"""Smart card insertion/removal monitoring classes.
CardObserver is a base class for objects that are to be notified
upon smart card insertion/removal.
CardMonitor is a singleton object notifying registered CardObservers
upon reader insertion/removal.
__author__ = "http://www.gemalto.com"
Copyright 2001-2010 gemalto
Author: Jean-Daniel Aussel, mailto:jean-daniel.aussel@gemalto.com
This file is part of pyscard.
pyscard is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
pyscard is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with pyscard; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
"""
from sys import exc_info
from threading import Thread,Event
from time import sleep
from smartcard.System import readers
from smartcard.Exceptions import CardRequestTimeoutException
from smartcard.Observer import Observer
from smartcard.Observer import Observable
from smartcard.CardType import AnyCardType
from smartcard.CardRequest import CardRequest
_START_ON_DEMAND_=False
# CardObserver interface
class CardObserver(Observer):
"""
CardObserver is a base abstract class for objects that are to be notified
upon smartcard reader insertion/removal.
"""
def __init__(self):
pass
def update( self, observable, (addedcards, removedcards) ):
"""Called upon reader insertion/removal.
observable:
addedcards: list of added readers causing notification
removedcards: list of removed readers causing notification
"""
pass
class CardMonitor:
"""Class that monitors smart card insertion/removal.
and notify observers
note: a card monitoring thread will be running
as long as the card monitor has observers, or CardMonitor.stop()
is called. Do not forget to delete all your observers by
calling deleteObserver, or your program will run forever...
Uses the singleton pattern from Thinking in Python
Bruce Eckel, http://mindview.net/Books/TIPython to make sure
there is only one CardMonitor.
"""
class __CardMonitorSingleton( Observable ):
"""The real smartcard monitor class.
A single instance of this class is created
by the public CardMonitor class.
"""
def __init__( self ):
Observable.__init__(self)
if _START_ON_DEMAND_:
self.rmthread=None
else:
self.rmthread = CardMonitoringThread( self )
def addObserver( self, observer ):
"""Add an observer.
We only start the card monitoring thread when
there are observers.
"""
Observable.addObserver( self, observer )
if _START_ON_DEMAND_:
if self.countObservers()>0 and self.rmthread==None:
self.rmthread = CardMonitoringThread( self )
else:
observer.update( self, (self.rmthread.cards, [] ) )
def deleteObserver( self, observer ):
"""Remove an observer.
We delete the CardMonitoringThread reference when there
are no more observers.
"""
Observable.deleteObserver( self, observer )
if _START_ON_DEMAND_:
if self.countObservers()==0:
if self.rmthread!=None:
self.rmthread=None
def __str__( self ):
return 'CardMonitor'
# the singleton
instance = None
def __init__(self):
if not CardMonitor.instance:
CardMonitor.instance = CardMonitor.__CardMonitorSingleton()
def __getattr__( self, name ):
return getattr( self.instance, name )
class CardMonitoringThread:
"""Card insertion thread.
This thread waits for card insertion.
"""
class __CardMonitoringThreadSingleton( Thread ):
"""The real card monitoring thread class.
A single instance of this class is created
by the public CardMonitoringThread class.
"""
def __init__(self, observable):
Thread.__init__(self)
self.observable=observable
self.stopEvent = Event()
self.stopEvent.clear()
self.cards = []
self.setDaemon(True)
# the actual monitoring thread
def run(self):
"""Runs until stopEvent is notified, and notify
observers of all card insertion/removal.
"""
self.cardrequest = CardRequest( timeout=0.1 )
while self.stopEvent.isSet()!=1:
try:
currentcards = self.cardrequest.waitforcardevent()
addedcards=[]
for card in currentcards:
if not self.cards.__contains__( card ):
addedcards.append( card )
removedcards=[]
for card in self.cards:
if not currentcards.__contains__( card ):
removedcards.append( card )
if addedcards!=[] or removedcards!=[]:
self.cards=currentcards
self.observable.setChanged()
self.observable.notifyObservers( (addedcards, removedcards) )
# when CardMonitoringThread.__del__() is invoked in response to shutdown,
# e.g., when execution of the program is done, other globals referenced
# by the __del__() method may already have been deleted.
# this causes ReaderMonitoringThread.run() to except with a TypeError
# or AttributeError
except TypeError:
pass
except AttributeError:
pass
except:
try:
import sys
print sys.exc_info()[1]
print sys.exc_info()[2]
print sys.exc_info()[0]
except:
pass
# stop the thread by signaling stopEvent
def stop(self):
self.stopEvent.set()
# the singleton
instance = None
def __init__(self, observable):
if not CardMonitoringThread.instance:
CardMonitoringThread.instance = CardMonitoringThread.__CardMonitoringThreadSingleton( observable )
CardMonitoringThread.instance.start()
def __getattr__( self, name ):
if self.instance:
return getattr( self.instance, name )
# commented to avoid bad clean-up sequence of python where __del__ is called when
# some objects it uses are already gargabe collected
#def __del__(self):
# if CardMonitoringThread.instance!=None:
# CardMonitoringThread.instance.stop()
# CardMonitoringThread.instance = None
if __name__ == "__main__":
from smartcard.CardMonitoring import CardMonitor
print 'insert or remove cards in the next 10 seconds'
# a simple card observer that prints added/removed cards
class printobserver( CardObserver ):
def __init__( self, obsindex ):
self.obsindex=obsindex
def update( self, observable, (addedcards, removedcards) ):
print "%d - added: " % self.obsindex, addedcards
print "%d - removed: " % self.obsindex, removedcards
class testthread( Thread ):
def __init__(self, obsindex ):
Thread.__init__(self)
self.readermonitor = CardMonitor()
self.obsindex = obsindex
self.observer=None
def run(self):
# create and register observer
self.observer = printobserver( self.obsindex )
self.readermonitor.addObserver(self.observer)
sleep(10)
self.readermonitor.deleteObserver(self.observer)
t1 = testthread(1)
t2 = testthread(2)
t1.start()
t2.start()
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