USB MagTek Card Reader in Ruby

gistfile1.rb

require 'rubygems'
require 'usb'  # this is the ruby-usb gem, I'm also using libusb 1.0 and linux
require 'logger'

class MagTek
  def initialize
    @device = find_device
    interface = @device.interfaces.first
    @endpoint = interface.endpoints.first
    @logger = Logger.new("/var/log/monitor_usb.log")
    @logger.level = Logger::INFO
  end

  def open
    close
    begin
      @handle = @device.open
      @handle.usb_detach_kernel_driver_np(0,0) rescue nil
      @handle.usb_claim_interface(0)
      @open = true
      return true
    rescue
      return false
    end
  end

  def close
    return true unless @open
    @handle.usb_release_interface(0)
    @handle.usb_close
    @open = false
    true
  end
  def read(options={})
    @logger.debug "Reading from USB ... "
    clear_swipes
    data = ""
    char = (0..7).to_a.pack("c*")
    begin
      # read in one character first
      size = @handle.usb_interrupt_read(@endpoint.bEndpointAddress, char, 0)
      data += char
      @logger.debug "Read in char: #{char.inspect}"
      converted_data = convert_data(data)
      @logger.debug "Data is now: #{clean_data(converted_data)}"
      # then read in 1 char at a time until we reach the new line at the end
      until (converted_data = convert_data(data)).include? "\\n" do
        begin
          size = @handle.usb_bulk_read(@endpoint.bEndpointAddress, char, -1)
        rescue Errno::ETIMEDOUT => e
          # nothing ... we know it is going to time out, that's the point
        end
        data += char
      end
      converted_data = convert_data(data)
      @logger.debug "Data is now: #{clean_data(converted_data)}"
    rescue Errno::EBUSY => e
      @logger.error e.message
      @logger.error "Will try to detach the kernel driver."
      @handle.usb_detach_kernel_driver_np(0,0) rescue nil
      return false
    rescue Exception => e
      @logger.error "could not read from USB. Will try to reset it."
      @logger.error e.message
      begin
        @handle.usb_reset()
      rescue Exception => e2
        @logger.error e2.message
        @logger.error "Could not reset, make sure device is plugged in. And then restart usb monitor daemon."
        @logger.error "Exiting"
        exit(1)
      end
      @handle.usb_detach_kernel_driver_np(0,0) rescue nil
      return false
    end

    data = convert_data(data)
    name = get_name(data)
    drivers_license_number = get_drivers_license_number(data)
    if name or drivers_license_number
      return [true, name, drivers_license_number]
    else
      begin
        @handle.usb_reset()
      rescue Exception => e
        @logger.error e.message
        @logger.error "Could not reset, make sure device is plugged in.  Or unplug and replug device."
        @logger.error "Exiting"
        exit(1)
      end
      return false
    end
  end

  private

  # clean the pipes
  def clear_swipes
    @logger.debug "Clearing swipes"
    data = (0..7).to_a.pack("c*")
    # used to be 50.times with just snl badge
    10.times do |x|
      begin
        @handle.usb_interrupt_read(@endpoint.bEndpointAddress, data, -1)
      rescue Errno::ETIMEDOUT => e
        # seeing a new line usually means we've reached the end
        if ["\\n"].include?(char = convert_data(data))
          @logger.debug "Done clearing swipes: reached blank or new line: #{char.inspect}"
          return
        end
        @logger.debug "Timed out while clearing"
        next
      rescue Exception => e
        @logger.debug "Done clearing swipes: #{e.message}"
        return
      end
    end
    @logger.debug "Done clearing swipes: reached end of count"
  end

  def get_name(data)
    @logger.debug "Getting Name: DATA: #{clean_data(data).inspect}"
    # match for drivers license
    match = /%.*?\^(.*\$.*\$.*?)\^.*?\^/.match(data)
    return nil unless match
    name = match.captures.first.gsub(/\$/, " ")
    @logger.debug "Got name: #{name}"
    return name
  end

  def get_drivers_license_number(data)
    @logger.debug "Getting Drivers License Number: DATA: #{clean_data(data).inspect}"
    # match for drivers license
    match = /\?;\d{6}(\d+)=\d+/.match(data)
    return nil unless match
    lic_num = match.captures.first
    lic_num = lic_num[-4..-1] # only last 4 digits
    @logger.debug "Got lic. num: #{lic_num}"
    return lic_num
  end

  # some cards we use have SSN on them, definitely don't want that in the logs, so clear it out
  def clean_data(data)
    ssn = nil
    if data =~ /%(\d{9})/
      ssn = $1
    end
    data = data.gsub(ssn, "SSN-not-loggable") if ssn
    return data
  end

  def find_device
    return USB.devices.find{|u| u.idProduct == 0x0001 && u.idVendor == 0x0801}
  end

  def convert_data_slices(data)
    data.map do |d|
      d[0].to_i == 2 ? key_pages_shift[d[2].to_i] : key_pages[d[2].to_i]
    end.join("")
  end

  def convert_data(data)
    data = data.unpack('C*')
    convert_data_slices(data.each_slice(8).to_a)
  end

  # keycode mapping, we seem to be 1 character off otherwise :(
  # by some manner of luck, I discovered this mapping here - https://github.com/guyzmo/tmsr33-pyusb/blob/master/tmsr33_pyusb.py
  def key_pages
    [
    '', '', '', '',
    'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
    'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
    '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '\n', '^]', '^H',
    '^I', ' ', '-', '=', '[', ']', '\\', '>', ';', "'", '`', ',', '.',
    '/', 'CapsLock', 'F1', 'F2', 'F3', 'F4', 'F5', 'F6', 'F7', 'F8', 'F9', 'F10', 'F11', 'F12',
    'PS', 'SL', 'Pause', 'Ins', 'Home', 'PU', '^D', 'End', 'PD', '->', '<-', '-v', '-^', 'NL',
    'KP/', 'KP*', 'KP-', 'KP+', 'KPE', 'KP1', 'KP2', 'KP3', 'KP4', 'KP5', 'KP6', 'KP7', 'KP8',
    'KP9', 'KP0', '\\', 'App', 'Pow', 'KP=', 'F13', 'F14' ]
  end

  def key_pages_shift
    [
    '', '', '', '',
    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
    'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
    '!', '@', '#', '$', '%', '^', '&', '*', '(', ')', '\n', '^]', '^H',
    '^I', ' ', '_', '+', '{', '}', '|', '<', ':', '"', '~', '<', '>',
    '?', 'CapsLock', 'F1', 'F2', 'F3', 'F4', 'F5', 'F6', 'F7', 'F8', 'F9', 'F10', 'F11', 'F12',
    'PS', 'SL', 'Pause', 'Ins', 'Home', 'PU', '^D', 'End', 'PD', '->', '<-', '-v', '-^', 'NL',
    'KP/', 'KP*', 'KP-', 'KP+', 'KPE', 'KP1', 'KP2', 'KP3', 'KP4', 'KP5', 'KP6', 'KP7', 'KP8',
    'KP9', 'KP0', '|', 'App', 'Pow', 'KP=', 'F13', 'F14' ]
  end
end