Parse Polygon Smart Contract using Go

go.mod

module poly

go 1.18

require github.com/ethereum/go-ethereum v1.10.21

require (
	github.com/StackExchange/wmi v0.0.0-20180116203802-5d049714c4a6 // indirect
	github.com/btcsuite/btcd/btcec/v2 v2.2.0 // indirect
	github.com/deckarep/golang-set v1.8.0 // indirect
	github.com/decred/dcrd/dcrec/secp256k1/v4 v4.0.1 // indirect
	github.com/go-ole/go-ole v1.2.1 // indirect
	github.com/go-stack/stack v1.8.0 // indirect
	github.com/gorilla/websocket v1.4.2 // indirect
	github.com/shirou/gopsutil v3.21.4-0.20210419000835-c7a38de76ee5+incompatible // indirect
	github.com/tklauser/go-sysconf v0.3.5 // indirect
	github.com/tklauser/numcpus v0.2.2 // indirect
	golang.org/x/crypto v0.0.0-20210921155107-089bfa567519 // indirect
	golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a // indirect
	gopkg.in/natefinch/npipe.v2 v2.0.0-20160621034901-c1b8fa8bdcce // indirect
)

mrc20.abi

[{"constant":true,"inputs":[],"name":"name","outputs":[{"internalType":"string","name":"","type":"string"}],"payable":false,"stateMutability":"pure","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"","type":"address"}],"name":"setParent","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"totalSupply","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes","name":"sig","type":"bytes"},{"internalType":"uint256","name":"amount","type":"uint256"},{"internalType":"bytes32","name":"data","type":"bytes32"},{"internalType":"uint256","name":"expiration","type":"uint256"},{"internalType":"address","name":"to","type":"address"}],"name":"transferWithSig","outputs":[{"internalType":"address","name":"from","type":"address"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"uint256","name":"amount","type":"uint256"}],"name":"withdraw","outputs":[],"payable":true,"stateMutability":"payable","type":"function"},{"constant":true,"inputs":[],"name":"decimals","outputs":[{"internalType":"uint8","name":"","type":"uint8"}],"payable":false,"stateMutability":"pure","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"user","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"}],"name":"deposit","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"_childChain","type":"address"},{"internalType":"address","name":"_token","type":"address"}],"name":"initialize","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"parent","outputs":[{"internalType":"address","name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"parentOwner","outputs":[{"internalType":"address","name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"address","name":"account","type":"address"}],"name":"balanceOf","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[],"name":"renounceOwnership","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"currentSupply","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"hash","type":"bytes32"},{"internalType":"bytes","name":"sig","type":"bytes"}],"name":"ecrecovery","outputs":[{"internalType":"address","name":"result","type":"address"}],"payable":false,"stateMutability":"pure","type":"function"},{"constant":true,"inputs":[],"name":"owner","outputs":[{"internalType":"address","name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"isOwner","outputs":[{"internalType":"bool","name":"","type":"bool"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"networkId","outputs":[{"internalType":"bytes","name":"","type":"bytes"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"symbol","outputs":[{"internalType":"string","name":"","type":"string"}],"payable":false,"stateMutability":"pure","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"value","type":"uint256"}],"name":"transfer","outputs":[{"internalType":"bool","name":"","type":"bool"}],"payable":true,"stateMutability":"payable","type":"function"},{"constant":true,"inputs":[],"name":"EIP712_TOKEN_TRANSFER_ORDER_SCHEMA_HASH","outputs":[{"internalType":"bytes32","name":"","type":"bytes32"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"","type":"bytes32"}],"name":"disabledHashes","outputs":[{"internalType":"bool","name":"","type":"bool"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"address","name":"spender","type":"address"},{"internalType":"uint256","name":"tokenIdOrAmount","type":"uint256"},{"internalType":"bytes32","name":"data","type":"bytes32"},{"internalType":"uint256","name":"expiration","type":"uint256"}],"name":"getTokenTransferOrderHash","outputs":[{"internalType":"bytes32","name":"orderHash","type":"bytes32"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"CHAINID","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"EIP712_DOMAIN_HASH","outputs":[{"internalType":"bytes32","name":"","type":"bytes32"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"EIP712_DOMAIN_SCHEMA_HASH","outputs":[{"internalType":"bytes32","name":"","type":"bytes32"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"newOwner","type":"address"}],"name":"transferOwnership","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"token","outputs":[{"internalType":"address","name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"inputs":[],"payable":false,"stateMutability":"nonpayable","type":"constructor"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"from","type":"address"},{"indexed":true,"internalType":"address","name":"to","type":"address"},{"indexed":false,"internalType":"uint256","name":"value","type":"uint256"}],"name":"Transfer","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"token","type":"address"},{"indexed":true,"internalType":"address","name":"from","type":"address"},{"indexed":false,"internalType":"uint256","name":"amount","type":"uint256"},{"indexed":false,"internalType":"uint256","name":"input1","type":"uint256"},{"indexed":false,"internalType":"uint256","name":"output1","type":"uint256"}],"name":"Deposit","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"token","type":"address"},{"indexed":true,"internalType":"address","name":"from","type":"address"},{"indexed":false,"internalType":"uint256","name":"amount","type":"uint256"},{"indexed":false,"internalType":"uint256","name":"input1","type":"uint256"},{"indexed":false,"internalType":"uint256","name":"output1","type":"uint256"}],"name":"Withdraw","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"token","type":"address"},{"indexed":true,"internalType":"address","name":"from","type":"address"},{"indexed":true,"internalType":"address","name":"to","type":"address"},{"indexed":false,"internalType":"uint256","name":"amount","type":"uint256"},{"indexed":false,"internalType":"uint256","name":"input1","type":"uint256"},{"indexed":false,"internalType":"uint256","name":"input2","type":"uint256"},{"indexed":false,"internalType":"uint256","name":"output1","type":"uint256"},{"indexed":false,"internalType":"uint256","name":"output2","type":"uint256"}],"name":"LogTransfer","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"token","type":"address"},{"indexed":true,"internalType":"address","name":"from","type":"address"},{"indexed":true,"internalType":"address","name":"to","type":"address"},{"indexed":false,"internalType":"uint256","name":"amount","type":"uint256"},{"indexed":false,"internalType":"uint256","name":"input1","type":"uint256"},{"indexed":false,"internalType":"uint256","name":"input2","type":"uint256"},{"indexed":false,"internalType":"uint256","name":"output1","type":"uint256"},{"indexed":false,"internalType":"uint256","name":"output2","type":"uint256"}],"name":"LogFeeTransfer","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"previousOwner","type":"address"},{"indexed":true,"internalType":"address","name":"newOwner","type":"address"}],"name":"OwnershipTransferred","type":"event"}]

output.txt

$ go build . && ./poly --rpc https://virulent-fluent-isle.matic.quiknode.pro/625d8404f145726303e9637515d142dc12c630a8/ --block 31742819
Chain ID: 137 Latest: 31747503
Found method: name
Found method: owner
Found method: transfer
Found method: disabledHashes
Found method: parentOwner
Found method: networkId
Found method: getTokenTransferOrderHash
Found method: withdraw
Found method: initialize
Found method: CHAINID
Found method: parent
Found method: renounceOwnership
Found method: symbol
Found method: token
Found method: transferWithSig
Found method: balanceOf
Found method: ecrecovery
Found method: EIP712_DOMAIN_SCHEMA_HASH
Found method: currentSupply
Found method: isOwner
Found method: EIP712_DOMAIN_HASH
Found method: totalSupply
Found method: EIP712_TOKEN_TRANSFER_ORDER_SCHEMA_HASH
Found method: setParent
Found method: decimals
Found method: deposit
Found method: transferOwnership
All methods found

Found 65 transactions in block: 31742819

Txn Hash: 0x14bfd28ca9c17b60126d9f48f59789b19afc1c117dc6bbb291ff0a961e72db7c Method: withdraw Inputs: map[amount:+50000000000000000000]

Done parsing Block: 31742819. Found 1 txns involving contract.

poly.go

package main

import (
	"bytes"
	"context"
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"math/big"

	"github.com/ethereum/go-ethereum/accounts/abi"
	"github.com/ethereum/go-ethereum/ethclient"
)

var path = flag.String("rpc", "", "Polygon Bor JSON RPC path")
var blockId = flag.Int64("block", 31740481, "Fetch this block from Polygon")

// https://polygonscan.com/address/0x0000000000000000000000000000000000001010
const contractAddr = "0x0000000000000000000000000000000000001010"

func Check(err error) {
	if err != nil {
		log.Fatalf("Got error: %v", err)
	}
}

func main() {
	flag.Parse()

	client, err := ethclient.Dial(*path)
	if err != nil {
		log.Fatal(err)
	}

	chainID, err := client.NetworkID(context.Background())
	if err != nil {
		log.Fatal(err)
	}

	header, err := client.HeaderByNumber(context.Background(), nil)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Printf("Chain ID: %d Latest: %08d\n", chainID.Uint64(), header.Number)

	fdata, err := ioutil.ReadFile("mrc20.abi")
	Check(err)

	contractAbi, err := abi.JSON(bytes.NewReader(fdata))
	Check(err)

	for m := range contractAbi.Methods {
		fmt.Printf("Found method: %s\n", m)
	}
	fmt.Printf("All methods found\n\n")

	bno := new(big.Int).SetInt64(*blockId)
	block, err := client.BlockByNumber(context.Background(), bno)
	Check(err)

	fmt.Printf("Found %d transactions in block: %d\n\n", len(block.Transactions()), *blockId)
	var valid int
	for _, tx := range block.Transactions() {
		// Only pick the txns which are interfacing with the right contract.
		if tx.To() == nil || tx.To().String() != contractAddr {
			continue
		}
		input := tx.Data()
		if len(input) < 4 {
			fmt.Printf("Input data of size: %d\n", len(input))
			continue
		}
		valid++
		m, err := contractAbi.MethodById(input[:4]) // first 4 bytes = method id.
		Check(err)

		in := make(map[string]interface{})
		Check(m.Inputs.UnpackIntoMap(in, input[4:]))

		fmt.Printf("Txn Hash: %s Method: %s Inputs: %+v\n", tx.Hash().String(), m.Name, in)
	}
	fmt.Printf("\nDone parsing Block: %d. Found %d txns involving contract.\n", *blockId, valid)
}