Add subdomain to localhost URL

Question

I am writing an web application that behaves differently depending on a url prefix. The format is something like:

   https://myprefix.mycompany.com

The web app behaves differently based on myprefix. My web app extract that part from the URL and act on that.

However, when I test on my local, I use an localhost address:

   https://localhost:1234

I counldn't do something like:

   https://myprefix.localhost:1234

What is the best way for me to test this scenario?

Many thanks

Answer 1

I'm not sure about same behaviour at windows. I'm working on linux mint.

You can use lvh.me:port as a local domain. You can imagine that your project is deployed on localhost:port on this domain.

Instead of sub.localhost:port you've to use sub.lvh.me:port

UPD

sub.localhost:port works at chrome. Firefox automatically adds www. at the beginning of entered domain that can cause problems with subdomains testing

Answer 2

Unfortunately, because localhost is not a proper domain, you can't add a subdomain to it like that. You can, however, trick your computer into thinking it owns a specific domain and test things that way. For instance, if you have a UNIX-based operating system, open (as root) the file /etc/hosts and add a line (or lines) like this:

127.0.0.1    example.com
127.0.0.1    subdomain.example.com

Your computer will now treat both example.com and subdomain.example.com as belonging to itself. If you visit either in your web browser, they will work the same, in principle, as localhost, but your web server will see the correct domain in its Host header.