P2P communication using Android smartphone and nfcpy - nfc-p2p

Question

I would like to send a NDEF message from my NFC reader (using nfcpy on Linux) to my smartphone. I have the following code.
#!/usr/bin/python
# -*- coding: latin-1 -*-
# -----------------------------------------------------------------------------
# Copyright 2010-2011 Stephen Tiedemann <stephen.tiedemann#googlemail.com>
#
# Licensed under the EUPL, Version 1.1 or - as soon they
# will be approved by the European Commission - subsequent
# versions of the EUPL (the "Licence");
# You may not use this work except in compliance with the
# Licence.
# You may obtain a copy of the Licence at:
#
# http://www.osor.eu/eupl
#
# Unless required by applicable law or agreed to in
# writing, software distributed under the Licence is
# distributed on an "AS IS" basis,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
# express or implied.
# See the Licence for the specific language governing
# permissions and limitations under the Licence.
# -----------------------------------------------------------------------------
import logging
log = logging.getLogger('main')
import os
import sys
import time
import argparse
sys.path.insert(1, os.path.split(sys.path[0])[0])
from cli import CommandLineInterface
import nfc
import nfc.snep
import nfc.ndef
class DefaultServer(nfc.snep.SnepServer):
def __init__(self, llc):
service_name = 'urn:nfc:sn:snep'
super(DefaultServer, self).__init__(llc, service_name)
def put(self, ndef_message):
log.info("default snep server got put request")
log.info(ndef_message.pretty())
return nfc.snep.Success
class ValidationServer(nfc.snep.SnepServer):
def __init__(self, llc):
service_name = "urn:nfc:xsn:nfc-forum.org:snep-validation"
super(ValidationServer, self).__init__(llc, service_name, 10000)
self.ndef_message_store = dict()
def put(self, ndef_message):
log.info("validation snep server got put request")
key = (ndef_message.type, ndef_message.name)
log.info("store ndef message under key " + str(key))
self.ndef_message_store[key] = ndef_message
return nfc.snep.Success
def get(self, acceptable_length, ndef_message):
log.info("validation snep server got get request")
key = (ndef_message.type, ndef_message.name)
log.info("client requests ndef message with key " + str(key))
if key in self.ndef_message_store:
ndef_message = self.ndef_message_store[key]
log.info("found matching ndef message")
log.info(ndef_message.pretty())
if len(str(ndef_message)) <= acceptable_length:
return ndef_message
else: return nfc.snep.ExcessData
return nfc.snep.NotFound
class TestProgram(CommandLineInterface):
def __init__(self):
parser = argparse.ArgumentParser()
super(TestProgram, self).__init__(
parser, groups="llcp dbg clf")
def on_llcp_startup(self, clf, llc):
self.default_snep_server = DefaultServer(llc)
self.validation_snep_server = ValidationServer(llc)
return llc
def on_llcp_connect(self, llc):
self.default_snep_server.start()
self.validation_snep_server.start()
return True
if __name__ == '__main__':
TestProgram().run()
Where, and how, should I make a NDEF messege en send it with the existing server to my smartphone? The other way arround (from smartphone to NFC reader is working already).
Thanks in advance!

Answer 1

The Simple NDEF Exchange Protocol that is used to send NDEF messages is a client/server protocol. The code sample provided implements a SNEP server and thus succeeds in receiving an NDEF message from the phone. To send an NDEF message a SNEP client must be used, the equivalent in nfcpy is examples/snep-test-client.py. But the much better option is to use examples/beam.py send ndef <file.ndef>.