feat: add autoban (#509)

Author: ReenigneArcher

README.md

@@ -45,6 +45,7 @@ platforms such as GitHub discussions/issues might be added in the future.
 |----------------------------------|----------|------------------------------------------------------|--------------------------------------------------------------------------------------------|
 | DATA_REPO                        | False    | `https://github.com/LizardByte/support-bot-data`     | Repository to store persistent data. This repository should be private!                    |
 | DATA_REPO_BRANCH                 | False    | `master`                                             | Branch to store persistent data.                                                           |
+| DISCORD_AUTOBAN_CHANNEL_ID       | False    | `None`                                               | Channel ID where any message posted results in an automatic ban (7-day message deletion).  |
 | DISCORD_BOT_TOKEN                | True     | `None`                                               | Token from Bot page on discord developer portal.                                           |
 | DISCORD_CLIENT_ID                | True     | `None`                                               | Discord OAuth2 client id.                                                                  |
 | DISCORD_CLIENT_SECRET            | True     | `None`                                               | Discord OAuth2 client secret.                                                              |

sample.env

@@ -6,6 +6,7 @@ DAILY_TASKS_UTC_HOUR=12
 SUPPORT_COMMANDS_BRANCH=master
 
 # Secret settings
+DISCORD_AUTOBAN_CHANNEL_ID=
 DISCORD_BOT_TOKEN=
 DISCORD_LEVEL_UP_CHANNEL_ID=
 DISCORD_LOG_CHANNEL_ID=

src/discord_bot/cogs/autoban.py

@@ -0,0 +1,81 @@
+# standard imports
+import logging
+import os
+
+# lib imports
+import discord
+from discord.ext import commands
+
+# Get logger for this module
+logger = logging.getLogger(__name__)
+
+
+class AutoBanCog(discord.Cog):
+    """
+    Discord cog that automatically bans any user who posts in the configured autoban channel.
+    """
+
+    def __init__(self, bot):
+        self.bot = bot
+
+    @commands.Cog.listener()
+    async def on_message(self, message: discord.Message):
+        """
+        Listen for messages and ban the author if the message is in the autoban channel.
+
+        Any message sent to the channel defined by ``DISCORD_AUTOBAN_CHANNEL_ID`` will result in
+        the author being banned from the guild. All messages from the user within the past 7 days
+        are also deleted. Bot messages are ignored.
+
+        Parameters
+        ----------
+        message : discord.Message
+            The message object that triggered this event.
+        """
+        if message.author.bot:
+            return
+
+        autoban_channel_id = os.getenv('DISCORD_AUTOBAN_CHANNEL_ID')
+        if not autoban_channel_id:
+            return
+
+        if message.channel.id != int(autoban_channel_id):
+            return
+
+        guild = message.guild
+        if not guild:
+            return
+
+        try:
+            await guild.ban(
+                user=message.author,
+                reason="Automatic ban: posted in restricted channel.",
+                delete_message_seconds=604800,  # Delete messages from the past 7 days
+            )
+            logger.warning(
+                "Auto-banned user %s (%s) for posting in channel %s (%s).",
+                message.author,
+                message.author.id,
+                message.channel.name,
+                message.channel.id,
+            )
+        except discord.Forbidden:
+            logger.error(
+                "Missing permissions to ban user %s (%s) in guild %s (%s).",
+                message.author,
+                message.author.id,
+                guild.name,
+                guild.id,
+            )
+        except discord.HTTPException as e:
+            logger.error(
+                "HTTP error while banning user %s (%s): %s",
+                message.author,
+                message.author.id,
+                e,
+                exc_info=True,
+            )
+
+
+def setup(bot: discord.Bot):
+    bot.add_cog(AutoBanCog(bot=bot))