1. 正常下载漫画，requests 阻塞式。

import requests, bs4, time

import asyncio, aiohttp

def get_image_urls(url):

res = requests.get(url)

res.raise_for_status()

soup = bs4.BeautifulSoup(res.text, 'lxml')

imgs = soup.select('div.list img')

for img in imgs:

yield img.get('data-kksrc')

def download_image(image_url, filename):

res = requests.get(image_url)

res.raise_for_status()

image = res.content

with open(r'e:\path\mh\{}.jpg'.format(filename), 'wb') as fp:

fp.write(image)

if __name__ == '__main__':

site_url = 'https://www.kuaikanmanhua.com/web/comic/105372/'

t_url = 'https://www.kuaikanmanhua.com/web/comic/15559/'

image_urls = [image_url for image_url in get_image_urls(site_url)]

t_list = [image_url for image_url in get_image_urls(t_url)]

image_urls.extend(t_list)

start = time.time()

for filename, url in enumerate(image_urls, start=1):

download_image(url, filename)

print('总计：{:.2f}s'.format(time.time()-start))

2. 异步包 asyncio 基本用法

import asyncio

import time

async def asynct():

print('asyncio...')

await asyncio.sleep(1)

def main():

start = time.time()

loop = asyncio.get_event_loop()

tasks = [asynct() for i in range(10)]

tasks_wait = asyncio.wait(tasks)

loop.run_until_complete(tasks_wait)

loop.close()

print('total: {:.2f}s'.format(time.time()-start))

if __name__ == '__main__':

main()

结果：

asyncio...

asyncio...

asyncio...

asyncio...

asyncio...

asyncio...

asyncio...

asyncio...

asyncio...

asyncio...

total: 1.01s

asyncio.sleep(1) 并不会阻塞运行，而是返回主线程继续运行，所以不会等待 10s 时间。

3. 异步下载漫画

import asyncio, aiohttp

import requests, bs4

import time

import tqdm

import concurrent.futures as futures

async def download_images(url, filename):

async with aiohttp.ClientSession() as session:

async with session.get(url) as res:

image = await res.content.read()

with open(r'e:\path\mh\{}.jpg'.format(filename), 'wb') as fp:

fp.write(image)

def test():

site_url = 'https://www.kuaikanmanhua.com/web/comic/105372/'

t_url = 'https://www.kuaikanmanhua.com/web/comic/15559/'

image_urls = [image_url for image_url in get_image_urls(site_url)]

t_list = [image_url for image_url in get_image_urls(t_url)]

image_urls.extend(t_list)

start = time.time()

loop = asyncio.get_event_loop()

tasks = [download_images(url, filename) for filename, url in enumerate(image_urls, start=1)]

coro = asyncio.wait(tasks)

loop.run_until_complete(coro)

loop.close()

print('总计：{:.2f}s'.format(time.time() - start))

if __name__ == '__main__':

test()

4. 以线程方式异步请求

def download_image(image_url, filename):

res = requests.get(image_url)

res.raise_for_status()

image = res.content

with open(r'e:\path\mh\{}.jpg'.format(filename), 'wb') as fp:

fp.write(image)

def test1():

site_url = 'https://www.kuaikanmanhua.com/web/comic/105372/'

t_url = 'https://www.kuaikanmanhua.com/web/comic/15559/'

image_urls = [image_url for image_url in get_image_urls(site_url)]

t_list = [image_url for image_url in get_image_urls(t_url)]

image_urls.extend(t_list)

start = time.time()

loop = asyncio.get_event_loop()

for filename, url in enumerate(image_urls, start=1):

loop.run_in_executor(None, download_image, url, filename)

print('总计：{:.2f}s'.format(time.time() - start))

if __name__ == '__main__':

test1()

这种方式是最快的，244张漫画图片只需要 0.11s。上面的方式大约都要 10s，奇怪的是 3 异步下载需要 9s 多，并没有比正常下载快多少。

5. 异步下载加入进度条，更好的观察下载进度

async def download_images(url, filename):

async with aiohttp.ClientSession() as session:

async with session.get(url) as res:

image = await res.content.read()

with open(r'e:\path\mh\{}.jpg'.format(filename), 'wb') as fp:

fp.write(image)

async def download_images_tqdm(image_urls):

tasks = [download_images(url, filename) for filename, url in enumerate(image_urls, start=1)]

fs = asyncio.as_completed(tasks)

tqdm_iter = tqdm.tqdm(fs, total=len(image_urls))

for future in tqdm_iter:

await future

def test2():

site_url = 'https://www.kuaikanmanhua.com/web/comic/105372/'

t_url = 'https://www.kuaikanmanhua.com/web/comic/15559/'

image_urls = [image_url for image_url in get_image_urls(site_url)]

t_list = [image_url for image_url in get_image_urls(t_url)]

image_urls.extend(t_list)

start = time.time()

loop = asyncio.get_event_loop()

loop.run_until_complete(download_images_tqdm(image_urls))

loop.close()

print('总计：{:.2f}s'.format(time.time() - start))

if __name__ == '__main__':

test2()

6. 使用 concurrent.futures 线程方式请求

def download_image2(*args):

res = requests.get(args[0][1])

res.raise_for_status()

image = res.content

with open(r'e:\path\mh\{}.jpg'.format(args[0][0]), 'wb') as fp:

fp.write(image)

def test3():

site_url = 'https://www.kuaikanmanhua.com/web/comic/105372/'

t_url = 'https://www.kuaikanmanhua.com/web/comic/15559/'

image_urls = [image_url for image_url in get_image_urls(site_url)]

t_list = [image_url for image_url in get_image_urls(t_url)]

image_urls.extend(t_list)

start = time.time()

with futures.ThreadPoolExecutor(max_workers=16) as executor:

executor.map(download_image2, enumerate(image_urls, start=1))

print('总计：{:.2f}s'.format(time.time() - start))

if __name__ == '__main__':

test3()

这种方式根据 max_workers 最大线程数设置不同值，得到的结果差距在 1s 左右，总共耗时 3.95s，比异步请求要快。

总结：

各运行两次

正常下载： 9.44s， 9.87s

异步下载： 9.54s， 3.58s

线程方式异步下载： 0.11s， 0.23s

线程方式下载： 3.87s， 4.32s

最快且相对稳定的是 线程方式异步下载