如何用Python读取Gmail正文中的特定数据？

pip install --upgrade google-api-python-client google-auth-httplib2 google-auth-oauthlib

import os.path
import base64
import re
from google.auth.transport.requests import Request
from google.oauth2.credentials import Credentials
from google_auth_oauthlib.flow import InstalledAppFlow
from googleapiclient.discovery import build

# 如果修改了这些范围，请删除文件 token.json
SCOPES = ['https://www.googleapis.com/auth/gmail.readonly']

def main():
    """显示用户的Gmail中的邮件正文并提取特定数据"""
    creds = None
    # token.json文件存储用户的访问和刷新令牌，并且在授权流程中自动创建
    if os.path.exists('token.json'):
        creds = Credentials.from_authorized_user_file('token.json', SCOPES)
    # 如果没有（有效的）凭据，请让用户登录
    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.json', SCOPES)
            creds = flow.run_local_server(port=0)
        # 将凭据保存到token.json文件中，以便下次使用
        with open('token.json', 'w') as token:
            token.write(creds.to_json())

    # 使用凭据调用Gmail API
    service = build('gmail', 'v1', credentials=creds)

    # 获取用户的邮件列表
    results = service.users().messages().list(userId='me', maxResults=10).execute()
    messages = results.get('messages', [])

    if not messages:
        print('No messages found.')
    else:
        print('Messages:')
        for message in messages:
            msg = service.users().messages().get(userId='me', id=message['id']).execute()
            msg_str = base64.urlsafe_b64decode(msg['payload']['body']['data']).decode('utf-8')
            print(f"Message snippet: {msg['snippet']}")
            print(f"Message body: {msg_str}")

            # 使用正则表达式提取特定数据
            pattern = re.compile(r'your_regex_pattern_here')
            matches = pattern.findall(msg_str)
            for match in matches:
                print(f"Found data: {match}")

if __name__ == '__main__':
    main()