Simplify.

opcua-to-http-gw/opcua-to-http-gw.py

@@ -14,9 +14,7 @@ import argparse
 import logging
 import __main__
 
-# #################################
-# Configure
-# XXX: addn erp5_username and erp5_password!
+# command line handling
 parser = argparse.ArgumentParser(description='Run OPCUA Server.')
 a = parser.add_argument
 a('--ip', help='The IP address on which the OPCUA Server runs', default="127.0.0.1")
@@ -34,6 +32,7 @@ erp5_username = args.erp5_username
 erp5_password = args.erp5_password
 ERP5_REQUEST_API = "ERP5Site_handleOPCUARequest"
 
+# ERP5 backend storage for OPCUA Document
 @dataclass(frozen=True)
 class ERP5Handler(asyncua.common.subscription.SubHandler):
   url: str
@@ -58,16 +57,15 @@ class ERP5Handler(asyncua.common.subscription.SubHandler):
   def event_notification(self, event):
     self.call(event=event)
 
-erp5_handler = None
-if erp5_url is not None:
-  erp5_handler = ERP5Handler(erp5_url)
+# init main ERP5 storage
+erp5_handler = ERP5Handler(erp5_url)
 
-  class InternalSession(asyncua.server.internal_session.InternalSession):
-    async def read(self, params):
-      erp5_handler.call(params=params)
-      return await super().read(params)
+class InternalSession(asyncua.server.internal_session.InternalSession):
+
+  async def read(self, params):
+    erp5_handler.call(params=params)
+    return await super().read(params)
 
-# #################################
 # Start OPCUA Server
 async def main():
   _logger = logging.getLogger(__name__)
@@ -80,7 +78,6 @@ async def main():
   if xml is not None:
     await server.import_xml(xml)
 
-
   # read previous state as saved in ERP5 backend
   erp5_json = erp5_handler.call(http_method="GET").json()
   _logger.error(erp5_json)
@@ -91,22 +88,21 @@ async def main():
     # XXX: this leads to a change notification which calls ERP5 and endless loop!
     #await node.write_value(v)
 
-  if erp5_handler:
-    subscription = await server.create_subscription(1000, erp5_handler)
-    await subscription.subscribe_events()
-    nodes = await asyncua.common.ua_utils.get_nodes_of_namespace(server)
-    await subscription.subscribe_data_change(nodes)
+  subscription = await server.create_subscription(1000, erp5_handler)
+  await subscription.subscribe_events()
+  nodes = await asyncua.common.ua_utils.get_nodes_of_namespace(server)
+  await subscription.subscribe_data_change(nodes)
 
-    def create_session(name,
-                      user=asyncua.server.users.User(role=asyncua.server.users.UserRole.Anonymous),
-                      external=False):
-      self = server.iserver
-      return InternalSession(self, self.aspace, self.subscription_service, name, user=user, external=external)
+  def create_session(name,
+                    user=asyncua.server.users.User(role=asyncua.server.users.UserRole.Anonymous),
+                    external=False):
+    self = server.iserver
+    return InternalSession(self, self.aspace, self.subscription_service, name, user=user, external=external)
 
-    server.iserver.create_session = create_session
-    _logger.info("Added subscription for erp5 handler.")
-  _logger.info("Starting server!")
+  server.iserver.create_session = create_session
 
+  # start OPCUA server
+  _logger.info("Starting server!")
   async with server:
     while True:
       await asyncio.sleep(1)