41 lines
1.3 KiB
Python
41 lines
1.3 KiB
Python
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import asyncio
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async def fetch(host):
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"""从指定的站点抓取信息(协程函数)"""
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print(f'Start fetching {host}\n')
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# 跟服务器建立连接
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reader, writer = await asyncio.open_connection(host, 80)
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# 构造请求行和请求头
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writer.write(b'GET / HTTP/1.1\r\n')
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writer.write(f'Host: {host}\r\n'.encode())
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writer.write(b'\r\n')
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# 清空缓存区(发送请求)
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await writer.drain()
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# 接收服务器的响应(读取响应行和响应头)
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line = await reader.readline()
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while line != b'\r\n':
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print(line.decode().rstrip())
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line = await reader.readline()
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print('\n')
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writer.close()
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def main():
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"""主函数"""
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urls = ('www.sohu.com', 'www.douban.com', 'www.163.com')
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# 获取系统默认的事件循环
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loop = asyncio.get_event_loop()
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# 用生成式语法构造一个包含多个协程对象的列表
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tasks = [fetch(url) for url in urls]
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# 通过asyncio模块的wait函数将协程列表包装成Task（Future子类）并等待其执行完成
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# 通过事件循环的run_until_complete方法运行任务直到Future完成并返回它的结果
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futures = asyncio.wait(tasks)
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print(futures, type(futures))
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loop.run_until_complete(futures)
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loop.close()
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if __name__ == '__main__':
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main()
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