title: How to fetch meta properties (images, videos, titles..) from links like Facebook does?
body: <p>I'm trying to add a functionality for a webapp where when users post links, the title picture URL is fetched somehow, so that it can be displayed on my web app.  </p>
  
  <p>Facebook does this already; when you share a link it fetches this information and displays the title, a blurb, a picture etc.</p>
  
  <p>I know that it identifies the pertinent data as such:</p>
  
  <pre><code> &lt;meta name="title" content="title" /&gt;
   &lt;meta name="description" content="description " /&gt;
   &lt;link rel="image_src" href="thumbnail_image" /&gt;
  </code></pre>
  
  <p>But how could I it actually fetch these strings?</p>
  
  <p>I'm programming in Ruby on Rails, so an answer compatible with that, or using javascript perhaps, would be most useful!</p>