changes from code review, added docs

asyncua/client/ua_client.py

@@ -7,14 +7,10 @@ from typing import Dict, List
 from asyncua import ua
 from typing import Optional
 from ..ua.ua_binary import struct_from_binary, uatcp_to_binary, struct_to_binary, nodeid_from_binary, header_from_binary
-from ..ua.uaerrors import BadTimeout, BadNoSubscription, BadSessionClosed
+from ..ua.uaerrors import BadTimeout, BadNoSubscription, BadSessionClosed, UaStructParsingError
 from ..common.connection import SecureConnection
 
 
-class ResponseParseError(ValueError):
-    """Error while parsing responses."""
-
-
 class UASocketProtocol(asyncio.Protocol):
     """
     Handle socket connection and send ua messages.
@@ -442,7 +438,7 @@ class UaClient:
         self.logger.info("create_subscription success SubscriptionId %s", response.Parameters.SubscriptionId)
         if not self._publish_task or self._publish_task.done():
             # Start the publish cycle if it is not yet running
-            self._publish_task = self.loop.create_task(self._publish_cycle())
+            self._publish_task = self.loop.create_task(self._publish_loop())
         return response.Parameters
 
     async def delete_subscriptions(self, subscription_ids):
@@ -473,10 +469,10 @@ class UaClient:
             response = struct_from_binary(ua.PublishResponse, data)
         except Exception:
             self.logger.exception("Error parsing notification from server")
-            raise ResponseParseError
+            raise UaStructParsingError
         return response
 
-    async def _publish_cycle(self):
+    async def _publish_loop(self):
         """
         Start publish cycle that sends a publish request and waits for the publish response in an endless loop.
         Forward the `PublishResult` to the matching `Subscription` by callback.
@@ -505,7 +501,7 @@ class UaClient:
                 self.logger.info("BadNoSubscription received, ignoring because it's probably valid.")
                 # End task
                 return
-            except ResponseParseError:
+            except UaStructParsingError:
                 ack = None
                 continue
             subscription_id = response.Parameters.SubscriptionId

asyncua/server/internal_subscription.py

@@ -48,11 +48,17 @@ class InternalSubscription:
         self.monitored_item_srv.delete_all_monitored_items()
 
     def _trigger_publish(self):
-        if self._task and self.data.RevisedPublishingInterval <= 0.0:  # ToDo: check against Spec.
+        """
+        Trigger immediate publication (if requested by the PublishingInterval).
+        """
+        if self._task and self.data.RevisedPublishingInterval <= 0.0:
+            # Publish immediately (as fast as possible)
             self.publish_results()
 
     async def _subscription_loop(self):
-        """Publication cycle."""
+        """
+        Start the publication loop running at the RevisedPublishingInterval.
+        """
         try:
             while True:
                 await asyncio.sleep(self.data.RevisedPublishingInterval / 1000.0)

asyncua/ua/uaerrors/_base.py

@@ -84,3 +84,7 @@ class UaStatusCodeError(_AutoRegister("Meta", (UaError,), {})):
 
 class UaStringParsingError(UaError):
     pass
+
+
+class UaStructParsingError(UaError):
+    pass