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