Add support for relay user distinguishers. Fixes #750

mautrix_telegram/config.py

@@ -183,6 +183,7 @@ class Config(BaseBridgeConfig):
             del self["bridge.message_formats"]
         copy_dict("bridge.message_formats", override_existing_map=False)
         copy("bridge.emote_format")
+        copy("bridge.relay_user_distinguishers")
 
         copy("bridge.state_event_formats.join")
         copy("bridge.state_event_formats.leave")

mautrix_telegram/example-config.yaml

@@ -330,9 +330,12 @@ bridge:
         # List of user IDs for whom the previous flag is flipped.
         # e.g. if bridge_notices.default is false, notices from other users will not be bridged, but
         #      notices from users listed here will be bridged.
-        exceptions:
-        - "@importantbot:example.com"
+        exceptions: []
 
+    # An array of possible values for the $distinguisher variable in message formats.
+    # Each user gets one of the values here, based on a hash of their user ID.
+    # If the array is empty, the $distinguisher variable will also be empty.
+    relay_user_distinguishers: ["🟦", "🟣", "🟩", "⭕️", "🔶", "⬛️", "🔵", "🟢"]
     # The formats to use when sending messages to Telegram via the relay bot.
     # Text msgtypes (m.text, m.notice and m.emote) support HTML, media msgtypes don't.
     #
@@ -340,16 +343,17 @@ bridge:
     #   $sender_displayname - The display name of the sender (e.g. Example User)
     #   $sender_username    - The username (Matrix ID localpart) of the sender (e.g. exampleuser)
     #   $sender_mxid        - The Matrix ID of the sender (e.g. @exampleuser:example.com)
+    #   $distinguisher      - A random string from the options in the relay_user_distinguishers array.
     #   $message            - The message content
     message_formats:
-        m.text: "<b>$sender_displayname</b>: $message"
-        m.notice: "<b>$sender_displayname</b>: $message"
-        m.emote: "* <b>$sender_displayname</b> $message"
-        m.file: "<b>$sender_displayname</b> sent a file: $message"
-        m.image: "<b>$sender_displayname</b> sent an image: $message"
-        m.audio: "<b>$sender_displayname</b> sent an audio file: $message"
-        m.video: "<b>$sender_displayname</b> sent a video: $message"
-        m.location: "<b>$sender_displayname</b> sent a location: $message"
+        m.text: "$distinguisher <b>$sender_displayname</b>: $message"
+        m.notice: "$distinguisher <b>$sender_displayname</b>: $message"
+        m.emote: "* $distinguisher <b>$sender_displayname</b> $message"
+        m.file: "$distinguisher <b>$sender_displayname</b> sent a file: $message"
+        m.image: "$distinguisher <b>$sender_displayname</b> sent an image: $message"
+        m.audio: "$distinguisher <b>$sender_displayname</b> sent an audio file: $message"
+        m.video: "$distinguisher <b>$sender_displayname</b> sent a video: $message"
+        m.location: "$distinguisher <b>$sender_displayname</b> sent a location: $message"
     # Telegram doesn't have built-in emotes, this field specifies how m.emote's from authenticated
     # users are sent to telegram. All fields in message_formats are supported. Additionally, the
     # Telegram user info is available in the following variables:
@@ -365,9 +369,9 @@ bridge:
     #
     # Set format to an empty string to disable the messages for that event.
     state_event_formats:
-        join: "<b>$displayname</b> joined the room."
-        leave: "<b>$displayname</b> left the room."
-        name_change: "<b>$prev_displayname</b> changed their name to <b>$displayname</b>"
+        join: "$distinguisher <b>$displayname</b> joined the room."
+        leave: "$distinguisher <b>$displayname</b> left the room."
+        name_change: "$distinguisher <b>$prev_displayname</b> changed their name to $distinguisher <b>$displayname</b>"
 
     # Filter rooms that can/can't be bridged. Can also be managed using the `filter` and
     # `filter-mode` management commands.

mautrix_telegram/portal.py

@@ -1194,6 +1194,7 @@ class Portal(DBPortal, BasePortal):
             "mxid": user.mxid,
             "username": user.mxid_localpart,
             "displayname": escape_html(displayname),
+            "distinguisher": self._get_distinguisher(user.mxid),
             **kwargs,
         }
         return Template(tpl).safe_substitute(tpl_args)
@@ -1410,6 +1411,28 @@ class Portal(DBPortal, BasePortal):
             # We'll just assume the user is already in the chat.
             pass
 
+    @staticmethod
+    def hash_user_id(val: UserID) -> int:
+        """
+        A simple Matrix user ID hashing algorithm that matches what Element does.
+
+        Args:
+            val: the Matrix user ID.
+
+        Returns:
+            A 32-bit hash of the user ID.
+        """
+        out = 0
+        for char in val:
+            out = (out << 5) - out + ord(char)
+            # Emulate JS's 32-bit signed bitwise OR `hash |= 0`
+            out = (out & 2**31 - 1) - (out & 2**31)
+        return abs(out)
+
+    def _get_distinguisher(self, user_id: UserID) -> str:
+        ruds = self.get_config("relay_user_distinguishers") or []
+        return ruds[self.hash_user_id(user_id) % len(ruds)] if ruds else ""
+
     async def _apply_msg_format(self, sender: u.User, content: MessageEventContent) -> None:
         if not isinstance(content, TextMessageEventContent) or content.format != Format.HTML:
             content.format = Format.HTML
@@ -1427,6 +1450,7 @@ class Portal(DBPortal, BasePortal):
             message=content.formatted_body,
             body=content.body,
             formatted_body=content.formatted_body,
+            distinguisher=self._get_distinguisher(sender.mxid),
         )
         content.formatted_body = Template(tpl).safe_substitute(tpl_args)