好吧，首先，因为这将是一个单一用户的应用程序.你的开发人员将是唯一一个使用它，你只是发送邮箱programmiclly让清除一些事情开始.

1. 您不需要验证此应用程序.是的，你需要像你所做的那样通过not a verified application个屏幕.别担心.
2. 通过单击send to production按钮在生产中设置应用程序.将使您能够请求不会过期的刷新令牌.你想要这个.同样，忽略显示您将需要验证您的应用程序的屏幕.
3. 测试用户，只要您只使用您创建项目的用户登录，就不需要测试用户.别理它.
4. 这只是你使用的应用程序使用https://mail.google.com/范围
5. 不要担心将作用域添加到Google云项目中，这只是为了验证.重要的是代码中的内容.

好的，都清楚了.

您现在有两个 Select .

1. XOAuth2，这就是您现在正在做的.
2. 应用程序密码.只需在你的谷歌账户上创建一个应用程序密码，然后用它来取代你的实际谷歌密码，你现有的代码就可以工作了.How I send emails with Python. In 2.2 minutes flat!个

Xoauth2

如果您想使用XOauth2，那么您可以使用Google API Python客户端库来帮助您获取所需的授权令牌

#   To install the Google client library for Python, run the following command:
#   pip install --upgrade google-api-python-client google-auth-httplib2 google-auth-oauthlib


from __future__ import print_function

import base64
import os.path
import smtplib
from email.mime.text import MIMEText

import google.auth.exceptions
from google.auth.transport.requests import Request
from google.oauth2.credentials import Credentials
from google_auth_oauthlib.flow import InstalledAppFlow
from googleapiclient.errors import HttpError

# If modifying these scopes, delete the file token.json.
SCOPES = ['https://mail.google.com/']

# usr token storage

USER_TOKENS = 'token.json'

# application credentials

CREDENTIALS = 'C:\YouTube\dev\credentials.json'


def getToken() -> str:
    """ Gets a valid Google access token with the mail scope permissions. """

    creds = None

    # The file token.json stores the user's access and refresh tokens, and is
    # created automatically when the authorization flow completes for the first
    # time.
    if os.path.exists(USER_TOKENS):
        try:
            creds = Credentials.from_authorized_user_file(USER_TOKENS, SCOPES)
            creds.refresh(Request())
        except google.auth.exceptions.RefreshError as error:
            # if refresh token fails, reset creds to none.
            creds = None
            print(f'An error occurred: {error}')
    # If there are no (valid) credentials available, let the user log in.
    if not creds or not creds.valid:
        if creds and creds.expired and creds.refresh_token:
            creds.refresh(Request())
        else:
            flow = InstalledAppFlow.from_client_secrets_file(
                CREDENTIALS, SCOPES)
            creds = flow.run_local_server(port=0)
        # Save the credentials for the next run
        with open(USER_TOKENS, 'w') as token:
            token.write(creds.to_json())

    try:

        return creds.token
    except HttpError as error:
        # TODO(developer) - Handle errors from authorization request.
        print(f'An error occurred: {error}')


def generate_oauth2_string(username, access_token, as_base64=False) -> str:

    # creating the authorization string needed by the auth server.
    #auth_string = 'user=%s\1auth=Bearer %s\1\1' % (username, access_token)

    auth_string = 'user=' + username + '\1auth=Bearer ' + access_token + '\1\1'
    if as_base64:
        auth_string = base64.b64encode(auth_string.encode('ascii')).decode('ascii')
    return auth_string


def send_email(host, port, subject, msg, sender, recipients):
    access_token = getToken()
    auth_string = generate_oauth2_string(sender, access_token, as_base64=True)

    msg = MIMEText(msg)
    msg['Subject'] = subject
    msg['From'] = sender
    msg['To'] = ', '.join(recipients)

    server = smtplib.SMTP(host, port)
    server.starttls()
    server.docmd('AUTH', 'XOAUTH2 ' + auth_string)
    server.sendmail(sender, recipients, msg.as_string())
    server.quit()


def main():
    host = "smtp.gmail.com"
    port = 587

    user = "test@gmail.com"

    subject = "Test email Oauth2"
    msg = "Hello world"
    sender = user
    recipients = [user]
    send_email(host, port, subject, msg, sender, recipients)


if __name__ == '__main__':
    main()