commit -- why not

Demo/pdist/client.py

@@ -0,0 +1,133 @@
+"""RPC Client module."""
+
+import sys
+import socket
+import pickle
+import __builtin__
+import os
+
+
+# Default verbosity (0 = silent, 1 = print connections, 2 = print requests too)
+VERBOSE = 1
+
+
+class Client:
+	
+	"""RPC Client class.  No need to derive a class -- it's fully generic."""
+	
+	def __init__(self, address, verbose = VERBOSE):
+		if type(address) == type(0):
+			address = ('', address)
+		self._address = address
+		self._verbose = verbose
+		if self._verbose: print "Connecting to %s ..." % repr(address)
+		self._socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+		self._socket.connect(address)
+		if self._verbose: print "Connected."
+		self._lastid = 0 # Last id for which a reply has been received
+		self._nextid = 1 # Id of next request
+		self._replies = {} # Unprocessed replies
+		self._rf = self._socket.makefile('r')
+		self._wf = self._socket.makefile('w')
+		self._methods = self._call('.methods')
+	
+	def __del__(self):
+		self._close()
+	
+	def _close(self):
+		if self._rf: self._rf.close()
+		self._rf = None
+		if self._wf: self._wf.close()
+		self._wf = None
+		if self._socket: self._socket.close()
+		self._socket = None
+	
+	def __getattr__(self, name):
+		if name in self._methods:
+			method = _stub(self, name)
+			setattr(self, name, method) # XXX circular reference
+			return method
+		raise AttributeError, name
+	
+	def _setverbose(self, verbose):
+		self._verbose = verbose
+	
+	def _call(self, name, *args):
+		return self._vcall(name, args)
+	
+	def _vcall(self, name, args):
+		return self._recv(self._vsend(name, args))
+	
+	def _send(self, name, *args):
+		return self._vsend(name, args)
+	
+	def _send_noreply(self, name, *args):
+		return self._vsend(name, args, 0)
+	
+	def _vsend_noreply(self, name, args):
+		return self._vsend(name, args, 0)
+	
+	def _vsend(self, name, args, wantreply = 1):
+		id = self._nextid
+		self._nextid = id+1
+		if not wantreply: id = -id
+		request = (name, args, id)
+		if self._verbose > 1: print "sending request: %s" % repr(request)
+		wp = pickle.Pickler(self._wf)
+		wp.dump(request)
+		return id
+	
+	def _recv(self, id):
+		exception, value, rid = self._vrecv(id)
+		if rid != id:
+			raise RuntimeError, "request/reply id mismatch: %d/%d" % (id, rid)
+		if exception is None:
+			return value
+		x = exception
+		if hasattr(__builtin__, exception):
+			x = getattr(__builtin__, exception)
+		elif exception in ('posix.error', 'mac.error'):
+			x = os.error
+		if x == exception:
+			exception = x
+		raise exception, value		
+	
+	def _vrecv(self, id):
+		self._flush()
+		if self._replies.has_key(id):
+			if self._verbose > 1: print "retrieving previous reply, id = %d" % id
+			reply = self._replies[id]
+			del self._replies[id]
+			return reply
+		aid = abs(id)
+		while 1:
+			if self._verbose > 1: print "waiting for reply, id = %d" % id
+			rp = pickle.Unpickler(self._rf)
+			reply = rp.load()
+			del rp
+			if self._verbose > 1: print "got reply: %s" % repr(reply)
+			rid = reply[2]
+			arid = abs(rid)
+			if arid == aid:
+				if self._verbose > 1: print "got it"
+				return reply
+			self._replies[rid] = reply
+			if arid > aid:
+				if self._verbose > 1: print "got higher id, assume all ok"
+				return (None, None, id)
+	
+	def _flush(self):
+		self._wf.flush()
+
+
+class _stub:
+	
+	"""Helper class for Client -- each instance serves as a method of the client."""
+	
+	def __init__(self, client, name):
+		self._client = client
+		self._name = name
+	
+	def __call__(self, *args):
+		return self._client._vcall(self._name, args)
+