Check whether image exists on remote URL

I am generating dynamic URLs of images for book ISBNs. I need a reliable way with PHP to check whether the images actually exist at the remote url. I tried various approaches with different PHP libraries, curl, etc., but none of them works well, some of them are downright slow. Given the fact that I need to generate (and check!) about 60 URLS for each book in my database, this is a huge waiting time. Any clues?

function checkRemoteFile($url)
{
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL,$url);
    // don't download content
    curl_setopt($ch, CURLOPT_NOBODY, 1);
    curl_setopt($ch, CURLOPT_FAILONERROR, 1);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

    $result = curl_exec($ch);
    curl_close($ch);
    if($result !== FALSE)
    {
        return true;
    }
    else
    {
        return false;
    }
}

--> that is the fastest way if your host supports curl

Use getimagesize() method like this

$external_link = ‘http://www.example.com/example.jpg’;
if (@getimagesize($external_link)) {
echo  “image exists “;
} else {
echo  “image does not exist “;
}

There is no "easy" way here - at a very minimum, you need to generate a HEAD request and check the resulting content type to make sure it's an image. That's not taking into account possible referrer issues. curl is the way to go here.

You could use curl. Just set the curl option CURLOPT_NOBODY to true. This will skip body information and only get the head (thus http code as well). Then, you could use the CURLOPT_FAILONERROR to turn this whole process into a true/false type check