Created
November 10, 2020 03:42
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Generic URLFinder with asyncio and semaphore. Python 3.8+ only
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Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.3) Gecko/20090913 Firefox/3.5.3, | |
Mozilla/5.0 (Windows; U; Windows NT 6.1; en; rv:1.9.1.3) Gecko/20090824 Firefox/3.5.3 (.NET CLR 3.5.30729), | |
Mozilla/5.0 (Windows; U; Windows NT 5.2; en-US; rv:1.9.1.3) Gecko/20090824 Firefox/3.5.3 (.NET CLR 3.5.30729), | |
Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.1) Gecko/20090718 Firefox/3.5.1, | |
Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US) AppleWebKit/532.1 (KHTML, like Gecko) Chrome/4.0.219.6 Safari/532.1, | |
Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; InfoPath.2), | |
Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.2; Win64; x64; Trident/4.0), | |
Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; SV1; .NET CLR 2.0.50727; InfoPath.2), | |
Mozilla/5.0 (Windows; U; MSIE 7.0; Windows NT 6.0; en-US), | |
Mozilla/4.0 (compatible; MSIE 6.1; Windows XP), | |
Opera/9.80 (Windows NT 5.2; U; ru) Presto/2.5.22 Version/10.51 |
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import asyncio | |
import random | |
from typing import Callable, Generator, Optional | |
import aiohttp | |
from loguru import logger | |
AGENT_FILE = "agents.ini" | |
async def fetch( | |
session: aiohttp.ClientSession, url: str, handler: Callable | |
) -> Optional[str]: | |
try: | |
async with session.get(url, timeout=10) as response: | |
return await handler(url, response) | |
except aiohttp.ClientResponseError as e: | |
logger.warning(e.code) | |
except asyncio.TimeoutError: | |
logger.debug(f"{url} timeout") | |
except Exception as e: | |
logger.warning(e) | |
async def url_finder(urls: Generator, handler: Callable, max_tasks: int = 20): | |
tasks = [] | |
sem = asyncio.Semaphore(max_tasks) | |
async with aiohttp.ClientSession(headers={"User-Agent": random_agent()}) as session: # type: ignore | |
for url in urls: | |
task = asyncio.create_task(fetch(session, url, handler)) | |
task.add_done_callback(lambda _: sem.release()) | |
tasks.append(task) | |
await sem.acquire() | |
responses = await asyncio.gather(*tasks) | |
return [r for r in responses if r is not None] | |
def random_agent() -> str: | |
return random.choice([line.strip() for line in list(open(AGENT_FILE))]) |
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asyncio.run
is like await, and it creates an event loop. Previouslycreate_event_loop().run_till_completion()
.asyncio.create_task
is non-blocking. Comparable toensure_future()
.https://stackoverflow.com/questions/36342899/asyncio-ensure-future-vs-baseeventloop-create-task-vs-simple-coroutine
I keep coming back to this:
https://stackoverflow.com/questions/34753401/difference-between-coroutine-and-future-task-in-python-3-5