Parse a string as if it were a querystring in Ruby on Rails

Question

I have a string like this:

"foo=bar&bar=foo&hello=hi"

Does Ruby on Rails provide methods to parse this as if it is a querystring, so I get a hash like this:

{
    :foo => "bar",
    :bar => "foo",
    :hello => "hi"
}

Or must I write it myself?

EDIT

Please note that the string above is not a real querystring from a URL, but rather a string stored in a cookie from Facebook Connect.

Answer 1

The answer depends on the version of Rails that you are using. If you are using 2.3 or later, use Rack's builtin parser for params

 Rack::Utils.parse_nested_query("a=2") #=> {"a" => "2"}

If you are on older Rails, you can indeed use CGI::parse. Note that handling of hashes and arrays differs in subtle ways between modules so you need to verify whether the data you are getting is correct for the method you choose.

You can also include Rack::Utils into your class for shorthand access.