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取消

TxTypeCancel 取消事務池中具有相同 nonce 的事務的執行。當已提交的交易在一定時間內似乎未得到處理時，這種交易類型就很有用。

從web3py_ext導入extend，將 web3 擴展為 kaia web3

從 eth_account、web3py_ext 和 cytoolz 中導入必要的實用程序

使用 kairos testnet 端點創建 Web3 實例

此外，您還可以將提供商 URL 從 kairos 更改為 quicknode 。

從私人密鑰加載賬戶

發送alue transfer tx。 It will be in the tx pool and canceled before execution. 如果取消 tx 已執行，則會失敗。

創建一個TxType.CANCEL類型的空事務。您可以使用 empty_tx 工具來獲取已填寫默認字段的 tx。

使用 merge 工具將 from 和 nonce 字段合併到空 tx 中。

使 nonce 與之前發送的 value transfer tx 相同。您需要設置要取消的相同的 tx nonce。

使用 fill_transaction 為交易對象添加更多參數，如 gas 限制...

用用戶的私鑰簽署cancel tx

從已簽署的 tx 中的簽名中恢復簽名人地址

您可以使用Account.decode_transaction工具對 RLP 編碼的 tx 進行解碼，如果您想讓輸出格式更漂亮，請使用to_pretty工具。

將tx發送到區塊鏈。它將返回 tx 哈希值，用於等待接收

如果交易已在區塊鏈中完成，wait_for_transaction_receipt 方法會返回交易收據。

最後，得到結果。

cancel_example.py


from web3py_ext import extend
from web3 import Web3
from eth_account import Account
from web3py_ext.transaction.transaction import (
    empty_tx,
    fill_transaction,
    TxType
)
from web3py_ext.utils.klaytn_utils import to_pretty
from cytoolz import merge
w3 = Web3(Web3.HTTPProvider(
    'https://public-en-kairos.node.kaia.io'
    ))
def web3_cancel_sign_recover():
    user1 = Account.from_key('0x0e4ca6d38096ad99324de0dde108587e5d7c600165ae4cd6c2462c597458c2b8')
    value_transfer_tx = empty_tx(TxType.VALUE_TRANSFER)
    value_transfer_tx = merge(value_transfer_tx, {
        'from':user1.address,
        'to':user1.address,
        'value':Web3.to_peb(10, "klay")
    })
    value_transfer_tx = fill_transaction(value_transfer_tx, w3)
    signed_tx = Account.sign_transaction(value_transfer_tx, user1.key)
    w3.eth.send_raw_transaction(signed_tx.rawTransaction)
    cancel_tx = empty_tx(TxType.CANCEL)
    cancel_tx = merge(cancel_tx, {
        'from' : user1.address,
        'nonce' : value_transfer_tx['nonce']
    })
    cancel_tx = fill_transaction(cancel_tx, w3)
    # sign the kaia specific transaction type with web3py
    signed_tx = Account.sign_transaction(cancel_tx, user1.key)
    print("\nraw transaction of signed tx:", signed_tx.rawTransaction.hex())
    recovered_tx = Account.recover_transaction(signed_tx.rawTransaction)
    print("\nrecovered sender address", recovered_tx)
    decoded_tx = Account.decode_transaction(signed_tx.rawTransaction)
    print("\ndecoded transaction:", to_pretty(decoded_tx))
    tx_hash = w3.eth.send_raw_transaction(signed_tx.rawTransaction)
    tx_receipt = w3.eth.wait_for_transaction_receipt(tx_hash)
    print('tx hash: ', tx_hash, 'receipt: ', tx_receipt)
web3_cancel_sign_recover()

output


❯ py cancel_example.py
raw transaction of signed tx: 0x38f86b82036f850ba43b740083026d1894a2a8854b1802d8cd5de631e690817c253d6a9153f847f8458207f5a0a559852e977476bfa6ba263a9c1f1f4b60608b82752d73a3f1162e341e7b5f06a07f12a242ad1cdbc08966e62af4c8749fc438e058b1344a4f11ba206f207ddc84
recovered sender address 0xA2a8854b1802D8Cd5De631E690817c253d6a9153
decoded transaction: {
  "type": 56,
  "nonce": 879,
  "gasPrice": 50000000000,
  "gas": 159000,
  "from": "0xA2a8854b1802D8Cd5De631E690817c253d6a9153",
  "signatures": [
    {
      "v": 2037,
      "r": 74789788593375966616662801192824717129914792416281096168085546212656613646086,
      "s": 57476654897736400463186412232435765147976539862827431359170424955204316028036
    }
  ],
  "chainId": 1001
}
tx hash:  0x3b1278d3748b638a41ffc40ed4cffc6c789ceffbd924f9b00ae7b53f26815686 receipt:  AttributeDict({'blockHash': HexBytes('0x672deecd07b84c2b524f160fccc6ce0d20486bdde914a7c7065e2de0ed723635'), 'blockNumber': 147364137, 'contractAddress': None, 'cumulativeGasUsed': 349674, 'effectiveGasPrice': 25000000000, 'from': '0xA2a8854b1802D8Cd5De631E690817c253d6a9153', 'gasUsed': 21000, 'logs': [], 'logsBloom': HexBytes('0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000'), 'status': 1, 'to': '0xA2a8854b1802D8Cd5De631E690817c253d6a9153', 'transactionHash': HexBytes('0x3b1278d3748b638a41ffc40ed4cffc6c789ceffbd924f9b00ae7b53f26815686'), 'transactionIndex': 3, 'type': 0})