Webhooks

const crypto = require("crypto");

function verify(rawBody, headers, secret) {
  const h = Object.fromEntries(
    Object.entries(headers).map(([k, v]) => [k.toLowerCase(), v]),
  );
  const ts = h["x-roomagen-timestamp"];
  const got = h["x-roomagen-signature"];

  // A malformed or missing header is a failed verification, not an exception:
  // timingSafeEqual throws on a length mismatch, so check before calling it.
  if (typeof ts !== "string" || typeof got !== "string") return false;

  const expected =
    "v1=" + crypto.createHmac("sha256", secret).update(`${ts}.${rawBody}`).digest("hex");
  if (got.length !== expected.length) return false;
  if (!crypto.timingSafeEqual(Buffer.from(got), Buffer.from(expected))) return false;

  // Reject replays: the signature stays valid forever, the timestamp does not.
  const age = Math.abs(Date.now() / 1000 - Number(ts));
  return Number.isFinite(age) && age < 300;
}

import hmac, hashlib, time
from typing import Mapping

def verify(raw_body: bytes, headers: Mapping[str, str], secret: str) -> bool:
    h = {k.lower(): v for k, v in headers.items()}
    ts = h.get("x-roomagen-timestamp")
    got = h.get("x-roomagen-signature")
    if ts is None or got is None:
        return False

    signed = f"{ts}.".encode() + raw_body
    expected = "v1=" + hmac.new(secret.encode(), signed, hashlib.sha256).hexdigest()

    # compare_digest is constant-time and safe on unequal lengths.
    if not hmac.compare_digest(expected, got):
        return False

    # Reject replays: the signature stays valid forever, the timestamp does not.
    try:
        return abs(time.time() - int(ts)) < 300
    except ValueError:
        return False