title: Facebook Like "Object Invalid value" and URL could not be parsed
body: <p>I am getting this error when I did my OG check at facebook<br>
  <a href="https://developers.facebook.com/tools/debug/og/object?q=http%3A%2F%2Fwww.dreampiece.com.au%2Findex.php%3Fmain_page%3Dproduct_info%26cPath%3D2_7%26products_id%3D459" rel="nofollow">https://developers.facebook.com/tools/debug/og/object?q=http%3A%2F%2Fwww.dreampiece.com.au%2Findex.php%3Fmain_page%3Dproduct_info%26cPath%3D2_7%26products_id%3D459</a></p>
  
  <blockquote>
    <p>Object at URL 'http://www.dreampiece.com.au/index.php?main_page=product_info&amp;cPath=2_7&amp;products_id=459' of type 'product' is invalid because the given value '' for property 'og:url' could not be parsed as type 'url'.</p>
  </blockquote>
  
  <p>This is my page source,</p>
  
  <pre><code>&lt;meta property="og:type" content="product" /&gt;
  &lt;meta property="og:url" content="" /&gt;
  &lt;meta property="og:description" content="&amp;nbsp; &amp;nbsp; &amp;nbsp; &amp;nbsp; Product Details:    Total Qty: One Pc Materials: Alloy Electroplate &amp;amp; Rhinestones Size: Pendant - 2.5 cm x 1.6 cm; Length&amp;nbsp;-&amp;nbsp;40.6 cm (Ext 7.2 cm) Country of Origin: Japan Colour:&amp;nbsp;Golden&amp;nbsp;" /&gt;
  &lt;meta property="og:site_name" content="DreamPiece Accessories" /&gt;
  &lt;meta property="fb:admins" content="120867161308451" /&gt;
  &lt;meta property="og:image" content="http://www.dreampiece.com.au/images/Products/m02040.jpg" /&gt;
  </code></pre>
  
  <p>Could it caused by the blank og:url? I am using code as below,</p>
  
  <pre><code>&lt;meta property="og:url" content="&lt;?php echo $canonicalLink; ?&gt;" /&gt;
  </code></pre>