asyncio Queue的使用例子

import aiohttp
import asyncio
import async_timeout
from urllib.parse import urljoin, urldefrag


root_url = "http://python.org/"
crawled_urls, url_hub = [], [root_url, "%s/sitemap.xml" % (root_url), "%s/robots.txt" % (root_url)]
headers = {'user-agent': 'Opera/9.80 (X11; Linux x86_64; U; en) Presto/2.2.15 Version/10.10'}


async def get_body(url):
    async with aiohttp.ClientSession() as session:
        try:
            with async_timeout.timeout(10):
                async with session.get(url, headers=headers) as response:
                    if response.status == 200:
                        html = await response.text()
                        return {'error': '', 'html': html}
                    else:
                        return {'error': response.status, 'html': ''}
        except Exception as err:
            return {'error': err, 'html': ''}

async def handle_task(task_id, work_queue):
    while not work_queue.empty():
        queue_url = await work_queue.get()
        if not queue_url in crawled_urls:
            crawled_urls.append(queue_url)
            body = await get_body(queue_url)
            if not body['error']:
                for new_url in get_urls(body['html']):
                    if root_url in new_url and not new_url in crawled_urls:
                        work_queue.put_nowait(new_url)
            else:
                print(f"Error: {body['error']} - {queue_url}")

def remove_fragment(url):
    pure_url, frag = urldefrag(url)
    return pure_url

def get_urls(html):
    new_urls = [url.split('"')[0] for url in str(html).replace("'",'"').split('href="')[1:]]
    return [urljoin(root_url, remove_fragment(new_url)) for new_url in new_urls]

if __name__ == "__main__":
    q = asyncio.Queue()
    [q.put_nowait(url) for url in url_hub]    
    loop = asyncio.get_event_loop()
    tasks = [handle_task(task_id, q) for task_id in range(3)]
    loop.run_until_complete(asyncio.wait(tasks))
    loop.close()
    for u in crawled_urls:
        print(u)
    print('-'*30)
    print(len(crawled_urls))