Modify Rack App

For one of my ruby applications i need the server to route requests based on the subdomain. There are ways to do this using other gems but i decided to make my own "middleware". This code runs applications based on where the request is going to.

config.ru

require './subdomain'
require './www'

run Rack::Subdomain.new([
  {
    :subdomain => "test", 
    :application => Sinatra::Application
  }
]);

subdomain.rb

module Rack
  class Subdomain
    def initialize(app)
      @app = app
    end

    def call(env)
      @app.each do |app|
        match = 'test'.match(app[:subdomain])
        if match
          return app[:application].call(env)
        end
      end
    end
  end
end

My question is how can i modify this working code to work exactly the same but have it called by code that looks like this:

run Rack::Subdomain do
  map 'www' do
    Example::WWW
  end

  map 'api' do
    Example::API
  end
end

With suggested code:

config.ru

require './subdomain'
require './www'

run Rack::Subdomain.new do |x|
  x.map 'test' do
    Sinatra::Application
  end
end

subdomain.rb

module Rack
  class Subdomain
    def initialize(routes = nil)
      @routes = routes
      yield self
    end

    def map(subdomain)
      @routes << { subdomain: subdomain, application: yield }
    end

    def call(env)
      @routes.each do |route|
        match = 'test'.match(route[:subdomain])
        if match
          return route[:application].call(env)
        end
      end
    end
  end
end

Solution

You call the above "working code" but it doesn't seem to detect the subdomain at all, but wires it to the literal 'test'. At any rate, you can implement a pattern similar to what you want by making a map method which adds entries to your list of subdomain->application routes. I've renamed your @app to @routes since it is a hash of routes, not an application reference.

module Rack
  class Subdomain
    def initialize(routes = [])
      @routes = routes
      yield self if block_given?
    end

    def map(subdomain)
      @routes << { subdomain: subdomain, application: yield }
    end

    def call(env)
      @routes.each do |route|
        match = 'test'.match(route[:subdomain])
        if match
          return route[:application].call(env)
        end
      end
    end
  end
end

rsd = Rack::Subdomain.new do |x|
  x.map 'www' do
    Example::WWW
  end

  x.map 'api' do
    Example::API
  end
end

run rsd