Contract name: BoredApeYachtClub
2023-06-13 16:32:57 Info Contract address: 0xbc4ca0eda7647a8ab7c2061c2e118a18a936f13d
The contract with the address ```0xbc4ca0eda7647a8ab7c2061c2e118a18a936f13d``` is determined to be ERC721 standard.
In this part, we introduced how to determine ERC721 contracts, so contracts like ERC20, which do not support the ERC165 standard, will have to be identified in another way. Do you know how to check if a contract is ERC20 standard?
## Encoding calldata
What is ```calldata```? By the author's understanding, a simple layman's description here is:
> The "calldata" is the encoding of a function call or parameter in Ethereum, and the "calldata" is encoded according to the ABI (Application Binary Interface) specification of the contract.
For example, we can encode the ```balanceOf``` and ```transfer``` method calls of the ERC20 contract we studied in the previous course, together with the parameters of the calls, into a ```calldata```. In some application scenarios, such as **interaction between contracts**, this scenario will use ```calldata```, and of course there are many other application scenarios that are not listed here.
How to code a smart contract function call to get ```calldata```?
In the FMZ Quant Trading Platform, you can use ```exchange.IO("encode", ...)``` to encode smart contract function calls, the use of exchange.IO("encode", ...) is very simple. The first parameter of the function is the fixed string ```"encode"```; the second parameter is the address of the smart contract; the third parameter is the name of the smart contract method to be encoded; the rest of the parameters are passed to the specific parameter value of the smart contract method to be encoded.
### eth_sendRawTransaction
When we encode a smart contract method call and generate the corresponding ```calldata``` data, if this smart contract method is a Write method (i.e.: write operation), we need to use the generated ```calldata``` data as the data field of the transaction and then use the Ethereum RPC method ```eth_ sendRawTransaction``` to send a request containing the raw data of that transaction to the Ethereum network.
The ```eth_sendRawTransaction``` method has only one parameter, ```data```:
> data: The signed transaction (typically signed with a library, using your private key)
The ```data``` parameter is a transaction data after the signature calculation, and the transaction data structure of Ethereum has the following main fields:
```javascript
{
"nonce": "0x1", // Number of transactions on the account of the sender of the transaction
"gasPrice": "0x12a05f200", // Traded Gas price
"gasLimit": "0x5208", // Gas limit for trading
"to": "0xAb8483F64d9C6d1EcF9b849Ae677dD3315835cb2", // Target contract address or recipient address
"value": "0x4563918244F40000", // Number of Ethereum transferred
"data": "0x0123456789ABCDEF", // Data to send to the contract
}
How to sign an Ethereum transaction?
In the FMZ Quant Trading Platform, we use the Encode() function to perform the signature calculation, the specific example we write in the subsequent course “Execute Write method calldata”.
For the execution of the calldata of the Read method, we use the previously learned RPC method: eth_call to execute it. We explained the eth_call RPC method of the Ethereum only did a demonstration of the Write method of the smart contract, in this section, we use the calldata method to demonstrate the execution of the smart contract Read method call. Let’s use the balanceOf method of the WETH contract to read the current balance of WETH tokens in the wallet.
We use the debugging tool to test on the Ethereum mainnet at:
function toAmount(s, decimals) {
return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
}
function main() {
// ABI for WETH contracts
var abiWETH = `[{"constant":true,"inputs":[],"name":"name","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"guy","type":"address"},{"name":"wad","type":"uint256"}],"name":"approve","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"totalSupply","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"src","type":"address"},{"name":"dst","type":"address"},{"name":"wad","type":"uint256"}],"name":"transferFrom","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"wad","type":"uint256"}],"name":"withdraw","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"decimals","outputs":[{"name":"","type":"uint8"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"name":"","type":"address"}],"name":"balanceOf","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"symbol","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"dst","type":"address"},{"name":"wad","type":"uint256"}],"name":"transfer","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[],"name":"deposit","outputs":[],"payable":true,"stateMutability":"payable","type":"function"},{"constant":true,"inputs":[{"name":"","type":"address"},{"name":"","type":"address"}],"name":"allowance","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"payable":true,"stateMutability":"payable","type":"fallback"},{"anonymous":false,"inputs":[{"indexed":true,"name":"src","type":"address"},{"indexed":true,"name":"guy","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Approval","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"src","type":"address"},{"indexed":true,"name":"dst","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Transfer","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"dst","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Deposit","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"src","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Withdrawal","type":"event"}]`
// WETH contract address
var wethAddress = "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2"
// Register ABI for WETH contracts
exchange.IO("abi", wethAddress, abiWETH)
// The wallet address of the currently configured exchange object
var walletAddress = exchange.IO("address")
// Coded WETH contract's deposit method call
var calldataForDeposit = exchange.IO("encode", wethAddress, "balanceOf(address)", walletAddress)
Log("calldataForDeposit:", "0x" + calldataForDeposit)
// Construct the transaction as the first parameter of eth_call
var transaction = {
"from" : walletAddress,
"to" : wethAddress,
"data" : "0x" + calldataForDeposit,
}
// The second parameter of eth_call
var blockNumber = "latest"
// Call with eth_call
var ret = exchange.IO("api", "eth", "eth_call", transaction, blockNumber)
var wethBalance = exchange.IO("decode", "uint256", ret) // You can use exchange.IO("decode", ...) function to decode
Log("wethBalance:", toAmount(wethBalance, 18)) // Converted from wei to WETH units
}
Run in the debugging tool:
2023-06-15 11:51:31 Info wethBalance: 0.015
2023-06-15 11:51:31 Info calldataForDeposit: 0x70a082310000000000000000000000006b3f11d807809b0b1e5e3243df04a280d9f94bf4
If the method of a smart contract has a return value, you can use the exchange.IO("decode", ...) function to decode it. You can see that the passing calldata method is the same as calling the smart contract’s balanceOf method directly, getting the WETH balance of 0.015 WETH for my test wallet.
For the execution of the Write method calldata, it is necessary to use the RPC method: eth_sendRawTransaction.
Let’s use the debugging tool and test it on the Ethereum mainnet at:
function toAmount(s, decimals) {
return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
}
function toInnerAmount(s, decimals) {
return (BigDecimal(s)*BigDecimal(Math.pow(10, decimals))).toFixed(0)
}
function main() {
// ABI for WETH contracts
var abiWETH = `[{"constant":true,"inputs":[],"name":"name","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"guy","type":"address"},{"name":"wad","type":"uint256"}],"name":"approve","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"totalSupply","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"src","type":"address"},{"name":"dst","type":"address"},{"name":"wad","type":"uint256"}],"name":"transferFrom","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"wad","type":"uint256"}],"name":"withdraw","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"decimals","outputs":[{"name":"","type":"uint8"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"name":"","type":"address"}],"name":"balanceOf","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"symbol","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"dst","type":"address"},{"name":"wad","type":"uint256"}],"name":"transfer","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[],"name":"deposit","outputs":[],"payable":true,"stateMutability":"payable","type":"function"},{"constant":true,"inputs":[{"name":"","type":"address"},{"name":"","type":"address"}],"name":"allowance","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"payable":true,"stateMutability":"payable","type":"fallback"},{"anonymous":false,"inputs":[{"indexed":true,"name":"src","type":"address"},{"indexed":true,"name":"guy","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Approval","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"src","type":"address"},{"indexed":true,"name":"dst","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Transfer","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"dst","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Deposit","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"src","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Withdrawal","type":"event"}]`
// WETH contract address
var wethAddress = "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2"
// Register ABI for WETH contract
exchange.IO("abi", wethAddress, abiWETH)
// The wallet address of the currently configured exchange object
var walletAddress = exchange.IO("address")
// Coded WETH contract's deposit method call
var calldataForDeposit = exchange.IO("encode", wethAddress, "deposit")
Log("calldataForDeposit:", "0x" + calldataForDeposit)
// Get nonce
var nonce = exchange.IO("api", "eth", "eth_getTransactionCount", walletAddress, "pending")
// Get gasPrice
var gasPrice = exchange.IO("api", "eth", "eth_gasPrice")
// Call the deposit method to change ETH to WETH, you need to transfer ETH, here we convert 0.01ETH to a hexadecimal value in wei
var innerAmount = BigInt(Number(toInnerAmount(0.005, 18))).toString(16)
// The transaction call object:
var obj = {
"from" : walletAddress,
"to" : wethAddress,
"gasPrice" : gasPrice,
"value" : "0x" + innerAmount,
"data" : "0x" + calldataForDeposit,
}
// Calculate gasLimit
var gasLimit = exchange.IO("api", "eth", "eth_estimateGas", obj)
// Construct a transaction
var transaction = {
"to": wethAddress,
"value": toAmount("0x" + innerAmount, 0), // Convert to decimal
"data": "0x" + calldataForDeposit,
"gasLimit": toAmount(gasLimit, 0), // Convert to decimal
"gasPrice": toAmount(gasPrice, 0), // Convert to decimal
"nonce": toAmount(nonce, 0), // Convert to decimal
"chainId": 1, // Ethereum mainnet Id
}
Log("transaction:", transaction)
// Signature, your key is replaced with your private key
var signedTx = Encode("signTx", "string", "hex", JSON.stringify(transaction), "hex", "0x" + "your key")
Log("signedTx:", "0x" + signedTx)
// Call eth_sendRawTransaction to send a transaction
var ret = exchange.IO("api", "eth", "eth_sendRawTransaction", "0x" + signedTx)
return ret
}
Run in the debugging tool:
2023-06-15 09:58:50 Info signedTx: 0xf86f4f8504202067888...
2023-06-15 09:58:50 Info transaction: {"to":"0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2","value":5000000000000000,"data":"0xd0e30db0","gasLimit":27938,"gasPrice":17718863752,"nonce":79,"chainId":1}
2023-06-15 09:58:50 Info calldataForDeposit: 0xd0e30db0
Execute var ret = exchange.IO("api", "eth", "eth_sendRawTransaction", "0x" + signedTx) function and the returned Transaction Hash is: 0x2ff585504b0fe59b0122f696e8808abfe2f3ce263448066533f3bb8a4f55e8e6. The eth_sendRawTransaction call executes the calldata in it, calling the deposit method of the WETH contract to swap the 0.005 ETH sent for WETH.
Before a user’s transaction is packaged into the Ethereum blockchain by miners, all transactions will be pooled in Mempool (transaction memory pool), where “miners” also look for transactions with high fees to be packaged first, in order to maximize mining benefits. Therefore, usually the higher the transaction’s gasPrice setting, the more likely it is to be packaged.
Some transaction scripts will also sniff Mempool in the hope of finding some profitable transactions. For example, if a transaction is set with a high exchange slippage, the transaction could be subject to a "sandwich attack’’ by these transactionscripts. So how do these scripts listen for pending (pending, to-be-packaged) transactions in Mempool?
Use the RPC method we learned before: eth_getBlockByNumber, but we do not pass the specific blockNumber this time, we use the "pending" tag.
function main() {
var data = exchange.IO("api", "eth", "eth_getBlockByNumber", "pending", true)
if (Array.isArray(data.transactions)) {
for (var i = 0; i < data.transactions.length; i++) {
Log(data.transactions[i])
}
}
}
Run in the debugging tool:
2023-06-18 19:23:05 Info {"blockNumber":"0x10b2027","type":"0x2","accessList":[],"blockHash":"0xf833ed36435c53d63bd7109bb1e85383075534410c14573881bf26d912f46a89","from":"0xd50521974d62f1fa34b8e81cb742ccf6147d05ff","gasPrice":"0x32ea2db37","hash":"0xf8f10f8f473c340b021298feb48d0affe529e8737a309c4cc1902e8989ef0914","input":"0xa22cb4650000000000000000000000001e0049783f008a0085193e00003d00cd54003c710000000000000000000000000000000000000000000000000000000000000001","v":"0x0","value":"0x0","maxFeePerGas":"0x48a413364","maxPriorityFeePerGas":"0x5f5e100","nonce":"0x8","r":"0x8c1cc36f43b02c9e9e454153588cc9d38757f1da69ec49d3cfdda74ab69e06a8","s":"0x2f3dd3e5ddf9e5d42c128a8e900026aca7568fa83c68cf332e1328066ee8d03a","transactionIndex":"0x3a","chainId":"0x1","gas":"0x1142d","to":"0x8c3c0274c33f263f0a55d129cfc8eaa3667a9e8b"}
2023-06-18 19:23:05 Info {"input":"0x646174613a2c7b2270223a226572632d3230222c226f70223a226d696e74222c227469636b223a2265746873222c226964223a223139323732222c22616d74223a2231303030227d","nonce":"0x1d","blockHash":"0xf833ed36435c53d63bd7109bb1e85383075534410c14573881bf26d912f46a89","from":"0xe7fa86855af674837cea1b58f88b5352543ca27b","gas":"0x81cc","gasPrice":"0x32ea2db37","to":"0xe7fa86855af674837cea1b58f88b5352543ca27b","chainId":"0x1","transactionIndex":"0x39","type":"0x2","value":"0x0","accessList":[],"blockNumber":"0x10b2027","hash":"0x55702f5d14736fc9d0c58fdac2d2052a602db171c46b5e1fa9ff6af5c277f9a2","maxFeePerGas":"0x48a413364","maxPriorityFeePerGas":"0x5f5e100","r":"0x5a703d389d23b51adf8ef0f55db8876e7392636797b68a4be6afe73e76d7e1f2","s":"0x4b4bb11257c4434a0acc2672357f8793476e4bfdf98bc30d2389ce335e7de64e","v":"0x1"}
2023-06-18 19:23:05 Info {"gas":"0x186a0","nonce":"0x46533","r":"0xfeea052a4ac2283ca058a657a806ba0916d8e7d52d2a577f150c40eb1dfbec65","s":"0x5bf0089a3c060ba787b67a205b44e1065a0d11d132b41737ab9adf0f55066811","transactionIndex":"0x38","value":"0x78f0975742c400","blockHash":"0xf833ed36435c53d63bd7109bb1e85383075534410c14573881bf26d912f46a89","chainId":"0x1","hash":"0x56bdf1b38e23db66e8d1c4014d1e9f690a9217d8a0232489210325fc69e25cf9","v":"0x25","input":"0x","type":"0x0","blockNumber":"0x10b2027","gasPrice":"0x4a817c800","from":"0x97b9d2102a9a65a26e1ee82d59e42d1b73b68689","to":"0xcb513e99c020e9d15a6eafef873fef5d9f078221"}
...
Extract one piece of the data:
{
"blockNumber": "0x10b2027",
"type": "0x2",
"accessList": [],
"blockHash": "0xf833ed36435c53d63bd7109bb1e85383075534410c14573881bf26d912f46a89",
"from": "0xd50521974d62f1fa34b8e81cb742ccf6147d05ff",
"gasPrice": "0x32ea2db37",
"hash": "0xf8f10f8f473c340b021298feb48d0affe529e8737a309c4cc1902e8989ef0914",
"input": "0xa22cb4650000000000000000000000001e0049783f008a0085193e00003d00cd54003c710000000000000000000000000000000000000000000000000000000000000001",
"v": "0x0",
"value": "0x0",
"maxFeePerGas": "0x48a413364",
"maxPriorityFeePerGas": "0x5f5e100",
"nonce": "0x8",
"r": "0x8c1cc36f43b02c9e9e454153588cc9d38757f1da69ec49d3cfdda74ab69e06a8",
"s": "0x2f3dd3e5ddf9e5d42c128a8e900026aca7568fa83c68cf332e1328066ee8d03a",
"transactionIndex": "0x3a",
"chainId": "0x1",
"gas": "0x1142d",
"to": "0x8c3c0274c33f263f0a55d129cfc8eaa3667a9e8b"
}
In the FMZ Quant Trading Platform, we use the Dial function to create WebSocket connections, you can check the FMZ API documentation to learn the Dial function.
The test code in this section runs in the Ethereum mainnet environment, and it is easier to use the FMZ Quant to test in live trading due to the use of WebSocket protocol communication. The Websocket protocol subscription messages are:
{"jsonrpc": "2.0", "id": 1, "method": "eth_subscribe", "params": ["newPendingTransactions"]}
In addition to newPendingTransactions, you can also subscribe to newHeads, logs.
Receiving data pushed by WebSocket connections:
{
"jsonrpc": "2.0",
"method": "eth_subscription",
"params": {
"subscription": "0x2c5c087b4aa188e008f4747828ef4e61",
"result": "0x69c4251cecb814e17cfe7a5ee41742a616f9a4d1bbf245c49b186b1006fd14d3"
}
}
Then further query transaction according to which: "result": "0x69c4251cecb814e17cfe7a5ee41742a616f9a4d1bbf245c49b186b1006fd14d3". For a specific transaction, we use the Ethereum RPC method eth_getTransactionByHash to query.
var ws = null
function main () {
// {"jsonrpc": "2.0", "id": 1, "method": "eth_subscribe", "params": ["xxxxx"]} , "xxxxx" is the specific message to subscribe to
var payload = {"jsonrpc": "2.0", "id": 1, "method": "eth_subscribe", "params": ["newPendingTransactions"]}
// wss://mainnet.infura.io/ws/v3/xxxxx , "xxxxx" is your infura key
var infuraKey = "your key"
ws = Dial("wss://mainnet.infura.io/ws/v3/" + infuraKey + "|reconnect=true&payload=" + JSON.stringify(payload))
if (!ws) {
throw "websocket link infura failed!"
}
// eth_getTransactionByHash call count
var getTransactionCounter = 0
var beginTS = new Date().getTime()
// Loop to get messages
while (true) {
// Receive push messages
var data = ws.read()
if (data) {
var ts = new Date().getTime()
if (ts - beginTS >= 1000) {
getTransactionCounter = 0
beginTS = ts
}
// Check transaction details based on txHash
if (ts - beginTS < 1000 && getTransactionCounter >= 100) {
Sleep(1000)
getTransactionCounter = 0
beginTS = ts
}
var obj = JSON.parse(data)
if (obj["params"] && obj["params"]["result"]) {
var transcationInfo = exchange.IO("api", "eth", "eth_getTransactionByHash", obj["params"]["result"])
Log(obj["params"]["result"], "transcationInfo:", transcationInfo)
}
getTransactionCounter++
}
LogStatus(_D())
}
}
function onexit() {
Log("Disconnect WS connection")
ws.close()
}
Create a live trading to run the above code, you can receive the data pushed by the WebSocket connection, the data is pushed constantly, we extract one of them - transaction:
{
"maxPriorityFeePerGas": "0x5f5e100",
"nonce": "0x1a9",
"accessList": [],
"blockNumber": "0x10b1c9f",
"from": "0x5888700be02f52c8adf85890886ef84a6b8a7829",
"blockHash": "0x92c3d77ea218cdc0967ab74b6005bb393b92355047f206c7e2d59d41828e7fa9",
"chainId": "0x1",
"gasPrice": "0x34fdbf43d",
"s": "0x7d86ae29a786a61b9e74a7a9e2cc4b39b7913aa3d4c3816ccb07528fed82048a",
"to": "0xfc2068c3d47b575a60f6a4a7bf60dea0ac368e01",
"type": "0x2",
"v": "0x1",
"value": "0x0",
"gas": "0x1aad3",
"hash": "0x2c77c0704aefbb26db460cbb71efdb488df968ad53d2c2b3f1e1172056b40b22",
"input": "0x42842e0e0000000000000000000000005888700be02f52c8adf85890886ef84a6b8a7829000000000000000000000000d2d07e4d1bb0f40ac3e4aa7cc3ad05d348bfd2c3000000000000000000000000000000000000000000000000000000000000180b",
"maxFeePerGas": "0x4712d1273",
"r": "0x8ec58f95f6d9729a6eee075e6976658b6c5346cbc90eb68ac361a40af073b10e",
"transactionIndex": "0xc1"
}
Excerpted (partial omission) log data:
2023-06-18 16:20:07 Info Disconnect WS connection
2023-06-18 16:20:07 Info 0xba07ca903f9eafbfa7d494bb26197713034b9ca2dd3c19bc0898af3f35b59343 transcationInfo: {"accessList":[],"from":"0xe2977d60182da068dfd78693f96362ee7a2e9644","nonce":"0xf","value":"0x0","blockHash":"0x92c3d77ea218cdc0967ab74b6005bb393b92355047f206c7e2d59d41828e7fa9","blockNumber":"0x10b1c9f","chainId":"0x1","hash":"0xba07ca903f9eafbfa7d494bb26197713034b9ca2dd3c19bc0898af3f35b59343","maxFeePerGas":"0x530c30b70","r":"0xf28bfdf372a5401a2e00675c6ebe8d5e73f2c955db44b1aa56240b9197d6cbc7","type":"0x2","v":"0x0","gas":"0x21079","gasPrice":"0x367b3783d","input":"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","maxPriorityFeePerGas":"0x1dcd6500","s":"0x71d51246bb60e792f963a3c75c46fd8f557921ce6face7224c944e1768a76ca","to":"0x0b51eb9d0e54c562fedc07ceba453f05b70c4b79","transactionIndex":"0x40"}
2023-06-18 16:20:07 Info 0x2c77c0704aefbb26db460cbb71efdb488df968ad53d2c2b3f1e1172056b40b22 transcationInfo: {"maxPriorityFeePerGas":"0x5f5e100","nonce":"0x1a9","accessList":[],"blockNumber":"0x10b1c9f","from":"0x5888700be02f52c8adf85890886ef84a6b8a7829","blockHash":"0x92c3d77ea218cdc0967ab74b6005bb393b92355047f206c7e2d59d41828e7fa9","chainId":"0x1","gasPrice":"0x34fdbf43d","s":"0x7d86ae29a786a61b9e74a7a9e2cc4b39b7913aa3d4c3816ccb07528fed82048a","to":"0xfc2068c3d47b575a60f6a4a7bf60dea0ac368e01","type":"0x2","v":"0x1","value":"0x0","gas":"0x1aad3","hash":"0x2c77c0704aefbb26db460cbb71efdb488df968ad53d2c2b3f1e1172056b40b22","input":"0x42842e0e0000000000000000000000005888700be02f52c8adf85890886ef84a6b8a7829000000000000000000000000d2d07e4d1bb0f40ac3e4aa7cc3ad05d348bfd2c3000000000000000000000000000000000000000000000000000000000000180b","maxFeePerGas":"0x4712d1273","r":"0x8ec58f95f6d9729a6eee075e6976658b6c5346cbc90eb68ac361a40af073b10e","transactionIndex":"0xc1"}
2023-06-18 16:20:07 Info 0xbc42d5db10e5cb2e888c76005c522cb2474a0c0a7325feb867b618f69ff26f2a transcationInfo: {"accessList":[],"blockNumber":"0x10b1c9f","gas":"0x1cc12b","hash":"0xbc42d5db10e5cb2e888c76005c522cb2474a0c0a7325feb867b618f69ff26f2a","maxFeePerGas":"0x6ab262e5c","value":"0x0","v":"0x1","chainId":"0x1","from":"0xc1b634853cb333d3ad8663715b08f41a3aec47cc","input":"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
2023-06-18 16:20:06 Info 0xff0945c3d682a37e18ee433d56c8bedbb93d9ac368af968ed8d53b655575e8e5 transcationInfo: {"gas":"0x5208","s":"0x63572e1fa060841b939cea0849154e55781fe0efcbdfe5ce6979b44ce0980e4a","transactionIndex":"0xa7","value":"0x113e9d515e400","blockHash":"0x92c3d77ea218cdc0967ab74b6005bb393b92355047f206c7e2d59d41828e7fa9","hash":"0xff0945c3d682a37e18ee433d56c8bedbb93d9ac368af968ed8d53b655575e8e5","nonce":"0x2","r":"0x698fe26331ad39ba89c4d30985b707792ea4ab09b25205727f8fac2a6120b54a","gasPrice":"0x35458af00","from":"0x228d93af92d03184c07aa9e39b3d2d61b666686d","input":"0x","to":"0x0246177b98a5e42835cdcfaac1c274d3e6c39486","v":"0x26","blockNumber":"0x10b1c9f","type":"0x0","chainId":"0x1"}
...
In the previous course, we wrote a monitoring program to monitor pending transactions on Ethereum, get the pushed transaction hash via WebSocket protocol, and then query the specific transaction details based on the transaction hash.
Next we want to do further parsing of the input field data in the transaction details data. The input field data looks like a jumble of hexadecimal data, but it actually encodes the content of the transaction: including the functions called, and the parameters entered, etc.
After repeated and extensive testing, we found that the timeliness and quantity of data pushed over by the WebSocket connection has a lot to do with the RPC node currently in use, and the pushed data received by two different RPC node services (e.g., infura, ALCHEMY) when creating a WebSocket connection at the same time is not exactly the same, and since the current scenario generates a large number of requests, we still need to use a more stable and faster RPC service. The WebSocket connection also pushes a lot of transaction hashes that have been Pending for a long time, and when using eth_getTransactionByHash to query, you often get a null value (tested on FMZ, node.js).
We use the alchemy RPC node this time: wss://eth-mainnet.g.alchemy.com/v2/oKmOQKbneVkxgHZfibs-iFhIlIAl6HDN. The node supports both WebSocket and REST protocols.
We monitor the multicall(uint256,bytes[]) method of the router smart contract of the Uniswap decentralized exchange, so we need to calculate the function signature hash of the method first.
// Take the first 8 characters of the complete hash
// multicall: 0x5ae401dc
var sigHash = "0x" + Encode("keccak256", "string", "hex", "multicall(uint256,bytes[])").slice(0, 8)
Based on the example in the previous lesson, we have made some modifications. When receiving messages pushed by the WebSocket connection, the latest data is received using var data = ws.read(-2) method, and the read() function parameter is set to -2 to indicate that the latest data is returned immediately. We only care about the Transaction that contains the multicall call, using if (tx && tx.input.indexOf(sigHash) ! == -1) to determine the filter.
2 custom functions need to be designed:
calcAllFuncSigHash(): Calculate signature hash for all methods based on ABI.decodeCall(): Decoding function.Next, when the multicall call is detected, the decoding operation can start, and the parameters of the multicall method are decoded for the first time: deadline and data. deadline is a timestamp that is better understood, and data is another encoded calldata, so you still need to continue to use the decodeCall() function to decode it.
Example of a complete implementation:
var ws = null
var arrLog = []
const ABI_Route = '[{"inputs":[{"internalType":"address","name":"_factoryV2","type":"address"},{"internalType":"address","name":"factoryV3","type":"address"},{"internalType":"address","name":"_positionManager","type":"address"},{"internalType":"address","name":"_WETH9","type":"address"}],"stateMutability":"nonpayable","type":"constructor"},{"inputs":[],"name":"WETH9","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveMax","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveMaxMinusOne","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveZeroThenMax","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveZeroThenMaxMinusOne","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes","name":"data","type":"bytes"}],"name":"callPositionManager","outputs":[{"internalType":"bytes","name":"result","type":"bytes"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes[]","name":"paths","type":"bytes[]"},{"internalType":"uint128[]","name":"amounts","type":"uint128[]"},{"internalType":"uint24","name":"maximumTickDivergence","type":"uint24"},{"internalType":"uint32","name":"secondsAgo","type":"uint32"}],"name":"checkOracleSlippage","outputs":[],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"uint24","name":"maximumTickDivergence","type":"uint24"},{"internalType":"uint32","name":"secondsAgo","type":"uint32"}],"name":"checkOracleSlippage","outputs":[],"stateMutability":"view","type":"function"},{"inputs":[{"components":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMinimum","type":"uint256"}],"internalType":"struct IV3SwapRouter.ExactInputParams","name":"params","type":"tuple"}],"name":"exactInput","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"tokenIn","type":"address"},{"internalType":"address","name":"tokenOut","type":"address"},{"internalType":"uint24","name":"fee","type":"uint24"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMinimum","type":"uint256"},{"internalType":"uint160","name":"sqrtPriceLimitX96","type":"uint160"}],"internalType":"struct IV3SwapRouter.ExactInputSingleParams","name":"params","type":"tuple"}],"name":"exactInputSingle","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMaximum","type":"uint256"}],"internalType":"struct IV3SwapRouter.ExactOutputParams","name":"params","type":"tuple"}],"name":"exactOutput","outputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"tokenIn","type":"address"},{"internalType":"address","name":"tokenOut","type":"address"},{"internalType":"uint24","name":"fee","type":"uint24"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMaximum","type":"uint256"},{"internalType":"uint160","name":"sqrtPriceLimitX96","type":"uint160"}],"internalType":"struct IV3SwapRouter.ExactOutputSingleParams","name":"params","type":"tuple"}],"name":"exactOutputSingle","outputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[],"name":"factory","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"factoryV2","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"}],"name":"getApprovalType","outputs":[{"internalType":"enum IApproveAndCall.ApprovalType","name":"","type":"uint8"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"token0","type":"address"},{"internalType":"address","name":"token1","type":"address"},{"internalType":"uint256","name":"tokenId","type":"uint256"},{"internalType":"uint256","name":"amount0Min","type":"uint256"},{"internalType":"uint256","name":"amount1Min","type":"uint256"}],"internalType":"struct IApproveAndCall.IncreaseLiquidityParams","name":"params","type":"tuple"}],"name":"increaseLiquidity","outputs":[{"internalType":"bytes","name":"result","type":"bytes"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"token0","type":"address"},{"internalType":"address","name":"token1","type":"address"},{"internalType":"uint24","name":"fee","type":"uint24"},{"internalType":"int24","name":"tickLower","type":"int24"},{"internalType":"int24","name":"tickUpper","type":"int24"},{"internalType":"uint256","name":"amount0Min","type":"uint256"},{"internalType":"uint256","name":"amount1Min","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"}],"internalType":"struct IApproveAndCall.MintParams","name":"params","type":"tuple"}],"name":"mint","outputs":[{"internalType":"bytes","name":"result","type":"bytes"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes32","name":"previousBlockhash","type":"bytes32"},{"internalType":"bytes[]","name":"data","type":"bytes[]"}],"name":"multicall","outputs":[{"internalType":"bytes[]","name":"","type":"bytes[]"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"deadline","type":"uint256"},{"internalType":"bytes[]","name":"data","type":"bytes[]"}],"name":"multicall","outputs":[{"internalType":"bytes[]","name":"","type":"bytes[]"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes[]","name":"data","type":"bytes[]"}],"name":"multicall","outputs":[{"internalType":"bytes[]","name":"results","type":"bytes[]"}],"stateMutability":"payable","type":"function"},{"inputs":[],"name":"positionManager","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"value","type":"uint256"}],"name":"pull","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[],"name":"refundETH","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"value","type":"uint256"},{"internalType":"uint256","name":"deadline","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermit","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"nonce","type":"uint256"},{"internalType":"uint256","name":"expiry","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermitAllowed","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"nonce","type":"uint256"},{"internalType":"uint256","name":"expiry","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermitAllowedIfNecessary","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"value","type":"uint256"},{"internalType":"uint256","name":"deadline","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermitIfNecessary","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMin","type":"uint256"},{"internalType":"address[]","name":"path","type":"address[]"},{"internalType":"address","name":"to","type":"address"}],"name":"swapExactTokensForTokens","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMax","type":"uint256"},{"internalType":"address[]","name":"path","type":"address[]"},{"internalType":"address","name":"to","type":"address"}],"name":"swapTokensForExactTokens","outputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"}],"name":"sweepToken","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"}],"name":"sweepToken","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"sweepTokenWithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"sweepTokenWithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"int256","name":"amount0Delta","type":"int256"},{"internalType":"int256","name":"amount1Delta","type":"int256"},{"internalType":"bytes","name":"_data","type":"bytes"}],"name":"uniswapV3SwapCallback","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"}],"name":"unwrapWETH9","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"}],"name":"unwrapWETH9","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"unwrapWETH9WithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"unwrapWETH9WithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"value","type":"uint256"}],"name":"wrapETH","outputs":[],"stateMutability":"payable","type":"function"},{"stateMutability":"payable","type":"receive"}]'
function calcAllFuncSigHash(jsonABI) {
var mapSigHash = {}
for (var i in jsonABI) {
var ele = jsonABI[i]
if (typeof(ele["name"]) != "undefined") {
if (ele["inputs"]) {
var funcName = ele["name"]
if (ele["inputs"].length == 0) {
var methodId = "0x" + Encode("keccak256", "string", "hex", funcName + "()").slice(0, 8)
mapSigHash[methodId] = {"argsTypeList": [], "argsNameList": [], "funcName": funcName}
} else {
var arr = []
var arrName = []
var argPrototype = []
for (var j in ele["inputs"]) {
var inputType = ele["inputs"][j]["type"]
if (inputType == "tuple") {
var components = ele["inputs"][j]["components"]
var tupleType = []
var protoType = []
for (var componentsIdx = 0; componentsIdx < components.length; componentsIdx++) {
tupleType.push(components[componentsIdx]["type"])
protoType.push(components[componentsIdx]["name"] + " " + components[componentsIdx]["type"])
}
arr.push("(" + tupleType.join() + ")")
arrName.push(ele["inputs"][j]["name"])
// Prototype
argPrototype.push("tuple" + "(" + protoType.join() + ")")
} else {
arr.push(inputType)
arrName.push(ele["inputs"][j]["name"])
// Prototype
argPrototype.push(inputType)
}
}
var functionSignature = funcName + "(" + arr.join() + ")"
var methodId = "0x" + Encode("keccak256", "string", "hex", functionSignature).slice(0, 8)
mapSigHash[methodId] = {"argsTypeList": arr, "argsNameList": arrName, "funcName": funcName, "argPrototype": argPrototype}
}
}
}
}
return mapSigHash
}
function decodeCall(input, abi) {
var mapSigHash = calcAllFuncSigHash(JSON.parse(abi))
var methodId = input.slice(0, 10)
var data = input.slice(10)
var decodedArgs = {}
var infoMethod = mapSigHash[methodId]
if (typeof(infoMethod) == "undefined") {
return [methodId, mapSigHash]
}
var arr = []
for (var i = 0; i < infoMethod["argsTypeList"].length; i++) {
if (infoMethod["argsTypeList"][i].startsWith("(")) {
arr.push(infoMethod["argPrototype"][i])
} else {
arr.push(infoMethod["argsTypeList"][i])
}
}
if (arr.length == 0) {
return {"funcName": infoMethod["funcName"], "args": decodedArgs}
}
var args = exchange.IO("decode", arr.join(), data)
if (!Array.isArray(args)) {
args = [args]
}
if (args.length != infoMethod["argsNameList"].length) {
Log("args:", args)
Log("infoMethod:", infoMethod)
throw "The decoded args are not equal to the argsNameList"
}
for (var i = 0; i < infoMethod["argsNameList"].length; i++) {
var key = infoMethod["argsNameList"][i]
var value = args[i]
decodedArgs[key] = value
}
return {"funcName": infoMethod["funcName"], "args": decodedArgs}
}
function main () {
// {"jsonrpc": "2.0", "id": 1, "method": "eth_subscribe", "params": ["xxxxx"]} , "xxxxx" is the specific message of the subscription
var payload = {"jsonrpc": "2.0", "id": 1, "method": "eth_subscribe", "params": ["newPendingTransactions"]}
// Use the alchemy service
ws = Dial("wss://eth-mainnet.g.alchemy.com/v2/oKmOQKbneVkxgHZfibs-iFhIlIAl6HDN" + "|reconnect=true&payload=" + JSON.stringify(payload))
if (!ws) {
throw "websocket link to alchemy failed!"
}
// eth_getTransactionByHash call count
var getTransactionCounter = 0
// Start Timestamp
var beginTS = new Date().getTime()
// Calculate function signature hash
var sigHash = "0x" + Encode("keccak256", "string", "hex", "multicall(uint256,bytes[])").slice(0, 8)
Log("sigHash:", sigHash)
// Loop for messages
while (true) {
var msg = ""
var recv = null
// Receive pushed messages, use the read parameter -2, and return the latest data immediately
var data = ws.read(-2)
if (data && data != "") {
var ts = new Date().getTime()
if (ts - beginTS >= 1000) {
getTransactionCounter = 0
beginTS = ts
}
// Check transaction details based on txHash
if (ts - beginTS < 1000 && getTransactionCounter >= 100) {
Sleep(1000)
getTransactionCounter = 0
beginTS = ts
}
var obj = JSON.parse(data)
if (obj["params"] && obj["params"]["result"]) {
var txHash = obj["params"]["result"]
var tx = exchange.IO("api", "eth", "eth_getTransactionByHash", txHash)
if (tx && tx.input.indexOf(sigHash) !== -1) {
// Decode transaction details
arrLog = []
var decodedInput = decodeCall(tx.input, ABI_Route)
// Log("----------------", txHash, "/", decodedInput["funcName"], "----------------", "#FF0000")
arrLog.push("----------------" + txHash + "/" + decodedInput["funcName"] + "----------------" + "#FF0000")
arrLog.push(tx.from + " -> " + tx.to)
for (var i = 0; i < decodedInput["args"][