[commands] Add is_owner check and Bot.is_owner.

discord/ext/commands/bot.py

@@ -140,6 +140,7 @@ class BotBase(GroupMixin):
         self._after_invoke = None
         self.description = inspect.cleandoc(description) if description else ''
         self.pm_help = pm_help
+        self.owner_id = options.get('owner_id')
         self.command_not_found = options.pop('command_not_found', 'No command called "{}" found.')
         self.command_has_no_subcommands = options.pop('command_has_no_subcommands', 'Command {0.name} has no subcommands.')
 
@@ -275,6 +276,26 @@ class BotBase(GroupMixin):
 
         return (yield from discord.utils.async_all(f(ctx) for f in self._checks))
 
+    @asyncio.coroutine
+    def is_owner(self, user):
+        """Checks if a :class:`User` or :class:`Member` is the owner of
+        this bot.
+
+        If an :attr:`owner_id` is not set, it is fetched automatically
+        through the use of :meth:`application_info`.
+
+        Parameters
+        -----------
+        user: :class:`abc.User`
+            The user to check for.
+        """
+
+        if self.owner_id is None:
+            app = yield from self.application_info()
+            self.owner_id = owner_id = app.owner.id
+            return user.id == owner_id
+        return user.id == self.owner_id
+
     def before_invoke(self, coro):
         """A decorator that registers a coroutine as a pre-invoke hook.
 
@@ -815,6 +836,10 @@ class Bot(BotBase, discord.Client):
         subcommand but the command does not have any subcommands. Defaults to
         ``"Command {0.name} has no subcommands."``. The first format argument is the
         :class:`Command` attempted to get a subcommand and the second is the name.
+    owner_id: Optional[int]
+        The ID that owns the bot. If this is not set and is then queried via
+        :meth:`is_owner` then it is fetched automatically using
+        :meth:`application_info`.
     """
     pass
 

discord/ext/commands/core.py

@@ -37,7 +37,7 @@ from . import converter as converters
 __all__ = [ 'Command', 'Group', 'GroupMixin', 'command', 'group',
             'has_role', 'has_permissions', 'has_any_role', 'check',
             'bot_has_role', 'bot_has_permissions', 'bot_has_any_role',
-            'cooldown', 'guild_only', ]
+            'cooldown', 'guild_only', 'is_owner']
 
 def wrap_callback(coro):
     @functools.wraps(coro)
@@ -1104,6 +1104,24 @@ def guild_only():
 
     return check(predicate)
 
+def is_owner():
+    """A :func:`check` that checks if the person invoking this command is the
+    owner of the bot.
+
+    This is powered by :meth:`Bot.is_owner`.
+
+    This check raises a special exception, :exc:`NotOwner` that is derived
+    from :exc:`CheckFailure`.
+    """
+
+    @asyncio.coroutine
+    def predicate(ctx):
+        if not (yield from ctx.bot.is_owner(ctx.author)):
+            raise NotOwner('You do not own this bot.')
+        return True
+
+    return check(predicate)
+
 def cooldown(rate, per, type=BucketType.default):
     """A decorator that adds a cooldown to a :class:`Command`
     or its subclasses.

discord/ext/commands/errors.py

@@ -29,7 +29,7 @@ from discord.errors import DiscordException
 __all__ = [ 'CommandError', 'MissingRequiredArgument', 'BadArgument',
            'NoPrivateMessage', 'CheckFailure', 'CommandNotFound',
            'DisabledCommand', 'CommandInvokeError', 'TooManyArguments',
-           'UserInputError', 'CommandOnCooldown' ]
+           'UserInputError', 'CommandOnCooldown', 'NotOwner' ]
 
 class CommandError(DiscordException):
     """The base exception type for all command related errors.
@@ -100,6 +100,10 @@ class NoPrivateMessage(CheckFailure):
     """
     pass
 
+class NotOwner(CheckFailure):
+    """Exception raised when the message author is not the owner of the bot."""
+    pass
+
 class DisabledCommand(CommandError):
     """Exception raised when the command being invoked is disabled."""
     pass