pdf-reader

pdf-reader parses PDF files in Ruby and exposes pages, text, metadata, fonts, images (XObjects) and the raw object graph. page.text returns the text with an approximate layout (spacing based on positions); page.runs returns text runs with coordinates and font sizes. For custom processing, it can walk a page’s content stream and call your receiver object for every operator. It decrypts files with RC4 and AES encryption when you have the password.

pdf-reader doesn’t render or modify PDFs. Text extraction quality depends on the file: fonts without a Unicode mapping produce garbage, and scanned PDFs need OCR.

Installation#

gem install pdf-reader

Basic usage: extract text from a PDF#

require "pdf-reader"

reader = PDF::Reader.new("in.pdf")
puts "PDF #{reader.pdf_version}, #{reader.page_count} pages"
reader.pages.each do |page|
  puts "--- page #{page.number} ---"
  puts page.text
end

PDF::Reader.new also accepts an IO object, e.g. StringIO.new(data) for a PDF in memory.

How to read PDF metadata#

reader = PDF::Reader.new("in.pdf")
info = reader.info      # Info dictionary as a Hash with symbol keys
puts info[:Title], info[:Author], info[:Producer]
puts reader.metadata    # XMP metadata XML, or nil

How to get text runs with positions#

page = reader.page(1)
puts page.attributes[:MediaBox].inspect   # [0, 0, 595.28, 841.89]
page.runs.first(10).each do |run|
  puts "#{run.text} x=#{run.x} y=#{run.y} size=#{run.font_size}"
end

How to list fonts and images on a page#

page = reader.page(1)
puts page.fonts.keys.inspect              # resource names, e.g. [:F1, :F2]
page.xobjects.each do |name, stream|
  puts "#{name}: #{stream.hash[:Subtype]} #{stream.hash[:Width]}x#{stream.hash[:Height]}"
end

How to open an encrypted PDF#

reader = PDF::Reader.new("secret.pdf", password: "user")
puts reader.page(1).text

Tips#

• page.raw_content returns the decompressed content stream, handy for debugging.
• page.walk(receiver) calls methods like show_text and begin_text_object on your object for each content operator.
• reader.objects gives access to every object by reference for low-level inspection.