OCR with Google Docs API

google_ocr.rb

require 'open-uri'
require "rubygems"
require "mechanize"

BANNER = "Usage: ruby google_ocr.rb http://ec2.images-amazon.com/images/I/21IVvn7zGAL._SL500_AA300_.jpg"
EMAIL = "email here"
PASSWD = "password here"

def main(args)
	unless file = args.shift
		abort BANNER
	end
	@mech = Mechanize.new
	#require 'logger'; @mech.log = Logger.new(STDOUT)
	@mech.request_headers = { "GData-Version" => "3.0" }
	auth(EMAIL, PASSWD)
	doc_id = upload(file)
	puts download(doc_id)
end

def upload(file)
	data = open(file).read
	@mech.post(
		"http://docs.google.com/feeds/default/private/full?ocr=true&lang=ja", data,
		"Content-Type" => "image/png", "Content-Length" => data.length, "Slug" => file
	)
	regexp = %r{^http://docs\.google\.com/feeds/default/private/full/document%3A(.+)$}
	@mech.page.response['location'][regexp, 1]
end

def download(doc_id)
	@mech.get(
		"http://docs.google.com/feeds/download/documents/Export",
		"docID" => doc_id, "exportFormat" => "txt", "format" => "txt"
	)
	@mech.page.content
end

def auth(email, passwd)
	@mech.post(
		"https://www.google.com/accounts/ClientLogin",
		"Email" => email, "Passwd" => passwd, "service" => "writely"
	)
	token = @mech.page.content[/Auth=(.+)/, 1]
	@mech.request_headers.update("Authorization" => "GoogleLogin auth=#{token}")
end

main(ARGV)