[commands] Add PartialMessageConverter

1 files changed, 35 insertions, 13 deletions

diff --git a/discord/ext/commands/converter.py b/discord/ext/commands/converter.py
index a3392482..aff96aac 100644
--- a/discord/ext/commands/converter.py
+++ b/discord/ext/commands/converter.py
@@ -37,6 +37,7 @@ __all__ = (
     'MemberConverter',
     'UserConverter',
     'MessageConverter',
+    'PartialMessageConverter',
     'TextChannelConverter',
     'InviteConverter',
     'RoleConverter',
@@ -251,21 +252,18 @@ class UserConverter(IDConverter):
 
         return result
 
-class MessageConverter(Converter):
-    """Converts to a :class:`discord.Message`.
-
-    .. versionadded:: 1.1
+class PartialMessageConverter(Converter):
+    """Converts to a :class:`discord.PartialMessage`.
 
-    The lookup strategy is as follows (in order):
+    .. versionadded:: 1.7
 
-    1. Lookup by "{channel ID}-{message ID}" (retrieved by shift-clicking on "Copy ID")
-    2. Lookup by message ID (the message **must** be in the context channel)
-    3. Lookup by message URL
+    The creation strategy is as follows (in order):
 
-    .. versionchanged:: 1.5
-         Raise :exc:`.ChannelNotFound`, :exc:`.MessageNotFound` or :exc:`.ChannelNotReadable` instead of generic :exc:`.BadArgument`
+    1. By "{channel ID}-{message ID}" (retrieved by shift-clicking on "Copy ID")
+    2. By message ID (The message is assumed to be in the context channel.)
+    3. By message URL
     """
-    async def convert(self, ctx, argument):
+    def _get_id_matches(self, argument):
         id_regex = re.compile(r'(?:(?P<channel_id>[0-9]{15,21})-)?(?P<message_id>[0-9]{15,21})$')
         link_regex = re.compile(
             r'https?://(?:(ptb|canary|www)\.)?discord(?:app)?\.com/channels/'
@@ -275,12 +273,36 @@ class MessageConverter(Converter):
         match = id_regex.match(argument) or link_regex.match(argument)
         if not match:
             raise MessageNotFound(argument)
-        message_id = int(match.group("message_id"))
         channel_id = match.group("channel_id")
+        return int(match.group("message_id")), int(channel_id) if channel_id else None
+
+    async def convert(self, ctx, argument):
+        message_id, channel_id = self._get_id_matches(argument)
+        channel = ctx.bot.get_channel(channel_id) if channel_id else ctx.channel
+        if not channel:
+            raise ChannelNotFound(channel_id)
+        return discord.PartialMessage(channel=channel, id=message_id)
+        
+class MessageConverter(PartialMessageConverter):
+    """Converts to a :class:`discord.Message`.
+
+    .. versionadded:: 1.1
+
+    The lookup strategy is as follows (in order):
+
+    1. Lookup by "{channel ID}-{message ID}" (retrieved by shift-clicking on "Copy ID")
+    2. Lookup by message ID (the message **must** be in the context channel)
+    3. Lookup by message URL
+
+    .. versionchanged:: 1.5
+         Raise :exc:`.ChannelNotFound`, :exc:`.MessageNotFound` or :exc:`.ChannelNotReadable` instead of generic :exc:`.BadArgument`
+    """
+    async def convert(self, ctx, argument):
+        message_id, channel_id = self._get_id_matches(argument)
         message = ctx.bot._connection._get_message(message_id)
         if message:
             return message
-        channel = ctx.bot.get_channel(int(channel_id)) if channel_id else ctx.channel
+        channel = ctx.bot.get_channel(channel_id) if channel_id else ctx.channel
         if not channel:
             raise ChannelNotFound(channel_id)
         try: