Add support for `async for` in Client.logs_from.

This is a breaking change. Code will still work in Python 3.4 as-is but
if you use Python 3.5 you will have to change your code to the new
`async for` syntax as the older version is not supported in 3.5.

On the other hand, this comes with performance improvements if you use
Python 3.5 as it will lazily load 100 message chunks on an as needed
basis rather than loading all messages in one go.

1 files changed, 47 insertions, 33 deletions

diff --git a/discord/client.py b/discord/client.py
index 7e49aa89..98f62a44 100644
--- a/discord/client.py
+++ b/discord/client.py
@@ -41,6 +41,7 @@ from .permissions import Permissions
 from . import utils
 from .enums import ChannelType, ServerRegion
 from .voice_client import VoiceClient
+from .iterators import LogsFromIterator
 
 import asyncio
 import aiohttp
@@ -53,6 +54,7 @@ import itertools
 import zlib
 from random import randint as random_integer
 
+PY35 = sys.version_info >= (3, 5)
 log = logging.getLogger(__name__)
 request_logging_format = '{method} {response.url} has returned {response.status}'
 request_success_log = '{response.url} with {json} received {data}'
@@ -1115,24 +1117,6 @@ class Client:
 
     @asyncio.coroutine
     def _logs_from(self, channel, limit=100, before=None, after=None):
-        url = '{}/{}/messages'.format(endpoints.CHANNELS, channel.id)
-        params = {
-            'limit': limit
-        }
-
-        if before:
-            params['before'] = before.id
-        if after:
-            params['after'] = after.id
-
-        response = yield from aiohttp.get(url, params=params, headers=self.headers, loop=self.loop)
-        log.debug(request_logging_format.format(method='GET', response=response))
-        yield from utils._verify_successful_response(response)
-        messages = yield from response.json()
-        return messages
-
-    @asyncio.coroutine
-    def logs_from(self, channel, limit=100, *, before=None, after=None):
         """|coro|
 
         This coroutine returns a generator that obtains logs from a specified channel.
@@ -1172,24 +1156,54 @@ class Client:
                 if message.content.startswith('!hello'):
                     if message.author == client.user:
                         yield from client.edit_message(message, 'goodbye')
+
+        Python 3.5 Usage ::
+
+            counter = 0
+            async for message in client.logs_from(channel, limit=500):
+                if message.author == client.user:
+                    counter += 1
         """
+        url = '{}/{}/messages'.format(endpoints.CHANNELS, channel.id)
+        params = {
+            'limit': limit
+        }
 
-        def generator(data):
-            for message in data:
-                yield Message(channel=channel, **message)
-
-        result = []
-        while limit > 0:
-            retrieve = limit if limit <= 100 else 100
-            data = yield from self._logs_from(channel, retrieve, before, after)
-            if len(data):
-                limit -= retrieve
-                result.extend(data)
-                before = Object(id=data[-1]['id'])
-            else:
-                break
+        if before:
+            params['before'] = before.id
+        if after:
+            params['after'] = after.id
+
+        response = yield from aiohttp.get(url, params=params, headers=self.headers, loop=self.loop)
+        log.debug(request_logging_format.format(method='GET', response=response))
+        yield from utils._verify_successful_response(response)
+        messages = yield from response.json()
+        return messages
+
+    if PY35:
+        def logs_from(self, channel, limit=100, *, before=None, after=None):
+            return LogsFromIterator(self, channel, limit, before, after)
+    else:
+        @asyncio.coroutine
+        def logs_from(self, channel, limit=100, *, before=None, after=None):
+            def generator(data):
+                for message in data:
+                    yield Message(channel=channel, **message)
+
+            result = []
+            while limit > 0:
+                retrieve = limit if limit <= 100 else 100
+                data = yield from self._logs_from(channel, retrieve, before, after)
+                if len(data):
+                    limit -= retrieve
+                    result.extend(data)
+                    before = Object(id=data[-1]['id'])
+                else:
+                    break
+
+            return generator(result)
 
-        return generator(result)
+    logs_from.__doc__ = _logs_from.__doc__
 
     # Member management