Python 3.7 批量下载多个文件 -- 协程

批量下载系统中多个文件

import aiohttp
import asyncio
import urllib.request
import http.cookiejar

# 1. 登录系统，获取Cookie值

cookiejar = http.cookiejar.CookieJar()  #构建一个CookieJar对象实例来保存cookie  【CookieJar是对于Cookie类的一个类似管理类的封装】
handler = urllib.request.HTTPCookieProcessor(cookiejar)     #使用HTTPCookieProcessor()来创建cookie处理器对象，参数为CookieJar()对象
opener = urllib.request.build_opener(handler)   #通过build_opener()来构建opener

# headers、请求登录接口，传递地址和参数
headers = {
    'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:90.0) Gecko/20100101 Firefox/90.0',
    'Accept': 'application/json, text/javascript, */*; q=0.01',
    'Accept-Encoding': 'gzip, deflate',
    'Accept-Language': 'zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2',
    'Connection': 'keep-alive',
    'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8'
}
url_login = 'http://xxx.xxx.xx.xx/xxxx/login'
FormData = {'username':'xxxxx', 'password':'xxxxx'}     #<class 'dict'>
postdata = urllib.parse.urlencode(FormData).encode()    #<class 'bytes'>

request = urllib.request.Request(url_login, postdata)
response = opener.open(request) #访问系统地址，访问之后会自动保存cookie到cookiejar中
for item in cookiejar:
    Cookie = '%s=%s' % (item.name, item.value)
headers['Cookie'] = Cookie  # 向headers中追加Cookie，没有Cookie值，系统会认为用户尚未登录


#文件地址
URL = ['http://xxx.xxx.xx.xx/xxxx/downloadTemplate?templateName=userTemplate.xlsx',
       'http://xxx.xxx.xx.xx/xxxx/downloadTemplate?templateName=ProductTemplate.xlsx',
       'http://xxx.xxx.xx.xx/xxxx/downloadTemplate?templateName=ProductGroup.xlsx',
       'http://xxx.xxx.xx.xx/xxxx/downloadTemplate?templateName=MaterialTemplate.xlsx',
       'http://xxx.xxx.xx.xx/xxxx/downloadTemplate?templateName=exceptionTemplate.xlsx',
        'http://xxx.xxx.xx.xx/xxxx/downloadTemptale?templateName=saleOrderTemplate.xlsx',
       '']
count = len(URL)



async def job(session, url, headers=headers):
    # 声明为异步函数
    name = url.split('=')[-1]
    # 获得名字
    file = await session.get(url, headers=headers)
    # 触发到await就切换，等待get到数据
    filecode = await file.read()
    # 读取内容
    with open('D:/xx/TemplateFiles/Excels/'+ str(name), 'wb') as f:
        # 写入到指定目录下的文件中
        f.write(filecode)
    return str(url)

async def main(loop, URL):
    async with aiohttp.ClientSession() as session:  
        # 建立会话session
        tasks = [loop.create_task(job(session, URL[_])) for _ in range(count)]
        # 建立所有任务
        finished, unfinished = await asyncio.wait(tasks)
        # 触发await，等待任务完成
        all_results = [r.result() for r in finished]
        # 获取所有结果
        print("请求下载数", count, "已下载数: ", len(all_results))



loop = asyncio.get_event_loop()
loop.run_until_complete(main(loop, URL))
loop.close()