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"""RPC Implemention, 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
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 socket
import select
import SocketServer
import struct
import cPickle as pickle
import threading
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 `fn`
copy_reg.pickle(types.CodeType, pickle_code, unpickle_code)
# copy_reg.pickle(types.FunctionType, pickle_function, unpickle_function)
BUFSIZE = 8*1024
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 EOFError:
pass
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
import os
os._exit(0)
objecttable = {}
class SocketIO:
nextseq = 0
def __init__(self, sock, objtable=None, debugging=None):
self.mainthread = threading.currentThread()
if debugging is not None:
self.debugging = debugging
self.sock = sock
if objtable is None:
objtable = objecttable
self.objtable = objtable
self.cvar = threading.Condition()
self.responses = {}
self.cvars = {}
self.interrupted = False
def close(self):
sock = self.sock
self.sock = None
if sock is not None:
sock.close()
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, request):
self.debug("localcall:", request)
try:
how, (oid, methodname, args, kwargs) = request
except TypeError:
return ("ERROR", "Bad request format")
assert how == "call"
if not self.objtable.has_key(oid):
return ("ERROR", "Unknown object id: %s" % `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: %s" % `methodname`)
method = getattr(obj, methodname)
try:
ret = method(*args, **kwargs)
if isinstance(ret, RemoteObject):
ret = remoteref(ret)
return ("OK", ret)
except SystemExit:
raise
except socket.error:
pass
except:
self.debug("localcall:EXCEPTION")
traceback.print_exc(file=sys.__stderr__)
return ("EXCEPTION", None)
def remotecall(self, oid, methodname, args, kwargs):
self.debug("remotecall:asynccall: ", oid, methodname)
# XXX KBK 06Feb03 self.interrupted logic may not be necessary if
# subprocess is threaded.
if self.interrupted:
self.interrupted = False
raise KeyboardInterrupt
seq = self.asynccall(oid, methodname, args, kwargs)
return self.asyncreturn(seq)
def asynccall(self, oid, methodname, args, kwargs):
request = ("call", (oid, methodname, args, kwargs))
seq = self.newseq()
self.debug(("asynccall:%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=None)
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 == "EXCEPTION":
self.debug("decoderesponse: EXCEPTION")
return None
if how == "ERROR":
self.debug("decoderesponse: Internal ERROR:", what)
raise RuntimeError, what
raise SystemError, (how, what)
def mainloop(self):
"""Listen on socket until I/O not ready or EOF
Main thread pollresponse() will loop looking for seq number None, which
never comes, and exit on EOFError.
"""
try:
self.getresponse(myseq=None, wait=None)
except EOFError:
pass
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.mainthread:
# Main thread: does all reading of requests or responses
# Loop here, blocking each time until socket is ready.
while 1:
response = self.pollresponse(myseq, wait)
if response is not None:
return response
else:
# Auxiliary thread: wait for notification from main thread
self.cvar.acquire()
self.cvars[myseq] = self.cvar
while not self.responses.has_key(myseq):
self.cvar.wait()
response = self.responses[myseq]
del self.responses[myseq]
del self.cvars[myseq]
self.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:
print >>sys.__stderr__, "Cannot pickle:", `message`
raise
s = struct.pack("<i", len(s)) + s
while len(s) > 0:
try:
n = self.sock.send(s)
except AttributeError:
# socket was closed
raise IOError
else:
s = s[n:]
def ioready(self, wait=0.0):
r, w, x = select.select([self.sock.fileno()], [], [], wait)
return len(r)
buffer = ""
bufneed = 4
bufstate = 0 # meaning: 0 => reading count; 1 => reading data
def pollpacket(self, wait=0.0):
self._stage0()
if len(self.buffer) < self.bufneed:
if not self.ioready(wait):
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=0.0):
packet = self.pollpacket(wait)
if packet is None:
return None
try:
message = pickle.loads(packet)
except:
print >>sys.__stderr__, "-----------------------"
print >>sys.__stderr__, "cannot unpickle packet:", `packet`
traceback.print_stack(file=sys.__stderr__)
print >>sys.__stderr__, "-----------------------"
raise
return message
def pollresponse(self, myseq, wait=0.0):
"""Handle messages received on the socket.
Some messages received may be asynchronous 'call' commands, and
some may be responses intended for other threads.
Loop until message with myseq sequence number is received. Save others
in self.responses and notify the owning thread, except that 'call'
commands are handed off to localcall() and the response sent back
across the link with the appropriate sequence number.
"""
while 1:
message = self.pollmessage(wait)
if message is None: # socket not ready
return None
#wait = 0.0 # poll on subsequent passes instead of blocking
seq, resq = message
self.debug("pollresponse:%d:myseq:%s" % (seq, myseq))
if resq[0] == "call":
self.debug("pollresponse:%d:localcall:call:" % seq)
response = self.localcall(resq)
self.debug("pollresponse:%d:localcall:response:%s"
% (seq, response))
self.putmessage((seq, response))
continue
elif seq == myseq:
return resq
else:
self.cvar.acquire()
cv = self.cvars.get(seq)
# response involving unknown sequence number is discarded,
# probably intended for prior incarnation
if cv is not None:
self.responses[seq] = resq
cv.notify()
self.cvar.release()
continue
#----------------- end class SocketIO --------------------
class RemoteObject:
# Token mix-in class
pass
def remoteref(obj):
oid = id(obj)
objecttable[oid] = obj
return RemoteProxy(oid)
class RemoteProxy:
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.setsockopt(socket.SOL_SOCKET,
socket.SO_REUSEADDR, 1)
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] == '127.0.0.1':
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:
__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 not self.__attributes.has_key(name):
raise AttributeError, name
__getattr__.DebuggerStepThrough=1
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 callable(attr):
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 callable(attr):
attributes[name] = 1
class MethodProxy:
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
#
# Self Test
#
def testServer(addr):
# XXX 25 Jul 02 KBK needs update to use rpc.py register/unregister methods
class RemotePerson:
def __init__(self,name):
self.name = name
def greet(self, name):
print "(someone called greet)"
print "Hello %s, I am %s." % (name, self.name)
print
def getName(self):
print "(someone called getName)"
print
return self.name
def greet_this_guy(self, name):
print "(someone called greet_this_guy)"
print "About to greet %s ..." % name
remote_guy = self.server.current_handler.get_remote_proxy(name)
remote_guy.greet("Thomas Edison")
print "Done."
print
person = RemotePerson("Thomas Edison")
svr = RPCServer(addr)
svr.register('thomas', person)
person.server = svr # only required if callbacks are used
# svr.serve_forever()
svr.handle_request() # process once only
def testClient(addr):
"demonstrates RPC Client"
# XXX 25 Jul 02 KBK needs update to use rpc.py register/unregister methods
import time
clt=RPCClient(addr)
thomas = clt.get_remote_proxy("thomas")
print "The remote person's name is ..."
print thomas.getName()
# print clt.remotecall("thomas", "getName", (), {})
print
time.sleep(1)
print "Getting remote thomas to say hi..."
thomas.greet("Alexander Bell")
#clt.remotecall("thomas","greet",("Alexander Bell",), {})
print "Done."
print
time.sleep(2)
# demonstrates remote server calling local instance
class LocalPerson:
def __init__(self,name):
self.name = name
def greet(self, name):
print "You've greeted me!"
def getName(self):
return self.name
person = LocalPerson("Alexander Bell")
clt.register("alexander",person)
thomas.greet_this_guy("alexander")
# clt.remotecall("thomas","greet_this_guy",("alexander",), {})
def test():
addr=("localhost",8833)
if len(sys.argv) == 2:
if sys.argv[1]=='-server':
testServer(addr)
return
testClient(addr)
if __name__ == '__main__':
test()
|