How to work with dynamic virtual subdomains in Linux?

Question

linux

We have Elementary OS based on Ubuntu 12.
The Rails application needs to dynamically create subdomains locally.
I could not find an analogue of pow.cx for my system (there is no installation documentation for xip.io on the network).
Help out.

Answer 1

/etc/hosts

Answer 2

1) Create a "*" (asterisk) entry in bind, it must come after all entries for the domain. This will need to be done once.
2) Parse the HTTP request header "Host: ..." in the application. You can put, for example, nginx as a frontend and do hostname mapping at its level.