python异步图像下载（多个URL）

Question

我正在学习Python 4/5个月，这是我从零开始构建的第三个项目，但我不能自己解决这个问题。

此脚本为每个给定的url下载1个图像。我不能找到一个解决方案，如何实现线程池执行器或异步在这个脚本。我不知道如何链接与图像编号的url保存图像部分。我建立了我需要下载的所有网址的判决，但我实际上如何保存正确名称的图像？还有其他建议吗？

另外，目前的网址都是假的。

同步版本：

    import requests
    import argparse
    import re
    import os
    import logging

    from bs4 import BeautifulSoup


    parser = argparse.ArgumentParser()
    parser.add_argument("-n", "--num", help="Book number", type=int, required=True) 
    parser.add_argument("-p", dest=r"path_name", default=r"F:\Users\123", help="Save to dir", )
    args = parser.parse_args()



    logging.basicConfig(format='%(asctime)s - %(name)s - %(levelname)s - %(message)s',
                        level=logging.ERROR)
    logger = logging.getLogger(__name__)  


    def get_parser(url_c):  
        url = f'https://test.net/g/{url_c}/1'
        logger.info(f'Main url: {url_c}')
        responce = requests.get(url, timeout=5) # timeout will raise an exeption
        if responce.status_code == 200:
            page = requests.get(url, timeout=5).content
            soup = BeautifulSoup(page, 'html.parser')
            return soup
        else:
            responce.raise_for_status()


    def get_locators(soup): # take get_parser
        # Extract first/last page num
        first = int(soup.select_one('span.current').string)
        logger.info(f'First page: {first}')
        last = int(soup.select_one('span.num-pages').string) + 1

        # Extract img_code and extension
        link = soup.find('img', {'class': 'fit-horizontal'}).attrs["src"]
        logger.info(f'Locator code: {link}')
        code = re.search('galleries.([0-9]+)\/.\.(\w{3})', link)
        book_code = code.group(1)   # internal code 
        extension = code.group(2)   # png or jpg

        # extract Dir book name
        pattern = re.compile('pretty":"(.*)"')
        found = soup.find('script', text=pattern)
        string = pattern.search(found.text).group(1)
        dir_name = string.split('"')[0]
        logger.info(f'Dir name: {dir_name}')

        logger.info(f'Hidden code: {book_code}')
        print(f'Extension: {extension}')
        print(f'Tot pages: {last}')
        print(f'')

        return {'first_p': first, 
                'last_p': last, 
                'book_code': book_code, 
                'ext': extension, 
                'dir': dir_name
                }


    def setup_download_dir(path, dir):  # (args.path_name, locator['dir'])
        # Make folder if it not exist
        filepath = os.path.join(f'{path}\{dir}')
        if not os.path.exists(filepath):
            try:
                os.makedirs(filepath)
                print(f'Directory created at: {filepath}')
            except OSError as err:
                print(f"Can't create {filepath}: {err}")    
         return filepath 


    def main(locator, filepath):
        for image_n in range(locator['first_p'], locator['last_p']):
            url = f"https://i.test.net/galleries/{locator['book_code']}/{image_n}.{locator['ext']}"
            logger.info(f'Url Img: {url}')
            responce = requests.get(url, timeout=3)
            if responce.status_code == 200:
                img_data = requests.get(url, timeout=3).content 
            else:    
                responce.raise_for_status()    # raise exepetion 

            with open((os.path.join(filepath, f"{image_n}.{locator['ext']}")), 'wb') as handler:
                handler.write(img_data) # write image
                print(f'Img {image_n} - DONE')


    if __name__ == '__main__':
        try:
            locator = get_locators(get_parser(args.num))    # args.num ex. 241461
            main(locator, setup_download_dir(args.path_name, locator['dir'])) 
        except KeyboardInterrupt:
            print(f'Program aborted...' + '\n')

URL列表：

    def img_links(locator):
        image_url = []
        for num in range(locator['first_p'], locator['last_p']):
            url = f"https://i.test.net/galleries/{locator['book_code']}/{num}.{locator['ext']}"
            image_url.append(url)
        logger.info(f'Url List: {image_url}')       
        return image_url

Answer 1

我在《流畅的python》一书中找到了解决方案。下面是代码片段：

    def download_many(cc_list, base_url, verbose, concur_req):
        counter = collections.Counter()
        with futures.ThreadPoolExecutor(max_workers=concur_req) as executor:
            to_do_map = {}
            for cc in sorted(cc_list):
                future = executor.submit(download_one, cc, base_url, verbose)
                to_do_map[future] = cc
            done_iter = futures.as_completed(to_do_map)
            if not verbose:
                done_iter = tqdm.tqdm(done_iter, total=len(cc_list))
            for future in done_iter:
                try:
                    res = future.result()
                except requests.exceptions.HTTPError as exc:
                    error_msg = 'HTTP {res.status_code} - {res.reason}'
                    error_msg = error_msg.format(res=exc.response)
                except requests.exceptions.ConnectionError as exc:
                    error_msg = 'Connection error'
                else:
                    error_msg = ''
                    status = res.status
                if error_msg:
                    status = HTTPStatus.error
                counter[status] += 1
                if verbose and error_msg:
                    cc = to_do_map[future]
                    print('*** Error for {}: {}'.format(cc, error_msg))
        return counter