Solana 历史账户 API（测试版）

# State of the account right after the transaction at index 10 in slot 445000000
curl https://mainnet.helius-rpc.com/?api-key=YOUR_API_KEY \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": "1",
    "method": "getHistoricalAccountInfo",
    "params": [
      "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
      { "slot": 445000000, "transactionIndex": 10 },
      { "encoding": "jsonParsed" }
    ]
  }'

"lastUpdatedAt": { "slot": 444999837, "transactionIndex": 700 }

const url = `https://mainnet.helius-rpc.com/?api-key=${process.env.HELIUS_API_KEY}`;
const COVERAGE_START_SLOT = 444959999;

type Position = { slot?: number; transactionIndex?: number };

async function getAccountHistory(address: string, start: Position = {}, maxStates = 100) {
  const states = [];
  let position = start;

  while (states.length < maxStates) {
    const response = await fetch(url, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({
        jsonrpc: "2.0",
        id: "1",
        method: "getHistoricalAccountInfo",
        params: [address, position, { encoding: "base64" }],
      }),
    });
    const { result, error } = await response.json();
    if (error) throw new Error(`${error.code}: ${error.message}`);

    const account = result.value;
    if (!account) break; // The account didn't exist before this write

    states.push(account);
    const { slot, transactionIndex } = account.lastUpdatedAt;
    if (slot <= COVERAGE_START_SLOT) break; // Reached the start of history coverage

    // Step to the position just before this write
    position = transactionIndex ? { slot, transactionIndex: transactionIndex - 1 } : { slot: slot - 1 };
  }

  return states; // Newest first
}