https://gist.github.com/Jimbly/d996bd8c80ae1a376a0b 적용 실제
https://expressjs.com/en/resources/middleware/vhost.html
Install
API
vhost(hostname, handle)
Create a new middleware function to hand off request to handle when the incoming host for the request matches hostname. The function is called as handle(req, res, next), like a standard middleware.
hostname can be a string or a RegExp object. When hostname is a string it can contain * to match 1 or more characters in that section of the hostname. When hostname is a RegExp, it will be forced to case-insensitive (since hostnames are) and will be forced to match based on the start and end of the hostname.
When host is matched and the request is sent down to a vhost handler, the req.vhost property will be populated with an object. This object will have numeric properties corresponding to each wildcard (or capture group if RegExp object provided) and the hostname that was matched.
Examples
using with connect for static serving
using with connect for user subdomains
using with any generic request handler