06_watch.py

# SPDX-License-Identifier: MIT
"""06 - Watch a transaction until it reaches N confirmations.

Polls the explorer's /tx/:txid/status every 30s.
confirmations = current tip height - the tx's block height + 1.

    python 06_watch.py <txid> [confirmations]
"""
import sys
import time
import requests
from config import api

if len(sys.argv) < 2:
    sys.exit("usage: python 06_watch.py <txid> [confirmations]")
txid = sys.argv[1]
want = int(sys.argv[2]) if len(sys.argv) > 2 else 1

while True:
    r = requests.get(api(f"/tx/{txid}/status"), timeout=15)
    if not r.ok:
        # 404 = the network has not seen this txid yet (not broadcast, still
        # propagating, or a typo). Keep waiting.
        print(f"{txid[:16]}... not seen yet (HTTP {r.status_code})")
    else:
        status = r.json()
        if status.get("confirmed"):
            tip = int(requests.get(api("/blocks/tip/height"), timeout=15).text)
            confs = tip - status["block_height"] + 1
            print(f"{txid[:16]}... {confs} confirmation(s)")
            if confs >= want:
                print("done.")
                break
        else:
            print(f"{txid[:16]}... unconfirmed (in the mempool)")
    time.sleep(30)