some fixes and example update

examples/listen.rb

@@ -1,4 +1,7 @@
 require 'ruby-nfc'
+require 'logger'
+
+logger = Logger.new(STDOUT)
 
 puts "Library version: %s" % NFC.version
 readers = NFC::Reader.all
@@ -24,17 +27,17 @@
  puts "Page 1: %s" % read(1).unpack('H*').pop
  processed!
  when IsoDep::Tag
- select ["F75246544101"].pack('H*')
+ select! ["F75246544101"].pack('H*')
  # sending APDU command to tag using send_apdu method
  apdu = ['A00D010018B455CAF0F331AF703EFA2E2D744EC7E22AA64076CD19F6D0'].pack('H*')
- puts send_apdu(apdu).unpack('H*').pop
+ puts send_apdu(apdu)
 
  # sending APDU command with "<<" operator which is alias to send_apdu
  # response = tag << apdu
  # puts response.unpack('H*').pop
  processed!
  end
  rescue Exception => e
- puts e
+ logger.debug e
  end
 end

lib/ruby-nfc/apdu/apdu.rb

@@ -86,7 +86,7 @@ def initialize(sw)
  @code = sw
  message = STATUS_STRINGS[sw] || "Unknown error"
 
- super("#{sw.to_s(16)} #{message}")
+ super("#{sw.to_s(16).upcase} #{message}")
  end
  end
 end

lib/ruby-nfc/apdu/response.rb

@@ -38,7 +38,7 @@ def data
  end
 
  def to_s
- @response.unpack('H*').pop
+ @response.unpack('H*').pop.upcase
  end
 
  def [](index)

lib/ruby-nfc/tags/isodep.rb

@@ -35,12 +35,6 @@ def connect(&block)
  )
 
  if res > 0
- # trying to select applet if applet identifier was given
- if aid
- sw = send_apdu("\x00\xA4\x04\x00#{aid.size.chr}#{aid}")
- raise IsoDep::Error, "Application not found: #{aid.unpack('H*').pop}" unless "\x90\x00" == sw
- end
-
  super(&block)
  else
  raise IsoDep::Error, "Can't select tag: #{res}"
@@ -51,6 +45,26 @@ def disconnect
  0 == LibNFC.nfc_initiator_deselect_target(@reader.ptr)
  end
 
+ # Public: select application with give AID
+ #
+ # aid - Identifier of the application that should be selected
+ #
+ # Returns APDU::Response
+ def select(aid)
+ send_apdu("\x00\xA4\x04\x00#{aid.size.chr}#{aid}")
+ end
+
+ # Public: same as select but raises an APDU::Errno exception if
+ # application not present on the card or SW is not equal to 0x9000
+ #
+ # aid - Identifier of the application that should be selected
+ #
+ # Returns APDU::Response
+ # Raises APDU::Errno
+ def select!(aid)
+ select(aid).raise_errno!
+ end
+
  # Public: Select application with given AID (Application Identifier)
  # 
  # aid - Application Identifier of an applet located on a card
@@ -82,7 +96,7 @@ def send_apdu(apdu)
 
  raise IsoDep::Error, "APDU sending failed: #{res_len}" if res_len < 0
 
- APDU::Response.from_string(response_buffer.get_bytes(0, res_len).to_s)
+ APDU::Response.new(response_buffer.get_bytes(0, res_len).to_s)
  end
 
  # Public: Send APDU command to tag and raises APDU::Errno exception