Add server-side widget support for poll/tictactoe.

zerver/lib/widget.py

@@ -1,6 +1,12 @@
 from typing import MutableMapping, Any
 from django.conf import settings
 
+import re
+import json
+
+from zerver.models import SubMessage
+
+
 def get_fixed_content_for_widget(content: str) -> str:
     if not settings.ALLOW_SUB_MESSAGES:
         return content
@@ -17,3 +23,25 @@ def do_widget_post_save_actions(message: MutableMapping[str, Any]) -> None:
     '''
     if not settings.ALLOW_SUB_MESSAGES:
         return
+    content = message['message'].content
+    sender_id = message['message'].sender_id
+    message_id = message['message'].id
+
+    widget_type = None
+    extra_data = None
+    if content in ['/poll', '/tictactoe']:
+        widget_type = content[1:]
+
+    if widget_type:
+        content = dict(
+            widget_type=widget_type,
+            extra_data=extra_data
+        )
+        submessage = SubMessage(
+            sender_id=sender_id,
+            message_id=message_id,
+            msg_type='widget',
+            content=json.dumps(content),
+        )
+        submessage.save()
+        message['submessages'] = SubMessage.get_raw_db_rows([message_id])