'''Module for Send Python Object Through Socket (SPOTS).
This module implements the Zero SPOTS Protocol, the Query/Reply Protocol,
the Query/Reply Interface, and a shortcut for constructing QRI objects.'''
################################################################################
__version__ = '$Revision: 0 $'
__date__ = 'March 27, 2007'
__author__ = 'Stephen "Zero" Chappell <my.bios@gmail.com>'
__credits__ = '''\
T. Parker, for testing code that led to this module.
B. Brown, for teaching me some math courses.
G. Rossum, for allowing thread support in Python.'''
################################################################################
import cPickle as _cPickle
import sys as _sys
import thread as _thread
import time as _time
################################################################################
class ZSP:
'ZSP(socket) -> ZSP'
def __init__(self, socket):
'Initialize the Zero SPOTS Protocol object.'
self.__file = socket.makefile('b', 0)
def send(self, obj):
'Send one object.'
_cPickle.dump(obj, self.__file, _cPickle.HIGHEST_PROTOCOL)
def recv(self):
'Receive one object.'
return _cPickle.load(self.__file)
################################################################################
class QRP:
'QRP(ZSP) -> QRP'
def __init__(self, ZSP):
'Initialize the Query/Reply Protocol object.'
self.__ZSP = ZSP
self.__error = None
self.__Q_anchor = []
self.__Q_packet = []
self.__R_anchor = {}
self.__Q_lock = _thread.allocate_lock()
self.__R_lock = _thread.allocate_lock()
_thread.start_new_thread(self.__thread, ())
def send_Q(self, ID, obj):
'Send one query.'
if self.__error:
raise self.__error
self.__ZSP.send((False, ID, obj))
def recv_Q(self, timeout=None):
'Receive one query.'
if self.__error:
raise self.__error
if timeout is not None:
if not isinstance(timeout, (float, int, long)):
raise TypeError, 'timeout must be of type float, int, or long'
if not timeout >= 0:
raise ValueError, 'timeout must be greater than or equal to 0'
self.__Q_lock.acquire()
try:
try:
if self.__Q_packet:
Q = True
ID, obj = self.__Q_packet.pop()
else:
Q = False
anchor = [_thread.allocate_lock()]
anchor[0].acquire()
self.__Q_anchor.append(anchor)
finally:
self.__Q_lock.release()
except AttributeError:
raise self.__error
if Q:
return ID, obj
if timeout:
_thread.start_new_thread(self.__Q_thread, (timeout, anchor))
anchor[0].acquire()
try:
Q = anchor[1]
except IndexError:
if self.__error:
raise self.__error
raise Warning
return Q
def send_R(self, ID, obj):
'Send one reply.'
if self.__error:
raise self.__error
self.__ZSP.send((True, ID, obj))
def recv_R(self, ID, timeout=None):
'Receive one reply.'
if self.__error:
raise self.__error
if timeout is not None:
if not isinstance(timeout, (float, int, long)):
raise TypeError, 'timeout must be of type float, int, or long'
if not timeout >= 0:
raise ValueError, 'timeout must be greater than or equal to 0'
anchor = [_thread.allocate_lock()]
anchor[0].acquire()
self.__R_lock.acquire()
try:
try:
self.__R_anchor[ID] = anchor
finally:
self.__R_lock.release()
except AttributeError:
raise self.__error
if timeout:
_thread.start_new_thread(self.__R_thread, (timeout, ID))
anchor[0].acquire()
try:
R = anchor[1]
except IndexError:
if self.__error:
raise self.__error
raise Warning
return R
def __thread(self):
'Private class method.'
try:
while True:
R, ID, obj = self.__ZSP.recv()
if R:
self.__R_lock.acquire()
if self.__R_anchor.has_key(ID):
self.__R_anchor[ID].append(obj)
self.__R_anchor[ID][0].release()
del self.__R_anchor[ID]
self.__R_lock.release()
else:
self.__Q_lock.acquire()
if self.__Q_anchor:
anchor = self.__Q_anchor.pop()
anchor.append((ID, obj))
anchor[0].release()
else:
self.__Q_packet.append((ID, obj))
self.__Q_lock.release()
except Exception, error:
if isinstance(error, EOFError):
self.__error = EOFError
else:
self.__error = IOError
self.__Q_lock.acquire()
for anchor in self.__Q_anchor:
anchor[0].release()
del self.__Q_anchor
del self.__Q_packet
self.__Q_lock.release()
self.__R_lock.acquire()
for key in self.__R_anchor:
self.__R_anchor[key][0].release()
del self.__R_anchor
self.__R_lock.release()
def __Q_thread(self, timeout, anchor):
'Private class method.'
_time.sleep(timeout)
self.__Q_lock.acquire()
if not self.__error and anchor in self.__Q_anchor:
anchor[0].release()
self.__Q_anchor.remove(anchor)
self.__Q_lock.release()
def __R_thread(self, timeout, ID):
'Private class method.'
_time.sleep(timeout)
self.__R_lock.acquire()
if not self.__error and self.__R_anchor.has_key(ID):
self.__R_anchor[ID][0].release()
del self.__R_anchor[ID]
self.__R_lock.release()
################################################################################
class QRI:
'QRI(QRP) -> QRI'
def __init__(self, QRP):
'Initialize the Query/Reply Interface object.'
self.__QRP = QRP
self.__ID = 0
self.__lock = _thread.allocate_lock()
def call(self, obj, timeout=None):
'Send one query and receive one reply.'
self.__lock.acquire()
ID = ''.join(chr(self.__ID >> shift & 0xFF) for shift in xrange(24, -8, -8))
self.__ID = (self.__ID + 1) % (2 ** 32)
self.__lock.release()
self.__QRP.send_Q(ID, obj)
return self.__QRP.recv_R(ID, timeout)
def query(self, timeout=None):
'Receive one query.'
return self.__QRP.recv_Q(timeout)
def reply(self, ID, obj):
'Send one reply.'
self.__QRP.send_R(ID, obj)
################################################################################
def qri(socket):
'Construct a QRI object.'
return QRI(QRP(ZSP(socket)))
################################################################################
if __name__ == '__main__':
_sys.stdout.write('Content-Type: text/plain\n\n')
_sys.stdout.write(file(_sys.argv[0]).read())
