How to get Absolute Path of Jekyll Bootstrap Page

I tried to add a facebook share link to a jekyll bootstrap page, however when adding the href that FB will use in the share I used {{ HOME_PATH }}. This turns out to be the relative path of /, however (which FB does not understand). Does anybody know how to get the absolute path without having to hard-code it?

Code that gives a /

<a name="fb_share" type="button"
            share_url="{{ HOME_PATH }}">Share this event on Facebook</a>
 

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