如何使用服务账号oauth2 Python客户端通过Google邮箱设置API进行身份验证？

Question

我正在使用Python 2.6和Google API的客户端库，想要获取对电子邮件设置的认证访问权限：

f = file(SERVICE_ACCOUNT_PKCS12_FILE_PATH, 'rb')
key = f.read()
f.close()
credentials = client.SignedJwtAssertionCredentials(SERVICE_ACCOUNT_EMAIL, key,      scope='https://apps-apis.google.com/a/feeds/emailsettings/2.0/', sub=user_email)

http = httplib2.Http()
http = credentials.authorize(http)
return discovery.build('email-settings', 'v2', http=http)

当我执行这段代码时，出现了以下错误： UnknownApiNameOrVersion: name: email-settings version: v2

请问电子邮件设置V2的API名称和版本是什么？ 可以用服务账户来使用它吗？ 谢谢！

Answer 1

如果你的应用里有多个地方需要使用EmailSettings这个API，这里有一个可以重复使用的函数，它会返回一个“客户端”对象：

def google_get_emailsettings_credentials():
    '''
    Google's EmailSettings API is not yet service-based, so delegation data
    has to be accessed differently from our other Google functions.
    TODO: Refactor when API is updated.
    '''

    with open(settings.GOOGLE_PATH_TO_KEYFILE) as f:
        private_key = f.read()

    client = EmailSettingsClient(domain='example.com')
    credentials = SignedJwtAssertionCredentials(
        settings.GOOGLE_CLIENT_EMAIL,
        private_key,
        scope='https://apps-apis.google.com/a/feeds/emailsettings/2.0/',
        sub=settings.GOOGLE_SUB_USER)
    auth2token = gdata.gauth.OAuth2TokenFromCredentials(credentials)
    auth2token.authorize(client)

    return client

你可以在其他地方调用这个函数，比如用来访问DelegationFeed：

client = google_get_emailsettings_credentials()
uri = client.MakeEmailSettingsUri(username, 'delegation')
delegates_xml = client.get_entry(
        uri=uri,
        desired_class=gdata.apps.emailsettings.data.EmailSettingsDelegationFeed)

Answer 2

看起来，emailsettings这个API在Discovery API中是不可用的。Discovery API的作用是提供一个API的详细信息，比如有哪些可用的方法等等。

可以查看在PHP客户端API上提出的以下问题。

https://github.com/google/google-api-php-client/issues/246

我不太明白为什么emailsettings在Discovery API中不可用，或者是否有计划让它可用。感觉这些系统和库很多都没有人维护了。

不过，已经不再更新的gdata客户端库是支持这个功能的。可以试试下面这个例子，我可以确认它是可以正常工作的。

https://code.google.com/p/gdata-python-client/source/browse/samples/apps/emailsettings_example.py

Answer 3

我找到了一个方法，可以通过服务账户的oauth2来获取邮箱设置：
这里有一个例子：

  SERVICE_ACCOUNT_EMAIL = ''
  SERVICE_ACCOUNT_PKCS12_FILE_PATH = ''
  EMAIL_SETTING_URI = "https://apps-apis.google.com/a/feeds/emailsettings/2.0/%s/%s/%s" 

 def fctEmailSettings():

    user_email = "user@mail.com"
    f = file(SERVICE_ACCOUNT_PKCS12_FILE_PATH, 'rb')
    key = f.read()
    f.close()
    credentials = client.SignedJwtAssertionCredentials(SERVICE_ACCOUNT_EMAIL, key, scope='https://apps-apis.google.com/a/feeds/emailsettings/2.0/', sub=user_email)
    auth2token = OAuth2TokenFromCredentials(credentials)
    ESclient = EmailSettingsClient(domain='doamin.com')
    auth2token.authorize(ESclient)
    username = 'username'
    setting='forwarding'
    uri = ESclient.MakeEmailSettingsUri(username, setting)
    entry = ESclient.get_entry(uri = uri,  desired_class = GS.gdata.apps.emailsettings.data.EmailSettingsEntry)