MAB.EmailReplyParser

A library for parsing plain-text email replies and removing quotes, signatures etc.

Usage

In both examples, we'll assume that body is a string variable containing the plain text message body extracted from an email. This library does not deal with MIME parsing at all; for that you should definitely use MimeKit.

From F#

open MAB.EmailReplyParser

// Returns just the reply portion of the message body 
EmailReplyParser.getReply body

// Returns a normalised* string[] representing the lines in the message body
EmailReplyParser.getLinesPlainText body

// Returns a list of EmailReplyLine records containing information about
// each line (what it is, whether it should be visible etc)
EmailReplyParser.getLines body

From C#

using MAB.EmailReplyParser;

EmailReplyParser.getReply(body);
EmailReplyParser.getLinesPlainText(body);
EmailReplyParser.getLines(body);

In almost every case, EmailReplyParser.getReply is the function you'll actually want to use. The others can be useful if you're getting incorrect results and need to visualise how the text has been split up and classified.

* In this instance, "normalisation" means applying some pre-processing to the message body, like making sure quote headers aren't split across multiple lines and adding a blank line before separators.

Rationale

There are already a bunch of parsers out there which do roughly the same job, most of which are ports of the GitHub email parser library. However, that library looks to have been abandoned for some time, and there are several pull requests which fix issues with newer reply/signature patterns but have never been merged.

I created this library to try and consolidate the updates from the various existing libraries, while also taking a different approach to the general parsing logic (which I believe is easier to inspect and debug).

Inspiration

Thanks to these libraries, without which I wouldn't have had a clue where to start!

• https://github.com/github/email_reply_parser (Ruby)
• https://github.com/zapier/email-reply-parser (Python)
• https://github.com/EricJWHuang/EmailReplyParser (C#)
• https://github.com/mailgun/talon (Python)