如何使用 web3.js 獲取事務發出的事件

我正在用 Javascript 編寫使用者界面，並且正在使用 web3.js 庫。

我有確認交易的交易雜湊。我想獲取該事務發出的所有事件的數組。

我不一定需要所有事件，只需要我的智能合約通過執行該交易發出的事件。

這可以使用 web3.js 完成嗎？有什麼好方法可以做到這一點？

如果您使用的是 Web3 v1，那麼您可以使用web3.eth.getTransactionReceipt(tx). 它返回logs屬性作為結果的一部分。

您可以通過查看事件的topics屬性來對事件進行分類。

樣本getTransactionReceipt結果：

{
   "transactionHash": "0x7e2e90d913246933b30049c568d9a9768eca5be6fed331656458c2a479f30908",
   "transactionIndex": 0,
   "blockHash": "0x2af7bb564cc6a4155895b3238d5a0f227ecae2bfc5e65d24be5066f7a0e1b035",
   "blockNumber": 127,
   "from": "0x9442ed348b161af888e6cb999951ae8b961f7b4b",
   "to": "0xf1365f7f85c20885cab2472d36c59861bcfbd071",
   "gasUsed": 298630,
   "cumulativeGasUsed": 298630,
   "contractAddress": null,
   "logs": [
       {
           "logIndex": 0,
           "transactionIndex": 0,
           "transactionHash": "0x7e2e90d913246933b30049c568d9a9768eca5be6fed331656458c2a479f30908",
           "blockHash": "0x2af7bb564cc6a4155895b3238d5a0f227ecae2bfc5e65d24be5066f7a0e1b035",
           "blockNumber": 127,
           "address": "0xF1365F7F85C20885caB2472d36c59861BCfbD071",
           "data": "0x",
           "topics": [
               "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef",
               "0x0000000000000000000000000000000000000000000000000000000000000000",
               "0x0000000000000000000000005b1b89a48c1fb9b6ef7fb77c453f2aaf4b156d45",
               "0x0000000000000000000000000000000000000000000000000000000000000000"
           ],
           "type": "mined",
           "id": "log_3b3793c3"
       },
       {
           "logIndex": 1,
           "transactionIndex": 0,
           "transactionHash": "0x7e2e90d913246933b30049c568d9a9768eca5be6fed331656458c2a479f30908",
           "blockHash": "0x2af7bb564cc6a4155895b3238d5a0f227ecae2bfc5e65d24be5066f7a0e1b035",
           "blockNumber": 127,
           "address": "0xF1365F7F85C20885caB2472d36c59861BCfbD071",
           "data": "0x00000000000000000000000000000000000000000000000000000000000dbba00000000000000000000000005b1b89a48c1fb9b6ef7fb77c453f2aaf4b156d45",
           "topics": [
               "0xc0300f89fa66c737609c90575f912c101a539bdc6659f1562ba9b0868f8d181d",
               "0x0000000000000000000000000000000000000000000000000000000000000000"
           ],
           "type": "mined",
           "id": "log_f5493494"
       }
   ],
   "status": true,
   "logsBloom": "0x00000000000000000000000000000100000000000000000000000000000000002000000000000000000000000000000000000000000000040000000000000000000000000000000000800008000008000000000000000000000000000000000000000000020000000000000000000800000000000000000000400010000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000002000002000000000000000000020000000000200000000000000000000020000000000000000000000000000000000000000000000000000000000000000000",
   "v": "0x2dc32acb6eb",
   "r": "0xc61fe8837727dda287ab1253006832ca7546a191580dd2e3d676f5e77bdd3c9f",
   "s": "0x6db737b383a9cfd5f59bc41351adf0665fea86b6708c123f7103413d43972859"
}

這有點令人費解，因為 Web3 不直接暴露事務發出的事件，但可以通過跟踪事務來查詢。

1. 跟踪交易：https ://github.com/ethereum/go-ethereum/wiki/Management-APIs#debug_tracetransaction
2. 它將為每條交易指令返回一個資訊塊。（本例中為 PUSH1）

{深度：1，錯誤：“”，gas：162106，gasCost：3，記憶體：null，op：“ PUSH1 ”，pc：0，堆棧：

$$ $$， 貯存： {} } 3. 過濾操作碼 LOG0 – LOG4。這些指令用於引發事件。

4. 從屬於 OPCODE 塊的數據中解碼事件名稱

引用自：https://ethereum.stackexchange.com/questions/66454