Question

I wondered if there were any plugins or methods which allow me to convert resource routes which allow me to place the controller name as a subdomain.

Examples:

map.resources :users
map.resource :account
map.resources :blog
...

example.com/users/mark
example.com/account
example.com/blog/subject
example.com/blog/subject/edit
...

#becomes

users.example.com/mark
account.example.com
blog.example.com/subject
blog.example.com/subject/edit
...

I realise I can do this with named routes but wondered if there were some way to keep my currently succinct routes.rb file.

Answer 1

The best way to do it is to write a simple rack middleware library that rewrites the request headers so that your rails app gets the url you expect but from the user’s point of view the url doesn’t change. This way you don’t have to make any changes to your rails app (or the routes file)

For example the rack lib would rewrite: users.example.com => example.com/users

This gem should do exactly that for you: http://github.com/jtrupiano/rack-rewrite

UPDATED WITH CODE EXAMPLE

Note: this is quickly written, totally untested, but should set you on the right path. Also, I haven’t checked out the rack-rewrite gem, which might make this even simpler

# your rack middleware lib.  stick this in you lib dir
class RewriteSubdomainToPath

  def initialize(app)
    @app = app
  end

  def call(env)
    original_host = env['SERVER_NAME']
    subdomain = get_subdomain(original_host)
    if subdomain
      new_host = get_domain(original_host)
      env['PATH_INFO'] = [subdomain, env['PATH_INFO']].join('/')
      env['HTTP_X_FORWARDED_HOST'] = [original_host, new_host].join(', ')
      logger.info("Reroute: mapped #{original_host} => #{new_host}") if defined?(Rails.logger)
    end

    @app.call(env)

  end

  def get_subdomain
    # code to find a subdomain.  simple regex is probably find, but you might need to handle 
    # different TLD lengths for example .co.uk
    # google this, there are lots of examples

  end

  def get_domain
    # get the domain without the subdomain. same comments as above
  end
end

# then in an initializer
Rails.application.config.middleware.use RewriteSubdomainToPath