1 files changed, 92 insertions, 0 deletions
diff --git a/youtube_dl/extractor/subtitles.py b/youtube_dl/extractor/subtitles.py
new file mode 100644
index 000000000..97215f289
--- /dev/null
+++ b/youtube_dl/extractor/subtitles.py
@@ -0,0 +1,92 @@
+from .common import InfoExtractor
+
+from ..utils import (
+    compat_str,
+    ExtractorError,
+)
+
+
+class SubtitlesInfoExtractor(InfoExtractor):
+    @property
+    def _have_to_download_any_subtitles(self):
+        return any([self._downloader.params.get('writesubtitles', False),
+                    self._downloader.params.get('writeautomaticsub'),
+                    self._downloader.params.get('allsubtitles', False)])
+
+    def _list_available_subtitles(self, video_id, webpage=None):
+        """ outputs the available subtitles for the video """
+        sub_lang_list = self._get_available_subtitles(video_id)
+        auto_captions_list = self._get_available_automatic_caption(video_id, webpage)
+        sub_lang = ",".join(list(sub_lang_list.keys()))
+        self.to_screen(u'%s: Available subtitles for video: %s' %
+                       (video_id, sub_lang))
+        auto_lang = ",".join(auto_captions_list.keys())
+        self.to_screen(u'%s: Available automatic captions for video: %s' %
+                       (video_id, auto_lang))
+
+    def extract_subtitles(self, video_id, video_webpage=None):
+        """
+        returns {sub_lang: sub} ,{} if subtitles not found or None if the
+        subtitles aren't requested.
+        """
+        if not self._have_to_download_any_subtitles:
+            return None
+        available_subs_list = {}
+        if self._downloader.params.get('writeautomaticsub', False):
+            available_subs_list.update(self._get_available_automatic_caption(video_id, video_webpage))
+        if self._downloader.params.get('writesubtitles', False) or self._downloader.params.get('allsubtitles', False):
+            available_subs_list.update(self._get_available_subtitles(video_id))
+
+        if not available_subs_list:  # error, it didn't get the available subtitles
+            return {}
+        if self._downloader.params.get('allsubtitles', False):
+            sub_lang_list = available_subs_list
+        else:
+            if self._downloader.params.get('subtitleslangs', False):
+                requested_langs = self._downloader.params.get('subtitleslangs')
+            elif 'en' in available_subs_list:
+                requested_langs = ['en']
+            else:
+                requested_langs = [list(available_subs_list.keys())[0]]
+
+            sub_lang_list = {}
+            for sub_lang in requested_langs:
+                if not sub_lang in available_subs_list:
+                    self._downloader.report_warning(u'no closed captions found in the specified language "%s"' % sub_lang)
+                    continue
+                sub_lang_list[sub_lang] = available_subs_list[sub_lang]
+
+        subtitles = {}
+        for sub_lang, url in sub_lang_list.items():
+            subtitle = self._request_subtitle_url(sub_lang, url)
+            if subtitle:
+                subtitles[sub_lang] = subtitle
+        return subtitles
+
+    def _request_subtitle_url(self, sub_lang, url):
+        """ makes the http request for the subtitle """
+        try:
+            sub = self._download_webpage(url, None, note=False)
+        except ExtractorError as err:
+            self._downloader.report_warning(u'unable to download video subtitles for %s: %s' % (sub_lang, compat_str(err)))
+            return
+        if not sub:
+            self._downloader.report_warning(u'Did not fetch video subtitles')
+            return
+        return sub
+
+    def _get_available_subtitles(self, video_id):
+        """
+        returns {sub_lang: url} or {} if not available
+        Must be redefined by the subclasses
+        """
+        pass
+
+    def _get_available_automatic_caption(self, video_id, webpage):
+        """
+        returns {sub_lang: url} or {} if not available
+        Must be redefined by the subclasses that support automatic captions,
+        otherwise it will return {}
+        """
+        self._downloader.report_warning(u'Automatic Captions not supported by this server')
+        return {}