[khanacademy] Add support (Fixes #2066)

3 files changed, 82 insertions, 0 deletions

diff --git a/youtube_dl/extractor/__init__.py b/youtube_dl/extractor/__init__.py
index 009d3b60f..99ba725d9 100644
--- a/youtube_dl/extractor/__init__.py
+++ b/youtube_dl/extractor/__init__.py
@@ -98,6 +98,7 @@ from .justintv import JustinTVIE
 from .jpopsukitv import JpopsukiIE
 from .kankan import KankanIE
 from .keezmovies import KeezMoviesIE
+from .khanacademy import KhanAcademyIE
 from .kickstarter import KickStarterIE
 from .keek import KeekIE
 from .liveleak import LiveLeakIE
diff --git a/youtube_dl/extractor/common.py b/youtube_dl/extractor/common.py
index 2a5e8076c..0ec365eaa 100644
--- a/youtube_dl/extractor/common.py
+++ b/youtube_dl/extractor/common.py
@@ -1,4 +1,5 @@
 import base64
+import json
 import os
 import re
 import socket
@@ -260,6 +261,15 @@ class InfoExtractor(object):
             xml_string = transform_source(xml_string)
         return xml.etree.ElementTree.fromstring(xml_string.encode('utf-8'))
 
+    def _download_json(self, url_or_request, video_id,
+                       note=u'Downloading JSON metadata',
+                       errnote=u'Unable to download JSON metadata'):
+        json_string = self._download_webpage(url_or_request, video_id, note, errnote)
+        try:
+            return json.loads(json_string)
+        except ValueError as ve:
+            raise ExtractorError('Failed to download JSON', cause=ve)
+
     def report_warning(self, msg, video_id=None):
         idstr = u'' if video_id is None else u'%s: ' % video_id
         self._downloader.report_warning(
diff --git a/youtube_dl/extractor/khanacademy.py b/youtube_dl/extractor/khanacademy.py
new file mode 100644
index 000000000..772bb5671
--- /dev/null
+++ b/youtube_dl/extractor/khanacademy.py
@@ -0,0 +1,71 @@
+from __future__ import unicode_literals
+
+import re
+
+from .common import InfoExtractor
+from ..utils import (
+    unified_strdate,
+)
+
+
+class KhanAcademyIE(InfoExtractor):
+    _VALID_URL = r'^https?://(?:www\.)?khanacademy\.org/(?P<key>[^/]+)/(?:[^/]+/){,2}(?P<id>[^?#/]+)(?:$|[?#])'
+    IE_NAME = 'KhanAcademy'
+
+    _TEST = {
+        'url': 'http://www.khanacademy.org/video/one-time-pad',
+        'file': 'one-time-pad.mp4',
+        'md5': '7021db7f2d47d4fff89b13177cb1e8f4',
+        'info_dict': {
+            'title': 'The one-time pad',
+            'description': 'The perfect cipher',
+            'duration': 176,
+            'uploader': 'Brit Cruise',
+            'upload_date': '20120411',
+        }
+    }
+
+    def _real_extract(self, url):
+        m = re.match(self._VALID_URL, url)
+        video_id = m.group('id')
+
+        if m.group('key') == 'video':
+            data = self._download_json(
+                'http://api.khanacademy.org/api/v1/videos/' + video_id,
+                video_id, 'Downloading video info')
+
+            upload_date = unified_strdate(data['date_added'])
+            uploader = ', '.join(data['author_names'])
+            return {
+                '_type': 'url_transparent',
+                'url': data['url'],
+                'id': video_id,
+                'title': data['title'],
+                'thumbnail': data['image_url'],
+                'duration': data['duration'],
+                'description': data['description'],
+                'uploader': uploader,
+                'upload_date': upload_date,
+            }
+        else:
+            # topic
+            data = self._download_json(
+                'http://api.khanacademy.org/api/v1/topic/' + video_id,
+                video_id, 'Downloading topic info')
+
+            entries = [
+                {
+                    '_type': 'url',
+                    'url': c['url'],
+                    'id': c['id'],
+                    'title': c['title'],
+                }
+                for c in data['children'] if c['kind'] in ('Video', 'Topic')]
+
+            return {
+                '_type': 'playlist',
+                'id': video_id,
+                'title': data['title'],
+                'description': data['description'],
+                'entries': entries,
+            }