Apex Strip Email Replies Method

gistfile1.txt

/**
 *	This utility attempts to strip the reply portion of an email by looking for common reply seperators
 *  The reply separator depends on the email client, so it is not likely to strip all replies 100%
 *  This is a best effort for known email client formats. 
 *
 *  @param String original email message body
 *  @returns String email message with the reply lines stripped
 */
public static String stripResponse(String email) {
	
	// Normalize line breaks
	email.replaceAll('\r\n', '\n');
	
	// Check for On ... wrote: that break to multiple lines and force to one line for filtering
	Pattern p = Pattern.compile('(?m)^On .+<[^>]+> wrote:$');
	Matcher m = p.matcher(email);
	if (m.find()) {
		email = email.substring(0,m.start()-1) + email.substring(m.start(), m.end()).replaceAll('\n', '') + email.substring(m.end()+1);
	}
	
	String[] lines = email.split('\n');
	String out = '';
	
	Boolean firstLine = true;
	for (String line : lines) {
		
		// Make sure the reply is not the first line of the message (workaround for Cirrus Insight in particular which starts with From:)
		if (!firstLine) { 
			if (line.equals('--') || line.equals('-- ') || 
				line.startsWith('-----Original Message-----') || 
				line.startsWith('--------------- Original Message ---------------') ||
				line.startsWith('________________________________') || 
				(line.startsWith('On ') && line.endsWith(' wrote:')) ||
				line.startsWith('From: ') ||
				line.startsWith('Sent from my iPhone')) {
					break;
			}
		}
		firstLine = false;
		out += line + '\n';
	}
	return out;
}