[Pysnmp-dev] [PATCH] first commit of twisted transport and dispatcher

[Filippo G. <fi...@tr...>]

Hi,
the patch below ought to add a dispatcher and an udp transport to be used with
twisted, IOW you can use pysnmp while running a twisted reactor.

thanks in advance,
filippo
---
 pysnmp/v4/carrier/twisted/dispatch.py |   61 +++++++++++++++++++++++++++
 pysnmp/v4/carrier/twisted/udp.py      |   74 +++++++++++++++++++++++++++++++++
 2 files changed, 135 insertions(+), 0 deletions(-)
 create mode 100644 pysnmp/v4/carrier/twisted/__init__.py
 create mode 100644 pysnmp/v4/carrier/twisted/dispatch.py
 create mode 100644 pysnmp/v4/carrier/twisted/udp.py

diff --git a/pysnmp/v4/carrier/twisted/__init__.py b/pysnmp/v4/carrier/twisted/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/pysnmp/v4/carrier/twisted/dispatch.py b/pysnmp/v4/carrier/twisted/dispatch.py
new file mode 100644
index 0000000..cba5074
--- /dev/null
+++ b/pysnmp/v4/carrier/twisted/dispatch.py
@@ -0,0 +1,61 @@
+#!/usr/bin/env python
+#
+# -*- python -*-
+#
+#  File: transport.py
+#
+#  Copyright (C) 2008 Truelite Srl <in...@tr...>
+#
+#  Author: Filippo Giunchedi <fi...@tr...>
+#
+#  This program is free software; you can redistribute it and/or modify
+#  it under the terms of the GNU General Public License Version 2
+#  as published by the Free Software Foundation
+#
+# Description:
+# Transport dispatcher based on twisted.internet.reactor
+
+from time import time
+
+from twisted.internet import reactor, task
+
+from pysnmp.carrier.base import AbstractTransportDispatcher
+
+class ReactorDispatcher(AbstractTransportDispatcher):
+    """TransportDispatcher based on twisted.internet.reactor"""
+    def __init__(self, *args, **kwargs):
+        AbstractTransportDispatcher.__init__(self)
+
+        self.timeout = 1
+        if kwargs.has_key('timeout'):
+            self.timeout = kwargs['timeout']
+
+        self.loopingcall = task.LoopingCall(self.handleTimeout)
+
+    def handleTimeout(self):
+        self.handleTimerTick(time())
+
+    def runDispatcher(self, timeout=0.0):
+        if not reactor.running:
+            reactor.run()
+
+# jobstarted/jobfinished might be okay as-is
+
+    def registerTransport(self, tDomain, transport):
+        if not self.loopingcall.running and self.timeout > 0:
+            self.loopingcall.start(self.timeout, now = False)
+        AbstractTransportDispatcher.registerTransport(self, tDomain, transport)
+        # Ugly, but we need to call handleTimerTick() asyncronously from transports now.
+        # IOW, it is not possibile to call handleTimerTick after poll()ing every transport' socket
+        transport.dispatcher = self
+
+    def unregisterTransport(self, tDomain):
+        t = AbstractTransportDispatcher.getTransport(self, tDomain)
+        if t is not None:
+            AbstractTransportDispatcher.unregisterTransport(self, tDomain)
+            t.closeTransport()
+
+        if len(self._AbstractTransportDispatcher__transports) == 0:
+            # the last transport has been removed, stop the timeout
+            if self.loopingcall.running:
+                self.loopingcall.stop()
diff --git a/pysnmp/v4/carrier/twisted/udp.py b/pysnmp/v4/carrier/twisted/udp.py
new file mode 100644
index 0000000..dbb657a
--- /dev/null
+++ b/pysnmp/v4/carrier/twisted/udp.py
@@ -0,0 +1,74 @@
+#!/usr/bin/env python
+#
+# -*- python -*-
+#
+#  File: transport.py
+#
+#  Copyright (C) 2008 Truelite Srl <in...@tr...>
+#
+#  Author: Filippo Giunchedi <fi...@tr...>
+#
+#  This program is free software; you can redistribute it and/or modify
+#  it under the terms of the GNU General Public License Version 2
+#  as published by the Free Software Foundation
+#
+# Description:
+# twisted DatagramProtocol UDP transport
+
+from time import time
+
+from twisted.internet import reactor
+from twisted.internet.protocol import DatagramProtocol
+
+from pysnmp.carrier import error
+
+class ReactorUDPTransport(DatagramProtocol):
+    """UDP Transport based on twisted, to be used with ReactorDispatcher"""
+
+    def __init__(self):
+        self.__writeQ = []
+
+# twisted API
+    def datagramReceived(self, datagram, address):
+        if self._cbFun is not None:
+            self._cbFun(self, address, datagram)
+        else:
+            raise error.CarrierError('Unable to call cbFun')
+
+        if self.dispatcher is not None:
+            self.dispatcher.handleTimerTick(time())
+        else:
+            raise error.CarrierError('Unable to call handleTimerTick')
+
+    def startProtocol(self):
+        while self.__writeQ:
+            msg, addr = self.__writeQ.pop(0)
+            self.transport.write(msg, addr)
+
+    def stopProtocol(self):
+        self.unregisterCbFun()
+        self.dispatcher = None
+
+# asyncore AbstractSocketTransport API
+    def openClientMode(self, iface=''):
+        self._lport = reactor.listenUDP(0, self, iface)
+        return self
+
+    def openServerMode(self, iface=None):
+        self._lport = reactor.listenUDP(iface[1], self, iface[0])
+        return self
+
+    def sendMessage(self, outgoingMessage, transportAddress):
+        if self.transport is None:
+            self.__writeQ.append((outgoingMessage, transportAddress))
+        else:
+            self.transport.write(outgoingMessage, transportAddress)
+
+    def registerCbFun(self, cbFun):
+        self._cbFun = cbFun
+
+    def unregisterCbFun(self):
+        self._cbFun = None
+
+    def closeTransport(self):
+        self.transport.stopListening()
-- 
1.6.0.6