Simple regex to replace first part of URL

Question

Given

• http://localhost:3000/something
• http://www.domainname.com/something
• https://domainname.com/something

How do I select whatever is before the /something and replace it with staticpages?

The input URL is the result of a request.referer, but since you can't render request.referer (and I don't want a redirect_to), I'm trying to manually construct the appropriate template using controller/action where action is always the route, and I just need to replace the domain with the controller staticpages.

Answer 1

You could use a regex like this:

(https?://)(.*?)(/.*)

Working demo

As you can see in the Substitution section, you can use capturing group and concatenates the strings you want to generate the needed urls.

The idea of the regex is to capture the string before and after the domain and use \1 + staticpages + \3.

If you want to change the protocol to ftp, you could play with capturing group index and use this replacement string:

ftp://\2\3

So, you would have:

ftp://localhost:3000/something
ftp://www.domainname.com/something
ftp://domainname.com/something