How to mass resolve a domain list to find valid domains

README.md

Input

• domains: A list of domains without protocol or any slashes. Example: ["google.com", "amazon.com"]

code.py

import asyncio

async def attempt_connection_domain(host) -> tuple[bool, bool]: # returns: [successful, https_supported]
    try:
        async with asyncio.timeout(5):
            await asyncio.open_connection(host, 443)
            return True, True
    except (asyncio.TimeoutError, OSError):
        try:
            async with asyncio.timeout(5):
                await asyncio.open_connection(host, 80)
                return True, False
        except (asyncio.TimeoutError, OSError):
            return False, False

async def try_all_domain(domain):
    success = https = False
    success, https = await attempt_connection_domain(domain)
    if not success:
        if domain.startswith('www.'):
            return None
        else:
            return await try_all_domain('www.' + domain)
    front = "http"
    if https:
        front += "s"
    return f"{front}://{domain}"
  
async def run_domains():
    return dict(zip(domains, await asyncio.gather(*map(lambda domain: try_all_domain(domain), domains))))