Google backend oAuth with Python3?

Question

我查询谷歌日历，一个用Python 2.7编写的程序，在服务器到服务器模式下（使用证书）。通常像这样：

        with open('mycertfromgoogleconsole.p12', 'rb') as f:
            private_key = f.read()
        credentials = oauth2client.client.SignedJwtAssertionCredentials(
            '[e-mail],
            private_key,
            'https://www.googleapis.com/auth/calendar.readonly',
            sub='[e-mail]'
        )
        http_auth = credentials.authorize(httplib2.Http())
        service = apiclient.discovery.build('calendar', 'v3', http=http_auth)

我现在需要将脚本移植到 Python 3.4，但找不到支持 oAuth 后端版本的库（有几个似乎支持 Web 版本）。你知道有没有可用的吗？（理想情况下是直接替代品，但这接近奇迹）

Answer 1

我终于设法让它工作了，下面的代码遵循 Google API 文档，最后一个请求生成上面文档中"处理响应"中提到的令牌数据

import requests
import jwt
import arrow
import OpenSSL.crypto

class GetToken(object):
    """
    Get Google API token as documented at https://developers.google.com/identity/protocols/OAuth2ServiceAccount
    """
    def __init__(self):
        self.expires = 0
        self.token = None
    def gettoken(self):
        now = arrow.now().timestamp
        # is the token still valid and exists ? (within a 10 seconds margin)
        if now < (self.expires - 10) and self.token:
            return self.token
        self.expires = now + 3600
        claim = {
            "iss": "[e-mail]",
            "scope": "https://www.googleapis.com/auth/calendar.readonly",
            "aud": "https://www.googleapis.com/oauth2/v3/token",
            "exp": now,
            "iat": now,
            "sub": "[e-mail]"
        }
        p12 = OpenSSL.crypto.load_pkcs12(open('certificate_from_google_api_console.p12', 'rb').read(), 'notasecret')
        private_key = OpenSSL.crypto.dump_privatekey(OpenSSL.crypto.FILETYPE_PEM, p12.get_privatekey()).decode('utf-8')
        myjwt = jwt.encode(claim, private_key, algorithm='RS256', headers={"alg": "RS256", "typ": "JWT"}).decode('utf-8')
        data = {
            "grant_type": "urn:ietf:params:oauth:grant-type:jwt-bearer",
            "assertion": myjwt
        }
        headers = {"Content-Type": "application/x-www-form-urlencoded"}
        r = requests.post("https://www.googleapis.com/oauth2/v3/token", data=data, headers=headers)
        print(r.json())
if __name__ == "__main__":
    t = GetToken()
    t.gettoken()