ee: redirect url with trailing forward slash - redirect

Question

How can I redirect to the correct page if somebody adds a trailing forward slash to a url in expression engine?
For example:
A) www.acme.com/event - is the correct url
B) www.acme.com/event/ - has the same content
The problem is I'm using Disqus as a commenting system and it interprets both as different pages. So the simple solution is to redirect to url A when the trailing slash appears.
{if segment_2=="event/"}
{redirect="/event"}
{/if}
This doesn't seem to work. Any ideas that don't involve .htaccess? It's only for one page.
Thanks.

Answer 1

Rewriting my comment as an answer...
Looks like the URL doesn't matter. It's the value of disqus_url that uniquely identifies that page. You should be able to set that reliably.
From the documentation...
disqus_url
Tells the Disqus service the URL of the current page. If undefined,
Disqus will take the window.location.href. This URL is used to look up
or create a thread if disqus_identifier is undefined. In addition,
this URL is always saved when a thread is being created so that Disqus
knows what page a thread belongs to.
While the window.location.href is used in absence of disqus_url, we
highly recommend defining this variable. If a user visits your page at
the URL http://example.com/helloworld.html?123, Disqus may in fact
load a different thread than if the user came from
http://example.com/helloworld.html.
To make sure the right thread is always displayed, you should define
on your page, using an absolute URL, var disqus_url =
'http://example.com/helloworld.html';