Add inReplyTo to incoming messages.

lib/pleroma/web/ostatus/ostatus.ex

@@ -65,6 +65,14 @@ def handle_note(doc) do
       "actor" => actor.ap_id
     }
 
+    inReplyTo = string_from_xpath("/entry/thr:in-reply-to[1]/@href", doc)
+
+    object = if inReplyTo do
+      Map.put(object, "inReplyTo", inReplyTo)
+    else
+      object
+    end
+
     ActivityPub.create(to, actor, context, object, %{}, date)
   end
 

test/fixtures/incoming_note_activity_answer.xml

+<?xml version="1.0" encoding="UTF-8" ?><entry xmlns="http://www.w3.org/2005/Atom" xmlns:thr="http://purl.org/syndication/thread/1.0" xmlns:activity="http://activitystrea.ms/spec/1.0/" xmlns:georss="http://www.georss.org/georss" xmlns:ostatus="http://ostatus.org/schema/1.0" xmlns:poco="http://portablecontacts.net/spec/1.0" xmlns:media="http://purl.org/syndication/atommedia" xmlns:statusnet="http://status.net/schema/api/1/">
+ <activity:object-type>http://activitystrea.ms/schema/1.0/note</activity:object-type>
+ <id>tag:gs.example.org:4040,2017-04-25:noticeId=55:objectType=note</id>
+ <title>New note by lambda</title>
+ <content type="html">hey.</content>
+ <link rel="alternate" type="text/html" href="http://gs.example.org:4040/index.php/notice/55"/>
+ <status_net notice_id="55"></status_net>
+ <activity:verb>http://activitystrea.ms/schema/1.0/post</activity:verb>
+ <published>2017-04-25T18:16:13+00:00</published>
+ <updated>2017-04-25T18:16:13+00:00</updated>
+ <author>
+  <activity:object-type>http://activitystrea.ms/schema/1.0/person</activity:object-type>
+  <uri>http://gs.example.org:4040/index.php/user/1</uri>
+  <name>lambda</name>
+  <link rel="alternate" type="text/html" href="http://gs.example.org:4040/index.php/lambda"/>
+  <link rel="avatar" type="image/png" media:width="96" media:height="96" href="http://gs.example.org:4040/theme/neo-gnu/default-avatar-profile.png"/>
+  <link rel="avatar" type="image/png" media:width="48" media:height="48" href="http://gs.example.org:4040/theme/neo-gnu/default-avatar-stream.png"/>
+  <link rel="avatar" type="image/png" media:width="24" media:height="24" href="http://gs.example.org:4040/theme/neo-gnu/default-avatar-mini.png"/>
+  <poco:preferredUsername>lambda</poco:preferredUsername>
+  <poco:displayName>lambda</poco:displayName>
+  <followers url="http://gs.example.org:4040/index.php/lambda/subscribers"></followers>
+  <statusnet:profile_info local_id="1"></statusnet:profile_info>
+ </author>
+ <thr:in-reply-to ref="http://pleroma.example.org:4000/objects/55bce8fc-b423-46b1-af71-3759ab4670bc" href="http://pleroma.example.org:4000/objects/55bce8fc-b423-46b1-af71-3759ab4670bc"></thr:in-reply-to>
+ <link rel="related" href="http://pleroma.example.org:4000/objects/55bce8fc-b423-46b1-af71-3759ab4670bc"/>
+ <link rel="ostatus:conversation" href="http://pleroma.example.org:4000/contexts/8f6f45d4-8e4d-4e1a-a2de-09f27367d2d0"/>
+ <ostatus:conversation>http://pleroma.example.org:4000/contexts/8f6f45d4-8e4d-4e1a-a2de-09f27367d2d0</ostatus:conversation>
+ <link rel="mentioned" ostatus:object-type="http://activitystrea.ms/schema/1.0/person" href="http://pleroma.example.org:4000/users/lain5"/>
+ <link rel="mentioned" ostatus:object-type="http://activitystrea.ms/schema/1.0/collection" href="http://activityschema.org/collection/public"/>
+ <source>
+  <id>http://gs.example.org:4040/index.php/api/statuses/user_timeline/1.atom</id>
+  <title>lambda</title>
+  <link rel="alternate" type="text/html" href="http://gs.example.org:4040/index.php/lambda"/>
+  <link rel="self" type="application/atom+xml" href="http://gs.example.org:4040/index.php/api/statuses/user_timeline/1.atom"/>
+  <link rel="license" href="https://creativecommons.org/licenses/by/3.0/"/>
+  <icon>http://gs.example.org:4040/theme/neo-gnu/default-avatar-profile.png</icon>
+  <updated>2017-04-25T18:16:13+00:00</updated>
+ </source>
+ <link rel="self" type="application/atom+xml" href="http://gs.example.org:4040/index.php/api/statuses/show/55.atom"/>
+ <link rel="edit" type="application/atom+xml" href="http://gs.example.org:4040/index.php/api/statuses/show/55.atom"/>
+ <statusnet:notice_info local_id="55" source="web"></statusnet:notice_info>
+</entry>

test/web/ostatus/ostatus_test.exs

@@ -13,6 +13,16 @@ test "handle incoming notes" do
     assert "http://pleroma.example.org:4000/users/lain3" in activity.data["to"]
   end
 
+  test "handle incoming replies" do
+    incoming = File.read!("test/fixtures/incoming_note_activity_answer.xml")
+    {:ok, activity} = OStatus.handle_incoming(incoming)
+
+    assert activity.data["type"] == "Create"
+    assert activity.data["object"]["type"] == "Note"
+    assert activity.data["object"]["inReplyTo"] == "http://pleroma.example.org:4000/objects/55bce8fc-b423-46b1-af71-3759ab4670bc"
+    assert "http://pleroma.example.org:4000/users/lain5" in activity.data["to"]
+  end
+
   describe "new remote user creation" do
     test "make new user or find them based on an 'author' xml doc" do
       incoming = File.read!("test/fixtures/user_name_only.xml")