Validation of guild invites.

We will now validate and convert any standard discord server invite to a
guild ID, and automatically add the name of the server as a comment.

This will ensure that the list of whitelisted guild IDs will be readable
and nice.

This also makes minor changes to list output aesthetics.

4 files changed, 78 insertions, 17 deletions

diff --git a/bot/cogs/allow_deny_lists.py b/bot/cogs/allow_deny_lists.py
index 8b3c892f5..d82d175cf 100644
--- a/bot/cogs/allow_deny_lists.py
+++ b/bot/cogs/allow_deny_lists.py
@@ -7,7 +7,7 @@ from discord.ext.commands import BadArgument, Cog, Context, group
 from bot import constants
 from bot.api import ResponseCodeError
 from bot.bot import Bot
-from bot.converters import ValidAllowDenyListType
+from bot.converters import ValidAllowDenyListType, ValidDiscordServerInvite
 from bot.pagination import LinePaginator
 from bot.utils.checks import with_role_check
 
@@ -31,6 +31,24 @@ class AllowDenyLists(Cog):
         """Add an item to an allow or denylist."""
         allow_type = "whitelist" if allowed else "blacklist"
 
+        # If this is a server invite, we gotta validate it.
+        if list_type == "GUILD_INVITE":
+            log.trace(f"{content} is a guild invite, attempting to validate.")
+            validator = ValidDiscordServerInvite()
+            guild_data = await validator.convert(ctx, content)
+
+            # If we make it this far without raising a BadArgument, the invite is
+            # valid. Let's convert the content to an ID.
+            log.trace(f"{content} validated as server invite. Converting to ID.")
+            content = guild_data.get("id")
+
+            # Unless the user has specified another comment, let's
+            # use the server name as the comment so that the list
+            # of guild IDs will be more easily readable when we
+            # display it.
+            if not comment:
+                comment = guild_data.get("name")
+
         # Try to add the item to the database
         log.trace(f"Trying to add the {content} item to the {list_type} {allow_type}")
         payload = {
@@ -100,17 +118,18 @@ class AllowDenyLists(Cog):
         # Build a list of lines we want to show in the paginator
         lines = []
         for item in result:
-            line = f"• {item.get('content')}"
+            line = f"• `{item.get('content')}`"
 
             if item.get("comment"):
-                line += f" ({item.get('comment')})"
+                line += f" - {item.get('comment')}"
 
             lines.append(line)
         lines = sorted(lines)
 
         # Build the embed
+        list_type_plural = list_type.lower().replace("_", " ").title() + "s"
         embed = Embed(
-            title=f"{allow_type.title()}ed {list_type.lower()} items ({len(result)} total)",
+            title=f"{allow_type.title()}ed {list_type_plural} ({len(result)} total)",
             colour=Colour.blue()
         )
         log.trace(f"Trying to list {len(result)} items from the {list_type.lower()} {allow_type}")
@@ -139,6 +158,7 @@ class AllowDenyLists(Cog):
             ctx: Context,
             list_type: ValidAllowDenyListType,
             content: str,
+            *,
             comment: Optional[str] = None,
     ) -> None:
         """Add an item to the specified allowlist."""
@@ -150,6 +170,7 @@ class AllowDenyLists(Cog):
             ctx: Context,
             list_type: ValidAllowDenyListType,
             content: str,
+            *,
             comment: Optional[str] = None,
     ) -> None:
         """Add an item to the specified denylist."""
diff --git a/bot/cogs/filtering.py b/bot/cogs/filtering.py
index 4d51bba2e..3ebb47a0f 100644
--- a/bot/cogs/filtering.py
+++ b/bot/cogs/filtering.py
@@ -18,22 +18,12 @@ from bot.constants import (
     Filter, Icons, URLs
 )
 from bot.utils.redis_cache import RedisCache
+from bot.utils.regex import INVITE_RE
 from bot.utils.scheduling import Scheduler
 
 log = logging.getLogger(__name__)
 
 # Regular expressions
-INVITE_RE = re.compile(
-    r"(?:discord(?:[\.,]|dot)gg|"                     # Could be discord.gg/
-    r"discord(?:[\.,]|dot)com(?:\/|slash)invite|"     # or discord.com/invite/
-    r"discordapp(?:[\.,]|dot)com(?:\/|slash)invite|"  # or discordapp.com/invite/
-    r"discord(?:[\.,]|dot)me|"                        # or discord.me
-    r"discord(?:[\.,]|dot)io"                         # or discord.io.
-    r")(?:[\/]|slash)"                                # / or 'slash'
-    r"([a-zA-Z0-9]+)",                                # the invite code itself
-    flags=re.IGNORECASE
-)
-
 SPOILER_RE = re.compile(r"(\|\|.+?\|\|)", re.DOTALL)
 URL_RE = re.compile(r"(https?://[^\s]+)", flags=re.IGNORECASE)
 ZALGO_RE = re.compile(r"[\u0300-\u036F\u0489]")
@@ -478,7 +468,7 @@ class Filtering(Cog):
                 return True
 
             guild_id = guild.get("id")
-            guild_invite_whitelist = self._get_allowlist_items(True, "guild_invite_id")
+            guild_invite_whitelist = self._get_allowlist_items(True, "guild_invite")
 
             if guild_id not in guild_invite_whitelist:
                 guild_icon_hash = guild["icon"]
diff --git a/bot/converters.py b/bot/converters.py
index edac67be2..7e21c1542 100644
--- a/bot/converters.py
+++ b/bot/converters.py
@@ -9,8 +9,10 @@ import dateutil.tz
 import discord
 from aiohttp import ClientConnectorError, ContentTypeError
 from dateutil.relativedelta import relativedelta
-from discord.ext.commands import BadArgument, Context, Converter, UserConverter
+from discord.ext.commands import BadArgument, Context, Converter, IDConverter, UserConverter
 
+from bot.constants import URLs
+from bot.utils.regex import INVITE_RE
 
 log = logging.getLogger(__name__)
 
@@ -34,6 +36,42 @@ def allowed_strings(*values, preserve_case: bool = False) -> t.Callable[[str], s
     return converter
 
 
+class ValidDiscordServerInvite(Converter):
+    """
+    A converter that validates whether a given string is a valid Discord server invite.
+
+    Raises 'BadArgument' if:
+    - The string is not a valid Discord server invite.
+    - The string is valid, but is an invite for a group DM.
+    - The string is valid, but is expired.
+
+    Returns a (partial) guild object if:
+    - The string is a valid vanity
+    - The string is a full invite URI
+    - The string contains the invite code (the stuff after discord.gg/)
+
+    See the Discord API docs for documentation on the guild object:
+    https://discord.com/developers/docs/resources/guild#guild-object
+    """
+
+    async def convert(self, ctx: Context, server_invite: str) -> dict:
+        """Check whether the string is a valid Discord server invite."""
+        invite_code = INVITE_RE.match(server_invite)
+        if invite_code:
+            response = await ctx.bot.http_session.get(
+                f"{URLs.discord_invite_api}/{invite_code[1]}"
+            )
+            if response.status != 404:
+                invite_data = await response.json()
+                return invite_data.get("guild")
+
+        id_converter = IDConverter()
+        if id_converter._get_id_match(server_invite):
+            raise BadArgument("Guild IDs are not supported, only invites.")
+
+        raise BadArgument("This does not appear to be a valid Discord server invite.")
+
+
 class ValidAllowDenyListType(Converter):
     """
     A converter that checks whether the given string is a valid AllowDenyList type.
diff --git a/bot/utils/regex.py b/bot/utils/regex.py
new file mode 100644
index 000000000..d194f93cb
--- /dev/null
+++ b/bot/utils/regex.py
@@ -0,0 +1,12 @@
+import re
+
+INVITE_RE = re.compile(
+    r"(?:discord(?:[\.,]|dot)gg|"                     # Could be discord.gg/
+    r"discord(?:[\.,]|dot)com(?:\/|slash)invite|"     # or discord.com/invite/
+    r"discordapp(?:[\.,]|dot)com(?:\/|slash)invite|"  # or discordapp.com/invite/
+    r"discord(?:[\.,]|dot)me|"                        # or discord.me
+    r"discord(?:[\.,]|dot)io"                         # or discord.io.
+    r")(?:[\/]|slash)"                                # / or 'slash'
+    r"([a-zA-Z0-9]+)",                                # the invite code itself
+    flags=re.IGNORECASE
+)