Strip signatures and replies from emails

If your system is in-house and/or you have a limited number of reply formats, it's possible to do a pretty good job. Here are the filters we have set up for email responses to trac tickets:

Drop all text after and including:

1. Lines that equal '-- \n' (standard email sig delimiter)
2. Lines that equal '--\n' (people often forget the space in sig delimiter; and this is not that common outside sigs)
3. Lines that begin with '-----Original Message-----' (MS Outlook default)
4. Lines that begin with '________________________________' (32 underscores, Outlook again)
5. Lines that begin with 'On ' and end with ' wrote:\n' (OS X Mail.app default)
6. Lines that begin with 'From: ' (failsafe four Outlook and some other reply formats)
7. Lines that begin with 'Sent from my iPhone'
8. Lines that begin with 'Sent from my BlackBerry'

Numbers 3 and 4 are 'begin with' instead of 'equals' because sometimes users will squash lines together on accident.

We try to be more liberal about stripping out replies, since it's much more of an annoyance (to us) have reply garbage than it is to correct missing text.

Anybody have other formats from the wild that they want to share?

Check out the email_reply_parser gem - https://github.com/github/email_reply_parser . It does a nice job handling this problem.

I don't believe you can do this reliably (signatures used to begin with '--' but I don't see that anymore). Perhaps you're better off asking people to reply inbetween text headers and then simply strip the reply from this ? It's not elegant, but perhaps more reliable.

e.g.

REPLY BETWEEN HERE -->AND HERE -->

so you'd simply look for the required headers above and take what's inbetween.