[dailymotion] Added support for subtitles + new InfoExtractor for

generic subtitle download.

The idea is that all subtitle downloaders must descend from SubtitlesIE
and implement only three basic methods to achieve the complete subtitle
download functionality. This will allow to reduce the code in YoutubeIE
once it is rewritten.

youtube_dl/extractor/dailymotion.py

@@ -1,14 +1,49 @@
 import re
 import json
+import itertools
+import socket
 
 from .common import InfoExtractor
+from .subtitles import SubtitlesIE
+
 from ..utils import (
+    compat_http_client,
+    compat_urllib_error,
     compat_urllib_request,
+    compat_str,
+    get_element_by_attribute,
+    get_element_by_id,
 
     ExtractorError,
 )
 
-class DailymotionIE(InfoExtractor):
+
+class DailyMotionSubtitlesIE(SubtitlesIE):
+
+    def _get_available_subtitles(self, video_id):
+        request = compat_urllib_request.Request('https://api.dailymotion.com/video/%s/subtitles?fields=id,language,url' % video_id)
+        try:
+            sub_list = compat_urllib_request.urlopen(request).read().decode('utf-8')
+        except (compat_urllib_error.URLError, compat_http_client.HTTPException, socket.error) as err:
+            self._downloader.report_warning(u'unable to download video subtitles: %s' % compat_str(err))
+            return {}
+        info = json.loads(sub_list)
+        if (info['total'] > 0):
+            sub_lang_list = dict((l['language'], l['url']) for l in info['list'])
+            return sub_lang_list
+        self._downloader.report_warning(u'video doesn\'t have subtitles')
+        return {}
+
+    def _get_subtitle_url(self, sub_lang, sub_name, video_id, format):
+        sub_lang_list = self._get_available_subtitles(video_id)
+        return sub_lang_list[sub_lang]
+
+    def _request_automatic_caption(self, video_id, webpage):
+        self._downloader.report_warning(u'Automatic Captions not supported by dailymotion')
+        return {}
+
+
+class DailymotionIE(DailyMotionSubtitlesIE): #,InfoExtractor):
     """Information Extractor for Dailymotion"""
 
     _VALID_URL = r'(?i)(?:https?://)?(?:www\.)?dailymotion\.[a-z]{2,3}/video/([^/]+)'
@@ -18,7 +53,7 @@ class DailymotionIE(InfoExtractor):
         u'file': u'x33vw9.mp4',
         u'md5': u'392c4b85a60a90dc4792da41ce3144eb',
         u'info_dict': {
-            u"uploader": u"Alex and Van .", 
+            u"uploader": u"Alex and Van .",
             u"title": u"Tutoriel de Youtubeur\"DL DES VIDEO DE YOUTUBE\""
         }
     }
@@ -57,17 +92,36 @@ class DailymotionIE(InfoExtractor):
 
         # TODO: support choosing qualities
 
-        for key in ['stream_h264_hd1080_url','stream_h264_hd_url',
-                    'stream_h264_hq_url','stream_h264_url',
+        for key in ['stream_h264_hd1080_url', 'stream_h264_hd_url',
+                    'stream_h264_hq_url', 'stream_h264_url',
                     'stream_h264_ld_url']:
-            if info.get(key):#key in info and info[key]:
+            if info.get(key):  # key in info and info[key]:
                 max_quality = key
-                self.to_screen(u'Using %s' % key)
+                self.to_screen(u'%s: Using %s' % (video_id, key))
                 break
         else:
             raise ExtractorError(u'Unable to extract video URL')
         video_url = info[max_quality]
 
+        # subtitles
+        video_subtitles = None
+        video_webpage = None
+
+        if self._downloader.params.get('writesubtitles', False) or self._downloader.params.get('allsubtitles', False):
+            video_subtitles = self._extract_subtitles(video_id)
+        elif self._downloader.params.get('writeautomaticsub', False):
+            video_subtitles = self._request_automatic_caption(video_id, video_webpage)
+
+        if self._downloader.params.get('listsubtitles', False):
+            self._list_available_subtitles(video_id)
+            return
+
+        if 'length_seconds' not in info:
+            self._downloader.report_warning(u'unable to extract video duration')
+            video_duration = ''
+        else:
+            video_duration = compat_urllib_parse.unquote_plus(video_info['length_seconds'][0])
+
         return [{
             'id':       video_id,
             'url':      video_url,
@@ -75,5 +129,6 @@ class DailymotionIE(InfoExtractor):
             'upload_date':  video_upload_date,
             'title':    self._og_search_title(webpage),
             'ext':      video_extension,
+            'subtitles':    video_subtitles,
             'thumbnail': info['thumbnail_url']
         }]