We want to offer users of our (web-based) personal document management solution the possibility to import documents sent as attachments to their GMail addresses.
Our current solution of just allowing our users's to store their login credentials in our web app and then using this to access the user's GMail inbox via IMAP is not only suboptimal from a security standpoint (we'd rather not store the login credentials, if possible), it also sometimes (maybe when we're polling too often or for too many users's) leads to the login attempts of our app being blocked by GMail. We get the error message "[ALERT] Please log in via your web browser: http://support.google.com/mail/accounts/bin/answer.py?answer=78754" from the IMAP server and our user's report that they see that GMail has blocked some "possible hacking attempts" or similar.
So my main questions are these:
- Would switching to OAuth for authentication (and still using IMAP to check our user's inbox, just authenticated with the OAuth tokens) help in this situation? I found documentation on how to do this, I just want to know if it would help in this situation.
- Are there any guidelines/quotas/restrictions on how often we should / are allowed to poll a user's inbox (or how many connections we open to GMail in parallel etc.)? I couldn't find anything about this in the developer docs at Googles site.
- Is there any other way besides IMAP to be able to import attachments from GMail messages into our app?