A way to get meta data from external url via php including opengraph items, so you can use it on your site.

read-metadata.php

<?php
// Url
$link = 'http://www.google.com';
//Get all meta tags and loop through them
if($link!=''){
	$sites_html = file_get_contents($link);
	$html = new DOMDocument();
	@$html->loadHTML($sites_html);
	$meta_og_img = null;
	foreach($html->getElementsByTagName('meta') as $meta) {
	    if($meta->getAttribute('name')=='title'){ 
	        $meta_title = $meta->getAttribute('content');
	    }
	    if($meta->getAttribute('name')=='author'){ 
	        $meta_author = $meta->getAttribute('content');
	    }
	    if($meta->getAttribute('name')=='description'){ 
	        $meta_description = $meta->getAttribute('content');
	    }
	    //Facebook
	    if($meta->getAttribute('property')=='og:title'){ 
	        $meta_og_title = $meta->getAttribute('content');
	    }
	    if($meta->getAttribute('property')=='og:site_name'){ 
	        $meta_og_sitename = $meta->getAttribute('content');
	    }
	    if($meta->getAttribute('property')=='og:image'){ 
	        $meta_og_img = $meta->getAttribute('content');
	    }
	}
}	
?>