Resume download with requests

resume.py

import os
import sys
import time
from urllib.parse import urlparse

import requests


def resume_download(url, filename):
    resp = requests.head(url)
    if "Accept-Ranges" not in resp.headers:
        print("Resumable downloads not supported")
        return

    if os.path.exists(filename):
        local_size = os.path.getsize(filename)
        print(f"Resume previous download ({local_size}B)...")
    else:
        local_size = 0

    resp = requests.get(url, headers={"Range": f"bytes={local_size}-"})
    with open(filename, "ab") as f:
        for chunk in resp.iter_content(chunk_size=1024):
            if not chunk:
                break
            f.write(chunk)
            print(".")
            time.sleep(1)


if __name__ == "__main__":
    url = sys.argv[1]
    parsed = urlparse(url)
    filename = os.path.basename(parsed.path)
    resume_download(url, filename)