Unique short names for images

Question

What would be the best way to rename my user-uploaded images to fairly short but unique names?

uniqid() ?

Answer 1

uniqid () will work.

But you can also use md5 () or sha1 () to create a hash value of the actual image. This will reduce redundant files if someone uploads the image twice.

Answer 2

You will have to agree that your file names will probably not be short, but RFC 4122 is the best practice, and one of the fastest PHP implementations is this:

// Execution (1000 IDs) took 7.509 milliseconds
// Example uuid: f40bc6a1-3bce-4472-add8-bbbe500b7f72
function mimec_uuid()
{
    return sprintf( '%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
        mt_rand( 0, 0xffff ), mt_rand( 0, 0xffff ), mt_rand( 0, 0xffff ),
        mt_rand( 0, 0x0fff ) | 0x4000,
        mt_rand( 0, 0x3fff ) | 0x8000,
        mt_rand( 0, 0xffff ), mt_rand( 0, 0xffff ), mt_rand( 0, 0xffff ) );
}

Personally, however, I used the following (faster and shorter) algorithm for projects that do not need to scale like Flickr:

// Execution (1000 IDs) took 5.097 milliseconds
// Example uuid: 2c2e4067d1c92109660b8deecae1be08
function xuuid()
{
    return md5(microtime() . mt_rand( 0, 0xffff ));
}

Answer 3

- ,

$imgName = md5($userEmail.microtime());

Answer 4

I allow the upload of images with the original image name for SEO purposes. Google et al. Find images of Batman or Eiffel Tower users if I keep the original file name unchanged. So I just add mktime to the beginning and then save it.

$imagename = str_replace(' ','-',$imagename);
$imagename = str_replace('_','-',$imagename);
$target_path = $_SERVER['DOCUMENT_ROOT']."/uploads/".mktime()."-".$imagename;

Answer 5

What is wrong with the 32-digit MD5 image file name? Not too long.

If you like Brian, you allow them to use their own file names, make sure you delete any bad characters: "", etc. for safety.