41 lines
1.3 KiB
Python
41 lines
1.3 KiB
Python
import asyncio
|
||
|
||
|
||
async def fetch(host):
|
||
"""从指定的站点抓取信息(协程函数)"""
|
||
print(f'Start fetching {host}\n')
|
||
# 跟服务器建立连接
|
||
reader, writer = await asyncio.open_connection(host, 80)
|
||
# 构造请求行和请求头
|
||
writer.write(b'GET / HTTP/1.1\r\n')
|
||
writer.write(f'Host: {host}\r\n'.encode())
|
||
writer.write(b'\r\n')
|
||
# 清空缓存区(发送请求)
|
||
await writer.drain()
|
||
# 接收服务器的响应(读取响应行和响应头)
|
||
line = await reader.readline()
|
||
while line != b'\r\n':
|
||
print(line.decode().rstrip())
|
||
line = await reader.readline()
|
||
print('\n')
|
||
writer.close()
|
||
|
||
|
||
def main():
|
||
"""主函数"""
|
||
urls = ('www.sohu.com', 'www.douban.com', 'www.163.com')
|
||
# 获取系统默认的事件循环
|
||
loop = asyncio.get_event_loop()
|
||
# 用生成式语法构造一个包含多个协程对象的列表
|
||
tasks = [fetch(url) for url in urls]
|
||
# 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
|
||
# 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
|
||
futures = asyncio.wait(tasks)
|
||
print(futures, type(futures))
|
||
loop.run_until_complete(futures)
|
||
loop.close()
|
||
|
||
|
||
if __name__ == '__main__':
|
||
main()
|