多執行緒下載檔案

出現異常的執行緒會自動重新下載, 所有的進度會在同一位置輪換顯示

 import os
    import datetime
    from urllib import request
    url_list = ["url1","url2","url3","url4"]
    base_path = "/download/"
    
    def download(url):
    
        print("start:", url, datetime.now())
        file_name = url + '.txt'
        path = os.path.join(base_path, file_name)
        try:
            request.urlretrieve(url, path, callback)
        except:
            download(url)
    
    def callback(a, b, c):
        per = 100.0 * a * b / c
        # print(a, b, c)
        if per > 100:
            per = 100
        print('\r%.2f%%, %d' % (per, c), end=" ")
    
    
    if __name__ == '__main__':
        print("name_list", len(url_list))
        thread_list = []
        for i in url_list:
            if url_list:
                url = url_list.pop(0)
                my_thread = Thread(target=download, args=(url,))
                thread_list.append(my_thread)
    
        for my_thread in thread_list:
            my_thread.start()
        for my_thread in thread_list:
            my_thread.join()