Fetch full Atom feed from Google Reader

example.rb

reader = Reader.new '[email protected]', PASSWORD

# fetch only unread items
feed = reader.fetch_all(FEED_URL, true) do |entry|
  # something with each entry
end

puts feed

reader.rb

require 'curb'
require 'nokogiri'
require 'addressable/uri'
require 'addressable/template'

class Reader
  LoginUrl = Addressable::URI.parse('https://www.google.com/accounts/ClientLogin')
  FeedUrl  = Addressable::Template.new 'https://www.google.com/reader/atom/feed/{feed}?{-join|&|n,client,ck,xt,c}'
  Params   = { :n => 1000, :client => 'ruby', :xt => 'user/-/state/com.google/read' }
  
  def initialize(email, password)
    @email, @password = email, password
    @curl = nil
  end
  
  class Error < StandardError
    attr_accessor :curl
  end
  
  def login
    login_url = LoginUrl.dup
    login_url.query_values = {
      :Email => @email, :Passwd => @password,
      :service => 'reader', :source => 'ruby',
      :continue => 'http://www.google.com/'
    }

    curl = Curl::Easy.new(login_url)
    perform_request(curl)
    
    auth_data = curl.body_str.split("\n").inject({}) { |hash, line|
      key, value = line.split('=')
      hash[key] = value
      hash
    }

    curl.encoding = 'gzip,deflate'
    curl.cookies = "SID=#{auth_data['SID']};"
    curl
  end
  
  def fetch_all(feed_url, unread = false, &block)
    continuation = nil
    timestamp = Time.now
    main = nil

    begin
      doc = fetch(feed_url, unread, timestamp, continuation)
      doc.at_xpath('//gr:continuation').tap { |el| continuation = el && el.text }
      entries = doc.xpath('//xmlns:entry')

      if main.nil?
        main = doc
      else
        parent = main.at_xpath('./xmlns:feed')
        entries.each { |entry| parent.add_child entry }
      end

      entries.each(&block) if block_given?
    end while continuation
    
    main
  end
  
  def fetch(feed_url, unread = false, timestamp = Time.now, continuation = nil)
    params = Params.merge :ck => timestamp.utc.to_i, :feed => feed_url.to_s
    params[:c] = continuation if continuation
    params.delete(:xt) unless unread

    @curl ||= login
    @curl.url = FeedUrl.expand(params)
    perform_request(@curl)
    Nokogiri::XML @curl.body_str
  end
  
  def perform_request(curl)
    curl.perform
    unless curl.response_code == 200
      raise Error.new("login failed").tap { |e| e.curl = curl }
    end
    curl
  end
end