Show localhost in URL for IPv6 addresses

[mirkonasato]

What does it do?

Treat :: like 0.0.0.0 and ::1 like 127.0.0.1 when showing the local Strapi URL.

Why is it needed?

By default Strapi listens on 0.0.0.0 i.e. only on IPv4. This is a problem because Node v18 (current LTS) defaults to IPv6. So if you're running another Node process, say a Next.js app, that tries to connect to Strapi it will probably fail with ECONNREFUSED ::1:1337. (Probably because it depends on how exactly the network is configured on your machine.)

That's why I set HOST=:: in .env. :: the IPv6 equivalent of 0.0.0.0.

But that way Strapi shows an invalid URL in the logs, which won't work if somebody tries to open it in the browser. Either strapi develop or strapi start print:

To manage your project 🚀, go to the administration panel at:
http://:::1337/admin

To access the server ⚡️, go to:
http://:::1337

This change should make it show http://localhost:1337, like it already does for 0.0.0.0.

How to test it?

Start a Strapi app and see what URL it prints to the console.

Related issue(s)/PR(s)

#12285