feat: add util method in edx-val for listing transcript_languages for…

… a course

edxval/__init__.py

@@ -2,4 +2,4 @@
 init
 """
 
-__version__ = '2.9.0'
+__version__ = '2.9.1'

edxval/api.py

@@ -1,12 +1,11 @@
 """
 The internal API for VAL.
 """
-
-
 import logging
 from enum import Enum
 from uuid import uuid4
 
+from django.conf import settings
 from django.core.exceptions import ObjectDoesNotExist, ValidationError
 from django.core.files.base import ContentFile
 from django.core.paginator import Paginator
@@ -18,6 +17,7 @@
 from lxml.etree import Element, SubElement
 from pysrt.srtexc import Error
 
+import cachetools.func
 from edxval.config.waffle import OVERRIDE_EXISTING_IMPORTED_TRANSCRIPTS
 from edxval.exceptions import (
     InvalidTranscriptFormat,
@@ -733,6 +733,26 @@ def get_videos_for_course(course_id, sort_field=None, sort_dir=SortDirection.asc
     )
 
 
+@cachetools.func.ttl_cache(maxsize=None, ttl=settings.TRANSCRIPT_LANG_CACHE_TIMEOUT)
+def get_transcript_languages(course_id, provider_type):
+    """
+    Returns a list of languages for which transcripts are available for a course
+
+    Args:
+        course_id (str): course id
+        provider_type (str): transcript provider type
+
+    Returns:
+        (list): A list of language codes
+    """
+    course_video_ids = CourseVideo.objects.filter(course_id=course_id, is_hidden=False).values_list('video__id')
+    transcript_languages = (
+        VideoTranscript.objects.filter(video__id__in=course_video_ids, provider=provider_type)
+        .values_list("language_code", flat=True).distinct()
+    )
+    return list(transcript_languages)
+
+
 def get_course_videos_qset(course_id):
     """
     Get a QuerySet of CourseVideos for a given course.

edxval/settings/base.py

@@ -193,3 +193,5 @@
         }
     },
 ]
+
+TRANSCRIPT_LANG_CACHE_TIMEOUT = 60 * 60 * 24  # 24 hours

edxval/tests/test_api.py

@@ -3189,6 +3189,18 @@ def test_get_transcript_details_for_course_no_course_videos(self):
 
         self.assertEqual(len(course_transcript), 0)
 
+    @data(
+        (TranscriptProviderType.THREE_PLAY_MEDIA, ['en']),
+        (TranscriptProviderType.CIELO24, ['fr'])
+    )
+    @unpack
+    def test_get_transcript_languages_for_course(self, provider_type, expected_languages):
+        """
+        Verify that `get_transcript_languages` api function works as expected.
+        """
+        transcript_languages = api.get_transcript_languages(self.course_id1, provider_type)
+        self.assertEqual(transcript_languages, expected_languages)
+
 
 @ddt
 class TranscriptPreferencesTest(TestCase):

requirements/base.in

@@ -11,3 +11,4 @@ pillow                              # for reserved keywords linter
 edx-toggles>=2.0.0
 lxml
 pysrt
+cachetools