如何确定Rails应用程序的PDF附件中有多少页？

Question

In my app a user can upload a PDF as an attachment.

I want to report how many pages it has.

Is there a Ruby library that would help with this?

Answer 1

  require 'rubygems'
  require 'pdf/reader'

  class PageReceiver
    attr_accessor :pages

    # Called when page parsing ends
    def page_count(arg)
      @pages = arg
    end
  end

  receiver = PageReceiver.new
  pdf = PDF::Reader.file("somefile.pdf", receiver, :pages => false)
  puts "#{receiver.pages} pages"