[commands] Add GuildStickerConverter

2 files changed, 58 insertions, 0 deletions

diff --git a/discord/ext/commands/converter.py b/discord/ext/commands/converter.py
index 740ca2f4..5740a188 100644
--- a/discord/ext/commands/converter.py
+++ b/discord/ext/commands/converter.py
@@ -74,6 +74,7 @@ __all__ = (
     'StoreChannelConverter',
     'ThreadConverter',
     'GuildChannelConverter',
+    'GuildStickerConverter',
     'clean_content',
     'Greedy',
     'run_converters',
@@ -823,6 +824,45 @@ class PartialEmojiConverter(Converter[discord.PartialEmoji]):
         raise PartialEmojiConversionFailure(argument)
 
 
+class GuildStickerConverter(IDConverter[discord.GuildSticker]):
+    """Converts to a :class:`~discord.GuildSticker`.
+
+    All lookups are done for the local guild first, if available. If that lookup
+    fails, then it checks the client's global cache.
+
+    The lookup strategy is as follows (in order):
+
+    1. Lookup by ID.
+    3. Lookup by name
+
+    .. versionadded:: 2.0
+    """
+
+    async def convert(self, ctx: Context, argument: str) -> discord.GuildSticker:
+        match = self._get_id_match(argument)
+        result = None
+        bot = ctx.bot
+        guild = ctx.guild
+
+        if match is None:
+            # Try to get the sticker by name. Try local guild first.
+            if guild:
+                result = discord.utils.get(guild.stickers, name=argument)
+
+            if result is None:
+                result = discord.utils.get(bot.stickers, name=argument)
+        else:
+            sticker_id = int(match.group(1))
+
+            # Try to look up sticker by id.
+            result = bot.get_sticker(sticker_id)
+
+        if result is None:
+            raise GuildStickerNotFound(argument)
+
+        return result
+
+
 class clean_content(Converter[str]):
     """Converts the argument to mention scrubbed version of
     said content.
@@ -1012,6 +1052,7 @@ CONVERTER_MAPPING: Dict[Type[Any], Any] = {
     discord.StoreChannel: StoreChannelConverter,
     discord.Thread: ThreadConverter,
     discord.abc.GuildChannel: GuildChannelConverter,
+    discord.GuildSticker: GuildStickerConverter,
 }
 
 
diff --git a/discord/ext/commands/errors.py b/discord/ext/commands/errors.py
index 0f0185be..5a581d51 100644
--- a/discord/ext/commands/errors.py
+++ b/discord/ext/commands/errors.py
@@ -54,6 +54,7 @@ __all__ = (
     'RoleNotFound',
     'BadInviteArgument',
     'EmojiNotFound',
+    'GuildStickerNotFound',
     'PartialEmojiConversionFailure',
     'BadBoolArgument',
     'MissingRole',
@@ -431,6 +432,22 @@ class PartialEmojiConversionFailure(BadArgument):
         self.argument = argument
         super().__init__(f'Couldn\'t convert "{argument}" to PartialEmoji.')
 
+class GuildStickerNotFound(BadArgument):
+    """Exception raised when the bot can not find the sticker.
+
+    This inherits from :exc:`BadArgument`
+
+    .. versionadded:: 2.0
+
+    Attributes
+    -----------
+    argument: :class:`str`
+        The sticker supplied by the caller that was not found
+    """
+    def __init__(self, argument):
+        self.argument = argument
+        super().__init__(f'Sticker "{argument}" not found.')
+
 class BadBoolArgument(BadArgument):
     """Exception raised when a boolean argument was not convertable.