如何使用 web3.py 获取合约地址的待处理交易？

Question

我想获取合约地址的待处理交易，我尝试了很多方法但不起作用

方法1：这似乎擅长对待处理交易进行排序，但我无法从我的地址获取任何交易，我不知道为什么。请帮助我

def main():
    block_filter = web3.eth.filter('pending') 
    log_loop(block_filter, 0)

def log_loop(block_filter, poll_interval):
    while True: 
        for event in block_filter.get_new_entries():
            if web3.eth.getTransaction(event)['from'] == my contract:
                print(event)

方法 2：这可以帮助我从我的地址获取交易，但它获得的所有交易均已确认，而不是待处理

def main():
    block_filter = web3.eth.filter({'fromBlock':'pending','toBlock':'pending', 'address':contract_address}) #this is not working, return nothing

    #block_filter = web3.eth.filter({'fromBlock':0,'toBlock':'pending', 'address':contract_address}) #return confirmed transaction, not pending

    #block_filter = web3.eth.filter({'fromBlock':'pending','toBlock':'latest', 'address':contract_address}) #return confirmed transaction, not pending

    #block_filter = web3.eth.filter({'fromBlock':'latest','toBlock':'pending', 'address':contract_address}) #return error from > to

    #block_filter = web3.eth.filter({'address':contract_address}) #return confirmed transaction, not pending
    log_loop(block_filter, 0)

def log_loop(block_filter, poll_interval):
    while True: 
        for event in block_filter.get_new_entries():
            print(event)

Answer 1

您可以使用 WebSocket 连接到您的节点来订阅新的待处理交易。有关更多信息，请检查 https:// geth.ethereum.org/docs/rpc/pubsub

这样您将收到所有待处理的交易 txHashes。
之后，您可以过滤它们并仅处理发送到所需令牌地址的令牌。
一种方法是对每个收到的 txHash 使用 web3.eth.get_transaction()。它会返回给您一个包含交易详细信息的字典。使用此字典中的“to”键来过滤是否将待处理的交易发送到所需的合约地址。
以下是建议的（稍作修改的）解决方案：
https： //community.infura.io/t/web3-py-how-to-subscribe-to-pending-ethereum-transactions-in-python/5409

import asyncio
import json
import requests
import websockets
from web3 import Web3


web3 = Web3(Web3.HTTPProvider(node_http_url))
# specific address to watch at 
watched_address = Web3.toChecksumAddress('0x....')

async def get_event():
    async with websockets.connect(node_ws_url) as ws:
        await ws.send('{"jsonrpc": "2.0", "id": 1, "method": "eth_subscribe", "params": ["newPendingTransactions"]}')
        subscription_response = await ws.recv()
        print(subscription_response)

        while True:
            try:
                message = await asyncio.wait_for(ws.recv(), timeout=15)
                response = json.loads(message)
                txHash = response['params']['result']
                print(txHash)

                tx = web3.eth.get_transaction(txHash)
                if tx['to'] == watched_address:
                    print("Pending transaction found with the following details:")
                    print({
                        "hash": txHash,
                        "from": tx["from"],
                        "value": web3.fromWei(tx["value"], 'ether')
                    })
                pass
            except:
                pass

if __name__ == "__main__":
    loop = asyncio.get_event_loop()
    while True:
        loop.run_until_complete(get_event())
 

如果您想要解码 tx['input'] 你可以使用 eth-abi
https://github.com/ethereum/eth-abi

或者如果您有合约 abi你可以创建web3合约并调用decode_function_input()

wa_contract = web3.eth.contract(address=watched_address, abi=watched_address_abi)  
func_obj, func_params = wa_contract.decode_function_input(tx['input'])