Generating dynamically a file

exec1

Hi,

I need to generate a file that contains informations a user may choose, and then allow the user to download this file.

But I'm actually facing some problems : initially, I wanted to use a random name (and use the file_exists() command) to be sure that the file doesn't exist.
Then, create it in /tmp.

I would just need to give a link to this file and it should work, the user could download it.

The problem is that it isn't very user-friendly to give a file with a random name, I would prefer a nicer one (such as "playlist.ext or so").

(only way I've found : create a random directory name and then the file in this directory. Is this a solution ?)

I am perhaps totally wrong in the way I'm trying to manage it, and would appreciate any help :-)

Thanks a lot !

Eric

dcomartin

Well what you could do is send them to a download page, which would be like:

download.php?file=thefilenamehere

Now you could take $HTTP_GET_VARS['file'] value and then open that file, then use something like this to force the download of that file, and it would have a name that you set in the header()

---- Example ----

$fd = fopen("/tmp/".$HTTP_GET_VARS['file'], "r");
$datafromfile = fread($fd, filesize("/tmp/".$HTTP_GET_VARS['file']));
fclose($fd);

header("Content-type: image/gif");
header("Content-Disposition: attachment; filename=thefilenameyouwant");

echo $datafromfile;

cordex

Remember that giving a user the ability to write and/or download files can be very dangerous. Using the code above, download.php?file=download.php might pull down the source for download.php unless the user files were all kept in a separate directory. If the user can enter information into a file using a form, might they also be able to write a short PHP script into the file (say, one that would give them file based access to your server) and then run it?

Just some things to consider when you're building a system like this.

-Ben

dcomartin

Very good point by Ben... You obviously want to have some tight security on doing this, but It was the only idea I could come up with for what you wanted to do 🙂

exec1

Thanks a lot for your answers, the
header("Content-Disposition: attachment; filename=playlist.des"); Derek wrote was exactly what I was looking for.
It's written in the PHP manual, but I havn't searched at the rigth place !

thanks to you two !

Eric

exec1

Yes, but the file I wanted to generate is a text file, so I do not eaven need to generate it on disk, an "echo" is enougth ! :-)

By the way, I still have a problem with "\n" that aren't displayed the same way under Linux and Win. Any idea on how I could convert it on server-side ?

(when I open the file with notepad, I get some black squares instead of end of line ...)

Bye, and thanks !

Eric

Anon

Don't use notepad, use at least wordpad, or get dreamweaver <<good program. You could also get a Php editor like PhpEd

exec1

the problem is not due to notepad, it is due to the fact that the end of lines are not properly encoded...