How to get the subdomain value from a url?

how can I开发者_Go百科 get the subdomain value in rails, is there a built-in way to do this?

e.g.

test123.example.com

I want the test123 part of the url.

---

Rails 3.0 has this capability built-in, you can access the subdomain from request.subdomain.

You can also route based on the subdomain:

class SupportSubdomain
  def self.matches?(request)
    request.subdomain == "support"
  end
end

Basecamp::Application.routes do
  constraints(SupportSubdomain) do
    match "/foo/bar", :to => "foo#bar"
  end
end

If you're using 2.3, you'll need to use a plugin such as subdomain-fu.

---

Use the following method inside your controller

request.subdomains

This Returns an array of subdomains

---

account_location is also a good plugin. After using it, you can find the account based on different subdomains. And you can find out subdomain from url just by writing

request.subdomains(0).first

in your code.

---

In case you are working with a string, and assuming it can be a true URI, you can do this to extract the subdomain.

require 'uri'

uri = URI.parse('http://test123.example.com')
uri.host.split('.').first
=> "test123"

https://stackoverflow.com/a/13243810/3407381

---

Simple in your controller just do the following

unless request.subdomains.any?
   #No domains available redirect
   redirect_to subdomain: 'www'
end

---

You can use the SubdomainFu plugin. This plugin gives you a method current_subdomain which returns the current_subdomain of your app.

You can also have a look at this Railscast

UPDATE

You can also use request.subdomains this will give you an array of subdomains.

---

For anyone looking to get the subdomains on localhost using WEBrick:

Put config.action_dispatch.tld_length = 0 into config/environments/development.rb and everything should work.

Link to SO post here: Can I make Rails / WEBrick recognize entries in /etc/hosts as subdomains (instead of domains)?

Link to Github post: https://github.com/rails/rails/issues/12438

---

current domain with subdomains:

"#{request.subdomain}.#{request.domain}"
# or
"#{request.subdomains.join(".")}.#{request.domain}"

---

A bit late to the party but here's what I used in older versions of rails.

subdomain = request.subdomains.join('.')

It should be backwards compatible in newer versions