How to find out file extension?

Anon

hello again,

is there any function which returns the file extension of the file that is being uploaded from client's machine.

e.g. the file is named pic.gif and i am saving the file on my server with id names, which are auto_increment.

so, when i do that, the file is saved as 0001.
but i want to get the extension too, so that i can save it as 0001.gif or 0001.jpg etc.

thanks a lot,
Daarius ....

Anon

You could use the $userfile_type to get a mime type when the form is uploaded. If it's a gif then the mime type would be image/gif or something like that.

You could also parse the $userfile_name var to see what follows the '.' character which should be your file extension.

Also, you should check the type everytime someone uploads anything to your server to make sure it's not something you don't want like a .exe or something nasty.

Check out:

http://www.php.net/manual/html/features.file-upload.html

to see what I mean.
matt.

Anon

What if the user uploads a file that has more than one "." in it ie my.pic.gif?

Anon

You can use a regular expression to get only the letters after the last occurrence of '.'

This site has an excellent intro tutorial on regexp.

Go here:
<A HREF="http://www.phpbuilder.com/columns/dario19990616.php3">
http://www.phpbuilder.com/columns/dario19990616.php3</A>

Anon

thanks a lot guys for the hints.

i think i can check the type of the image with userfile_type() function, and then have a case statement, on gif, jpg and bmp (these are the types i am allowing to upload). so if its image/gif, i can have the extension to be '.gif' defined as vriable.

thank you,
Daarius...

Anon

Hi! Yeah Daarius, thats a good solution, but, if you want to have the REAL extension of the uploaded file, you could do something like this:

ereg(".(.)+$", $upload_filename, $ext);

and, in $ext[1] you've the REAL extension of the file.

Anyway, do it as you wish =)

inKel

PS: excuse my english

Anon

Just a minor correction to help those that run across the above example to grab the file extension.

ereg(".(.)+$", $upload_filename, $ext);

the + should be in the parenthesis otherwise you will just get the last character of the matched string.

Should be: ereg(".(.+)$", $upload_filename, $ext);

Thanks,
Troy

Anon

for the example "test.jpg.txt.doc"
the regex
ereg(".(.+)$", $fileNameAndPath, $ext)
produces
"jpg.txt.doc"

corrected version
ereg(".([a-zA-Z0-9_-]+)$", $fileNameAndPath, $ext);

produces
"doc"

so far

julian