nodejs_iap_signed_request.js

const jwt = require("jsonwebtoken");
const fs = require("fs");
const axios = require("axios");

const privateKey = fs.readFileSync("./AuthKey.p8");

// Production URL : https://api.storekit.itunes.apple.com/inApps/v1/transactions/{transactionId}
// Sandbox URL : https://api.storekit-sandbox.itunes.apple.com/inApps/v1/transactions/{transactionId}
async function getTransaction(token, ID) {
  try {
    const response = await axios.get(
      `https://api.storekit-sandbox.itunes.apple.com/inApps/v1/transactions/${ID}`,
      {
        headers: {
          Authorization: `Bearer ${token}`,
        },
      }
    );
    const signedTransaction = response.data;
    return decode(signedTransaction.signedTransactionInfo);
  } catch (error) {
    console.error(error);
  }
}

function decode(signedTransactionInfo) {
  // Split the JWS transaction into its components
  const [encodedHeader, encodedPayload, signature] =
    signedTransactionInfo.split(".");
  const header = base64UrlDecode(encodedHeader);
  const payload = base64UrlDecode(encodedPayload);
  console.log("Decoded Header: ", header);
  console.log("Decoded Payload: ", payload);
  return { header, payload };
}

// Base64 URL decode the header and payload
function base64UrlDecode(str) {
  const base64 = str.replace(/-/g, "+").replace(/_/g, "/");
  const json = Buffer.from(base64, "base64").toString("utf-8");
  return JSON.parse(json);
}

function generateToken(privateKey, keyID, issuerID, bundleID) {
  const header = {
    alg: "ES256",
    kid: keyID, // Key ID
    typ: "JWT",
  };

  const currentTime = Math.floor(Date.now() / 1000); // Current UNIX time in seconds

  const payload = {
    iss: issuerID, // Issuer ID
    iat: currentTime,
    exp: currentTime + 3600, // Expires in 1 hour
    aud: "appstoreconnect-v1",
    bid: bundleID, // Bundle ID
  };

  const token = jwt.sign(payload, privateKey, {
    algorithm: "ES256",
    header: header,
  });
  console.log(token);
  return token;
}

async function main() {
  const token = generateToken(
    privateKey,
    "keyID",
    "issuerID",
    "BundleID"
  );
  const result = await getTransaction(token, 2000000222075857);
  console.log({ result });
}

main();