基于Python asyncio的异步爬虫框架，如何使用和实现？

对于基于asyncio的异步爬虫框架，核心是利用aiohttp进行网络请求，配合asyncio的并发控制。下面是一个可直接运行的示例：

import asyncio
import aiohttp
from bs4 import BeautifulSoup

class AsyncCrawler:
    def __init__(self, concurrency=10):
        self.semaphore = asyncio.Semaphore(concurrency)
    
    async def fetch(self, session, url):
        async with self.semaphore:  # 控制并发数
            async with session.get(url) as response:
                return await response.text()
    
    async def parse(self, html):
        soup = BeautifulSoup(html, 'html.parser')
        # 这里写你的解析逻辑
        titles = soup.find_all('h1')
        return [title.get_text() for title in titles]
    
    async def crawl(self, url):
        async with aiohttp.ClientSession() as session:
            html = await self.fetch(session, url)
            data = await self.parse(html)
            return data
    
    async def crawl_many(self, urls):
        tasks = [self.crawl(url) for url in urls]
        results = await asyncio.gather(*tasks, return_exceptions=True)
        return results

# 使用示例
async def main():
    crawler = AsyncCrawler(concurrency=5)
    urls = [
        'https://httpbin.org/html',
        'https://httpbin.org/html',
        'https://httpbin.org/html'
    ]
    results = await crawler.crawl_many(urls)
    for url, result in zip(urls, results):
        if isinstance(result, Exception):
            print(f"{url} failed: {result}")
        else:
            print(f"{url}: {result}")

if __name__ == "__main__":
    asyncio.run(main())

实现要点：

1. 用aiohttp.ClientSession管理HTTP会话
2. asyncio.Semaphore限制并发连接数避免被封
3. asyncio.gather并发执行多个爬取任务
4. 异常处理确保单个任务失败不影响整体

建议：用生产者-消费者模式处理大规模爬取。

emmm…还没打完就发出去了

例如
http://域名 /article/123.html
http://域名 /article/124.html
http://域名 /
http://域名 /article/126.html
http://域名 /article/127.html

这样的 urls，第三个没有获取，会导致最后两个报错
我再定位下

request = Request(“http://www.lutec.com/”, load_js=True),直接 timeout，无法退出，是否要设置什么参数