具有 2 个列表作为变量的 concurrent.futures 多线程

Question

所以我想用并发期货对以下工作代码进行多线程处理，但到目前为止我尝试过的任何东西似乎都不起作用。

def download(song_filename_list, song_link_list):

    with requests.Session() as s:
    
        login_request = s.post(login_url, data= payload, headers= headers)

        for x in range(len(song_filename_list)):

            download_request = s.get(song_link_list[x], headers= download_headers, stream=True)

            if download_request.status_code == 200:
                print(f"Downloading {x+1} out of {len(song_filename_list)}!\n")
                pass
            else:
                print(f"\nStatus Code: {download_request.status_code}!\n")
                sys.exit()

            
            with open (song_filename_list[x], "wb") as file:
                file.write(download_request.content)

两个主要变量是song_filename_list和song_link_list 。

第一个列表包含每个文件的名称，第二个列表包含它们各自的下载链接。
所以每个文件的名称和链接都位于相同的位置。
例如： name_of_file1 = song_filename_list[0]和link_of_file1 = song_link_list[0]

---

这是多线程的最新尝试：

def download(song_filename_list, song_link_list):

    with requests.Session() as s:
    
        login_request = s.post(login_url, data= payload, headers= headers)

        x = []
        for i in range(len(song_filename_list)):
            x.append(i)


        with concurrent.futures.ThreadPoolExecutor() as executor:
            executor.submit(get_file, x)


def get_file(x):
    
    download_request = s.get(song_link_list[x], headers= download_headers, stream=True)

    if download_request.status_code == 200:
        print(f"Downloading {x+1} out of {len(song_filename_list)}!\n")
        pass
    else:
        print(f"\nStatus Code: {download_request.status_code}!\n")
        sys.exit()

        
    with open (song_filename_list[x], "wb") as file:
        file.write(download_request.content)

有人可以向我解释我做错了什么吗？
因为在get_file函数调用后什么也没有发生。
它跳过所有代码并退出而没有任何错误，那么我的逻辑哪里错了？

---

编辑 1：

添加打印后：

print(song_filename_list, song_link_list)
        with concurrent.futures.ThreadPoolExecutor() as executor:
            print("Before executor.map")
            executor.map(get_file, zip(song_filename_list, song_link_list))
            print("After executor.map")
            print(song_filename_list, song_link_list)

以及开始和结束get_file及其file.write 。

输出如下：

Succesfully logged in!

["songs names"] ["songs links"]    <- These are correct.
Before executor.map
After executor.map
["songs names"] ["songs links"]    <- These are correct.

Exiting.

换句话说，值是正确的，但它跳过了executor.map的get_file 。

---

编辑2：

以下是使用的值。

• song_filename_list = ['100049 Himeringo - Yotsuya-san ni Yoroshiku.osz', '1001507 ZUTOMAYO - Kan Saete Kuyashiiwa.osz']

• song_link_list = ['https://osu.ppy.sh/beatmapsets/100049/download', 'https://osu.ppy.sh/beatmapsets/1001507/download']

---

编辑 3：

经过一些修补后，这似乎有效。

for i in range(len(song_filename_list)):
    with concurrent.futures.ThreadPoolExecutor() as executor:
        executor.submit(get_file, song_filename_list, song_link_list, i, s)

def get_file(song_filename_list, song_link_list, i, s):
    
    download_request = s.get(song_link_list[i], headers= download_headers, stream=True)

    if download_request.status_code == 200:
        print("Downloading...")
        pass
    else:
        print(f"\nStatus Code: {download_request.status_code}!\n")
        sys.exit()
    
    with open (song_filename_list[i], "wb") as file:
        file.write(download_request.content)

Answer 1

在您的download()函数中，您提交整个数组，而您应该提交每个项目：

def download(song_filename_list, song_link_list):

    with requests.Session() as s:
    
        login_request = s.post(login_url, data=payload, headers= headers)

        for i in range(len(song_filename_list)):
            with concurrent.futures.ThreadPoolExecutor() as executor:
                executor.submit(get_file, i)

您可以使用 executor .map()方法简化此操作：

def download(song_filename_list, song_link_list):
  with requests.Session() as session:
    session.post(login_url, data=payload, headers=headers)

  with concurrent.futures.ThreadPoolExecutor() as executor:
    executor.map(get_file, song_filename_list, song_link_list)

get_file函数在哪里：

def get_file(song_name, song_link):
  with requests.Session() as session:
    download_request = session.get(song_link, headers=download_headers, stream=True)

  if download_request.status_code == 200:
    print(f"Downloaded {song_name}")
  else:
    print(f"\nStatus Code: {download_request.status_code}!\n")
  
  with open(song_name, "wb") as file:
    file.write(download_request.content)

这避免了线程之间共享状态，从而避免了潜在的数据竞争。

如果您需要监控下载了多少歌曲，您可以使用tqdm ，它有一个thread_map迭代器包装器，可以做到这一点。