How to implement user specific sub domains in rails

I am writing a rails application where users can have their own username based subdomain like GitHub pages => USERNAME.github.io

What I have done is created a controller which parses subdomain from the request and finds the corresponding user.

def show
 @user = User.where(name: request.subdomain)
end

now how should I write my route so that I can accept any user specific subdomain and direct it to the above controller

Solution

Yes, you can get the subdomain in your routes and direct to your controller.

You will get your subdomain either with a helper or in your routes with regexp. a regexp example is below

get '/', to: 'controller#show', constraints: { subdomain: '/^[a-zA-Z]*/' }

the above example should get a typical subdomain.

you can find some good examples here in the links below. The rails cast has a very good example of routing by subdomain