binascii.Error：无效的 base64 编码字符串：数据字符数 (41) 不能多于 1 4 的倍数

我正在尝试使用 py-vapid 、 pywebpush 和 django-push-notifications 通过 Webpush 发送通知。当我尝试从 django 管理网站发送测试通知时，我在控制台中收到此回溯日志：

      | Internal Server Error: /djangoadmin/push_notifications/webpushdevice/
      | Traceback (most recent call last):
      |   File "/usr/local/lib/python3.8/site-packages/asgiref/sync.py", line 518, in thread_handler
      |     raise exc_info[1]
      |   File "/usr/local/lib/python3.8/site-packages/django/core/handlers/exception.py", line 38, in inner
      |     response = await get_response(request)
      |   File "/usr/local/lib/python3.8/site-packages/django/core/handlers/base.py", line 233, in _get_response_async
      |     response = await wrapped_callback(request, *callback_args, **callback_kwargs)
      |   File "/usr/local/lib/python3.8/site-packages/asgiref/sync.py", line 468, in __call__
      |     ret = await asyncio.shield(exec_coro)
      |   File "/usr/local/lib/python3.8/site-packages/asgiref/current_thread_executor.py", line 40, in run
      |     result = self.fn(*self.args, **self.kwargs)
      |   File "/usr/local/lib/python3.8/site-packages/asgiref/sync.py", line 522, in thread_handler
      |     return func(*args, **kwargs)
      |   File "/usr/local/lib/python3.8/site-packages/django/contrib/admin/options.py", line 616, in wrapper
      |     return self.admin_site.admin_view(view)(*args, **kwargs)
      |   File "/usr/local/lib/python3.8/site-packages/django/utils/decorators.py", line 130, in _wrapped_view
      |     response = view_func(request, *args, **kwargs)
      |   File "/usr/local/lib/python3.8/site-packages/django/views/decorators/cache.py", line 44, in _wrapped_view_func
      |     response = view_func(request, *args, **kwargs)
      |   File "/usr/local/lib/python3.8/site-packages/django/contrib/admin/sites.py", line 232, in inner
      |     return view(request, *args, **kwargs)
      |   File "/usr/local/lib/python3.8/site-packages/django/utils/decorators.py", line 43, in _wrapper
      |     return bound_method(*args, **kwargs)
      |   File "/usr/local/lib/python3.8/site-packages/django/utils/decorators.py", line 130, in _wrapped_view
      |     response = view_func(request, *args, **kwargs)
      |   File "/usr/local/lib/python3.8/site-packages/django/contrib/admin/options.py", line 1723, in changelist_view
      |     response = self.response_action(request, queryset=cl.get_queryset(request))
      |   File "/usr/local/lib/python3.8/site-packages/django/contrib/admin/options.py", line 1408, in response_action
      |     response = func(self, request, queryset)
      |   File "/usr/local/lib/python3.8/site-packages/push_notifications/admin.py", line 109, in send_message
      |     self.send_messages(request, queryset)
      |   File "/usr/local/lib/python3.8/site-packages/push_notifications/admin.py", line 38, in send_messages
      |     r = device.send_message("Test single notification")
      |   File "/usr/local/lib/python3.8/site-packages/push_notifications/models.py", line 270, in send_message
      |     return webpush_send_message(self, message, **kwargs)
      |   File "/usr/local/lib/python3.8/site-packages/push_notifications/webpush.py", line 35, in webpush_send_message
      |     response = webpush(
      |   File "/usr/local/lib/python3.8/site-packages/pywebpush/__init__.py", line 560, in webpush
      |     vv = Vapid.from_string(private_key=vapid_private_key)
      |   File "/usr/local/lib/python3.8/site-packages/py_vapid/__init__.py", line 144, in from_string
      |     key = b64urldecode(pkey)
      |   File "/usr/local/lib/python3.8/site-packages/py_vapid/utils.py", line 14, in b64urldecode
      |     return base64.urlsafe_b64decode(data + b"===="[len(data) % 4:])
      |   File "/usr/local/lib/python3.8/base64.py", line 133, in urlsafe_b64decode
      |     return b64decode(s)
      |   File "/usr/local/lib/python3.8/base64.py", line 87, in b64decode
      |     return binascii.a2b_base64(s)
      | binascii.Error: Invalid base64-encoded string: number of data characters (41) cannot be 1 more than a multiple of 4

它似乎说我的密钥没有采用有效的格式来转换为 Base64，但我检查了 pywebpush文档和我的密钥格式正确。它们是用 VAPID EC2 private key PEM file 生成的，如下所示： py-vapid 以下是有问题的测试密钥：

import os
from cryptography.hazmat.primitives.serialization import Encoding, PrivateFormat, NoEncryption, PublicFormat
from py_vapid import Vapid
import base64

PROJECT_ROOT = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

# Generate VAPID key pair
vapid = Vapid()
vapid.generate_keys()

# Get public and private keys for the vapid key pair
vapid.save_public_key(os.path.join(PROJECT_ROOT, "keys", "webpush", "public_key.pem"))
public_key_bytes = vapid.public_key.public_bytes(Encoding.X962, PublicFormat.UncompressedPoint)

vapid.save_key(os.path.join(PROJECT_ROOT, "keys", "webpush", "private_key.pem"))


# Convert the public key to applicationServerKey format
application_server_key = base64.urlsafe_b64encode(public_key_bytes).replace(b'=', b'').decode('utf8')

with open(os.path.join(PROJECT_ROOT, "keys", "webpush", "ApplicationServerKey.key"), "w") as f:
    f.write(application_server_key)

我尝试使用 OpenSSL 手动生成密钥，但它仍然无法工作。

-----BEGIN PRIVATE KEY-----
MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQgFCZ0WxsNENwKK3Pf
c0HFZPDlr/KAmjIwB6Hz/OdH/YKhRANCAASFpOW98Q4xfCjD0Taog9ZstRQgS+Ch
L7HoOBGHFZAQwpEd83Qt58bnUCIZFwMZc4tyHKV+b0UxM2cMzm8pMI4z
-----END PRIVATE KEY-----

-----BEGIN PUBLIC KEY-----
MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEhaTlvfEOMXwow9E2qIPWbLUUIEvg
oS+x6DgRhxWQEMKRHfN0LefG51AiGRcDGXOLchylfm9FMTNnDM5vKTCOMw==
-----END PUBLIC KEY-----

I've tried to generate keys manually using OpenSSL but it still won't work.

错误信息 "binascii.Error: Invalid base64-encoded string: number of data characters (41) cannot be 1 more than a multiple of 4" 表明你正试图将一个无效的 Base64 字符串解码。问题并非出在你的密钥格式，而是出在你如何读取或使用密钥。

看起来你在代码中并没有直接使用私钥进行 Base64 解码。 py_vapid 库应该在内部处理这个过程。问题可能出现在以下地方：

1. 错误地读取私钥： 确保你正确地从文件中读取私钥，并且没有引入额外的空格或字符。使用 open() 函数时，最好使用 'rb' 模式以二进制格式读取文件，避免潜在的编码问题：

with open(os.path.join(PROJECT_ROOT, "keys", "webpush", "private_key.pem"), "rb") as f:
    private_key = f.read()

# ... 然后使用 private_key 字符串

1. vapid_private_key 变量的值不正确： 确认你将读取的私钥内容正确地传递给了 webpush() 函数中的 vapid_private_key 参数。 打印 vapid_private_key 的值，确保它包含正确的私钥字符串，包括 "-----BEGIN PRIVATE KEY-----" 和 "-----END PRIVATE KEY-----" 部分。

2. django-push-notifications 配置问题： 检查 django-push-notifications 的设置，确保你正确地配置了 VAPID 密钥路径或变量。

调试建议：

1. 打印 pkey 的值： 在 py_vapid/__init__.py 文件的 from_string 函数中，添加一行代码打印 pkey 的值，看看它是否是预期的私钥字符串：

    def from_string(cls, pkey):
        print("pkey:", pkey)  # 添加这行
        key = b64urldecode(pkey)
        # ...

1. 检查 django-push-notifications 设置： 仔细检查 settings.py 文件或其他相关配置文件，确保你正确配置了 VAPID 密钥路径或变量。

2. 使用调试器逐步执行代码： 使用调试器可以帮助你逐行检查代码，观察变量的值，并确定问题的确切位置。

如果以上步骤都不能解决问题，请提供以下信息：

• 你是如何调用 webpush() 函数的？请分享相关代码片段。
• django-push-notifications 的版本号。
• 你是如何配置 django-push-notifications 的 VAPID 密钥设置的？

通过提供更多信息，我可以更好地帮助你解决问题。