upload script questions

[Zuggy]

I'm fairly new to php and I'm trying to create and upload script that will upload a file to the server and then insert the location into the database. Example:

 

If the location is www.bobroxorz.com I want to be able to insert www.bobroxorz.com/upload/random.pdf to the database.

 

I want to make it so that I can use this script on several sites without having to change the code. I read that you can use $_SERVER['DOCUMENT_ROOT'] but when I tested it with an echo statement to see what I got all I got was an undefined index error.

 

The actual uploading to the server works just fine.

 

Also on a side note, so I'm not making multiple posts, Is there a more secure way of checking a files mime-types so that I'm not relying on the html because that can be faked. Example:

 

with html (only allows .pdf):

test.htm doesnt upload

test.htm.pdf does upload.

 

What I need is neither to be uploaded because it wouldnt take much for malwarex.exe to be uploaded as malwarex.exe.pdf. I read that there is a pear extension but that requires a server restart and the project I'm working on doesn't allow a restart of the production server so I don't want to rely on it while developing.