Refactor /cmd handling to be more extensible

src/backend/matrix_client.py

@@ -179,6 +179,21 @@ class MatrixClient(nio.AsyncClient):
         if host in ("127.0.0.1", "localhost", "::1"):
             proxy = None
 
+        # self is passed in explicitly, so that it will also be passed to
+        # handlers in the user config
+        self.cmd_handler_map = {
+            "me ":        MatrixClient.handle_cmd_emote,
+        }
+
+        try:
+            self.cmd_handler_map = {
+                **self.cmd_handler_map,
+                **backend.settings.Commands.get_cmd_handler_map(),
+            }
+        except (AttributeError, KeyError):
+            # make sure we don't break older configs
+            pass
+
         super().__init__(
             homeserver = homeserver,
             user       = user,
@@ -618,22 +633,40 @@ class MatrixClient(nio.AsyncClient):
         display_name_mentions: Optional[Dict[str, str]] = None,  # {id: name}
         reply_to_event_id:     Optional[str]            = None,
     ) -> None:
-        """Send a markdown `m.text` or `m.notice` (with `/me`) message ."""
+        if text.startswith("//") or text.startswith(r"\/"):
+            await self._send_text(room_id, text[1:], display_name_mentions, reply_to_event_id)
+        elif text.startswith("/"):
+            for k,v in self.cmd_handler_map.items():
+                if text.startswith("/"+k):
+                    await v(self, room_id, text[len("/"+k):], display_name_mentions, reply_to_event_id)
+                    break
+            else:
+                await self.send_fake_notice(
+                    room_id,
+                    r"That command was not recognised. To send a message starting with /, use //",
+                )
+        else:
+            await self._send_text(room_id, text, display_name_mentions, reply_to_event_id)
+
+
+    async def _send_text(
+        self,
+        room_id:               str,
+        text:                  str,
+        display_name_mentions: Optional[Dict[str, str]] = None,  # {id: name}
+        reply_to_event_id:     Optional[str]            = None,
+        emote:                 bool                     = False,
+    ) -> None:
+        """Send a markdown `m.text` or `m.emote` message ."""
 
         from_md = partial(
             HTML.from_markdown, display_name_mentions=display_name_mentions,
         )
 
-        escape = False
-        if text.startswith("//") or text.startswith(r"\/"):
-            escape = True
-            text   = text[1:]
-
         content: Dict[str, Any]
 
-        if text.startswith("/me ") and not escape:
+        if emote:
             event_type = nio.RoomMessageEmote
-            text       = text[len("/me "):]
             content    = {"body": text, "msgtype": "m.emote"}
             to_html    = from_md(text, inline=True, outgoing=True)
             echo_body  = from_md(text, inline=True)
@@ -699,6 +732,22 @@ class MatrixClient(nio.AsyncClient):
         await self._send_message(room_id, content, tx_id)
 
 
+    async def handle_cmd_emote(
+        self,
+        room_id:                str,
+        text:                   str,
+        display_name_mentions:  Optional[Dict[str, str]]  = None,  # {id: name}
+        reply_to_event_id:      Optional[str]             = None,
+    ):
+        await self._send_text(
+            room_id,
+            text,
+            display_name_mentions,
+            reply_to_event_id,
+            emote=True
+        )
+
+
     async def toggle_pause_transfer(
         self, room_id: str, uuid: Union[str, UUID],
     ) -> None:
@@ -1023,6 +1072,7 @@ class MatrixClient(nio.AsyncClient):
         room_id:        str,
         transaction_id: UUID,
         event_type:     Type[nio.Event],
+        fake_event:     bool = False,
         **event_fields,
     ) -> None:
         """Register a local model `Event` while waiting for the server.
@@ -1056,7 +1106,7 @@ class MatrixClient(nio.AsyncClient):
             sender_id     = self.user_id,
             sender_name   = our_info.display_name,
             sender_avatar = our_info.avatar_url,
-            is_local_echo = True,
+            is_local_echo = not fake_event,
             links         = Event.parse_links(content),
             **event_fields,
         )
@@ -1069,6 +1119,16 @@ class MatrixClient(nio.AsyncClient):
         await self.set_room_last_event(room_id, event)
 
 
+    async def send_fake_notice(self, room_id, msg):
+        await self._local_echo(
+            room_id,
+            uuid4(),
+            nio.RoomMessageNotice,
+            content = msg,
+            fake_event = True,
+        )
+
+
     async def _send_message(
         self, room_id: str, content: dict, transaction_id: UUID,
     ) -> None:

src/config/settings.py

@@ -541,3 +541,36 @@ class Keys:
 
         # Sign out checked sessions if any, else sign out all sessions.
         sign_out = ["Alt+S", "Delete"]
+
+class Commands:
+    # If you are an advanced user, here you can define new /commands
+    #
+    # get_cmd_handler_map should return a dictionary of the form
+    # {
+    #   "command": command_handling_function,
+    #   "another_command": ...
+    # }
+    #
+    # each command_handling_function should have the signature:
+    #
+    # async def command_handling_function(
+    #     matrix_client:          moment.backend.MatrixClient,
+    #     room_id:                str,
+    #     text:                   str,   # text after the end of /command
+    #     display_name_mentions:  Optional[Dict[str, str]]  = None,  # {id: name}
+    #     reply_to_event_id:      Optional[str]             = None,
+    # ) -> None:
+
+    # Example:
+
+    def get_cmd_handler_map(self):
+        return {
+          # "rot13 ": self.handle_cmd_rot13,
+        }
+
+    # @staticmethod
+    # def handle_cmd_rot13(matrix_client, room_id, text, display_name_mentions, reply_to_event_id):
+    #     import codecs
+    #     matrix_client._send_text(
+    #         room_id, codecs.encode(text, 'rot_13'), display_name_mentions, reply_to_event_id
+    #     )