scinote-web/app/utilities/wopi_util.rb

module WopiUtil
  require 'open-uri'

  # Used for timestamp
  UNIX_EPOCH_IN_CLR_TICKS = 621355968000000000
  CLR_TICKS_PER_SECOND = 10000000

  DISCOVERY_TTL = 1.days
  DISCOVERY_TTL.freeze

  # For more explanation see this:
  # http://stackoverflow.com/questions/11888053/
  # convert-net-datetime-ticks-property-to-date-in-objective-c
  def convert_to_unix_timestamp(timestamp)
    Time.at((timestamp - UNIX_EPOCH_IN_CLR_TICKS) / CLR_TICKS_PER_SECOND)
  end

  def get_action(extension, activity)
    current_wopi_discovery
    WopiAction.find_action(extension, activity)
  end

  def current_wopi_discovery
    discovery = WopiDiscovery.first
    return discovery if discovery && discovery.expires >= Time.now.to_i
    initialize_discovery(discovery)
  end

  private

  # Currently only saves Excel, Word and PowerPoint view and edit actions
  def initialize_discovery(discovery)
    Rails.logger.warn 'Initializing discovery'
    discovery.destroy if discovery

    @doc = Nokogiri::XML(open(ENV['WOPI_DISCOVERY_URL']))

    discovery = WopiDiscovery.new
    discovery.expires = Time.now.to_i + DISCOVERY_TTL
    key = @doc.xpath('//proof-key')
    discovery.proof_key_mod = key.xpath('@modulus').first.value
    discovery.proof_key_exp = key.xpath('@exponent').first.value
    discovery.proof_key_old_mod = key.xpath('@oldmodulus').first.value
    discovery.proof_key_old_exp = key.xpath('@oldexponent').first.value
    discovery.save!

    @doc.xpath('//app').each do |app|
      app_name = app.xpath('@name').first.value
      next unless %w(Excel Word PowerPoint WopiTest).include?(app_name)

      wopi_app = WopiApp.new
      wopi_app.name = app.xpath('@name').first.value
      wopi_app.icon = app.xpath('@favIconUrl').first.value
      wopi_app.wopi_discovery_id = discovery.id
      wopi_app.save!
      app.xpath('action').each do |action|
        name = action.xpath('@name').first.value
        next unless %w(view edit wopitest).include?(name)
        wopi_action = WopiAction.new
        wopi_action.action = name
        wopi_action.extension = action.xpath('@ext').first.value
        wopi_action.urlsrc = action.xpath('@urlsrc').first.value
        wopi_action.wopi_app_id = wopi_app.id
        wopi_action.save!
      end
    end
    discovery
  rescue
    Rails.logger.warn 'Initialization failed'
    discovery = WopiDiscovery.first
    discovery.destroy if discovery
  end
end