为了给公众号配图，找一些免费的高清图片。不过瘾，干脆爬下来好了。
代码如下：
#coding=utf-8__author__ = 'sixkery'import requests, asyncio, aiohttpimport os, timedef run_time(fn):
'''装饰器，用于查看图片下载运行时间'''
def wrapper(*args, **kwargs):
start = time.time()
fn(*args, **kwargs)
print('运行时间{}'.format(time.time() - start)) return wrapperclass Crawl_Image:
def __init__(self):
self.num = 1
if '图片' not in os.listdir('.'):
os.mkdir('图片')
self.path = os.path.join(os.path.abspath('.'),'图片')
os.chdir(self.path) def str_dict(self):
'''把字符串转化成字典，通常的请求头一个一个写成字典麻烦'''
headers = {}
heads = '''
authority: unsplash.com
method: GET
path: /napi/photos?page=13&per_page=12&order_by=latest
scheme: https
accept: */*
accept-encoding: gzip, deflate, br
accept-language: zh-CN,zh;q=0.9
cache-control: no-cache
cookie: _ga=GA1.2.1867787748.1541257560; uuid=fbe18d60-df79-11e8-af00-9f82294d3e27; xpos=%7B%7D; lsnp=Wn1U1YnKyn4; ugid=45e258e4a27fdb75969611bfa7b6227a5146352; _gid=GA1.2.104984706.1543905667; lux_uid=154390566744470013; _sp_ses.0295=*; _gat=1; _sp_id.0295=4996ac29-9203-4213-a46d-24cf83d147ce.1541257566.9.1543907256.1541399729.fcdb26b7-0b36-4bab-8056-898cc972167e
dpr: 1
pragma: no-cache
referer: https://unsplash.com/
user-agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.99 Safari/537.36
viewport-width: 1350
'''
heads = heads.split('n') for head in heads:
head = head.strip() if head:
head_key,head_value = head.split(':',1)
headers[head_key] = head_value.strip() return headers def request_url(self,url):
'''请求网页，获取图片的 url 。因为图片的请求不多，所以用同步就好'''
r = requests.get(url,headers=self.str_dict()) if r.status_code == 200: return r.json() async def get_image(self, url):
'''异步请求库aiohttp 加快图片 url 的网页请求'''
async with aiohttp.ClientSession() as session:
response = await session.get(url)
content = await response.read() return content async def download_image(self,image):
html = await self.get_image(image[0]) with open(image[1] + '.jpg','wb') as f:
f.write(html)
print('下载第{}张图片成功'.format(self.num))
self.num += 1 @run_time
def run(self):
for page in range(10):
url = 'https://unsplash.com/napi/photos?page={}&per_page=12&order_by=latest'.format(page)
links = self.request_url(url)
task = [asyncio.ensure_future(self.download_image((link['links']['download'],link['id']))) for link in links] # 获取事件循环 Eventloop
loop = asyncio.get_event_loop() # 执行协程
loop.run_until_complete(asyncio.wait(task))if __name__ == '__main__':
crawl_image = Crawl_Image()
crawl_image.run()首先开头的装饰器就是为了装逼，加上运行时间看看异步协程爬起来有多快。当然没有用同步的爬过。只知道异步速度杠杠滴。
关于字符串转换成字典这个，是嫌手动一个一个变成字典太麻烦。用 Python 做几行代码就搞定了。还是 Python厉害。
网站返回的是 json 的数据，那获取图片来说不是更简单。
关于 aiohttp 异步网络请求库，官网上有更加详细的解释。这里就不做搬运工啦。
异步协程这一块比较难理解，但是封装好的模块调用起来还是蛮方便的。希望大家都能掌握。
作者：sixkery
链接：https://www.jianshu.com/p/59333b5850ed
