Add support for message pinning.

This includes `Client.pin_message`, `Client.unpin_message` and
`Client.pins_from`. This also adds the `Message.pinned` attribute
to the `Message` object.

discord/client.py

@@ -1110,6 +1110,75 @@ class Client:
         data = yield from self.http.get_message(channel.id, id)
         return Message(channel=channel, **data)
 
+    @asyncio.coroutine
+    def pin_message(self, message):
+        """|coro|
+
+        Pins a message. You must have Manage Messages permissions
+        to do this in a non-private channel context.
+
+        Parameters
+        -----------
+        message: :class:`Message`
+            The message to pin.
+
+        Raises
+        -------
+        Forbidden
+            You do not have permissions to pin the message.
+        NotFound
+            The message or channel was not found.
+        HTTPException
+            Pinning the message failed, probably due to the channel
+            having more than 50 pinned messages.
+        """
+        yield from self.http.pin_message(message.channel.id, message.id)
+
+    @asyncio.coroutine
+    def unpin_message(self, message):
+        """|coro|
+
+        Unpins a message. You must have Manage Messages permissions
+        to do this in a non-private channel context.
+
+        Parameters
+        -----------
+        message: :class:`Message`
+            The message to unpin.
+
+        Raises
+        -------
+        Forbidden
+            You do not have permissions to unpin the message.
+        NotFound
+            The message or channel was not found.
+        HTTPException
+            Unpinning the message failed.
+        """
+        yield from self.http.unpin_message(message.channel.id, message.id)
+
+    @asyncio.coroutine
+    def pins_from(self, channel):
+        """|coro|
+
+        Returns a list of :class:`Message` that are currently pinned for
+        the specified :class:`Channel` or :class:`PrivateChannel`.
+
+        Parameters
+        -----------
+        channel: :class:`Channel` or :class:`PrivateChannel`
+            The channel to look through pins for.
+
+        Raises
+        -------
+        NotFound
+            The channel was not found.
+        HTTPException
+            Retrieving the pinned messages failed.
+        """
+
+        data = yield from self.http.pins_from(channel.id)
+        return [Message(channel=channel, **m) for m in data]
 
     def _logs_from(self, channel, limit=100, before=None, after=None):
         """|coro|

discord/http.py

@@ -278,6 +278,18 @@ class HTTPClient:
 
         return self.get(url, params=params, bucket=_func_())
 
+    def pin_message(self, channel_id, message_id):
+        url = '{0.CHANNELS}/{1}/pins/{2}'.format(self, channel_id, message_id)
+        return self.put(url, bucket=_func_())
+
+    def unpin_message(self, channel_id, message_id):
+        url = '{0.CHANNELS}/{1}/pins/{2}'.format(self, channel_id, message_id)
+        return self.delete(url, bucket=_func_())
+
+    def pins_from(self, channel_id):
+        url = '{0.CHANNELS}/{1}/pins'.format(self, channel_id)
+        return self.get(url, bucket=_func_())
+
     # Member management
 
     def kick(self, user_id, guild_id):

discord/message.py

@@ -90,12 +90,14 @@ class Message:
         The message ID.
     attachments : list
         A list of attachments given to a message.
+    pinned: bool
+        Specifies if the message is currently pinned.
     """
 
     __slots__ = [ 'edited_timestamp', 'timestamp', 'tts', 'content', 'channel',
                   'mention_everyone', 'embeds', 'id', 'mentions', 'author',
                   'channel_mentions', 'server', '_raw_mentions', 'attachments',
-                  '_clean_content', '_raw_channel_mentions', 'nonce',
+                  '_clean_content', '_raw_channel_mentions', 'nonce', 'pinned',
                   'role_mentions', '_raw_role_mentions' ]
 
     def __init__(self, **kwargs):
@@ -108,7 +110,8 @@ class Message:
         # sometimes the .%f modifier is missing
         self.edited_timestamp = utils.parse_time(data.get('edited_timestamp'))
         self.timestamp = utils.parse_time(data.get('timestamp'))
-        self.tts = data.get('tts')
+        self.tts = data.get('tts', False)
+        self.pinned = data.get('pinned', False)
         self.content = data.get('content')
         self.mention_everyone = data.get('mention_everyone')
         self.embeds = data.get('embeds')