How to extract Joomla image PHP for Opengraph

Question

I have been trying to develop my own opengraph. I found some codes online and try to merge them but to no avail. I wonder if I have done it wrong.

// Try to find image in article
         $img = 0;
         $fulltext = '';
         if (isset($row->fulltext) && $row->fulltext != '') {
        $fulltext = $row->fulltext;
         }
         $introtext = '';
         if (isset($row->introtext) && $row->introtext != '') {
            $fulltext = $row->introtext;
         }
         $content = $introtext . $fulltext;
         preg_match('/< *img[^>]*src *= *["\']?([^"\']*)/i', $content, $src);
         if (isset($src[1]) && $src[1] != '') {
            $timage = htmlspecialchars($src[1]));
            $img = 1;
         }

$doc =& JFactory::getDocument();
$doc->addCustomTag( '
<meta property="og:title" content="'.$this->escape($this->item->title).'"/>
<meta property="og:type" content="article"/>
<meta property="og:image" content="'.$timage.'";/>
');

Second Code I am experimenting (I received the Undefined Variable : timage

function get_joomla_image($url)
    {
            if (preg_match('/< *img[^>]*src *= *["\']?([^"\']*)/i', $url, $match)) {
            $timage = $match[1];
            echo $match[1];
        }
    }



// get the corresponding thumbnail images   
if (isset($match[1]) and !empty($match[1]))
{
 $timage= htmlspecialchars(JURI::root().$match[1]);
}

$doc =& JFactory::getDocument();
$doc->addCustomTag( '
<meta name="og:image" content="'.$timage.'">

Thank you Joomla guru for your help.

Answer 1

How about using DOMDocument instead of preg_match? That way you should be able to get all images in the body using getElementsByTagName(). Maybe something like this could work:

$buffer = JResponse::getBody();
$document = new DOMDocument();
@$document->loadHTML($buffer);

$images = $document->getElementsByTagName('img');

$images will be an object containing all elements (images) in your document. If you want to get the URL of the first image, you can use

 $image = $images->item(0)->getAttribute('src');

then

$doc = JFactory::getDocument();
$doc->addCustomTag( '
   <meta name="og:image" content="'.$image.'">
');

Just some quick ideas, you'll probably have to modify the code to make it work.

Answer 2

For your Error:- Undefined Variable : timage

I have noticed that $timage variable is declared inside condition statement in both code.

 if (isset($src[1]) && $src[1] != '') {
            $timage = htmlspecialchars($src[1]));
            $img = 1;
         }

If above condition fails, $timage variable will never be declared. Try declaring this variable outside statement and change value as per condition. Hope this helps.