Generating a unique ID in PHP

Question

I\'m trying to generate a unique ID in php in order to store user-uploaded content on a FS without conflicts. I\'m using php, and at the moment this little snippet is responsib

Answer 1

Since both uniqid() and rand() are functions based on the current time, rand() adds almost no entropy, since the time will change only a tiny amount between the respective calls.

As long as you use the more_entropy option, you should never have a collision within a single server. If you use clustering, be sure to include a prefix that differs between servers.

Answer 2

uniqid() is what you're looking for in most practical situations.

You can make it even more "uniq" by adding a large random number after it.

Answer 3

string uniqid ([ string $prefix [, bool $more_entropy ]] )

Gets a prefixed unique identifier based on the current time in microseconds.

USAGE: $id = uniqid(rand(), true);