Downloading pdfs for registered user

[J G, modificado hace 7 años.]

Hi,

I want to offer to registered users the possibility to download watermarked pdfs.
The PDF is written in LaTex.
What I want to achieve is the following:
1. If the user decides to download the PDF, the email address of the user is passed to a script
2. this script builds the watermarked pdf (with the user's email address as a watermark).
3. the script returns the watermarked pdf (or a reference to a location on the filesystem)

My questions are:
1. How can I call a script, eg from a purchasing module, and return the url to the document in some way?
2. How can I restrict the user the be able to download only his personalised pdf?

Best,

-- JG

[J G, modificado hace 7 años.]

Anyone?

Some directions would be greatly appreciated.