如何获取 Firebase 云消息传递的 OAuth2.0 令牌

Question

我已将我的网络应用设置为接收 Firebase 云消息，但为了发送它们，我知道我需要一个 OAuth2.0 令牌，它是从我的服务帐户私钥生成的。我已经下载了密钥并安装了适用于 Python 的 Google API 客户端库。这是我的代码：

from oauth2client import *
def _get_access_token():
  """Retrieve a valid access token that can be used to authorize requests.

  :return: Access token.
  """
  credentials = ServiceAccountCredentials.from_json_keyfile_name(
      'service-account.json', FCM_SCOPE)
  access_token_info = credentials.get_access_token()
  return access_token_info.access_token

_get_access_token()

当我运行它时，我得到了

Traceback (most recent call last):
  File "get-oauth-token.py", line 11, in <module>
    _get_access_token()
  File "get-oauth-token.py", line 7, in _get_access_token
    credentials = ServiceAccountCredentials.from_json_keyfile_name(
NameError: name 'ServiceAccountCredentials' is not defined

我假设我错过了一个导入，但我不确定是什么。

Answer 1

这应该可以解决：

from oauth2client.service_account import ServiceAccountCredentials
fsm_scope = 'https://www.googleapis.com/auth/firebase.messaging'

def _get_access_token():
    """Retrieve a valid access token that can be used to authorize requests.

    :return: Access token.
    """
    credentials = ServiceAccountCredentials.from_json_keyfile_name(
        'service-account.json', fsm_scope)
    access_token_info = credentials.get_access_token()
    return access_token_info.access_token

_get_access_token()