--- a/sat/plugins/plugin_xep_0277.py	Fri Apr 23 10:08:58 2021 +0200
+++ b/sat/plugins/plugin_xep_0277.py	Thu Apr 29 15:49:59 2021 +0200
@@ -100,6 +100,14 @@
             async_=True,
         )
         host.bridge.addMethod(
+            "mbPreview",
+            ".plugin",
+            in_sign="ssss",
+            out_sign="s",
+            method=self._mbPreview,
+            async_=True,
+        )
+        host.bridge.addMethod(
             "mbRetract",
             ".plugin",
             in_sign="ssss",
@@ -651,7 +659,7 @@
 
         defer.returnValue(item_elt)
 
-    ## publish ##
+    ## publish/preview ##
 
     def getCommentsNode(self, item_id):
         """Generate comment node
@@ -803,27 +811,32 @@
                         client, comments_service, comments_node, comments_affiliations
                     )
 
+    def friendlyId(self, data):
+        """Generate a user friendly id from title or content"""
+        id_base = regex.urlFriendlyText(data.get('title') or data.get('content', ''))
+        return f"{id_base}-{token_urlsafe(3)}"
+
     def _mbSend(self, service, node, data, profile_key):
         service = jid.JID(service) if service else None
         node = node if node else NS_MICROBLOG
         client = self.host.getClient(profile_key)
         data = data_format.deserialise(data)
-        return self.send(client, data, service, node)
+        return defer.ensureDeferred(self.send(client, data, service, node))
 
-    def friendlyId(self, data):
-        """Generate a user friendly id from title or content"""
-        id_base = regex.urlFriendlyText(data.get('title') or data.get('content', ''))
-        return f"{id_base}-{token_urlsafe(3)}"
-
-    @defer.inlineCallbacks
-    def send(self, client, data, service=None, node=NS_MICROBLOG):
+    async def send(
+        self,
+        client: SatXMPPEntity,
+        data: dict,
+        service: Optional[jid.JID] = None,
+        node: Optional[str] = NS_MICROBLOG
+    ) -> None:
         """Send XEP-0277's microblog data
 
-        @param data(dict): microblog data (must include at least a "content" or a "title" key).
+        @param data: microblog data (must include at least a "content" or a "title" key).
             see http://wiki.goffi.org/wiki/Bridge_API_-_Microblogging/en for details
-        @param service(jid.JID, None): PubSub service where the microblog must be published
+        @param service: PubSub service where the microblog must be published
             None to publish on profile's PEP
-        @param node(unicode, None): PubSub node to use (defaut to microblog NS)
+        @param node: PubSub node to use (defaut to microblog NS)
             None is equivalend as using default value
         """
         # TODO: check that all data keys are used, this would avoid sending publicly a private message
@@ -839,12 +852,43 @@
                 item_id = str(shortuuid.uuid())
 
         try:
-            yield self._manageComments(client, data, service, node, item_id, access=None)
+            await self._manageComments(client, data, service, node, item_id, access=None)
         except error.StanzaError:
             log.warning("Can't create comments node for item {}".format(item_id))
-        item = yield self.data2entry(client, data, item_id, service, node)
-        ret = yield self._p.publish(client, service, node, [item])
-        defer.returnValue(ret)
+        item = await self.data2entry(client, data, item_id, service, node)
+        return await self._p.publish(client, service, node, [item])
+
+    def _mbPreview(self, service, node, data, profile_key):
+        service = jid.JID(service) if service else None
+        node = node if node else NS_MICROBLOG
+        client = self.host.getClient(profile_key)
+        data = data_format.deserialise(data)
+        d = defer.ensureDeferred(self.preview(client, data, service, node))
+        d.addCallback(data_format.serialise)
+        return d
+
+    async def preview(
+        self,
+        client: SatXMPPEntity,
+        data: dict,
+        service: Optional[jid.JID] = None,
+        node: Optional[str] = NS_MICROBLOG
+    ) -> dict:
+        """Preview microblog data without publishing them
+
+        params are the same as for [send]
+        @return: microblog data as would be retrieved from published item
+        """
+        if node is None:
+            node = NS_MICROBLOG
+
+        item_id = data.get("id", "")
+
+        # we have to serialise then deserialise to be sure that all triggers are called
+        item_elt = await self.data2entry(client, data, item_id, service, node)
+        item_elt.uri = pubsub.NS_PUBSUB
+        return await self.item2mbdata(client, item_elt, service, node)
+
 
     ## retract ##