Twitter "Tweet" button does not count tweets? You may be doing it wrong :)

Some time ago, I decided to add the Twitter "Tweet" button to subpages of kalamonsoft.com, so that you could share your feelings about the software I make. The problem was - the button was not counting tweets. Now, it could mean that nobody cares to share their opinion about my products on Twitter, but it was unlikely, as Facebook and Google+ counters did go up.

Searching google did not help at all. I was just about to give up on this button, but I found this Twitter development discussions place, where you could ask questions and hopefully somebody listens. So I asked my question, and lo and behold, @episod answered (praise this guy).

The problem was - in order for the button to work, the HTTP HEAD request has to be properly handled by your site. Now, for most of the self-hosted sites this is not a problem as web servers have this built-in. But I am hosting my site on Google App Engine, and the site is implemented in Python. I am providing handlers to HTTP requests by overriding some methods of the webapp.RequestHandler class. Typically only the get() or post() method is overriden. Which makes HTTP HEAD not work - an error is returned and the twitter button does not like this.

After I added a trivial head() method override, the twitter button immediately started to work. 

So, if you want the twitter button to work on your site, remember to handle HEAD requests properly.