Handling errors

import random
import time

import requests

RETRYABLE = {429, 500, 502, 503}


def call(session: requests.Session, method: str, url: str, *, attempts: int = 5, **kwargs) -> requests.Response:
    """Send a request, retrying 429/5xx and network errors with backoff."""
    for attempt in range(attempts):
        try:
            resp = session.request(method, url, timeout=60, **kwargs)
        except requests.ConnectionError:
            resp = None
        if resp is not None and resp.status_code not in RETRYABLE:
            return resp  # success, or an error that retrying cannot fix
        if attempt == attempts - 1:
            break
        retry_after = resp.headers.get("Retry-After") if resp is not None else None
        delay = float(retry_after) if retry_after else min(60.0, 2 ** attempt) + random.random()
        time.sleep(delay)
    if resp is None:
        raise ConnectionError(f"{method} {url}: no response after {attempts} attempts")
    return resp


# session and API as in the Quickstart
resp = call(session, "GET", f"{API}/trademarks", params={"jurisdiction": "AD", "number": "48000"})
if resp.headers.get("Content-Type", "").startswith("application/problem+json"):
    problem = resp.json()
    raise RuntimeError(f"{problem['type']} ({problem['request_id']}): {problem['detail']}")

const RETRYABLE = new Set([429, 500, 502, 503]);
const sleep = (ms) => new Promise((r) => setTimeout(r, ms));

// Send a request, retrying 429/5xx and network errors with backoff.
async function call(url, init = {}, attempts = 5) {
  let res;
  for (let attempt = 0; attempt < attempts; attempt++) {
    try {
      res = await fetch(url, init);
    } catch {
      res = undefined; // network error
    }
    if (res && !RETRYABLE.has(res.status)) return res;
    if (attempt === attempts - 1) break;
    const retryAfter = res?.headers.get("Retry-After");
    await sleep(retryAfter ? Number(retryAfter) * 1000 : Math.min(60_000, 2 ** attempt * 1000) + Math.random() * 1000);
  }
  if (!res) throw new Error(`${url}: no response after ${attempts} attempts`);
  return res;
}

// API and headers as in the Quickstart
const res = await call(`${API}/trademarks?jurisdiction=AD&number=48000`, { headers });
if (res.headers.get("Content-Type")?.startsWith("application/problem+json")) {
  const problem = await res.json();
  throw new Error(`${problem.type} (${problem.request_id}): ${problem.detail}`);
}