data_import: Import Rocket.Chat threads as separate topics.

templates/zerver/help/import-from-rocketchat.md

@@ -80,25 +80,29 @@ root domain. Replace the last line above with the following, after replacing
 
 ## Caveats
 
-This import tool is currently beta and does not support importing
-the following data:
+This import tool is currently beta has the following known limitations:
 
--   User avatars
--   Default channels for new users
--   Starred messages
--   Threads as separate topics
--   Messages longer than Zulip's limit of 10,000 characters.
+-   User avatars are not imported.
+-   Default channels for new users are not imported.
+-   Starred messages are not imported.
+-   Messages longer than Zulip's limit of 10,000 characters are not
+    imported.
 -   Messages from Rocket.Chat Discussions are imported as topics
     inside the Zulip stream corresponding to the parent channel of the
     Rocket.Chat Discussion.
 -   Messages from Rocket.Chat Discussions having direct channels
     (i.e. private messages) as their parent are imported as normal
     private messages in Zulip.
+-   While Rocket.Chat Threads are in general imported as separate
+    topics, Rocket.Chat Threads within Rocket.Chat Discussions are
+    imported as normal messages within the topic containing that
+    Discussion, and Threads in Direct Messages are imported as normal
+    Zulip private messages.
 
-Additionally, because Rocket.Chat does not provide a stable data
-export API, the import tool may require small changes from time to
-time to account for changes in the Rocket.Chat database format.
-Please [contact us](/help/contact-support) if you counter any problems
-using this tool.
+Additionally, because Rocket.Chat does not provide a documented or
+stable data export API, the import tool may require small changes from
+time to time to account for changes in the Rocket.Chat database
+format.  Please [contact us](/help/contact-support) if you encounter
+any problems using this tool.
 
 [upgrade-zulip-from-git]: https://zulip.readthedocs.io/en/latest/production/upgrade-or-modify.html#upgrading-from-a-git-repository

zerver/data_import/rocketchat.py

@@ -547,14 +547,26 @@ def process_raw_message_batch(
 
 
 def get_topic_name(
-    message: Dict[str, Any], dsc_id_to_dsc_map: Dict[str, Dict[str, Any]], is_pm_data: bool = False
+    message: Dict[str, Any],
+    dsc_id_to_dsc_map: Dict[str, Dict[str, Any]],
+    thread_id_mapper: IdMapper,
+    is_pm_data: bool = False,
 ) -> str:
     if is_pm_data:
         return ""
     elif message["rid"] in dsc_id_to_dsc_map:
         dsc_channel_name = dsc_id_to_dsc_map[message["rid"]]["fname"]
         return f"{dsc_channel_name} (Imported from Rocket.Chat)"
+    elif message.get("replies"):
+        # Message is the start of a thread
+        thread_id = thread_id_mapper.get(message["_id"])
+        return f"Thread {thread_id} (Imported from Rocket.Chat)"
+    elif message.get("tmid"):
+        # Message is a part of a thread
+        thread_id = thread_id_mapper.get(message["tmid"])
+        return f"Thread {thread_id} (Imported from Rocket.Chat)"
     else:
+        # Normal channel message
         return "Imported from Rocket.Chat"
 
 
@@ -571,6 +583,7 @@ def process_messages(
     stream_id_to_recipient_id: Dict[int, int],
     huddle_id_mapper: IdMapper,
     huddle_id_to_recipient_id: Dict[int, int],
+    thread_id_mapper: IdMapper,
     room_id_to_room_map: Dict[str, Dict[str, Any]],
     dsc_id_to_dsc_map: Dict[str, Dict[str, Any]],
     direct_id_to_direct_map: Dict[str, Dict[str, Any]],
@@ -641,7 +654,9 @@ def process_messages(
             message_dict["recipient_id"] = stream_id_to_recipient_id[stream_id]
 
         # Add topic name to message_dict
-        message_dict["topic_name"] = get_topic_name(message, dsc_id_to_dsc_map, is_pm_data)
+        message_dict["topic_name"] = get_topic_name(
+            message, dsc_id_to_dsc_map, thread_id_mapper, is_pm_data
+        )
 
         # Add user mentions to message_dict
         mention_user_ids = set()
@@ -689,7 +704,9 @@ def process_messages(
                     continue
 
                 converted_topic_name = get_topic_name(
-                    message={"rid": mention_rc_channel_id}, dsc_id_to_dsc_map=dsc_id_to_dsc_map
+                    message={"rid": mention_rc_channel_id},
+                    dsc_id_to_dsc_map=dsc_id_to_dsc_map,
+                    thread_id_mapper=thread_id_mapper,
                 )
 
                 parent_rc_channel = room_id_to_room_map[parent_channel_id]
@@ -923,6 +940,7 @@ def do_convert_data(rocketchat_data_dir: str, output_dir: str) -> None:
     user_id_mapper = IdMapper()
     stream_id_mapper = IdMapper()
     huddle_id_mapper = IdMapper()
+    thread_id_mapper = IdMapper()
 
     process_users(
         user_id_to_user_map=user_id_to_user_map,
@@ -1055,6 +1073,7 @@ def do_convert_data(rocketchat_data_dir: str, output_dir: str) -> None:
         stream_id_to_recipient_id=stream_id_to_recipient_id,
         huddle_id_mapper=huddle_id_mapper,
         huddle_id_to_recipient_id=huddle_id_to_recipient_id,
+        thread_id_mapper=thread_id_mapper,
         room_id_to_room_map=room_id_to_room_map,
         dsc_id_to_dsc_map=dsc_id_to_dsc_map,
         direct_id_to_direct_map=direct_id_to_direct_map,
@@ -1080,6 +1099,7 @@ def do_convert_data(rocketchat_data_dir: str, output_dir: str) -> None:
         stream_id_to_recipient_id=stream_id_to_recipient_id,
         huddle_id_mapper=huddle_id_mapper,
         huddle_id_to_recipient_id=huddle_id_to_recipient_id,
+        thread_id_mapper=thread_id_mapper,
         room_id_to_room_map=room_id_to_room_map,
         dsc_id_to_dsc_map=dsc_id_to_dsc_map,
         direct_id_to_direct_map=direct_id_to_direct_map,