Structure of a PDF file? [closed]

Question

For a small project I have to parse pdf files and take a specific part of them (a simple chain of characters). I'd like to use python to do this and I've found several libraries that are capable of doing what I want in some ways.

But now after a few researches, I'm wondering what is the real structure of a pdf file, does anyone know if there is a spec or some explanations anywhere online? I've found a link on adobe but it seems that it's a dead link :(

Answer 1

Here is a link to Adobe's reference material

http://www.adobe.com/devnet/pdf/pdf_reference.html

You should know though that PDF is only about presentation, not structure. Parsing will not come easy.

Answer 2

I found the GNU Introduction to PDF to be helpful in understanding the structure. It includes an easily readable example PDF file that they describe in complete detail.

Other helpful links:

• PDF Succinctly book is longer and has helpful pictures.
• Introduction to the Insides of PDF is a presentation that isn't as in-depth but gives a quick overview and has lots of pictures.