Merge branch 'precondition-not-met-fallback' into 'master'

Implement fallback on precondition-not-met error when publishing devicelist and bundle

Closes #6

See merge request poezio/slixmpp-omemo!2

slixmpp_omemo/__init__.py

@@ -54,6 +54,7 @@ except (ImportError,):
 
 TRUE_VALUES = {True, 'true', '1'}
 PUBLISH_OPTIONS_NODE = 'http://jabber.org/protocol/pubsub#publish-options'
+PUBSUB_ERRORS = 'http://jabber.org/protocol/pubsub#errors'
 
 
 def b64enc(data: bytes) -> str:
@@ -245,6 +246,38 @@ class XEP_0384(BasePlugin):
     def my_device_id(self) -> int:
         return self._device_id
 
+    def _set_node_config(
+            self,
+            node: str,
+            persist_items: bool = True,
+            access_model: Optional[str] = None,
+        ) -> asyncio.Future:
+        form = Form()
+        form['type'] = 'submit'
+        form.add_field(
+            var='FORM_TYPE',
+            ftype='hidden',
+            value='http://jabber.org/protocol/pubsub#node_config',
+        )
+        if persist_items:
+            form.add_field(
+                var='pubsub#persist_items',
+                ftype='boolean',
+                value=True,
+            )
+        if access_model is not None:
+            form.add_field(
+                var='FORM_TYPE',
+                ftype='text-single',
+                value=access_model,
+            )
+
+        return self.xmpp['xep_0060'].set_node_config(
+            self.xmpp.boundjid.bare,
+            node,
+            form,
+        )
+
     async def _generate_bundle_iq(self) -> Iq:
         bundle = self._omemo.public_bundle.serialize(self.omemo_backend)
 
@@ -286,7 +319,19 @@ class XEP_0384(BasePlugin):
     async def _publish_bundle(self) -> None:
         if self._omemo.republish_bundle:
             iq = await self._generate_bundle_iq()
+            try:
                 await iq.send()
+            except IqError as e:
+                # TODO: Slixmpp should handle pubsub#errors so we don't have to
+                # fish the element ourselves
+                precondition = e.iq['error'].xml.find(
+                    '{%s}%s' % (PUBSUB_ERRORS, 'precondition-not-met'),
+                )
+                if precondition is not None:
+                    log.debug('The node we tried to publish was already '
+                              'existing with a different configuration. '
+                              'Trying to configure manually..')
+                    await self._set_node_config(OMEMO_BUNDLES_NS)
 
     async def _fetch_bundle(self, jid: str, device_id: int) -> Optional[ExtendedPublicBundle]:
         node = '%s:%d' % (OMEMO_BUNDLES_NS, device_id)
@@ -374,9 +419,21 @@ class XEP_0384(BasePlugin):
                 'pubsub#access_model': 'open',
             })
 
+        try:
             await self.xmpp['xep_0060'].publish(
                 own_jid.bare, OMEMO_DEVICES_NS, payload=payload, options=options,
             )
+        except IqError as e:
+            # TODO: Slixmpp should handle pubsub#errors so we don't have to
+            # fish the element ourselves
+            precondition = e.iq['error'].xml.find(
+                '{%s}%s' % (PUBSUB_ERRORS, 'precondition-not-met'),
+            )
+            if precondition is not None:
+                log.debug('The node we tried to publish was already '
+                          'existing with a different configuration. '
+                          'Trying to configure manually..')
+                await self._set_node_config(OMEMO_DEVICES_NS)
 
     def get_device_list(self, jid: JID) -> List[str]:
         """Return active device ids. Always contains our own device id."""