问题
Is there a way to check if a sent e-mail has been marked as spam or deleted?
I work with Rails 3.
回答1:
No, there isn't. After your mail has been sent to your receiver's SMTP server, there's no way to track it down anymore.
I know what you're thinking: how can some mail-clients track down wether an email has been read or not (e.g. in Outlook). They can do this by adding a little img-tag to their mails (html). When a user opens the mail, it'll open the path specified in the img's src-attribute. Since that's a script (like PHP or something), it can automatically sets a flag to 'seen' when a mail has been opened.
Of course, there are some other ways to track this down, but I think this is the most popular one.
However, this can't be done to check whether a mail has been rejected, deleted or moved to the spam-folder.
来源：https://stackoverflow.com/questions/7161899/how-can-i-detect-that-an-email-has-been-rejected-as-spam-by-the-recipient