pulls the already approved USDT from your address and sends you the XYZ tokens.
Approve is a function used to give permission the spender can be anyone an exchange or EOA to withdraw as many times from your token contract up to the _value.
You can check this reference here
As others said, Approve function can give permission to the spender to pulls the amount of token in your address. It can be used in: DEX (decentralized exchange) or in Custody services.
In custody services, after you approve the custody provider to take your token, whenever your wallet receives token, the custody provider is able to transfer your token into some internal wallets and keep them save for you. (It's just like how the traditional banks work)
I was wondering if there's a PancakeSwap API, that allows me to swap BNB for a token, and if it isn't possible, can I do it with Binance Smart Chain's API?
Thank you!
pancakeswap currently doesn't have APIs or sdk as Uniswap sdk. Best solution is connect to binance smart chain and connect to the pancakeswap router contract through web3.
function swapExactTokensForTokens(
uint amountIn,
uint amountOutMin,
address[] calldata path,
address to,
uint deadline
)
This is the function for swap tokens. You can refer the uniswap doc to get more information.
There's an API which allows you to find the best DEX on different blockchains, including BSC, and allows you to specify the DEX you want by excluding all of the other ones.
Here's a link to the API specification: https://0x.org/docs/api
An example you could type into the browser is:
https://bsc.api.0x.org/swap/v1/quote?buyToken=BUSD&sellToken=BNB&sellAmount=1000000000000000000&excludedSources=BakerySwap,Belt,DODO,DODO_V2,Ellipsis,Mooniswap,MultiHop,Nerve,SushiSwap,Smoothy,ApeSwap,CafeSwap,CheeseSwap,JulSwap,LiquidityProvider
This URL converts 1 BNB into BUSD on only Pancakeswap V1 and Pancakeswap V2.
You can also integrate this into a smart contract.
Hope this helps :D