metaplexIndexer.ts

import web3 from "@solana/web3.js";
import bs58 from "bs58";

//////////////////////////////////////////////////

const utf8TextDecoder = new TextDecoder("utf-8");
function decodeVariableUtf8String(buffer: Buffer, start: number, maxLength: number): string {
  const end = start + maxLength;

  let pos = start;
  for (; pos < end && buffer[pos] !== 0; ++pos);

  return utf8TextDecoder.decode(
    new Uint8Array(buffer.buffer, buffer.byteOffset + start, pos - start)
  );
}

const METAPLEX_PROGRAM_ID = new web3.PublicKey("metaqbxxUerdq28cj1RbAWkYQm3ybzjb6a8bt518x1s");

(async (rpcUrl: string) => {
  const conn = new web3.Connection(rpcUrl, "processed");

  const TARGET_UPDATE_AUTHORITY = new web3.PublicKey("TSLvdd1pWpHVjahSpsvCXUbgwsL3JAcvokwaKt1eokM");

  const mints = new Set<bigint>();
  conn.onProgramAccountChange(METAPLEX_PROGRAM_ID, (info: web3.KeyedAccountInfo) => {
    if (!info.accountInfo.data || info.accountInfo.data.byteLength < 128) {
      return;
    }

    const mintId =
      info.accountInfo.data.readBigUint64LE(33)
      | (info.accountInfo.data.readBigUint64LE(33 + 8) << 64n)
      | (info.accountInfo.data.readBigUint64LE(33 + 16) << 128n)
      | (info.accountInfo.data.readBigUint64LE(33 + 24) << 192n);

    if (mints.has(mintId)) {
      return;
    }
    mints.add(mintId);

    const mint = info.accountInfo.data.subarray(33, 33 + 32);
    const name = decodeVariableUtf8String(info.accountInfo.data, 69, 32);
    const symbol = decodeVariableUtf8String(info.accountInfo.data, 105, 10);

    console.log(JSON.stringify({
      mint: bs58.encode(mint),
      name,
      symbol,
    }));
  }, undefined, [
    { memcmp: { offset: 0, bytes: bs58.encode([0x04, ...TARGET_UPDATE_AUTHORITY.toBuffer()]) } },
  ]);
})(process.env.SOL_RPC_URL || "https://mainnet.helius-rpc.com/?api-key=00000000-0000-0000-0000-000000000000");