Allow iterators for playlist result entries

3 files changed, 26 insertions, 16 deletions

diff --git a/youtube_dl/YoutubeDL.py b/youtube_dl/YoutubeDL.py
index f89ac4e1d..56dc3d461 100755
--- a/youtube_dl/YoutubeDL.py
+++ b/youtube_dl/YoutubeDL.py
@@ -7,6 +7,7 @@ import collections
 import datetime
 import errno
 import io
+import itertools
 import json
 import locale
 import os
@@ -654,21 +655,28 @@ class YoutubeDL(object):
             if playlistend == -1:
                 playlistend = None
 
-            if isinstance(ie_result['entries'], list):
-                n_all_entries = len(ie_result['entries'])
-                entries = ie_result['entries'][playliststart:playlistend]
+            ie_entries = ie_result['entries']
+            if isinstance(ie_entries, list):
+                n_all_entries = len(ie_entries)
+                entries = ie_entries[playliststart:playlistend]
                 n_entries = len(entries)
                 self.to_screen(
                     "[%s] playlist %s: Collected %d video ids (downloading %d of them)" %
                     (ie_result['extractor'], playlist, n_all_entries, n_entries))
-            else:
-                assert isinstance(ie_result['entries'], PagedList)
-                entries = ie_result['entries'].getslice(
+            elif isinstance(ie_entries, PagedList):
+                entries = ie_entries.getslice(
                     playliststart, playlistend)
                 n_entries = len(entries)
                 self.to_screen(
                     "[%s] playlist %s: Downloading %d videos" %
                     (ie_result['extractor'], playlist, n_entries))
+            else:  # iterable
+                entries = list(itertools.islice(
+                    ie_entries, playliststart, playlistend))
+                n_entries = len(entries)
+                self.to_screen(
+                    "[%s] playlist %s: Downloading %d videos" %
+                    (ie_result['extractor'], playlist, n_entries))
 
             for i, entry in enumerate(entries, 1):
                 self.to_screen('[download] Downloading video #%s of %s' % (i, n_entries))
diff --git a/youtube_dl/extractor/common.py b/youtube_dl/extractor/common.py
index 5b5e33cea..cb6081dd0 100644
--- a/youtube_dl/extractor/common.py
+++ b/youtube_dl/extractor/common.py
@@ -158,8 +158,8 @@ class InfoExtractor(object):
 
 
     _type "playlist" indicates multiple videos.
-    There must be a key "entries", which is a list or a PagedList object, each
-    element of which is a valid dictionary under this specfication.
+    There must be a key "entries", which is a list, an iterable, or a PagedList
+    object, each element of which is a valid dictionary by this specification.
 
     Additionally, playlists can have "title" and "id" attributes with the same
     semantics as videos (see above).
diff --git a/youtube_dl/extractor/youtube.py b/youtube_dl/extractor/youtube.py
index addef9594..8b6e591a4 100644
--- a/youtube_dl/extractor/youtube.py
+++ b/youtube_dl/extractor/youtube.py
@@ -1262,8 +1262,12 @@ class YoutubeChannelIE(InfoExtractor):
             # The videos are contained in a single page
             # the ajax pages can't be used, they are empty
             video_ids = self.extract_videos_from_page(channel_page)
-        else:
-            # Download all channel pages using the json-based channel_ajax query
+            entries = [
+                self.url_result(video_id, 'Youtube', video_id=video_id)
+                for video_id in video_ids]
+            return self.playlist_result(entries, channel_id)
+
+        def _entries():
             for pagenum in itertools.count(1):
                 url = self._MORE_PAGES_URL % (pagenum, channel_id)
                 page = self._download_json(
@@ -1271,16 +1275,14 @@ class YoutubeChannelIE(InfoExtractor):
                     transform_source=uppercase_escape)
 
                 ids_in_page = self.extract_videos_from_page(page['content_html'])
-                video_ids.extend(ids_in_page)
+                for video_id in ids_in_page:
+                    yield self.url_result(
+                        video_id, 'Youtube', video_id=video_id)
 
                 if self._MORE_PAGES_INDICATOR not in page['load_more_widget_html']:
                     break
 
-        self._downloader.to_screen('[youtube] Channel %s: Found %i videos' % (channel_id, len(video_ids)))
-
-        url_entries = [self.url_result(video_id, 'Youtube', video_id=video_id)
-                       for video_id in video_ids]
-        return self.playlist_result(url_entries, channel_id)
+        return self.playlist_result(_entries(), channel_id)
 
 
 class YoutubeUserIE(InfoExtractor):