Merge pull request #17984 from edx/iahmad/exception_decorator

added exception decorator

cms/djangoapps/contentstore/tests/test_transcripts_utils.py

@@ -959,3 +959,43 @@ class TestGetTranscript(SharedModuleStoreTestCase):
 
         exception_message = text_type(no_en_transcript_exception.exception)
         self.assertEqual(exception_message, 'No transcript for `en` language')
+
+    @ddt.data(
+        transcripts_utils.TranscriptsGenerationException,
+        UnicodeDecodeError('aliencodec', b'\x02\x01', 1, 2, 'alien codec found!')
+    )
+    @patch('xmodule.video_module.transcripts_utils.Transcript')
+    def test_get_transcript_val_exceptions(self, exception_to_raise, mock_Transcript):
+        """
+        Verify that `get_transcript_from_val` function raises `NotFoundError` when specified exceptions raised.
+        """
+        mock_Transcript.convert.side_effect = exception_to_raise
+        transcripts_info = self.video.get_transcripts_info()
+        lang = self.video.get_default_transcript_language(transcripts_info)
+        edx_video_id = transcripts_utils.clean_video_id(self.video.edx_video_id)
+        with self.assertRaises(NotFoundError):
+            transcripts_utils.get_transcript_from_val(
+                edx_video_id,
+                lang=lang,
+                output_format=transcripts_utils.Transcript.SRT
+            )
+
+    @ddt.data(
+        transcripts_utils.TranscriptsGenerationException,
+        UnicodeDecodeError('aliencodec', b'\x02\x01', 1, 2, 'alien codec found!')
+    )
+    @patch('xmodule.video_module.transcripts_utils.Transcript')
+    def test_get_transcript_content_store_exceptions(self, exception_to_raise, mock_Transcript):
+        """
+        Verify that `get_transcript_from_contentstore` function raises `NotFoundError` when specified exceptions raised.
+        """
+        mock_Transcript.asset.side_effect = exception_to_raise
+        transcripts_info = self.video.get_transcripts_info()
+        lang = self.video.get_default_transcript_language(transcripts_info)
+        with self.assertRaises(NotFoundError):
+            transcripts_utils.get_transcript_from_contentstore(
+                self.video,
+                language=lang,
+                output_format=transcripts_utils.Transcript.SRT,
+                transcripts_info=transcripts_info
+            )

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

@@ -2,6 +2,7 @@
 Utility functions for transcripts.
 ++++++++++++++++++++++++++++++++++
 """
+from functools import wraps
 from django.conf import settings
 import os
 import copy
@@ -49,6 +50,26 @@ class TranscriptsRequestValidationException(Exception):  # pylint: disable=missi
     pass
 
 
+def exception_decorator(func):
+    """
+    Generate NotFoundError for TranscriptsGenerationException, UnicodeDecodeError.
+
+    Args:
+    `func`: Input function
+
+    Returns:
+    'wrapper': Decorated function
+    """
+    @wraps(func)
+    def wrapper(*args, **kwds):
+        try:
+            return func(*args, **kwds)
+        except (TranscriptsGenerationException, UnicodeDecodeError) as ex:
+            log.exception(text_type(ex))
+            raise NotFoundError
+    return wrapper
+
+
 def generate_subs(speed, source_speed, source_subs):
     """
     Generate transcripts from one speed to another speed.
@@ -855,6 +876,7 @@ class VideoTranscriptsMixin(object):
         }
 
 
+@exception_decorator
 def get_transcript_from_val(edx_video_id, lang=None, output_format=Transcript.SRT):
     """
     Get video transcript from edx-val.
@@ -909,6 +931,7 @@ def get_transcript_for_video(video_location, subs_id, file_name, language):
     return input_format, base_name, content
 
 
+@exception_decorator
 def get_transcript_from_contentstore(video, language, output_format, transcripts_info, youtube_id=None):
     """
     Get video transcript from content store.
@@ -954,7 +977,6 @@ def get_transcript_from_contentstore(video, language, output_format, transcripts
     language_prefix = '{}_'.format(language) if language else ''
     transcript_name = u'{}{}.{}'.format(language_prefix, base_name, output_format)
     transcript_content = Transcript.convert(transcript_content, input_format=input_format, output_format=output_format)
-
     if not transcript_content.strip():
         raise NotFoundError('No transcript content')