HI
Whats the best way to create a random name for a folder?
Its going to be used for a folder name to store documents. But lots of folders are going to be created and so need it to be unique each time if possible.
Length should probably be around 7 characters.
If it needs to be unique, then I would forget about it being random and just increment a counter. If you need to associate the contents of the folders with records in a database, all the better. You can just have an autoincrement column in your database and use it as part of the folder name.
Here's the function I use:
function makeRandomString($max=6) {
$i = 0; //Reset the counter.
$possible_keys = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
$keys_length = strlen($possible_keys);
$str = ""; //Let's declare the string, to add later.
while($i<$max) {
$rand = mt_rand(1,$keys_length-1);
$str.= $possible_keys[$rand];
$i++;
}
return $str;
}
EDIT: As Bill the Lizard said, you'd better add some kind of counter. Although very unlikely, it is possible that the same string can be created twice.
Is 7 char folder name a hard and fast rule (what is the cause of the limit)?
I use YYYYmmDDHHMMSS (and add millisecond if you find yourself getting many collisions).
Where
You may also want to test to see if the directory has already been created and then sleep for a random number of milliseconds before trying again.
PHP Code:
<?php
$dirName = date( 'YmdHis', time() );
@mkdir( $dirName )
?>
Do you really need it to be random?
If you need it to be unique I'd suggest creating a counter and converting the integer number to hex or even better base 36(26 chars + 10 digits). After creating the folder increase the counter and you're good to go.
with the requirement that it be unique and 7 characters i'd probably use a number encoded to base 36 (0-9 and a-z), that way you can just see what the last folder was and incrememnt it to create a new one.
Then check to see if it's unique and regenerate if it isn't. In a way this is better than saving state, like a counter, because less can go wrong.
do {
$f = "rh" . mt_rand(10000,99999);
} while (file_exists($f));
I think best approach to naming is using uniqid() function.
$folder_name = uniqid();// eg: 4b3403665fea6
or with a static prefix:
$folder_name = uniqid('folder_'));// eg: folder_537834f6e981a
or with today (date) prefix:
$folder_name = uniqid(date('h-i-s')._); //eg: 04-23-59_537835dff2017
In this example we can look a random key with min and max length.
substr(str_shuffle("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"), 0, $length)
