web3.py swapExactTokensForTokens 交易失败

Question

我正在尝试调用路由器合约的 swapExactTokensForTokens，我需要将 tokenA 交换为 tokenB。 这是交易的代码：

router = '0x0000000'
abi = '[{"inputs":[{"internalType":"address","name":"_factory","type":"address"},.... {"stateMutability":"payable","type":"receive"}]'

router_contract = w3.eth.contract(router, abi=abi)

tokenA = '0x000...'
tokenB = '0x000...'

path = [tokenA, tokenB]


txn = router_contract.functions.swapExactTokensForTokens(amount, min_amount, path, personal_wallet, (int(time()) +1000) ).buildTransaction({
        'gas': 81000,
        'gasPrice': w3.toWei('10', 'gwei'),
        'nonce':  w3.eth.get_transaction_count(personal_wallet),
    })

我在交易中收到以下错误：

交易截图

Answer 1

更新：

当增加 gas 并在buildTransaction中添加from字段时，上面的代码可以正常工作。

Answer 2

1. 计算预估gas
2. 在建立交易时提供估计的气体

function = router_contract.functions.swapExactTokensForTokens(数量,

    0,

    [

        tokenA,


        tokenB


    ],


    wallet,


    int(time.time()) + 10 * 60)


estimated_gas = function.estimateGas({'from':'0x10780b34025a93927ae62776Fe43419166ec88D2'})


tx_params = {


    'from': wallet,


    'gas': estimated_gas,


    'gasPrice': conf.w3.toWei('10', 'gwei'),


    'nonce': conf.w3.eth.getTransactionCount(wallet)


}

transaction = function.buildTransaction(tx_params)