ndef 0.2

NDEF (NFC Data Exchange Format) parser and verifier

Release v0.2 – January 7th, 2020

The ndef modules provides methods for encoding and decoding messages and records in the NDEF format according to NFC Forum technical specification. Its main purpose is to provide comprehensive verification of raw NDEF messages. It can be used to verify messages before writing them to an actual tag.

Available on PyPI.

Usage

Valid Message

>>> import ndef
>>> message_data = 'D1010F5402656E48656C6C6F20776F726C6421'.decode('hex')
>>> message = ndef.NdefMessage(message_data)
>>> record = message.records[0]
>>> record.tnf
1
>>> record.type
'T'
>>> record.id
>>> record.payload
'\x02enHello world!'
>>>

Invalid Message

>>> import ndef
>>> message_data = '9901050155610123456761'.decode('hex')
>>> message = ndef.NdefMessage(message_data)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "ndef\ndef.py", line 274, in __init__
    self.verify()
  File "ndef\ndef.py", line 278, in verify
    self._verify_begin_end()
  File "ndef\ndef.py", line 296, in _verify_begin_end
    raise InvalidNdefMessage("last record's ME flag is off")
ndef.ndef.InvalidNdefMessage: last record's ME flag is off
>>>

Create Message

>>> import ndef
>>> text_record = (ndef.TNF_WELL_KNOWN, ndef.RTD_TEXT, 'id', 'hello world')
>>> text_message = ndef.new_message(text_record)
>>> text_raw_ndef = text_message.to_buffer()
>>> text_raw_ndef.encode('hex')
'd9010b0254696468656c6c6f20776f726c64'
>>>

Alternatives

• nfcpy: full implementation of spec including actual communication code

• Python NDEF library and tools: aimed at security research

• pynfc: pythonic interface for the libnfc library

License

Copyright (c) 2014 Amir Szekely

This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.

Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:

   1. The origin of this software must not be misrepresented; you must not
   claim that you wrote the original software. If you use this software
   in a product, an acknowledgment in the product documentation would be
   appreciated but is not required.

   2. Altered source versions must be plainly marked as such, and must not be
   misrepresented as being the original software.

   3. This notice may not be removed or altered from any source
   distribution.