Consolidate get_transcript methods

There were two get_transcript methods. The broken one that was being
used (VideoTranscriptsMixin.get_transcript) is stripped out here - it
has been superseded by transcripts_utils.get_transcript. The latter
includes support for blockstore and VAL, while the former did not.

This fixes the `AttributeError: 'LibraryLocatorV2' object has no
attribute 'make_asset_key'` error seen when attempting to load a
transcript from a video through the xblock api when the video had the
transcript stored in blockstore.

Note that if you were previously using video.get_transcript, you should
now use `transcripts_utils.get_transcript(video, ...)`, and note that
the returned 'filename' will be prefixed with the language code, as
other `get_transcript*` functions already do.

common/lib/xmodule/xmodule/video_module/transcripts_utils.py

@@ -784,49 +784,6 @@ class VideoTranscriptsMixin(object):
         # to clean redundant language codes.
         return list(set(translations))
 
-    def get_transcript(self, transcripts, transcript_format='srt', lang=None):
-        """
-        Returns transcript, filename and MIME type.
-
-        transcripts (dict): A dict with all transcripts and a sub.
-
-        Raises:
-            - NotFoundError if cannot find transcript file in storage.
-            - ValueError if transcript file is empty or incorrect JSON.
-            - KeyError if transcript file has incorrect format.
-
-        If language is 'en', self.sub should be correct subtitles name.
-        If language is 'en', but if self.sub is not defined, this means that we
-        should search for video name in order to get proper transcript (old style courses).
-        If language is not 'en', give back transcript in proper language and format.
-        """
-        if not lang:
-            lang = self.get_default_transcript_language(transcripts)
-
-        sub, other_lang = transcripts["sub"], transcripts["transcripts"]
-        if lang == 'en':
-            if sub:  # HTML5 case and (Youtube case for new style videos)
-                transcript_name = sub
-            elif self.youtube_id_1_0:  # old courses
-                transcript_name = self.youtube_id_1_0
-            else:
-                log.debug("No subtitles for 'en' language")
-                raise ValueError
-
-            data = Transcript.asset(self.location, transcript_name, lang).data.decode('utf-8')
-            filename = u'{}.{}'.format(transcript_name, transcript_format)
-            content = Transcript.convert(data, 'sjson', transcript_format)
-        else:
-            data = Transcript.asset(self.location, None, None, other_lang[lang]).data.decode('utf-8')
-            filename = u'{}.{}'.format(os.path.splitext(other_lang[lang])[0], transcript_format)
-            content = Transcript.convert(data, 'srt', transcript_format)
-
-        if not content:
-            log.debug('no subtitles produced in get_transcript')
-            raise ValueError
-
-        return content, filename, Transcript.mime_types[transcript_format]
-
     def get_default_transcript_language(self, transcripts):
         """
         Returns the default transcript language for this video module.
@@ -910,7 +867,10 @@ def get_transcript_from_val(edx_video_id, lang=None, output_format=Transcript.SR
 
 def get_transcript_for_video(video_location, subs_id, file_name, language):
     """
-    Get video transcript from content store.
+    Get video transcript from content store. This is a lower level function and is used by
+    `get_transcript_from_contentstore`. Prefer that function instead where possible. If you
+    need to support getting transcripts from VAL or Blockstore as well, use the `get_transcript`
+    function instead.
 
     NOTE: Transcripts can be searched from content store by two ways:
     1. by an id(a.k.a subs_id) which will be used to construct transcript filename

common/lib/xmodule/xmodule/video_module/video_module.py

@@ -56,7 +56,7 @@ from .transcripts_utils import (
     VideoTranscriptsMixin,
     clean_video_id,
     get_html5_ids,
-    get_transcript_for_video,
+    get_transcript,
     subs_filename
 )
 from .video_handlers import VideoStudentViewHandlers, VideoStudioViewHandlers
@@ -593,12 +593,7 @@ class VideoBlock(
         possible_sub_ids = [self.sub, self.youtube_id_1_0] + get_html5_ids(self.html5_sources)
         for sub_id in possible_sub_ids:
             try:
-                get_transcript_for_video(
-                    self.location,
-                    subs_id=sub_id,
-                    file_name=sub_id,
-                    language=u'en'
-                )
+                _, sub_id, _ = get_transcript(self, lang=u'en', output_format=Transcript.TXT)
                 transcripts_info['transcripts'] = dict(transcripts_info['transcripts'], en=sub_id)
                 break
             except NotFoundError:
@@ -1029,10 +1024,7 @@ class VideoBlock(
         def _update_transcript_for_index(language=None):
             """ Find video transcript - if not found, don't update index """
             try:
-                transcripts = self.get_transcripts_info()
-                transcript = self.get_transcript(
-                    transcripts, transcript_format='txt', lang=language
-                )[0].replace("\n", " ")
+                transcript = get_transcript(self, lang=language, output_format=Transcript.TXT)[0].replace("\n", " ")
                 transcript_index_name = "transcript_{}".format(language if language else self.transcript_language)
                 video_body.update({transcript_index_name: transcript})
             except NotFoundError:

lms/djangoapps/courseware/tests/test_video_handlers.py

@@ -25,7 +25,12 @@ from xmodule.exceptions import NotFoundError
 from xmodule.modulestore import ModuleStoreEnum
 from xmodule.modulestore.django import modulestore
 from xmodule.video_module import VideoBlock
-from xmodule.video_module.transcripts_utils import Transcript, edxval_api, subs_filename
+from xmodule.video_module.transcripts_utils import (
+    Transcript,
+    edxval_api,
+    get_transcript,
+    subs_filename,
+)
 from xmodule.x_module import STUDENT_VIEW
 
 from .helpers import BaseTestXmodule
@@ -521,9 +526,8 @@ class TestTranscriptDownloadDispatch(TestVideo):
         request = Request.blank('/download')
         response = self.item.transcript(request=request, dispatch='download')
         self.assertEqual(response.status, '404 Not Found')
-        transcripts = self.item.get_transcripts_info()
         with self.assertRaises(NotFoundError):
-            self.item.get_transcript(transcripts)
+            get_transcript(self.item)
 
     @patch(
         'xmodule.video_module.transcripts_utils.get_transcript_for_video',
@@ -537,7 +541,7 @@ class TestTranscriptDownloadDispatch(TestVideo):
         self.assertEqual(response.headers['Content-Disposition'], 'attachment; filename="en_塞.srt"')
 
     @patch('xmodule.video_module.transcripts_utils.edxval_api.get_video_transcript_data')
-    @patch('xmodule.video_module.VideoBlock.get_transcript', Mock(side_effect=NotFoundError))
+    @patch('xmodule.video_module.get_transcript', Mock(side_effect=NotFoundError))
     def test_download_fallback_transcript(self, mock_get_video_transcript_data):
         """
         Verify val transcript is returned as a fallback if it is not found in the content store.
@@ -1196,8 +1200,7 @@ class TestGetTranscript(TestVideo):
         _upload_sjson_file(good_sjson, self.item.location)
         self.item.sub = _get_subs_id(good_sjson.name)
 
-        transcripts = self.item.get_transcripts_info()
-        text, filename, mime_type = self.item.get_transcript(transcripts)
+        text, filename, mime_type = get_transcript(self.item)
 
         expected_text = textwrap.dedent("""\
             0
@@ -1211,7 +1214,7 @@ class TestGetTranscript(TestVideo):
             """)
 
         self.assertEqual(text, expected_text)
-        self.assertEqual(filename[:-4], self.item.sub)
+        self.assertEqual(filename[:-4], 'en_' + self.item.sub)
         self.assertEqual(mime_type, 'application/x-subrip; charset=utf-8')
 
     def test_good_txt_transcript(self):
@@ -1234,27 +1237,27 @@ class TestGetTranscript(TestVideo):
 
         _upload_sjson_file(good_sjson, self.item.location)
         self.item.sub = _get_subs_id(good_sjson.name)
-        transcripts = self.item.get_transcripts_info()
-        text, filename, mime_type = self.item.get_transcript(transcripts, transcript_format="txt")
+        text, filename, mime_type = get_transcript(self.item, output_format=Transcript.TXT)
         expected_text = textwrap.dedent("""\
             Hi, welcome to Edx.
             Let's start with what is on your screen right now.""")
 
         self.assertEqual(text, expected_text)
-        self.assertEqual(filename, self.item.sub + '.txt')
+        self.assertEqual(filename, 'en_' + self.item.sub + '.txt')
         self.assertEqual(mime_type, 'text/plain; charset=utf-8')
 
     def test_en_with_empty_sub(self):
 
-        transcripts = {"transcripts": {}, "sub": ""}
+        self.item.sub = ""
+        self.item.transcripts = None
         # no self.sub, self.youttube_1_0 exist, but no file in assets
         with self.assertRaises(NotFoundError):
-            self.item.get_transcript(transcripts)
+            get_transcript(self.item)
 
         # no self.sub and no self.youtube_1_0, no non-en transcritps
         self.item.youtube_id_1_0 = None
-        with self.assertRaises(ValueError):
-            self.item.get_transcript(transcripts)
+        with self.assertRaises(NotFoundError):
+            get_transcript(self.item)
 
         # no self.sub but youtube_1_0 exists with file in assets
         good_sjson = _create_file(content=textwrap.dedent("""\
@@ -1276,7 +1279,7 @@ class TestGetTranscript(TestVideo):
         _upload_sjson_file(good_sjson, self.item.location)
         self.item.youtube_id_1_0 = _get_subs_id(good_sjson.name)
 
-        text, filename, mime_type = self.item.get_transcript(transcripts)
+        text, filename, mime_type = get_transcript(self.item)
         expected_text = textwrap.dedent("""\
             0
             00:00:00,270 --> 00:00:02,720
@@ -1289,7 +1292,7 @@ class TestGetTranscript(TestVideo):
             """)
 
         self.assertEqual(text, expected_text)
-        self.assertEqual(filename, self.item.youtube_id_1_0 + '.srt')
+        self.assertEqual(filename, 'en_' + self.item.youtube_id_1_0 + '.srt')
         self.assertEqual(mime_type, 'application/x-subrip; charset=utf-8')
 
     def test_non_en_with_non_ascii_filename(self):
@@ -1298,14 +1301,14 @@ class TestGetTranscript(TestVideo):
         _upload_file(self.srt_file, self.item_descriptor.location, u"塞.srt")
 
         transcripts = self.item.get_transcripts_info()
-        text, filename, mime_type = self.item.get_transcript(transcripts)
+        text, filename, mime_type = get_transcript(self.item)
         expected_text = textwrap.dedent(u"""
         0
         00:00:00,12 --> 00:00:00,100
         Привіт, edX вітає вас.
         """)
         self.assertEqual(text, expected_text)
-        self.assertEqual(filename, u"塞.srt")
+        self.assertEqual(filename, u"zh_塞.srt")
         self.assertEqual(mime_type, 'application/x-subrip; charset=utf-8')
 
     def test_value_error(self):
@@ -1316,7 +1319,7 @@ class TestGetTranscript(TestVideo):
 
         transcripts = self.item.get_transcripts_info()
         with self.assertRaises(ValueError):
-            self.item.get_transcript(transcripts)
+            get_transcript(self.item)
 
     def test_key_error(self):
         good_sjson = _create_file(content="""
@@ -1337,4 +1340,4 @@ class TestGetTranscript(TestVideo):
 
         transcripts = self.item.get_transcripts_info()
         with self.assertRaises(KeyError):
-            self.item.get_transcript(transcripts)
+            get_transcript(self.item)