协程的11

在一个线程中 如果遇到IO等待时间，线程不会呆呆等着，利用空闲时间再去做其他任务

案例 下载三张图片

• 普通方式

# todo pip install requests

import requests


def download_to_mylocal(url):
    print("开始下载", url)
    # 发送网络请求，下载图片
    response = requests.get(url)
    print("下载完成", url)
    file_name = url.split(".com")[-1].split(".jpg")[0].split("/")[-1]
    with open(file_name+'.jpg', mode="wb") as file_object:
        file_object.write(response.content)


if __name__ == "__main__":
    url_list = [
        "XX/31458PICm58PICKsqwrz9Ve8P_PIC2018.jpg!w1024_new_0",
        "XX/31Y58PICHCQS58PIC4iKcGYNQ_PIC2018.jpg!w1024_new_small",
        "XX/63H58PICAuF8vqJRcZ58PICMq_PIC2018.jpg!w1024_new_small"
    ]
    for item in url_list:
        download_to_mylocal(item)

• 协程方式(异步)

# todo 使用第三方模块 aiohttp

import aiohttp
import asyncio


async def fetch(session, url):
    print("发送请求", url)
    async with session.get(url, verify_ssl=False) as response:
        content = await response.content.read()
        file_name = url.split("/")[-1]
        with open(file_name, mode='wb') as file_object:
            file_object.write(content)
    print("下载完成", url)


async def main():
    async with aiohttp.ClientSession() as session:
        url_list = [
            "XXX/001345XOhx0.jpg",
            "XXX/220208/200740-16443220602c60.jpg",
            "XXX/234059-164381645989ad.jpg"
        ]
        tasks = [asyncio.create_task(fetch(session, url)) for url in url_list]

        await asyncio.wait(tasks)


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