plugin XEP-0470: create a default configuration if node config can't be accessed

sat/plugins/plugin_xep_0060.py

@@ -961,6 +961,14 @@ class XEP_0060(object):
         d.addCallback(cb)
         return d
 
+    def make_configuration_form(self, options: dict) -> data_form.Form:
+        """Build a configuration form"""
+        form = data_form.Form(
+            formType="submit", formNamespace=pubsub.NS_PUBSUB_NODE_CONFIG
+        )
+        form.makeFields(options)
+        return form
+
     def _setNodeConfiguration(self, service_s, nodeIdentifier, options, profile_key):
         client = self.host.getClient(profile_key)
         d = self.setConfiguration(
@@ -973,10 +981,7 @@ class XEP_0060(object):
         request.recipient = service
         request.nodeIdentifier = nodeIdentifier
 
-        form = data_form.Form(
-            formType="submit", formNamespace=pubsub.NS_PUBSUB_NODE_CONFIG
-        )
-        form.makeFields(options)
+        form = self.make_configuration_form(options)
         request.options = form
 
         d = request.send(client.xmlstream)

sat/plugins/plugin_xep_0470.py

@@ -194,6 +194,8 @@ class PubsubAttachments:
                     client, service, node
                 )
                 node_config = await self._p.getConfiguration(client, service, node)
+            elif e.condition == "forbidden":
+                node_config = self._p.make_configuration_form({})
             else:
                 raise e
         try: