Ruby on Rails route for wildcard subdomains to a controller/action

Question

I dynamically create URLs of the form username.users.example.com:

bob.users.example.com
tim.users.example.com
scott.users.example.com

Answer 1

You can constraint route dynamically based on some specific criteria by creating a matches? method

Lets say we have to filter sub domain of URL

constraints Subdomain do
  get '*path', to: 'users#show'
end

class Subdomain
  def self.matches?(request)
    (request.subdomain.present? && request.subdomain.start_with?('.users')
  end
end

What we are doing here is checking for URL if it start with sub domain users then only hit users#show action. Your class must have mathes? method either class method or instance method. If you want to make it a instance method then do

constraints Subdomain.new do
  get '*path', to: 'proxy#index'
end

you can achieve same thing using lambda as well like below.

Instead of writing class we can also use lambdas

get '*path', to: 'users#show', constraints: lambda{|request|request.env['SERVER_NAME'].match('.users')}