Script for book data scrapping

I gratefully accept any help with this task.
I'm planning to do data scrapping on the most popular sources and publishers, Amazon, Leanpub, O'Reilly, Packt.
Create a hash on every existing book, so that not to add it twice.
Add new books as Github Issues.
An interesting task, but I lack experience in Web Scrapping and don't have much time at the moment.