Using PHP for search within a PDF file

[Libra]

Hi all,

I'm trying to find a php class or application for doing searches
within a pdf file.
I need a repository for pdf files and I want to be able to perform
researches within these files.
I found some post suggesting to use pdftotext or similar and to store
the entire text on the DB, but I wonder if exists something else or,
maybe, any (GPL) project already running.

Thanks in advance

Libra