Match only links that contain only second level domains from a list of URLs

Question

I am trying to filter a list of links to match only those which are only a second level domain

Success:

https://www.thingisawesome.anything
https://thingisawesome.anything
http://www.thingisawesome.anything
http://thingisawesome.anything
http://thingisawesome.anything/
https://www.thingisawesome.anything/

Failure:

http://thingisawesome.ventures/index.html
https://subdomain.geocities.com/
https://www.twitter.com/8288hs98ff

This got me close:

(http)s?(:\/\/)(w*)(\.?)(\w*)(.)(\w*)(\/?)

But it would not reject the ones to fail, only match part of it.

[`anything`, `ventures`, and `com` are TLDs](https://en.wikipedia.org/wiki/Top-level_domain) in your examples. Am I correct in understanding that you want to match URLs that have only the `http` or `https` scheme, any second-level domain, and an optional subdomain of `www`? — Aankhen, Jul 20 '18 at 19:09
Sorry, I misspoke. I am not looking for TLDs, but instead a link that has only a second level domain, that is http or https. — Luke Pighetti, Jul 20 '18 at 19:14

Aankhen · Answer 1 · 2018-07-20T19:23:22.450

0

Based on the examples (which aren’t matching TLDs), which show newline-separated lists of URLs (no unencoded IDNs), and assuming the capture groups in your attempt aren’t used later, you want to match (in multiline mode):

the start of the line
http
an optional s
://
an optional www.
the 2LD and TLD, which can consist of letters, numbers, and hyphens (but not in the initial position)
an optional slash
the end of the line

Putting that together gives us:

^https?://(?:www\.)?[a-zA-Z0-9][a-zA-Z0-9-]+\.[a-zA-Z0-9][a-zA-Z0-9-]+/?$

Try it.

edited Jul 20 '18 at 19:23

answered Jul 20 '18 at 19:16

Aankhen

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19

Updated the regex. `\w` is too permissive for domain names. – Aankhen Jul 20 '18 at 19:21

Match only links that contain only second level domains from a list of URLs

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