Asynchronous and synchronous requests in Python 3.6

async.py

import asyncio
import json
import sys
from asyncio import ensure_future
from aiohttp import ClientSession

async def fetch(domain, session):
    url = 'http://localhost:8080/allicons.json'
    params = {'url': domain, 'format': 'png'} 
    async with session.get(url, params=params, timeout=600) as response:
        response = await response.json()
        icons = set(str(icon['height']) for icon in response.get('icons', []))
        if icons:
            print(domain, ' '.join(icons))

async def run(domains):
    async with ClientSession() as session:
        tasks = [ensure_future(fetch(domain, session)) for domain in domains]
        try:
            await asyncio.gather(*tasks)
        except Exception as e:
            #print(e)
            pass

def domains_from_stdin(stdin):
    return [line.split()[0] for line in stdin]

if __name__ == '__main__':
    domains = domains_from_stdin(sys.stdin)
    loop = asyncio.get_event_loop()
    future = asyncio.ensure_future(run(domains))
    loop.run_until_complete(future)

sync.py

import json
import requests
import sys

def get_icons(domain):
    url = 'http://localhost:8080/allicons.json?url={}&formats=png'.format(domain)
    req = requests.get(url)
    try:
        req_json = json.loads(req.text)
    except json.JSONDecodeError:
        return []
    icons = set() 
    for icon in req_json.get('icons', []):
        icons.add(icon['height'])
    return list(icons)

if __name__ == '__main__':
    domain = sys.argv[1].strip().split()[0][1:]
    print(get_icons(domain))