Check whether image exists on remote URL

Question

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?

Answer 1

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

Answer 2

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 “;
}

Answer 3

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.

Answer 4

I have been doing this for my real estate picture tracking...

$im = @imagecreatefromjpeg($pathtoimg);
if($im)
  imagedestroy($im); // dont save, just ack...
elseif(!$missing[$inum])
  $img404arr[] = $inum;

It 'seems' faster than downloading the actual image, taking about .3 seconds for each from images that avg 100k.

I wish I could just do a header check and read whether I get a 200 vs a 404 without downloading anything. Anyone have that handy?

Answer 5

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

Answer 6

You can use getimagesize()

Credit: http://junal.wordpress.com/2008/07/22/checking-if-an-image-url-exist/

Answer 7

It's probably moot at this point, but this works for me:

function is_webfile($webfile)
{
 $fp = @fopen($webfile, "r");
 if ($fp !== false)
  fclose($fp);

 return($fp);
}

Answer 8

Solution from https://www.experts-exchange.com

<?php
function url_exists($url) {
    if (!$fp = curl_init($url)) return false;
    return true;
}
?>

Answer 9

I am using this and modified from all other answers by myself. Exit or not exit image but we also have to handle error which is missing in other answers.

Here is what I am using :

function checkRemoteFile($url)
{
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_NOBODY, true);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true); // follow redirects

    // Set a maximum timeout of 10 seconds to prevent the script from hanging
    curl_setopt($ch, CURLOPT_TIMEOUT, 10); 

    // Execute the request and get the HTTP status code
    curl_exec($ch);
    $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);

    curl_close($ch);

    // Check the HTTP status code
    if($httpCode >= 200 && $httpCode < 300) {
        // The file exists and the server returned a successful HTTP status code
        return true;
    } else {
        // The file does not exist or the server returned an error HTTP status code
        return false;
    }
}

Answer 10

If the images all exist on the same remote server (or in the same network), you could run a web service on that server that will check the file system for the the image file and return a bool value indicating wheter the image exists or not.