6b474724ac
By transparently proxying between the XModuleDescriptor and the XModule, and between their runtimes, we can make them act as a single class, so that we can swap in an actual XBlock instead.
407 lines
15 KiB
Python
407 lines
15 KiB
Python
# pylint: disable=W0223
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"""Video is ungraded Xmodule for support video content.
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It's new improved video module, which support additional feature:
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- Can play non-YouTube video sources via in-browser HTML5 video player.
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- YouTube defaults to HTML5 mode from the start.
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- Speed changes in both YouTube and non-YouTube videos happen via
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in-browser HTML5 video method (when in HTML5 mode).
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- Navigational subtitles can be disabled altogether via an attribute
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in XML.
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"""
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import json
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import logging
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from lxml import etree
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from pkg_resources import resource_string
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import datetime
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import time
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from django.http import Http404
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from django.conf import settings
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from xmodule.x_module import XModule
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from xmodule.editing_module import TabsEditingDescriptor
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from xmodule.raw_module import EmptyDataRawDescriptor
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from xmodule.xml_module import is_pointer_tag, name_to_pathname, deserialize_field
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from xmodule.modulestore import Location
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from xblock.fields import Scope, String, Boolean, Float, List, Integer, ScopeIds
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from xblock.field_data import DictFieldData
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from xmodule.modulestore.inheritance import InheritanceKeyValueStore
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from xblock.runtime import DbModel
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log = logging.getLogger(__name__)
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class VideoFields(object):
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"""Fields for `VideoModule` and `VideoDescriptor`."""
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display_name = String(
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display_name="Display Name", help="Display name for this module.",
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default="Video",
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scope=Scope.settings
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)
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position = Integer(
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help="Current position in the video",
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scope=Scope.user_state,
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default=0
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)
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show_captions = Boolean(
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help="This controls whether or not captions are shown by default.",
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display_name="Show Captions",
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scope=Scope.settings,
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default=True
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)
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# TODO: This should be moved to Scope.content, but this will
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# require data migration to support the old video module.
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youtube_id_1_0 = String(
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help="This is the Youtube ID reference for the normal speed video.",
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display_name="Youtube ID",
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scope=Scope.settings,
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default="OEoXaMPEzfM"
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)
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youtube_id_0_75 = String(
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help="The Youtube ID for the .75x speed video.",
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display_name="Youtube ID for .75x speed",
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scope=Scope.settings,
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default=""
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)
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youtube_id_1_25 = String(
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help="The Youtube ID for the 1.25x speed video.",
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display_name="Youtube ID for 1.25x speed",
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scope=Scope.settings,
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default=""
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)
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youtube_id_1_5 = String(
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help="The Youtube ID for the 1.5x speed video.",
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display_name="Youtube ID for 1.5x speed",
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scope=Scope.settings,
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default=""
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)
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start_time = Float(
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help="Start time for the video.",
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display_name="Start Time",
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scope=Scope.settings,
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default=0.0
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)
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end_time = Float(
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help="End time for the video.",
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display_name="End Time",
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scope=Scope.settings,
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default=0.0
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)
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source = String(
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help="The external URL to download the video. This appears as a link beneath the video.",
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display_name="Download Video",
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scope=Scope.settings,
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default=""
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)
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html5_sources = List(
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help="A list of filenames to be used with HTML5 video. The first supported filetype will be displayed.",
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display_name="Video Sources",
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scope=Scope.settings,
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)
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track = String(
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help="The external URL to download the timed transcript track. This appears as a link beneath the video.",
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display_name="Download Track",
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scope=Scope.settings,
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default=""
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)
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sub = String(
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help="The name of the timed transcript track (for non-Youtube videos).",
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display_name="HTML5 Timed Transcript",
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scope=Scope.settings,
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default=""
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)
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class VideoModule(VideoFields, XModule):
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"""
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XML source example:
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<video show_captions="true"
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youtube="0.75:jNCf2gIqpeE,1.0:ZwkTiUPN0mg,1.25:rsq9auxASqI,1.50:kMyNdzVHHgg"
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url_name="lecture_21_3" display_name="S19V3: Vacancies"
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>
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<source src=".../mit-3091x/M-3091X-FA12-L21-3_100.mp4"/>
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<source src=".../mit-3091x/M-3091X-FA12-L21-3_100.webm"/>
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<source src=".../mit-3091x/M-3091X-FA12-L21-3_100.ogv"/>
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</video>
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"""
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video_time = 0
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icon_class = 'video'
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js = {
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'js': [
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resource_string(__name__, 'js/src/video/01_initialize.js'),
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resource_string(__name__, 'js/src/video/025_focus_grabber.js'),
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resource_string(__name__, 'js/src/video/02_html5_video.js'),
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resource_string(__name__, 'js/src/video/03_video_player.js'),
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resource_string(__name__, 'js/src/video/04_video_control.js'),
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resource_string(__name__, 'js/src/video/05_video_quality_control.js'),
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resource_string(__name__, 'js/src/video/06_video_progress_slider.js'),
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resource_string(__name__, 'js/src/video/07_video_volume_control.js'),
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resource_string(__name__, 'js/src/video/08_video_speed_control.js'),
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resource_string(__name__, 'js/src/video/09_video_caption.js'),
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resource_string(__name__, 'js/src/video/10_main.js')
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]
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}
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css = {'scss': [resource_string(__name__, 'css/video/display.scss')]}
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js_module_name = "Video"
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def handle_ajax(self, dispatch, data):
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"""This is not being called right now and we raise 404 error."""
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log.debug(u"GET {0}".format(data))
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log.debug(u"DISPATCH {0}".format(dispatch))
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raise Http404()
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def get_html(self):
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caption_asset_path = "/static/subs/"
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get_ext = lambda filename: filename.rpartition('.')[-1]
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sources = {get_ext(src): src for src in self.html5_sources}
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sources['main'] = self.source
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# for testing Youtube timeout in acceptance tests
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if getattr(settings, 'VIDEO_PORT', None):
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yt_test_url = "http://127.0.0.1:" + str(settings.VIDEO_PORT) + '/test_youtube/'
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else:
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yt_test_url = 'https://gdata.youtube.com/feeds/api/videos/'
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return self.system.render_template('video.html', {
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'youtube_streams': _create_youtube_string(self),
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'id': self.location.html_id(),
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'sub': self.sub,
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'sources': sources,
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'track': self.track,
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'display_name': self.display_name_with_default,
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# This won't work when we move to data that
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# isn't on the filesystem
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'data_dir': getattr(self, 'data_dir', None),
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'caption_asset_path': caption_asset_path,
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'show_captions': json.dumps(self.show_captions),
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'start': self.start_time,
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'end': self.end_time,
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'autoplay': settings.MITX_FEATURES.get('AUTOPLAY_VIDEOS', False),
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# TODO: Later on the value 1500 should be taken from some global
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# configuration setting field.
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'yt_test_timeout': 1500,
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'yt_test_url': yt_test_url
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})
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class VideoDescriptor(VideoFields, TabsEditingDescriptor, EmptyDataRawDescriptor):
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"""Descriptor for `VideoModule`."""
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module_class = VideoModule
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tabs = [
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# {
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# 'name': "Subtitles",
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# 'template': "video/subtitles.html",
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# },
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{
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'name': "Settings",
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'template': "tabs/metadata-edit-tab.html",
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'current': True
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}
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]
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def __init__(self, *args, **kwargs):
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super(VideoDescriptor, self).__init__(*args, **kwargs)
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# For backwards compatibility -- if we've got XML data, parse
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# it out and set the metadata fields
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if self.data:
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field_data = self._parse_video_xml(self.data)
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self._field_data.set_many(self, field_data)
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del self.data
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@classmethod
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def from_xml(cls, xml_data, system, org=None, course=None):
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"""
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Creates an instance of this descriptor from the supplied xml_data.
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This may be overridden by subclasses
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xml_data: A string of xml that will be translated into data and children for
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this module
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system: A DescriptorSystem for interacting with external resources
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org and course are optional strings that will be used in the generated modules
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url identifiers
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"""
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xml_object = etree.fromstring(xml_data)
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url_name = xml_object.get('url_name', xml_object.get('slug'))
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location = Location(
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'i4x', org, course, 'video', url_name
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)
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if is_pointer_tag(xml_object):
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filepath = cls._format_filepath(xml_object.tag, name_to_pathname(url_name))
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xml_data = etree.tostring(cls.load_file(filepath, system.resources_fs, location))
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field_data = cls._parse_video_xml(xml_data)
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field_data['location'] = location
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kvs = InheritanceKeyValueStore(initial_values=field_data)
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field_data = DbModel(kvs)
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video = system.construct_xblock_from_class(
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cls,
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# We're loading a descriptor, so student_id is meaningless
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# We also don't have separate notions of definition and usage ids yet,
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# so we use the location for both
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ScopeIds(None, location.category, location, location),
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field_data,
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)
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return video
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def definition_to_xml(self, resource_fs):
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"""
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Returns an xml string representing this module.
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"""
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xml = etree.Element('video')
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youtube_string = _create_youtube_string(self)
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# Mild workaround to ensure that tests pass -- if a field
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# is set to its default value, we don't need to write it out.
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if youtube_string and youtube_string != '1.00:OEoXaMPEzfM':
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xml.set('youtube', unicode(youtube_string))
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xml.set('url_name', self.url_name)
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attrs = {
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'display_name': self.display_name,
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'show_captions': json.dumps(self.show_captions),
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'start_time': datetime.timedelta(seconds=self.start_time),
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'end_time': datetime.timedelta(seconds=self.end_time),
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'sub': self.sub,
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}
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for key, value in attrs.items():
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# Mild workaround to ensure that tests pass -- if a field
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# is set to its default value, we don't write it out.
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if value:
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if key in self.fields and self.fields[key].is_set_on(self):
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xml.set(key, unicode(value))
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for source in self.html5_sources:
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ele = etree.Element('source')
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ele.set('src', source)
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xml.append(ele)
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if self.track:
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ele = etree.Element('track')
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ele.set('src', self.track)
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xml.append(ele)
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return xml
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@classmethod
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def _parse_youtube(cls, data):
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"""
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Parses a string of Youtube IDs such as "1.0:AXdE34_U,1.5:VO3SxfeD"
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into a dictionary. Necessary for backwards compatibility with
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XML-based courses.
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"""
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ret = {'0.75': '', '1.00': '', '1.25': '', '1.50': ''}
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videos = data.split(',')
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for video in videos:
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pieces = video.split(':')
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try:
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speed = '%.2f' % float(pieces[0]) # normalize speed
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# Handle the fact that youtube IDs got double-quoted for a period of time.
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# Note: we pass in "VideoFields.youtube_id_1_0" so we deserialize as a String--
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# it doesn't matter what the actual speed is for the purposes of deserializing.
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youtube_id = deserialize_field(cls.youtube_id_1_0, pieces[1])
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ret[speed] = youtube_id
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except (ValueError, IndexError):
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log.warning('Invalid YouTube ID: %s' % video)
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return ret
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@classmethod
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def _parse_video_xml(cls, xml_data):
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"""
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Parse video fields out of xml_data. The fields are set if they are
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present in the XML.
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"""
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xml = etree.fromstring(xml_data)
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field_data = {}
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conversions = {
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'start_time': cls._parse_time,
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'end_time': cls._parse_time
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}
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# Convert between key names for certain attributes --
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# necessary for backwards compatibility.
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compat_keys = {
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'from': 'start_time',
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'to': 'end_time'
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}
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sources = xml.findall('source')
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if sources:
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field_data['html5_sources'] = [ele.get('src') for ele in sources]
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field_data['source'] = field_data['html5_sources'][0]
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track = xml.find('track')
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if track is not None:
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field_data['track'] = track.get('src')
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for attr, value in xml.items():
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if attr in compat_keys:
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attr = compat_keys[attr]
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if attr in cls.metadata_to_strip + ('url_name', 'name'):
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continue
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if attr == 'youtube':
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speeds = cls._parse_youtube(value)
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for speed, youtube_id in speeds.items():
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# should have made these youtube_id_1_00 for
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# cleanliness, but hindsight doesn't need glasses
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normalized_speed = speed[:-1] if speed.endswith('0') else speed
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# If the user has specified html5 sources, make sure we don't use the default video
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if youtube_id != '' or 'html5_sources' in field_data:
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field_data['youtube_id_{0}'.format(normalized_speed.replace('.', '_'))] = youtube_id
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else:
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# Convert XML attrs into Python values.
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if attr in conversions:
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value = conversions[attr](value)
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else:
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# We export values with json.dumps (well, except for Strings, but
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# for about a month we did it for Strings also).
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value = deserialize_field(cls.fields[attr], value)
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field_data[attr] = value
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return field_data
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@classmethod
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def _parse_time(cls, str_time):
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"""Converts s in '12:34:45' format to seconds. If s is
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None, returns empty string"""
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if not str_time:
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return ''
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else:
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try:
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obj_time = time.strptime(str_time, '%H:%M:%S')
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return datetime.timedelta(
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hours=obj_time.tm_hour,
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minutes=obj_time.tm_min,
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seconds=obj_time.tm_sec
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).total_seconds()
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except ValueError:
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# We've seen serialized versions of float in this field
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return float(str_time)
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def _create_youtube_string(module):
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"""
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Create a string of Youtube IDs from `module`'s metadata
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attributes. Only writes a speed if an ID is present in the
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module. Necessary for backwards compatibility with XML-based
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courses.
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"""
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youtube_ids = [
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module.youtube_id_0_75,
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module.youtube_id_1_0,
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module.youtube_id_1_25,
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module.youtube_id_1_5
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]
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youtube_speeds = ['0.75', '1.00', '1.25', '1.50']
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return ','.join([':'.join(pair)
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for pair
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in zip(youtube_speeds, youtube_ids)
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if pair[1]])
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