disptacher vs transport compatibiilty verification moved into

base transport class

6 files changed, 17 insertions, 4 deletions

diff --git a/pysnmp/carrier/asynsock/base.py b/pysnmp/carrier/asynsock/base.py
index 30d9137..83de36c 100644
--- a/pysnmp/carrier/asynsock/base.py
+++ b/pysnmp/carrier/asynsock/base.py
@@ -2,10 +2,11 @@
 import socket, sys
 import asyncore
 from pysnmp.carrier import error
+from pysnmp.carrier.base import AbstractTransport
 from pysnmp.carrier.asynsock.dispatch import AsynsockDispatcher
 from pysnmp import debug
 
-class AbstractSocketTransport(asyncore.dispatcher):
+class AbstractSocketTransport(asyncore.dispatcher, AbstractTransport):
     protoTransportDispatcher = AsynsockDispatcher
     sockFamily = sockType = None
     retryCount = 0; retryInterval = 0
diff --git a/pysnmp/carrier/base.py b/pysnmp/carrier/base.py
index bb2424e..238da25 100644
--- a/pysnmp/carrier/base.py
+++ b/pysnmp/carrier/base.py
@@ -156,3 +156,10 @@ class AbstractTransportDispatcher:
             self.unregisterTransport(tDomain)
         self.unregisterRecvCbFun()
         self.unregisterTimerCbFun()
+
+
+class AbstractTransport:
+    protoTransportDispatcher = None
+    @classmethod
+    def isCompatibleWithDispatcher(cls, transportDispatcher):
+        return isinstance(transportDispatcher, cls.protoTransportDispatcher)
diff --git a/pysnmp/carrier/twisted/base.py b/pysnmp/carrier/twisted/base.py
index fba21da..fa1da90 100644
--- a/pysnmp/carrier/twisted/base.py
+++ b/pysnmp/carrier/twisted/base.py
@@ -9,8 +9,9 @@
 #  Description: twisted DatagramProtocol UDP transport
 #
 from pysnmp.carrier.twisted.dispatch import TwistedDispatcher
+from pysnmp.carrier.base import AbstractTransport
 
-class AbstractTwistedTransport:
+class AbstractTwistedTransport(AbstractTransport):
     protoTransportDispatcher = TwistedDispatcher
     """Base Twisted Transport, to be used with TwistedDispatcher"""
     def __init__(self):
diff --git a/pysnmp/entity/config.py b/pysnmp/entity/config.py
index b433583..55e0e67 100644
--- a/pysnmp/entity/config.py
+++ b/pysnmp/entity/config.py
@@ -309,8 +309,7 @@ def delTargetAddr(snmpEngine, addrName):
 
 def addTransport(snmpEngine, transportDomain, transport):
     if snmpEngine.transportDispatcher:
-        if not isinstance(snmpEngine.transportDispatcher,
-                          transport.protoTransportDispatcher):
+        if not transport.isCompatibleWithDispatcher(snmpEngine.transportDispatcher): 
             raise error.PySnmpError('Transport %r is not compatible with dispatcher %r' % (transport, snmpEngine.transportDispatcher))
     else:
         snmpEngine.registerTransportDispatcher(
diff --git a/pysnmp/entity/rfc3413/oneliner/cmdgen.py b/pysnmp/entity/rfc3413/oneliner/cmdgen.py
index c3565ed..829312a 100644
--- a/pysnmp/entity/rfc3413/oneliner/cmdgen.py
+++ b/pysnmp/entity/rfc3413/oneliner/cmdgen.py
@@ -85,6 +85,7 @@ class AsynCommandGenerator:
             self.__knownParams[paramsKey] = paramsName, 1
 
         if transportTarget.transportDomain in self.__knownTransports:
+            transportTarget.verifyDispatcherCompatibility(self.snmpEngine)
             transport, useCount = self.__knownTransports[transportTarget.transportDomain]
             self.__knownTransports[transportTarget.transportDomain] = transport, useCount + 1
         else:
diff --git a/pysnmp/entity/rfc3413/oneliner/target.py b/pysnmp/entity/rfc3413/oneliner/target.py
index 04d268a..3273dfc 100644
--- a/pysnmp/entity/rfc3413/oneliner/target.py
+++ b/pysnmp/entity/rfc3413/oneliner/target.py
@@ -25,6 +25,10 @@ class _AbstractTransportTarget:
         self.transport = self.protoTransport().openClientMode()
         return self.transport
 
+    def verifyDispatcherCompatibility(self, snmpEngine):
+        if not self.protoTransport.isCompatibleWithDispatcher(snmpEngine.transportDispatcher):
+            raise error.PySnmpError('Transport %r is not compatible with dispatcher %r' % (self.protoTransport, snmpEngine.transportDispatcher))
+
     def _resolveAddr(self, transportAddr): raise NotImplementedError()
 
 class UdpTransportTarget(_AbstractTransportTarget):