Regex detect empty line as end

Question

I want to extract a sequence out of some text.

The sequence begins with Diagnostic-Code:, the middle part can be any characters even over multiple lines and the end is marked by an empty line (after which the text continues, but this isn't part of the desired sequence).

This does work for the beginning and middle part, but the ending is found too late:

(?s)Diagnostic-Code: (.+)\n\n

The string looks something like this:

...
Status: 5.0.0
Diagnostic-Code: X-Postfix; test.com
*this*
*should*
*be included too*

--EA7634814EFB9.1516804532/mail.example.com
Content-Description: Undelivered Message
...

--------- edit ---------

Thank you for the anwer @Gurman!

But java.util.regex does somehow behave differently than regex101.com

Action: failed
Status: 5.1.1
Remote-MTA: dns; gmail-smtp-in.l.google.com
Diagnostic-Code: smtp; 550-5.1.1 The email account that you tried to reach does
    not exist. Please try 550-5.1.1 double-checking the recipient's email
    address for typos or 550-5.1.1 unnecessary spaces. Learn more at 550 5.1.1
    https://support.google.com/mail/?p=NoSuchUser u11si15276978wru.314 - gsmtp

--E8A363093CEC.1520529178/proxy03.hostname.net
Content-Description: Undelivered Message
Content-Type: message/rfc822

Return-Path: <no-reply@hostname.net>

The pattern matches the whole multiline diagnostic-code on regex101, but java only matches the first line as group 1:

smtp; 550-5.1.1 The email account that you tried to reach does

The java-code:

diagnosticCodePatter = Pattern.compile("(?i)diagnostic[-| ]Code: ([\\s\\S]*?[\\r\\n]{2})");
matcher = diagnosticCodePatter.matcher(message);
    if (matcher.find()) {
        diagnosticCode = matcher.group(0);

Just make the `.+` lazy using `?` after the quantifier like so `.+?` — ctwheels, Feb 28 '18 at 14:40

score 4 · Accepted Answer · answered Feb 28 '18 at 14:40

4

Try this regex:

Diagnostic-Code[\s\S]*?[\r\n]{2}

Click for Demo

Don't forget to escape \ with another \ in front of it, in Java.

Explanation

Diagnostic-Code - matches the text Diagnostic-Code
[\s\S]*? - matches 0+ occurrences of anycharacter(including newlines), as few as possible
[\r\n]{2} - matches 2 occurrences of either a newline character or a carriage-return.

answered Feb 28 '18 at 14:40

Gurmanjot Singh

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this did work perfectly for my cause, thank you for the extensive answer and explanation! – Jagmit Mar 04 '18 at 19:20
I've edited the question because I've got a followup problem. Can you have a look into this please? – Jagmit Mar 08 '18 at 17:44
@JagmitSingh Does [THIS](http://rextester.com/KMGVAD42439) help? – Gurmanjot Singh Mar 09 '18 at 04:15
@Gurnam found the problem. The cause was the infamous "\r\n" vs. "\n" irregularity. Really appreciate your help, wish i could buy you a coffee as a thank you over stackoverflow – Jagmit Mar 13 '18 at 14:47
@JagmitSingh Haha..that wouldn't be required. I am glad I could be of some help :) – Gurmanjot Singh Mar 13 '18 at 14:51

Regex detect empty line as end

1 Answers1