polished forwarding

tgbridge/discord_to_telegram.py

@@ -0,0 +1,96 @@
+# Discord → Telegram forwarding
+import io
+import discord
+from discord.ext import commands
+from telegram import Bot
+from telegram.error import TelegramError
+
+
+class DiscordToTelegramForwarder(commands.Cog):
+    """
+    Listens for Discord messages in configured channels and forwards them to
+    the paired Telegram group.
+
+    Routes are added via add_route(discord_channel_id, telegram_chat_id).
+    Bot messages and webhook messages are silently ignored to prevent loops.
+    """
+
+    def __init__(self, bot: commands.Bot, tg_token: str):
+        self.bot = bot
+        self._tg_bot = Bot(token=tg_token)
+        # discord_channel_id (int) -> telegram_chat_id (int)
+        self.routes: dict[int, int] = {}
+
+    def add_route(self, discord_channel_id: int, telegram_chat_id: int):
+        self.routes[discord_channel_id] = telegram_chat_id
+
+    # -- helpers --------------------------------------------------------------
+
+    def _format_header(self, message: discord.Message) -> str:
+        """Return a bold sender label: *Username* (Discord)"""
+        name = message.author.display_name
+        return f"*{discord.utils.escape_markdown(name)}* (Discord):"
+
+    async def _send_text(self, chat_id: int, text: str):
+        try:
+            await self._tg_bot.send_message(
+                chat_id=chat_id,
+                text=text,
+                parse_mode='Markdown',
+            )
+        except TelegramError as e:
+            print(f'[D->TG] send_message failed: {e}')
+
+    async def _send_attachment(self, chat_id: int, attachment: discord.Attachment, caption: str):
+        """Download a Discord attachment and upload it to Telegram."""
+        try:
+            file_bytes = await attachment.read()
+            buf = io.BytesIO(file_bytes)
+            buf.name = attachment.filename
+
+            mime = attachment.content_type or ''
+
+            if mime.startswith('image/') and not mime.startswith('image/gif'):
+                await self._tg_bot.send_photo(chat_id=chat_id, photo=buf, caption=caption, parse_mode='Markdown')
+            elif mime.startswith('video/') or mime == 'image/gif':
+                await self._tg_bot.send_video(chat_id=chat_id, video=buf, caption=caption, parse_mode='Markdown')
+            elif mime.startswith('audio/'):
+                await self._tg_bot.send_audio(chat_id=chat_id, audio=buf, caption=caption, parse_mode='Markdown')
+            else:
+                await self._tg_bot.send_document(chat_id=chat_id, document=buf, caption=caption, parse_mode='Markdown')
+
+        except TelegramError as e:
+            print(f'[D->TG] send_attachment failed ({attachment.filename}): {e}')
+        except Exception as e:
+            print(f'[D->TG] unexpected error for attachment {attachment.filename}: {e}')
+
+    # -- event handler --------------------------------------------------------
+
+    @commands.Cog.listener()
+    async def on_message(self, message: discord.Message):
+        # ignore bots (including ourselves) and webhook posts to prevent echo loops
+        if message.author.bot or message.webhook_id:
+            return
+
+        chat_id = self.routes.get(message.channel.id)
+        if chat_id is None:
+            return
+
+        header = self._format_header(message)
+        body = message.content or ''
+
+        # text portion
+        if body or not message.attachments:
+            full_text = f"{header}\n{body}".strip()
+            await self._send_text(chat_id, full_text)
+
+        # attachments
+        for i, attachment in enumerate(message.attachments):
+            # first attachment gets the header as caption; rest are bare
+            if i == 0:
+                caption = header if body else f"{header}\n{body}".strip()
+            else:
+                caption = ''
+            await self._send_attachment(chat_id, attachment, caption)
+
+        print(f'[D->TG] {message.author} (channel {message.channel.id}) -> tg chat {chat_id}')