How do I easily parse a URL with parameters in a Rails test?

Question

I have a some code that embeds a return_to URL into a redirect (like OpenID) that I want to test:

def test_uses_referrer_for_return_to
  expected_return_to = 'http://test.com/foo'
  @request.env['HTTP_REFERER'] = expected_return_to
  get :fazbot
  # @response.redirected_to looks like http://service.com?...&return_to=[URI-encoded version of URL above]&...
  encoded_return_to = (something_here)[:return_to]
  assert_equal expected_return_to, URI.unencode(encoded_return_to)
end

It's a Rails ActionController::TestCase, so I have access to all sorts of helper methods; I just can't find the right one.

Of course I could use URI.parse to get the params part of the URL, then split it on /&|?/ and then split again on '=', but I'm hoping this is already done for me. Plus, what if I miss some obscure rule in URL escaping or parameter parsing? There has to be something in ActionPack or ActiveSupport to do this, but I can't find it.

Thanks :)

Answer 1

CGI::parse(querystring) will parse a querystring into a hash. Then, CGI::unescape(string) will undo any URL-encoding in the value.

Alternatively, you can use Rack::Utils.parse_query and Rack::Utils.unescape if you're on a recent Rack-based version of Rails, and want to be super-modern.

I'm not aware of any Rails-specific helper methods that wrap these utility functions, but they're pretty simple to use, and CGI or Rack is already loaded in the Rails environment anyway.

Answer 2

You want Addressable for this.

uri = Addressable::URI.parse("http://example.com/?var=value")
uri.query_values # => {"var"=>"value"}
uri.query_values = {"one" => "1", "two" => "2"}
uri.to_s # => "http://example.com/?two=2&one=1"

It'll automatically handle all the escaping rules for you, and it has some other useful features, like not throwing exceptions for perfectly valid but obscure URIs like the built-in URI parser.

Update: It looks like Addressable will eventually be morphing into a replacement for the built-in URI parser in 1.9.x.