Demo 为 JavaScript 语言
连接到以太坊节点
:您需要确保您已经连接到一个可用的以太坊节点。您可以使用 web3.js 或其他以太坊开发库来连接到节点。在代码中,您需要指定节点的 HTTP 或 WebSocket 端点。获取代币合约实例
:使用代币的合约地址和 ABI,您需要创建一个代币合约的实例。您可以使用 web3.js 的 web3.eth.Contract 方法来实现这一点,将合约地址和 ABI 作为参数传递给合约实例。查询授权额度
:通过调用合约实例的 allowance 函数来查询授权额度。该函数需要两个参数:拥有者的地址和被授权者的地址。您可以通过在调用时提供这两个地址来查询授权额度。const { Web3 } = require('web3');
// Connect to an Ethereum node
const web3 = new Web3('https://xxxxx');
// token address and ABI
const tokenAddress = '0xxxxxxxxx';
// user address
const ownerAddress = '0xxxxxxxx';
// ETH dex token approval address
const spenderAddress = '0x40aa958dd87fc8305b97f2ba922cddca374bcd7f';
const tokenABI = [
{
"constant": true,
"inputs": [
{
"name": "_owner",
"type": "address"
},
{
"name": "_spender",
"type": "address"
}
],
"name": "allowance",
"outputs": [
{
"name": "",
"type": "uint256"
}
],
"payable": false,
"stateMutability": "view",
"type": "function"
}
];
// Create token contract instance
const tokenContract = new web3.eth.Contract(tokenABI, tokenAddress);
// Query token approve allowance function
async function getAllowance(ownerAddress, spenderAddress) {
try {
const allowance = await tokenContract.methods.allowance(ownerAddress, spenderAddress).call();
console.log(`Allowance for ${ownerAddress} to ${spenderAddress}: ${allowance}`);
} catch (error) {
console.error('Failed to query allowance:', error);
}
}
getAllowance(ownerAddress, spenderAddress).then(r => console.log(r));