如何为 web3py 中的合约创建的合约创建事件过滤器

How to create event filter for contract created by contract in web3py

我正在尝试为由我想要的合约创建的合约引发的事件创建一个过滤器。但是，我无法弄清楚。这是我现在拥有的。

MergeModule.sol

pragma solidity ^0.4.23;

contract MergeModule {
    event MergeEvent(uint prID);

    function MergeModule(){

    }

    function merge(uint prID) public {
        emit MergeEvent(prID);
    }
}

Handler.sol

pragma solidity ^0.4.23;

import "./merge_module.sol";

contract Handler {

    // a getter for this will automatically be made by the compiler
    address public mergeModule;

    function Handler() public {
        mergeModule = new MergeModule();
    }

    function execute() public {
        mergeModule.merge();
    }
}

test_handler.py

from web3 import Web3, EthereumTesterProvider
import unittest
import os
from eth_tester.exceptions import TransactionFailed
import tests.utils.utils as utils
from web3.utils.filters import Filter


class TestHandler(unittest.TestCase):
    PROJECT_ROOT = os.path.dirname(os.path.dirname(__file__))
    CONTRACT_ROOT = os.path.join(PROJECT_ROOT, "contracts")
    TEST_CONTRACT_ROOT = os.path.join(CONTRACT_ROOT, "test_contracts")

    def setUp(self):
        handler_contract_path = os.path.join(self.CONTRACT_ROOT, "handler.sol")

        # web3.py instance
        self.w3 = Web3(EthereumTesterProvider())

        self.contract, self.contract_address, self.contract_instance = utils.create_contract(self.CONTRACT_ROOT,
                                                                                             handler_contract_path,
                                                                                             "Handler", self.w3)


    def test_event_emitted(self):
        # this prints something different from self.contract_address
        print(self.contract_instance.mergeModule())

        # this creates a reference to the Handler contract. I know this because when I inspect it with the debugger I see `execute` as one of the functions
        merge_contract = self.w3.eth.contract(self.contract_instance.mergeModule())
        merge_event_filter: Filter = merge_contract.events.MergeEvent.createFilter(fromBlock=0)

        # do stuff here with the filter

utils.create_contract 或多或少做了 quickstart for web3py 中显示的内容，并进行了一些修改以处理编译多个文件。我怀疑在执行merge_contract = self.w3.eth.contract(self.contract_instance.mergeModule())时我需要传递mergeModule的abi但我不确定。

我在运行时得到的错误是：AttributeError: 'ContractEvents' object has no attribute 'MergeEvent' 这是有道理的，因为 merge_contract 是 Handler 合同而不是 MergeModule合同。

看来我是对的。将 abi 传递给 MergeModule 是关键。这是我编写的一个 hacky 函数，用于获取对合并模块的引用。

    def get_merge_module(self):
        from solc import compile_source, compile_files

        # compile all of my contract files, one of which is the solidity file with the merge module
        compiled_sol = compile_files(utils.get_contract_file_paths(self.CONTRACT_ROOT))


        contract_interface = compiled_sol[f'{os.path.join(self.CONTRACT_ROOT, "merge_module.sol")}:MergeModule']
        abi = contract_interface["abi"]

        merge_contract = self.w3.eth.contract(self.contract_instance.mergeModule(), abi=abi)

        return merge_contract

如何为 web3py 中的合约创建的合约创建事件过滤器

How to create event filter for contract created by contract in web3py

python

solidity

web3