def setUpClass(cls):
        super(TestSaveSubsToStore, cls).setUpClass()
        cls.course = CourseFactory.create(
            org=cls.org, number=cls.number, display_name=cls.display_name)

        cls.subs = {
            'start': [100, 200, 240, 390, 1000],
            'end': [200, 240, 380, 1000, 1500],
            'text': [
                'subs #1',
                'subs #2',
                'subs #3',
                'subs #4',
                'subs #5'
            ]
        }

        cls.subs_id = str(uuid4())
        filename = 'subs_{0}.srt.sjson'.format(cls.subs_id)
        cls.content_location = StaticContent.compute_location(cls.course.id, filename)

        # incorrect subs
        cls.unjsonable_subs = {1}  # set can't be serialized

        cls.unjsonable_subs_id = str(uuid4())
        filename_unjsonable = 'subs_{0}.srt.sjson'.format(cls.unjsonable_subs_id)
        cls.content_location_unjsonable = StaticContent.compute_location(cls.course.id, filename_unjsonable)

def remap_namespace(module, target_location_namespace):
    if target_location_namespace is None:
        return module

    # This looks a bit wonky as we need to also change the 'name' of the
    # imported course to be what the caller passed in
    if module.location.category != 'course':
        module.location = module.location._replace(
            tag=target_location_namespace.tag,
            org=target_location_namespace.org,
            course=target_location_namespace.course
        )
    else:
        original_location = module.location
        #
        # module is a course module
        #
        module.location = module.location._replace(
            tag=target_location_namespace.tag,
            org=target_location_namespace.org,
            course=target_location_namespace.course,
            name=target_location_namespace.name
        )
        # There is more re-namespacing work we have to do when
        # importing course modules

        # remap pdf_textbook urls
        for entry in module.pdf_textbooks:
            for chapter in entry.get('chapters', []):
                if StaticContent.is_c4x_path(chapter.get('url', '')):
                    chapter['url'] = StaticContent.renamespace_c4x_path(
                        chapter['url'], target_location_namespace
                    )

        # if there is a wiki_slug which is the same as the original location
        # (aka default value), then remap that so the wiki doesn't point to
        # the old Wiki.
        if module.wiki_slug == original_location.course:
            module.wiki_slug = target_location_namespace.course

        module.save()

    # then remap children pointers since they too will be re-namespaced
    if hasattr(module, 'children'):
        children_locs = module.children
        if children_locs is not None and children_locs != []:
            new_locs = []
            for child in children_locs:
                child_loc = Location(child)
                new_child_loc = child_loc._replace(
                    tag=target_location_namespace.tag,
                    org=target_location_namespace.org,
                    course=target_location_namespace.course
                )

                new_locs.append(new_child_loc.url())

            module.children = new_locs

    return module

    def setUp(self):

        super(TestSaveSubsToStore, self).setUp()
        self.course = CourseFactory.create(
            org=self.org, number=self.number, display_name=self.display_name)

        self.subs = {
            'start': [100, 200, 240, 390, 1000],
            'end': [200, 240, 380, 1000, 1500],
            'text': [
                'subs #1',
                'subs #2',
                'subs #3',
                'subs #4',
                'subs #5'
            ]
        }

        self.subs_id = str(uuid4())
        filename = 'subs_{0}.srt.sjson'.format(self.subs_id)
        self.content_location = StaticContent.compute_location(self.course.id, filename)
        self.addCleanup(self.clear_subs_content)

        # incorrect subs
        self.unjsonable_subs = set([1])  # set can't be serialized

        self.unjsonable_subs_id = str(uuid4())
        filename_unjsonable = 'subs_{0}.srt.sjson'.format(self.unjsonable_subs_id)
        self.content_location_unjsonable = StaticContent.compute_location(self.course.id, filename_unjsonable)

        self.clear_subs_content()

def verify_content_links(module, base_dir, static_content_store, link, remap_dict=None):
    if link.startswith('/static/'):
        # yes, then parse out the name
        path = link[len('/static/'):]

        static_pathname = base_dir / path

        if os.path.exists(static_pathname):
            try:
                content_loc = StaticContent.compute_location(module.location.org, module.location.course, path)
                filename = os.path.basename(path)
                mime_type = mimetypes.guess_type(filename)[0]

                with open(static_pathname, 'rb') as f:
                    data = f.read()

                content = StaticContent(content_loc, filename, mime_type, data, import_path=path)

                # first let's save a thumbnail so we can get back a thumbnail location
                (thumbnail_content, thumbnail_location) = static_content_store.generate_thumbnail(content)

                if thumbnail_content is not None:
                    content.thumbnail_location = thumbnail_location

                #then commit the content
                static_content_store.save(content)

                new_link = StaticContent.get_url_path_from_location(content_loc)

                if remap_dict is not None:
                    remap_dict[link] = new_link

                return new_link
            except Exception, e:
                logging.exception('Skipping failed content load from {0}. Exception: {1}'.format(path, e))

    def test_happy_path(self, modulestore_type, create_after_overview):
        """
        What happens when everything works like we expect it to.

        If `create_after_overview` is True, we will temporarily disable
        thumbnail creation so that the initial CourseOverview is created without
        an image_set, and the CourseOverviewImageSet is created afterwards. If
        `create_after_overview` is False, we'll create the CourseOverviewImageSet
        at the same time as the CourseOverview.
        """
        # Create a real (oversized) image...
        image = Image.new("RGB", (800, 400), "blue")
        image_buff = StringIO()
        image.save(image_buff, format="JPEG")
        image_buff.seek(0)
        image_name = "big_course_image.jpeg"

        with self.store.default_store(modulestore_type):
            course = CourseFactory.create(
                default_store=modulestore_type, course_image=image_name
            )

            # Save a real image here...
            course_image_asset_key = StaticContent.compute_location(course.id, course.course_image)
            course_image_content = StaticContent(course_image_asset_key, image_name, 'image/jpeg', image_buff)
            contentstore().save(course_image_content)

            # If create_after_overview is True, disable thumbnail generation so
            # that the CourseOverview object is created and saved without an
            # image_set at first (it will be lazily created later).
            if create_after_overview:
                self.set_config(enabled=False)

            # Now generate the CourseOverview...
            course_overview = CourseOverview.get_from_id(course.id)

            # If create_after_overview is True, no image_set exists yet. Verify
            # that, then switch config back over to True and it should lazily
            # create the image_set on the next get_from_id() call.
            if create_after_overview:
                self.assertFalse(hasattr(course_overview, 'image_set'))
                self.set_config(enabled=True)
                course_overview = CourseOverview.get_from_id(course.id)

            self.assertTrue(hasattr(course_overview, 'image_set'))
            image_urls = course_overview.image_urls
            config = CourseOverviewImageConfig.current()

            # Make sure the thumbnail names come out as expected...
            self.assertTrue(image_urls['raw'].endswith('big_course_image.jpeg'))
            self.assertTrue(image_urls['small'].endswith('big_course_image-jpeg-{}x{}.jpg'.format(*config.small)))
            self.assertTrue(image_urls['large'].endswith('big_course_image-jpeg-{}x{}.jpg'.format(*config.large)))

            # Now make sure our thumbnails are of the sizes we expect...
            for image_url, expected_size in [(image_urls['small'], config.small), (image_urls['large'], config.large)]:
                image_key = StaticContent.get_location_from_path(image_url)
                image_content = AssetManager.find(image_key)
                image = Image.open(StringIO(image_content.data))
                self.assertEqual(image.size, expected_size)

    def test_different_resolutions(self, src_dimensions):
        """
        Test various resolutions of images to make thumbnails of.

        Note that our test sizes are small=(200, 100) and large=(400, 200).

        1. Images should won't be blown up if it's too small, so a (100, 50)
           resolution image will remain (100, 50).
        2. However, images *will* be converted using our format and quality
           settings (JPEG, 75% -- the PIL default). This is because images with
           relatively small dimensions not compressed properly.
        3. Image thumbnail naming will maintain the naming convention of the
           target resolution, even if the image was not actually scaled to that
           size (i.e. it was already smaller). This is mostly because it's
           simpler to be consistent, but it also lets us more easily tell which
           configuration a thumbnail was created under.
        """
        # Create a source image...
        image = Image.new("RGB", src_dimensions, "blue")
        image_buff = StringIO()
        image.save(image_buff, format="PNG")
        image_buff.seek(0)
        image_name = "src_course_image.png"

        course = CourseFactory.create(course_image=image_name)

        # Save the image to the contentstore...
        course_image_asset_key = StaticContent.compute_location(course.id, course.course_image)
        course_image_content = StaticContent(course_image_asset_key, image_name, 'image/png', image_buff)
        contentstore().save(course_image_content)

        # Now generate the CourseOverview...
        config = CourseOverviewImageConfig.current()
        course_overview = CourseOverview.get_from_id(course.id)
        image_urls = course_overview.image_urls

        for image_url, target in [(image_urls['small'], config.small), (image_urls['large'], config.large)]:
            image_key = StaticContent.get_location_from_path(image_url)
            image_content = AssetManager.find(image_key)
            image = Image.open(StringIO(image_content.data))

            # Naming convention for thumbnail
            self.assertTrue(image_url.endswith('src_course_image-png-{}x{}.jpg'.format(*target)))

            # Actual thumbnail data
            src_x, src_y = src_dimensions
            target_x, target_y = target
            image_x, image_y = image.size

            # I'm basically going to assume the image library knows how to do
            # the right thing in terms of handling aspect ratio. We're just
            # going to make sure that small images aren't blown up, and that
            # we never exceed our target sizes
            self.assertLessEqual(image_x, target_x)
            self.assertLessEqual(image_y, target_y)

            if src_x < target_x and src_y < target_y:
                self.assertEqual(src_x, image_x)
                self.assertEqual(src_y, image_y)

def course_image_url(course):
    """Returns the image url for the course."""
    try:
        loc = StaticContent.compute_location(course.location.course_key, course.course_image)
    except InvalidKeyError:
        return ''
    path = StaticContent.serialize_asset_key_with_slash(loc)
    return path

def course_image_url(course):
    """Try to look up the image url for the course.  If it's not found,
    log an error and return the dead link"""
    if course.static_asset_path or modulestore().get_modulestore_type(course.location.course_id) == XML_MODULESTORE_TYPE:
        return '/static/' + (course.static_asset_path or getattr(course, 'data_dir', '')) + "/images/course_image.jpg"
    else:
        loc = StaticContent.compute_location(course.location.org, course.location.course, course.course_image)
        _path = StaticContent.get_url_path_from_location(loc)
        return _path

def course_image_url(course):
    """
    Return url of course image.
    Args:
        course(CourseDescriptor) : The course id to retrieve course image url.
    Returns:
        Absolute url of course image.
    """
    loc = StaticContent.compute_location(course.id, course.course_image)
    url = StaticContent.serialize_asset_key_with_slash(loc)
    return url

def create_course_image_thumbnail(course, dimensions):
    """Create a course image thumbnail and return the URL.

    - dimensions is a tuple of (width, height)
    """
    course_image_asset_key = StaticContent.compute_location(course.id, course.course_image)
    course_image = AssetManager.find(course_image_asset_key)  # a StaticContent obj

    _content, thumb_loc = contentstore().generate_thumbnail(course_image, dimensions=dimensions)

    return StaticContent.serialize_asset_key_with_slash(thumb_loc)

def asset_index(request, org, course, name):
    """
    Display an editable asset library

    org, course, name: Attributes of the Location for the item to edit
    """
    location = get_location_and_verify_access(request, org, course, name)

    upload_asset_callback_url = reverse('upload_asset', kwargs={
        'org': org,
        'course': course,
        'coursename': name
    })

    course_module = modulestore().get_item(location)

    course_reference = StaticContent.compute_location(org, course, name)
    assets = contentstore().get_all_content_for_course(course_reference)

    # sort in reverse upload date order
    assets = sorted(assets, key=lambda asset: asset['uploadDate'], reverse=True)

    if request.META.get('HTTP_ACCEPT', "").startswith("application/json"):
        return JsonResponse(assets_to_json_dict(assets))

    asset_display = []
    for asset in assets:
        asset_id = asset['_id']
        display_info = {}
        display_info['displayname'] = asset['displayname']
        display_info['uploadDate'] = get_default_time_display(asset['uploadDate'])

        asset_location = StaticContent.compute_location(asset_id['org'], asset_id['course'], asset_id['name'])
        display_info['url'] = StaticContent.get_url_path_from_location(asset_location)
        display_info['portable_url'] = StaticContent.get_static_path_from_location(asset_location)

        # note, due to the schema change we may not have a 'thumbnail_location' in the result set
        _thumbnail_location = asset.get('thumbnail_location', None)
        thumbnail_location = Location(_thumbnail_location) if _thumbnail_location is not None else None
        display_info['thumb_url'] = StaticContent.get_url_path_from_location(thumbnail_location) if thumbnail_location is not None else None

        asset_display.append(display_info)

    return render_to_response('asset_index.html', {
        'context_course': course_module,
        'assets': asset_display,
        'upload_asset_callback_url': upload_asset_callback_url,
        'remove_asset_callback_url': reverse('remove_asset', kwargs={
            'org': org,
            'course': course,
            'name': name
        })
    })

def get_versioned_asset_url(asset_path):
    """
    Creates a versioned asset URL.
    """
    try:
        locator = StaticContent.get_location_from_path(asset_path)
        content = AssetManager.find(locator, as_stream=True)
        return StaticContent.add_version_to_asset_path(asset_path, content.content_digest)
    except (InvalidKeyError, ItemNotFoundError):
        pass

    return asset_path

def _clear_assets(location):
    store = contentstore()

    content_location = StaticContent.compute_location(
        location.org, location.course, location.name
    )

    assets, __ = store.get_all_content_for_course(content_location)
    for asset in assets:
        asset_location = Location(asset["_id"])
        id = StaticContent.get_id_from_location(asset_location)
        store.delete(id)

def import_static_content(
    modules,
    course_loc,
    course_data_path,
    static_content_store,
    target_location_namespace,
    subpath="static",
    verbose=False,
):

    remap_dict = {}

    # now import all static assets
    static_dir = course_data_path / subpath

    verbose = True

    for dirname, dirnames, filenames in os.walk(static_dir):
        for filename in filenames:

            try:
                content_path = os.path.join(dirname, filename)
                if verbose:
                    log.debug("importing static content {0}...".format(content_path))

                fullname_with_subpath = content_path.replace(static_dir, "")  # strip away leading path from the name
                if fullname_with_subpath.startswith("/"):
                    fullname_with_subpath = fullname_with_subpath[1:]
                content_loc = StaticContent.compute_location(
                    target_location_namespace.org, target_location_namespace.course, fullname_with_subpath
                )
                mime_type = mimetypes.guess_type(filename)[0]

                with open(content_path, "rb") as f:
                    data = f.read()

                content = StaticContent(content_loc, filename, mime_type, data, import_path=fullname_with_subpath)

                # first let's save a thumbnail so we can get back a thumbnail location
                (thumbnail_content, thumbnail_location) = static_content_store.generate_thumbnail(content)

                if thumbnail_content is not None:
                    content.thumbnail_location = thumbnail_location

                # then commit the content
                static_content_store.save(content)

                # store the remapping information which will be needed to subsitute in the module data
                remap_dict[fullname_with_subpath] = content_loc.name
            except:
                raise

    return remap_dict

def asset_index(request, org, course, name, start=None, maxresults=None):
    """
    Display an editable asset library

    org, course, name: Attributes of the Location for the item to edit

    :param start: which index of the result list to start w/, used for paging results
    :param maxresults: maximum results
    """
    location = get_location_and_verify_access(request, org, course, name)

    upload_asset_callback_url = reverse('upload_asset', kwargs={
        'org': org,
        'course': course,
        'coursename': name
    })

    course_module = modulestore().get_item(location)

    course_reference = StaticContent.compute_location(org, course, name)
    if maxresults is not None:
        maxresults = int(maxresults)
        start = int(start) if start else 0
        assets = contentstore().get_all_content_for_course(
            course_reference, start=start, maxresults=maxresults,
            sort=[('uploadDate', DESCENDING)]
        )
    else:
        assets = contentstore().get_all_content_for_course(
            course_reference, sort=[('uploadDate', DESCENDING)]
        )

    asset_json = []
    for asset in assets:
        asset_id = asset['_id']
        asset_location = StaticContent.compute_location(asset_id['org'], asset_id['course'], asset_id['name'])
        # note, due to the schema change we may not have a 'thumbnail_location' in the result set
        _thumbnail_location = asset.get('thumbnail_location', None)
        thumbnail_location = Location(_thumbnail_location) if _thumbnail_location is not None else None

        asset_locked = asset.get('locked', False)
        asset_json.append(_get_asset_json(asset['displayname'], asset['uploadDate'], asset_location, thumbnail_location, asset_locked))

    return render_to_response('asset_index.html', {
        'context_course': course_module,
        'asset_list': json.dumps(asset_json),
        'upload_asset_callback_url': upload_asset_callback_url,
        'update_asset_callback_url': reverse('update_asset', kwargs={
            'org': org,
            'course': course,
            'name': name
        })
    })

def import_static_content(modules, course_loc, course_data_path, static_content_store, target_location_namespace,
                          subpath='static', verbose=False):

    remap_dict = {}

    # now import all static assets
    static_dir = course_data_path / subpath

    verbose = True

    for dirname, _, filenames in os.walk(static_dir):
        for filename in filenames:

            content_path = os.path.join(dirname, filename)
            if verbose:
                log.debug('importing static content %s...', content_path)

            try:
                with open(content_path, 'rb') as f:
                    data = f.read()
            except IOError:
                if filename.startswith('._'):
                    # OS X "companion files". See http://www.diigo.com/annotated/0c936fda5da4aa1159c189cea227e174
                    continue
                # Not a 'hidden file', then re-raise exception
                raise

            fullname_with_subpath = content_path.replace(static_dir, '')  # strip away leading path from the name
            if fullname_with_subpath.startswith('/'):
                fullname_with_subpath = fullname_with_subpath[1:]
            content_loc = StaticContent.compute_location(target_location_namespace.org, target_location_namespace.course, fullname_with_subpath)
            mime_type = mimetypes.guess_type(filename)[0]


            content = StaticContent(content_loc, filename, mime_type, data, import_path=fullname_with_subpath)

            # first let's save a thumbnail so we can get back a thumbnail location
            (thumbnail_content, thumbnail_location) = static_content_store.generate_thumbnail(content)

            if thumbnail_content is not None:
                content.thumbnail_location = thumbnail_location

            #then commit the content
            try:
                static_content_store.save(content)
            except Exception as err:
                log.exception('Error importing {0}, error={1}'.format(fullname_with_subpath, err))

            #store the remapping information which will be needed to subsitute in the module data
            remap_dict[fullname_with_subpath] = content_loc.name

    return remap_dict

def course_image_url(course, image_name=None):
    """Return url for image_name or default course image in given course assets.
    It allows us to override default course image in templates when this function is
    used whith image_name parameter, if the image is available. (see course_about.html)
    """
    image = image_name or course.course_image
    try:
        loc = StaticContent.compute_location(course.location.course_key, image)
        _ = contentstore().find(loc)
    except NotFoundError:
        loc = StaticContent.compute_location(course.location.course_key, course.course_image)

    return loc.to_deprecated_string()

def _get_asset_json(display_name, date, location, thumbnail_location, locked):
    """
    Helper method for formatting the asset information to send to client.
    """
    asset_url = StaticContent.get_url_path_from_location(location)
    return {
        'display_name': display_name,
        'date_added': get_default_time_display(date),
        'url': asset_url,
        'portable_url': StaticContent.get_static_path_from_location(location),
        'thumbnail': StaticContent.get_url_path_from_location(thumbnail_location) if thumbnail_location is not None else None,
        'locked': locked,
        # Needed for Backbone delete/update.
        'id': asset_url
    }

def delete_course(modulestore, contentstore, source_location, commit=False):
    # first check to see if the modulestore is Mongo backed
    if not isinstance(modulestore, MongoModuleStore):
        raise Exception("Expected a MongoModuleStore in the runtime. Aborting....")

    # check to see if the source course is actually there
    if not modulestore.has_item(source_location):
        raise Exception("Cannot find a course at {0}. Aborting".format(source_location))

    # first delete all of the thumbnails
    thumbs = contentstore.get_all_content_thumbnails_for_course(source_location)
    for thumb in thumbs:
        thumb_loc = Location(thumb["_id"])
        id = StaticContent.get_id_from_location(thumb_loc)
        print "Deleting {0}...".format(id)
        if commit:
            contentstore.delete(id)

    # then delete all of the assets
    assets = contentstore.get_all_content_for_course(source_location)
    for asset in assets:
        asset_loc = Location(asset["_id"])
        id = StaticContent.get_id_from_location(asset_loc)
        print "Deleting {0}...".format(id)
        if commit:
            contentstore.delete(id)

    # then delete all course modules
    modules = modulestore.get_items([source_location.tag, source_location.org, source_location.course, None, None, None])

    course_module = None
    for module in modules:
        if module.category != 'course':   # save deleting the course module for last
            print "Deleting {0}...".format(module.location)
            if commit:
                modulestore.delete_item(module.location)
        else:
            course_module = module

    if course_module:
        modulestore.delete_item(course_module.location)

    # finally delete the top-level course module itself
    print "Deleting {0}...".format(source_location)
    if commit:
        modulestore.delete_item(source_location)

    return True

    def get_html(self):
        if isinstance(modulestore(), MongoModuleStore):
            caption_asset_path = StaticContent.get_base_url_path_for_course_assets(self.location) + '/subs_'
        else:
            # VS[compat]
            # cdodge: filesystem static content support.
            caption_asset_path = "/static/subs/"

        get_ext = lambda filename: filename.rpartition('.')[-1]
        sources = {get_ext(src): src for src in self.html5_sources}
        sources['main'] = self.source

        return self.system.render_template('videoalpha.html', {
            'youtube_streams': _create_youtube_string(self),
            'id': self.location.html_id(),
            'sub': self.sub,
            'sources': sources,
            'track': self.track,
            'display_name': self.display_name_with_default,
            # This won't work when we move to data that
            # isn't on the filesystem
            'data_dir': getattr(self, 'data_dir', None),
            'caption_asset_path': caption_asset_path,
            'show_captions': json.dumps(self.show_captions),
            'start': self.start_time,
            'end': self.end_time,
            'autoplay': settings.MITX_FEATURES.get('AUTOPLAY_VIDEOS', True)
        })