PHP - Unique name for uploaded files?

[floyde]

Can I create a unique filename for user uploaded images using PHP's uniqid function? Will it do? or is there a risk of overwriting an exisitng image?

I also found this on the PHP manual, maybe it's less risky:

<?php
// no prefix
$token = md5(uniqid());

// better, difficult to guess
$better_token = md5(uniqid(rand(), true));
?>

thanks

 

[ac2102]

Could you not just do a check to see if the filename is already used?

You could use

file_exists("./path/to/file.jpg")

in an if or while statement to keep creating new names.

Having said that, i am only making this suggestion as i do not know the answer to your previous question! The methods you described would make the possibility of producing the same file name extremely small, but i don't know exactly how small!

Sorry if my answer seems a little vague, but that is the best i have for now!

Good luck with your project,

ac2102

 

[floyde]

Thanks, that will definately work. I'm still wondering if that's the standard way of doing it though.

 

[c-Row]

Another way would be to append/prepend the current timestamp. Works fine for us.

 

[ac2102]

Good thinking with the timestamp. Never used that for filenames, but will now!

Top choice,

ac2102

 

[Thom_Edwards]

my vote is the session id concatenated with a timestamp.

 

[c-Row]

my vote is the session id concatenated with a timestamp.

Now I guess that should be unique enough...

 

[floyde]

Now I guess that should be unique enough...

Yes, I think we have a winner