There’s one big common frustration among Gmail users on iPhone that you cannot receive instant notification for coming mails.  On the other hand, you know that Boxcar is one of the must-haves for iPhone bringing you a fully customizable push notification method that is flexible and easy to use.

It may seem enabling push notification for Gmail is as easy as setting up your Gmail account to forward important mails to your Boxcar address, but it actually isn’t.  Suppose you want to be only notified of mails hitting Inbox because you receive tons of mails on mailing lists or mail magazines that are tagged and archived by filters. You’ll find it not easy to write a filter rule that matches mails that will be dropping in Inbox, because in Gmail all filters are evaluated in parallel and you cannot define a rule based on tags added by other filters.

Another concern is your privacy.  Even if you managed to make up a filter rule and successfully set up forwarding to Boxcar, every mail forwarded would be relayed through external servers and end up having a copy on Boxcar.  I’m not saying I don’t trust Boxcar or relay servers, but there’s no point for you (nor for them!) to carry a private mail content including sensitive headers outside of Gmail just for notifying that a mail has received.

Here’s why I wrote bcbiff(1).  Bcbiff is a tool that checks the Inbox folder (or any specified folders) on an IMAP server for unread mails and sends a notification via Boxcar for each.  Mail bodies and headers other than From, Date and Subject are stripped off, and the Message-Id’s of the latest 100 unread mails are cached so that you get just one notification per mail.  Bcbiff supports multiple mailboxes and Boxcar accounts.

To use it, you need a server on which you can periodically run bcbiff (Ruby 1.8.7+ or 1.9.2+ required) and send email via the sendmail(1) command.  See README for details.

Have fun with it!