PHP How to generate a unique ID equal to that of the GOOGLE shortcuts

I confess that I do not know a way to do this automatically. But one solution I thought of was you make an associative table between an ID and the generated characters. You would do a function that would generate these 5 characters, check if these characters are already being used, otherwise save the ID and code in the database.

If you want a function to generate these characters I'm leaving an example here

function gerarCaracteres($tamanho = 5) {
    $caracteres = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyz';
    $retorno = '';
    $len = strlen($caracteres);
    for ($i = 1; $i <= $tamanho; $i++) {
        $rand = mt_rand(1, $len);
        $retorno .= $caracteres[$rand-1];
    }
    return $retorno;
}

There are a few things to consider:

My suggestion:

To create the URL use:

$int = random_int(PHP_INT_MIN, PHP_INT_MAX);

$base64 = base64_encode(pack('J*', $int)); 
$base64 = rtrim(strtr($base64, '+/', '-_'), '='); 

This code was based on this response . Use $int to store in database, $base64 to send to user.

Then, to convert again, use:

$url = 'CODIGO-DO-URL';

$base64 = strtr($url, '-_', '+/');
$base64 = base64_decode($base64);

$int = unpack("J*", $base64)[1];

In this way, search the database for $int . Of course, this may have worse performance, after all there is a cost for conversion. But, the storage space required will be less, this is evident. But, I believe the database is a bigger problem than converting, ie converting base64 to int still has bigger advantages.