Question

In my Rails controller, I have a URL that the user provides. I would like to extract the title from the <title>...</title> tag in the HTML of that URL, and assign it to a variable title. How can I do that?

EDIT: It would be a plus to do it without use of external package/library

Answer 1

I’ve just tried it with HTTParty to fetch the document, and Nokogiri to parse it:

Nokogiri::HTML::Document.parse(HTTParty.get("http://www.google.com").body).title
#=> "Google"

Updated:

This works with Net:HTTP, which is part of the ruby standard library, and a regex:

Net::HTTP.get(URI("http://twitter.com")) =~ /<title>(.*?)<\/title>/
$1 # get the first result from the matching
#=> "Twitter"

Updated:

=~ called “match” is a method on String and is used to match a regular expression against a String. It’s basically the same as Regexp#match but the receiver and argument are inverted.

string = "<title>my title</title>
regexp = /<title>(.*?)<\/title>/

string =~ regexp
$1 # => "my title"

regexp.match(string)
$1 # => "my title"

What happens when the HTML document you fetch does not contain a title, or title tag?

"<title></title>" =~ regexp
$1 # => ""

"" =~ regexp
$1 # => nil