Decoding solana transaction data

Question

I am currently trying to figure out how to decode data from a transaction instruction, but whatever i try it doesn't work.

Example data base58:

2K7nL28PxCW8ejnyCeuMpbWSTLdurgKFpsogNMAfkxaivrGSbx5pnrFeWkZY5EUDZL26WSoMa5kTRAuZiW7s3HifSXN9sWnRp1XnD71rTSxG3GNXxguzpgsXeDQfJx7A5TCPx9t7r5B3KcWsvbxXAivnaY6i82epDwEiCiZ7T2oLg3QsrcZqFjun6QF1

What i should be getting as values in an object:

{
  "mint": {
    "type": "publicKey",
    "data": "6Y6uxUWa2AtijqprubRwx2amJnZkXiK2FM7kJ6E6pump"
  },
  "solAmount": {
    "type": "u64",
    "data": "43099058"
  },
  "tokenAmount": {
    "type": "u64",
    "data": "1219512195121"
  },
  "isBuy": {
    "type": "bool",
    "data": true
  },
  "user": {
    "type": "publicKey",
    "data": "Bzen1deTMBZXh7etJheznKZtDF9KWfgacGSwWV6DPPZ2"
  },
  "timestamp": {
    "type": "i64",
    "data": "1718285628"
  },
  "virtualSolReserves": {
    "type": "u64",
    "data": "33750388325"
  },
  "virtualTokenReserves": {
    "type": "u64",
    "data": "953766803940863"
  }
}

Does anyone have an idea how to decode it?

Answer 1

Im using this repo: https://github.com/rckprtr/pumpdotfun-sdk

import bs58 from "bs58";
import idl from "../../src/IDL/pump-fun.json";
import {
  BorshCoder,
} from "@coral-xyz/anchor";
import { base64 } from "@coral-xyz/anchor/dist/cjs/utils/bytes";

const main = async () => {
  let base58Data =
    "2K7nL28PxCW8ejnyCeuMpbWSTLdurgKFpsogNMAfkxaivrGSbx5pnrFeWkZY5EUDZL26WSoMa5kTRAuZiW7s3HifSXN9sWnRp1XnD71rTSxG3GNXxguzpgsXeDQfJx7A5TCPx9t7r5B3KcWsvbxXAivnaY6i82epDwEiCiZ7T2oLg3QsrcZqFjun6QF1";

  let buffer = Buffer.from(bs58.decode(base58Data));
  //remove first 8 bytes for the event cpi
  buffer = buffer.slice(8);
  
  let coder = new BorshCoder(idl as any);
  let args = coder.events.decode(base64.encode(buffer));
  console.log(args);
};

main();

Results:

{
  data: {
    mint: PublicKey [PublicKey(6Y6uxUWa2AtijqprubRwx2amJnZkXiK2FM7kJ6E6pump)] {
      _bn: <BN: 52422028108045a3dfbc44fb5428a6cee7ea2f55bdd87164929a93663d3145ff>
    },
    solAmount: <BN: 291a3b2>,
    tokenAmount: <BN: 11bf0975831>,
    isBuy: true,
    user: PublicKey [PublicKey(Bzen1deTMBZXh7etJheznKZtDF9KWfgacGSwWV6DPPZ2)] {
      _bn: <BN: a359b05b86c4036aafbfaa3bda65369edf96fd8630852ee5d38e7fe79199b429>
    },
    timestamp: <BN: 666af53c>,
    virtualSolReserves: <BN: 7dbae0e65>,
    virtualTokenReserves: <BN: 36372238c25ff>,
    realSolReserves: <BN: df8a6265>,
    realTokenReserves: <BN: 264e0d7798dff>
  },
  name: 'TradeEvent'
}

Answer 2

for python, you can buffer 16 bytes and start with mint = buffer[0:32]

import base58
def decode_transaction_data(base58_data):
    buffer = base58.b58decode(base58_data)

    buffer = buffer[8:]

    mint = buffer[8:40]  
    sol_amount = int.from_bytes(buffer[40:48], "little") 
    token_amount = int.from_bytes(buffer[48:56], "little") 
    is_buy = bool(buffer[56])  
    user = buffer[57:89]  
    timestamp = int.from_bytes(buffer[89:97], "little", signed=True)  
    virtual_sol_reserves = int.from_bytes(buffer[97:105], "little") 
    virtual_token_reserves = int.from_bytes(buffer[105:113], "little") 
    real_sol_reserves = int.from_bytes(buffer[113:121], "little") 
    real_token_reserves = int.from_bytes(buffer[121:129], "little") 

    mint_base58 = base58.b58encode(mint).decode()
    user_base58 = base58.b58encode(user).decode()

    return {
        "mint": mint_base58,
        "sol_amount": sol_amount,
        "token_amount": token_amount,
        "is_buy": is_buy,
        "user": user_base58,
        "timestamp": timestamp,
        "virtual_sol_reserves": virtual_sol_reserves,
        "virtual_token_reserves": virtual_token_reserves,
        "real_sol_reserves": real_sol_reserves,
        "real_token_reserves": real_token_reserves,
    }

base58_data = "2K7nL28PxCW8ejnyCeuMpbWSTLdurgKFpsogNMAfkxaivrGSbx5pnrFeWkZY5EUDZL26WSoMa5kTRAuZiW7s3HifSXN9sWnRp1XnD71rTSxG3GNXxguzpgsXeDQfJx7A5TCPx9t7r5B3KcWsvbxXAivnaY6i82epDwEiCiZ7T2oLg3QsrcZqFjun6QF1"
decoded_data = decode_transaction_data(base58_data)

for key, value in decoded_data.items():
    print(f"{key}: {value}")