import requests

 import os

 from hashlib import md5

 from urllib.parse import urlencode

 from multiprocessing.pool import Pool

 GROUP_START = 1

 GROUP_END = 5

 def get_page(offset):

     params = {

         'offset': offset,

         'format': 'json',

         'keyword': '街拍',

         'autoload': 'true',

         'count': '',

         'cur_tab': '',

         'form': 'search_tab',

     }

     url  = 'https://www.toutiao.com/search_content/?' + urlencode(params)

     try:

         response = requests.get(url)

         if response.status_code == 200:

             return response.json()

     except requests.ConnectionError:

         return None

 def get_images(json):

     data = json.get('data')

     if data:

         for item in data:

             image_list = item.get('image_list')

             title = item.get('title')

             if image_list:

                 for image in image_list:

                     # 构造一个生成器，将图片和标题一起返回

                     yield {

                         'image': image.get('url'),

                         'title': title

                     }

 # item就是get_image()返回的一个字典

 # item里面的title创建一个文件夹

 def save_image(item):

     if not os.path.exists(item.get('title')):

         os.mkdir(item.get('title'))

     try:

         local_image_url = item.get('image')

         new_image_url = local_image_url.replace('list', 'large')

         response = requests.get('http:' + new_image_url)

         if response.status_code == 200:

             file_path = '{0}/{1}.{2}'.format(item.get('title'), md5(response.content).hexdigest(), 'jpg')

             # 判断路径是否存在，如果不存在，写入

             if not os.path.exists(file_path):

                 with open(file_path, 'wb')as f:

                     f.write(response.content)

             else:

                 print('Already Download', file_path)

     except:

         print('Failed to save image')

 # 定义一个offset数组，遍历，提取图片，下载

 def main(offset):

     json = get_page(offset)

     for item in get_images(json):

         print(item)

         save_image(item)

 if __name__ == '__main__':

     pool = Pool() # 创建进程池

     groups = ([x * 20 for x in range(GROUP_START, GROUP_END + 1)])

     pool.map(main, groups) # 第一个参数是函数，第二个参数是一个迭代器，将迭代器中的数字作为参数依次传入函数中

     pool.close() # 关闭pool，使其不在接受新的（主进程）任务

     pool.join() # 主进程阻塞后，让子进程继续运行完成，子进程运行完后，再把主进程全部关掉