Extend KeyError Ignored methods (when channel not opened)

haas_proxy/proxy.py

@@ -40,11 +40,42 @@ class ProxyService(service.Service):
         return self._port.stopListening()
 
 
-class SSHConnection(SSHConnectionTwisted):
+class SilenceKeyErrorsMeta(type):
+    """
+    Meta class to silence KeyErrors from given set of methods,
+
+    Note that the methods will return None on failure
+    """
+
+    def __new__(cls, name, bases, dct):
+        wrapped_type = super().__new__(cls, name, bases, dct)
+        for method_name in wrapped_type.IGNORED_KEY_ERROR_METHODS:
+            # pylint: disable=invalid-name,inconsistent-return-statements
+            def silenced_method(*args, **kwargs):
+                try:
+                    # pylint: disable=cell-var-from-loop
+                    return getattr(SSHConnectionTwisted, method_name)(*args, **kwargs)
+                except KeyError:
+                    pass
+            setattr(wrapped_type, method_name, silenced_method)
+
+        return wrapped_type
+
+
+class SSHConnection(SSHConnectionTwisted, metaclass=SilenceKeyErrorsMeta):
     """
     Overridden SSHConnection for disabling logs a traceback about a failed direct-tcpip connections
     """
 
+    # Some packets send data to the channel even it's not successfully opened.
+    # Very probably direct-tcpip types which has bad packet resulting in not
+    # responding in `ssh_CHANNEL_OPEN`. Ignore it as it's unimportant.
+    IGNORED_KEY_ERROR_METHODS = (
+        "ssh_CHANNEL_DATA",
+        "ssh_CHANNEL_CLOSE",
+        "ssh_CHANNEL_EOF",
+    )
+
     # pylint: disable=invalid-name,inconsistent-return-statements
     def ssh_CHANNEL_OPEN(self, packet):
         # pylint: disable=unbalanced-tuple-unpacking
@@ -66,16 +97,6 @@ class SSHConnection(SSHConnectionTwisted):
                 common.NS(networkString('unknown failure')) + common.NS(b'')
             )
 
-    # pylint: disable=invalid-name,inconsistent-return-statements
-    def ssh_CHANNEL_DATA(self, packet):
-        try:
-            return SSHConnectionTwisted.ssh_CHANNEL_DATA(self, packet)
-        except KeyError:
-            # Some packets send data to the channel even it's not successfully opened.
-            # Very probably direct-tcpip types which has bad packet resulting in not
-            # responding in `ssh_CHANNEL_OPEN`. Ignore it as it's unimportant.
-            pass
-
 
 # pylint: disable=abstract-method
 class ProxySSHFactory(factory.SSHFactory):