[英]How to get event log Web3.py?
I am using solidity 0.7.4, web3.py 5.12.2, and python 3.7.我正在使用solidity 0.7.4、web3.py 5.12.2 和python 3.7。
I am working with Windows 10.我正在使用 Windows 10。
My goal is to emit an event inside a solidity function, in order to retrieve the log after the function is executed.我的目标是在solidity 函数内发出一个事件,以便在函数执行后检索日志。
This is my event event logString(string arg);
这是我的事件
event logString(string arg);
And this is how I emit the event emit logString("example string");
这就是我发出事件的方式
emit logString("example string");
On Remix it works, and I am able to retrieve the string I emit, in the log of the transaction.在 Remix 上它可以工作,并且我能够在事务日志中检索我发出的字符串。
When I try it on Python, it doesn't work.当我在 Python 上尝试时,它不起作用。
This is my Python code:这是我的 Python 代码:
web3_instance = Web3(HTTPProvider("http://"+host+":"+port, request_kwargs={'timeout': timeout}))
Platform_contract= web3_instance.eth.contract(address=contract_address, abi=abi, bytecode=bytecode)
coinbase= web3_instance.eth.coinbase
functions= Platform_contract.functions
tx_hash =functions.market_clearing(n_clearings, t_clearing_first,supplier_bids,uniform_pricing,discriminative_pricing).transact({'from': coinbase})
tx_receipt = web3_instance.eth.getTransactionReceipt(tx_hash)
log_to_process = tx_receipt['logs'][0]
processed_log = Platform_contract.events.logString().processLog(log_to_process)
log = processed_log['args']['arg']
Unfortunately tx_receipt['logs']
is empty and I get an exception.不幸的是
tx_receipt['logs']
是空的,我得到一个例外。
Do you know how can I retrieve the log of the event?您知道如何检索事件日志吗?
I managed to solve the problem.我设法解决了这个问题。 I don't know why, I had to exactly specify the network_id in the truffle config.js.
我不知道为什么,我必须在 truffle config.js 中准确指定 network_id。 Then I migrated the contracts again and ran ganache-cli on that specific network_id.
然后我再次迁移合约并在该特定 network_id 上运行 ganache-cli。
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