"""RPC Implementation, originally written for the Python Idle IDE
For security reasons, GvR requested that Idle's Python execution server process
connect to the Idle process, which listens for the connection. Since Idle has
only one client per server, this was not a limitation.
+---------------------------------+ +-------------+
| SocketServer.BaseRequestHandler | | SocketIO |
+---------------------------------+ +-------------+
^ | register() |
| | unregister()|
| +-------------+
| ^ ^
| | |
| + -------------------+ |
| | |
+-------------------------+ +-----------------+
| RPCHandler | | RPCClient |
| [attribute of RPCServer]| | |
+-------------------------+ +-----------------+
The RPCServer handler class is expected to provide register/unregister methods.
RPCHandler inherits the mix-in class SocketIO, which provides these methods.
See the Idle run.main() docstring for further information on how this was
accomplished in Idle.
"""
import sys
import os
import socket
import select
import SocketServer
import struct
import cPickle as pickle
import threading
import Queue
import traceback
import copy_reg
import types
import marshal
def unpickle_code(ms):
co = marshal.loads(ms)
assert isinstance(co, types.CodeType)
return co
def pickle_code(co):
assert isinstance(co, types.CodeType)
ms = marshal.dumps(co)
return unpickle_code, (ms,)
# XXX KBK 24Aug02 function pickling capability not used in Idle
# def unpickle_function(ms):
# return ms
# def pickle_function(fn):
# assert isinstance(fn, type.FunctionType)
# return repr(fn)
copy_reg.pickle(types.CodeType, pickle_code, unpickle_code)
# copy_reg.pickle(types.FunctionType, pickle_function, unpickle_function)
BUFSIZE = 8*1024
LOCALHOST = '127.0.0.1'
class RPCServer(SocketServer.TCPServer):
def __init__(self, addr, handlerclass=None):
if handlerclass is None:
handlerclass = RPCHandler
SocketServer.TCPServer.__init__(self, addr, handlerclass)
def server_bind(self):
"Override TCPServer method, no bind() phase for connecting entity"
pass
def server_activate(self):
"""Override TCPServer method, connect() instead of listen()
Due to the reversed connection, self.server_address is actually the
address of the Idle Client to which we are connecting.
"""
self.socket.connect(self.server_address)
def get_request(self):
"Override TCPServer method, return already connected socket"
return self.socket, self.server_address
def handle_error(self, request, client_address):
"""Override TCPServer method
Error message goes to __stderr__. No error message if exiting
normally or socket raised EOF. Other exceptions not handled in
server code will cause os._exit.
"""
try:
raise
except SystemExit:
raise
except:
erf = sys.__stderr__
print>>erf, '\n' + '-'*40
print>>erf, 'Unhandled server exception!'
print>>erf, 'Thread: %s' % threading.currentThread().getName()
print>>erf, 'Client Address: ', client_address
print>>erf, 'Request: ', repr(request)
traceback.print_exc(file=erf)
print>>erf, '\n*** Unrecoverable, server exiting!'
print>>erf, '-'*40
os._exit(0)
#----------------- end class RPCServer --------------------
objecttable = {}
request_queue = Queue.Queue(0)
response_queue = Queue.Queue(0)
class SocketIO(object):
nextseq = 0
def __init__(self, sock, objtable=None, debugging=None):
self.sockthread = threading.currentThread()
if debugging is not None:
self.debugging = debugging
self.sock = sock
if objtable is None:
objtable = objecttable
self.objtable = objtable
self.responses = {}
self.cvars = {}
def close(self):
sock = self.sock
self.sock = None
if sock is not None:
sock.close()
def exithook(self):
"override for specific exit action"
os._exit(0)
def debug(self, *args):
if not self.debugging:
return
s = self.location + " " + str(threading.currentThread().getName())
for a in args:
s = s + " " + str(a)
print>>sys.__stderr__, s
def register(self, oid, object):
self.objtable[oid] = object
def unregister(self, oid):
try:
del self.objtable[oid]
except KeyError:
pass
def localcall(self, seq, request):
self.debug("localcall:", request)
try:
how, (oid, methodname, args, kwargs) = request
except TypeError:
return ("ERROR", "Bad request format")
if oid not in self.objtable:
return ("ERROR", "Unknown object id: %r" % (oid,))
obj = self.objtable[oid]
if methodname == "__methods__":
methods = {}
_getmethods(obj, methods)
return ("OK", methods)
if methodname == "__attributes__":
attributes = {}
_getattributes(obj, attributes)
return ("OK", attributes)
if not hasattr(obj, methodname):
return ("ERROR", "Unsupported method name: %r" % (methodname,))
method = getattr(obj, methodname)
try:
if how == 'CALL':
ret = method(*args, **kwargs)
if isinstance(ret, RemoteObject):
ret = remoteref(ret)
return ("OK", ret)
elif how == 'QUEUE':
request_queue.put((seq, (method, args, kwargs)))
return("QUEUED", None)
else:
return ("ERROR", "Unsupported message type: %s" % how)
except SystemExit:
raise
except socket.error:
raise
except:
msg = "*** Internal Error: rpc.py:SocketIO.localcall()\n\n"\
" Object: %s \n Method: %s \n Args: %s\n"
print>>sys.__stderr__, msg % (oid, method, args)
traceback.print_exc(file=sys.__stderr__)
return ("EXCEPTION", None)
def remotecall(self, oid, methodname, args, kwargs):
self.debug("remotecall:asynccall: ", oid, methodname)
seq = self.asynccall(oid, methodname, args, kwargs)
return self.asyncreturn(seq)
def remotequeue(self, oid, methodname, args, kwargs):
self.debug("remotequeue:asyncqueue: ", oid, methodname)
seq = self.asyncqueue(oid, methodname, args, kwargs)
return self.asyncreturn(seq)
def asynccall(self, oid, methodname, args, kwargs):
request = ("CALL", (oid, methodname, args, kwargs))
seq = self.newseq()
if threading.currentThread() != self.sockthread:
cvar = threading.Condition()
self.cvars[seq] = cvar
self.debug(("asynccall:%d:" % seq), oid, methodname, args, kwargs)
self.putmessage((seq, request))
return seq
def asyncqueue(self, oid, methodname, args, kwargs):
request = ("QUEUE", (oid, methodname, args, kwargs))
seq = self.newseq()
if threading.currentThread() != self.sockthread:
cvar = threading.Condition()
self.cvars[seq] = cvar
self.debug(("asyncqueue:%d:" % seq), oid, methodname, args, kwargs)
self.putmessage((seq, request))
return seq
def asyncreturn(self, seq):
self.debug("asyncreturn:%d:call getresponse(): " % seq)
response = self.getresponse(seq, wait=0.05)
self.debug(("asyncreturn:%d:response: " % seq), response)
return self.decoderesponse(response)
def decoderesponse(self, response):
how, what = response
if how == "OK":
return what
if how == "QUEUED":
return None
if how == "EXCEPTION":
self.debug("decoderesponse: EXCEPTION")
return None
if how == "EOF":
self.debug("decoderesponse: EOF")
self.decode_interrupthook()
return None
if how == "ERROR":
self.debug("decoderesponse: Internal ERROR:", what)
raise RuntimeError, what
raise SystemError, (how, what)
def decode_interrupthook(self):
""
raise EOFError
def mainloop(self):
"""Listen on socket until I/O not ready or EOF
pollresponse() will loop looking for seq number None, which
never comes, and exit on EOFError.
"""
try:
self.getresponse(myseq=None, wait=0.05)
except EOFError:
self.debug("mainloop:return")
return
def getresponse(self, myseq, wait):
response = self._getresponse(myseq, wait)
if response is not None:
how, what = response
if how == "OK":
response = how, self._proxify(what)
return response
def _proxify(self, obj):
if isinstance(obj, RemoteProxy):
return RPCProxy(self, obj.oid)
if isinstance(obj, types.ListType):
return map(self._proxify, obj)
# XXX Check for other types -- not currently needed
return obj
def _getresponse(self, myseq, wait):
self.debug("_getresponse:myseq:", myseq)
if threading.currentThread() is self.sockthread:
# this thread does all reading of requests or responses
while 1:
response = self.pollresponse(myseq, wait)
if response is not None:
return response
else:
# wait for notification from socket handling thread
cvar = self.cvars[myseq]
cvar.acquire()
while myseq not in self.responses:
cvar.wait()
response = self.responses[myseq]
self.debug("_getresponse:%s: thread woke up: response: %s" %
(myseq, response))
del self.responses[myseq]
del self.cvars[myseq]
cvar.release()
return response
def newseq(self):
self.nextseq = seq = self.nextseq + 2
return seq
def putmessage(self, message):
self.debug("putmessage:%d:" % message[0])
try:
s = pickle.dumps(message)
except pickle.PicklingError:
print >>sys.__stderr__, "Cannot pickle:", repr(message)
raise
s = struct.pack("<i", len(s)) + s
while len(s) > 0:
try:
r, w, x = select.select([], [self.sock], [])
n = self.sock.send(s[:BUFSIZE])
except (AttributeError, TypeError):
raise IOError, "socket no longer exists"
s = s[n:]
buffer = ""
bufneed = 4
bufstate = 0 # meaning: 0 => reading count; 1 => reading data
def pollpacket(self, wait):
self._stage0()
if len(self.buffer) < self.bufneed:
r, w, x = select.select([self.sock.fileno()], [], [], wait)
if len(r) == 0:
return None
try:
s = self.sock.recv(BUFSIZE)
except socket.error:
raise EOFError
if len(s) == 0:
raise EOFError
self.buffer += s
self._stage0()
return self._stage1()
def _stage0(self):
if self.bufstate == 0 and len(self.buffer) >= 4:
s = self.buffer[:4]
self.buffer = self.buffer[4:]
self.bufneed = struct.unpack("<i", s)[0]
self.bufstate = 1
def _stage1(self):
if self.bufstate == 1 and len(self.buffer) >= self.bufneed:
packet = self.buffer[:self.bufneed]
self.buffer = self.buffer[self.bufneed:]
self.bufneed = 4
self.bufstate = 0
return packet
def pollmessage(self, wait):
packet = self.pollpacket(wait)
if packet is None:
return None
try:
message = pickle.loads(packet)
except pickle.UnpicklingError:
print >>sys.__stderr__, "-----------------------"
print >>sys.__stderr__, "cannot unpickle packet:", repr(packet)
traceback.print_stack(file=sys.__stderr__)
print >>sys.__stderr__, "-----------------------"
raise
return message
def pollresponse(self, myseq, wait):
"""Handle messages received on the socket.
Some messages received may be asynchronous 'call' or 'queue' requests,
and some may be responses for other threads.
'call' requests are passed to self.localcall() with the expectation of
immediate execution, during which time the socket is not serviced.
'queue' requests are used for tasks (which may block or hang) to be
processed in a different thread. These requests are fed into
request_queue by self.localcall(). Responses to queued requests are
taken from response_queue and sent across the link with the associated
sequence numbers. Messages in the queues are (sequence_number,
request/response) tuples and code using this module removing messages
from the request_queue is responsible for returning the correct
sequence number in the response_queue.
pollresponse() will loop until a response message with the myseq
sequence number is received, and will save other responses in
self.responses and notify the owning thread.
"""
while 1:
# send queued response if there is one available
try:
qmsg = response_queue.get(0)
except Queue.Empty:
pass
else:
seq, response = qmsg
message = (seq, ('OK', response))
self.putmessage(message)
# poll for message on link
try:
message = self.pollmessage(wait)
if message is None: # socket not ready
return None
except EOFError:
self.handle_EOF()
return None
except AttributeError:
return None
seq, resq = message
how = resq[0]
self.debug("pollresponse:%d:myseq:%s" % (seq, myseq))
# process or queue a request
if how in ("CALL", "QUEUE"):
self.debug("pollresponse:%d:localcall:call:" % seq)
response = self.localcall(seq, resq)
self.debug("pollresponse:%d:localcall:response:%s"
% (seq, response))
if how == "CALL":
self.putmessage((seq, response))
elif how == "QUEUE":
# don't acknowledge the 'queue' request!
pass
continue
# return if completed message transaction
elif seq == myseq:
return resq
# must be a response for a different thread:
else:
cv = self.cvars.get(seq, None)
# response involving unknown sequence number is discarded,
# probably intended for prior incarnation of server
if cv is not None:
cv.acquire()
self.responses[seq] = resq
cv.notify()
cv.release()
continue
def handle_EOF(self):
"action taken upon link being closed by peer"
self.EOFhook()
self.debug("handle_EOF")
for key in self.cvars:
cv = self.cvars[key]
cv.acquire()
self.responses[key] = ('EOF', None)
cv.notify()
cv.release()
# call our (possibly overridden) exit function
self.exithook()
def EOFhook(self):
"Classes using rpc client/server can override to augment EOF action"
pass
#----------------- end class SocketIO --------------------
class RemoteObject(object):
# Token mix-in class
pass
def remoteref(obj):
oid = id(obj)
objecttable[oid] = obj
return RemoteProxy(oid)
class RemoteProxy(object):
def __init__(self, oid):
self.oid = oid
class RPCHandler(SocketServer.BaseRequestHandler, SocketIO):
debugging = False
location = "#S" # Server
def __init__(self, sock, addr, svr):
svr.current_handler = self ## cgt xxx
SocketIO.__init__(self, sock)
SocketServer.BaseRequestHandler.__init__(self, sock, addr, svr)
def handle(self):
"handle() method required by SocketServer"
self.mainloop()
def get_remote_proxy(self, oid):
return RPCProxy(self, oid)
class RPCClient(SocketIO):
debugging = False
location = "#C" # Client
nextseq = 1 # Requests coming from the client are odd numbered
def __init__(self, address, family=socket.AF_INET, type=socket.SOCK_STREAM):
self.listening_sock = socket.socket(family, type)
self.listening_sock.bind(address)
self.listening_sock.listen(1)
def accept(self):
working_sock, address = self.listening_sock.accept()
if self.debugging:
print>>sys.__stderr__, "****** Connection request from ", address
if address[0] == LOCALHOST:
SocketIO.__init__(self, working_sock)
else:
print>>sys.__stderr__, "** Invalid host: ", address
raise socket.error
def get_remote_proxy(self, oid):
return RPCProxy(self, oid)
class RPCProxy(object):
__methods = None
__attributes = None
def __init__(self, sockio, oid):
self.sockio = sockio
self.oid = oid
def __getattr__(self, name):
if self.__methods is None:
self.__getmethods()
if self.__methods.get(name):
return MethodProxy(self.sockio, self.oid, name)
if self.__attributes is None:
self.__getattributes()
if name in self.__attributes:
value = self.sockio.remotecall(self.oid, '__getattribute__',
(name,), {})
return value
else:
raise AttributeError, name
def __getattributes(self):
self.__attributes = self.sockio.remotecall(self.oid,
"__attributes__", (), {})
def __getmethods(self):
self.__methods = self.sockio.remotecall(self.oid,
"__methods__", (), {})
def _getmethods(obj, methods):
# Helper to get a list of methods from an object
# Adds names to dictionary argument 'methods'
for name in dir(obj):
attr = getattr(obj, name)
if hasattr(attr, '__call__'):
methods[name] = 1
if type(obj) == types.InstanceType:
_getmethods(obj.__class__, methods)
if type(obj) == types.ClassType:
for super in obj.__bases__:
_getmethods(super, methods)
def _getattributes(obj, attributes):
for name in dir(obj):
attr = getattr(obj, name)
if not hasattr(attr, '__call__'):
attributes[name] = 1
class MethodProxy(object):
def __init__(self, sockio, oid, name):
self.sockio = sockio
self.oid = oid
self.name = name
def __call__(self, *args, **kwargs):
value = self.sockio.remotecall(self.oid, self.name, args, kwargs)
return value
# XXX KBK 09Sep03 We need a proper unit test for this module. Previously
# existing test code was removed at Rev 1.27 (r34098).
