How to manipulate a URL in Rails/Ruby?

I want to manipulate a URL to get开发者_JAVA技巧 just the base site name.

For example I have the URL:

http://stackoverflow.com/questions/ask,

which should just return stackoverflow.

Also if I have the URL:

http://stackoverflow.com/questions/4988199/rails-3-mechanize-socketerror-getaddrinfo-host-or-name-not-known

it should also be only stackoverflow.

Final example, if I have the URL:

http://www.google.dk/search?q=ruby+string+manipulation

it should be google.

How do I strip away everything but the domain name of a URL?

You could use something already available in the std Ruby distribution:

irb(main):001:0> require "uri"
=> true
irb(main):002:0> a = URI.parse("http://www.google.com")
=> #<URI::HTTP:0x3b3eb78 URL:http://www.google.com>
irb(main):003:0> a.host
=> "www.google.com"
irb(main):004:0>

Probably the easiest solution would be to use the Domainatrix gem to take care of this for you. Once you have it installed, it's just a matter of doing this:

url = Domainatrix.parse("http://www.google.dk/search?q=ruby+string+manipulation")
url.domain # returns 'google'

There are a few more code examples and options on their github page.

If you don't want to use a separate gem, you can try some simple regex

(https?:\/\/)?(www\.)?([^\.]+).*