Get image from RSS Feeds with no image URL - php

Question

I would just like to to know how other developers manage to properly get/extract the first image in the blog main content of a site from URL in the RSS feed. This is the way I think of since the RSS feeds don't have image URL of the post/blog item in it. Though I keep on seeing
<img src="http://feeds.feedburner.com/~r/CookingLight/EatingSmart/~4/sIG3nePOu-c" />
but it's only 1px image. Does this one has relevant value to the feed item or can I convert this to maybe the actual image? Here's the RSS http://feeds.cookinglight.com/CookingLight/EatingSmart?format=xml
Anyway, here's my attempt to extract the image using the url in the feeds:
function extact_first_image( $url ) {
$content = file_get_contents($url);
// Narrow the html to get the main div with the blog content only.
// source: http://stackoverflow.com/questions/15643710/php-get-a-div-from-page-x
$PreMain = explode('<div id="main-content"', $content);
$main = explode("</div>" , $PreMain[1] );
// Regex that finds matches with img tags.
$output = preg_match_all('/<img[^>]+src=[\'"]([^\'"]+)[\'"][^>]*>/i', $main[12], $matches);
// Return the img in html format.
return $matches[0][0];
}
$url = 'http://www.cookinglight.com/eating-smart/nutrition-101/foods-that-fight-fat'; //Sample URL from the feed.
echo extact_first_image($url);
Obvious downside of this function:
It properly explodes if <div id="main-content" is found in the html. When there's another xml to parse with another structure, there will be another explode for that as well. It's very much static.
I guess its worth mentioning also is regarding the load time. When I perform loop through out the items in the feed, its even more longer.
I hope I made clear of the points. Feel free to drop in any ideas that could help optimize the solution perhaps.

Answer 1

The image urls are in the rss file, so you can get them just by parsing the xml. Each <item> element contains a <media:group> element that contains a <media:content> element. The url to the image for that item is in the "url" attribute of the <media:content> element. Here is some basic code (php) for extracting the image urls into an array:
$xml = simplexml_load_file("http://feeds.cookinglight.com/CookingLight/EatingSmart?format=xml");
$imageUrls = array();
foreach($xml->channel->item as $item)
{
array_push($imageUrls, (string)$item->children('media', true)->group->content->attributes()->url);
}
Keep in mind, though, that the media doesn't necessarily have to be an image. It can be a video or an audio recording. There might even be more than one <media:group>. You can check the "type" attribute of the <media:content> element to see what it is.