Ethereum: Web3 Contract (React) – Safeerc20 Low level called ERC20 Token (USDT)
As a development of the concept with the concept of interactive blockchain networks. .
The problem
The specifically, when a contract built in Ethereum (such as Esterscan) is used, attempts to call a function with an ERC20 token (such as USDT) triggers a failure.
The symptoms
The symptoms are as follows:
1.
2.
3.
The solution
To solve this problem, you have some options:
1.
- Implement a backup mechanism
:
Example of code
Here is a fragment of example code in solidity (the programming language used for Ethereum’s intelligent contracts) that demonstrates how it could implement a response mechanism:
`Solidity
Pragma solidity ^0.8.0;
Safeerc20Fallback Contract {
CALLFUNCTION FUNCTION () Public {
// First, try to call the function with Eth
if (msg.gender.balance> 1010 * 18) {
// If you succeed, return the value of the variable
uint256 result = msg.value / 10 ** 18;
Return result;
}
// If you are not successful, try to call the function with a token erc20
address [] memory tokens = [address (0x89f8c7ce9e77fbc2a3bc6bb5da1bf6cc4bfc94ce);
for (uint256 i = 0; i
// Obtain the Token contract
Token contract = token (address (tokens [i]));
// Try to call the function with the token
uint256 results = contract.callfunction ();
// If you succeed, return the value of the variable
If (result> 0) {
Return result;
}
}
// If it is not successful for both methods, reverse the transaction
Revert ();
}
}
Token structure {
Address the public token;
}
`
Conclusion
Safeerc20 low level calls with tokens ERC20 when Ethereum are used. Demonstrating how to implement an response mechanism for such cases.
The cause of the cause and development of its intelligent contract or web application.
