Files
edx-platform/common/lib/xmodule/xmodule/video_module.py
2014-01-09 14:19:56 -05:00

426 lines
16 KiB
Python

# pylint: disable=W0223
"""Video is ungraded Xmodule for support video content.
It's new improved video module, which support additional feature:
- Can play non-YouTube video sources via in-browser HTML5 video player.
- YouTube defaults to HTML5 mode from the start.
- Speed changes in both YouTube and non-YouTube videos happen via
in-browser HTML5 video method (when in HTML5 mode).
- Navigational subtitles can be disabled altogether via an attribute
in XML.
"""
import json
import logging
from lxml import etree
from pkg_resources import resource_string
import datetime
import time
import copy
from django.http import Http404
from django.conf import settings
from xmodule.x_module import XModule
from xmodule.editing_module import TabsEditingDescriptor
from xmodule.raw_module import EmptyDataRawDescriptor
from xmodule.xml_module import is_pointer_tag, name_to_pathname, deserialize_field
from xmodule.modulestore import Location
from xblock.fields import Scope, String, Boolean, List, Integer, ScopeIds
from xmodule.fields import RelativeTime
from xmodule.modulestore.inheritance import InheritanceKeyValueStore
from xblock.runtime import DbModel
log = logging.getLogger(__name__)
class VideoFields(object):
"""Fields for `VideoModule` and `VideoDescriptor`."""
display_name = String(
display_name="Display Name", help="Display name for this module.",
default="Video",
scope=Scope.settings
)
position = Integer(
help="Current position in the video",
scope=Scope.user_state,
default=0
)
show_captions = Boolean(
help="This controls whether or not captions are shown by default.",
display_name="Show Transcript",
scope=Scope.settings,
default=True
)
# TODO: This should be moved to Scope.content, but this will
# require data migration to support the old video module.
youtube_id_1_0 = String(
help="This is the Youtube ID reference for the normal speed video.",
display_name="Youtube ID",
scope=Scope.settings,
default="OEoXaMPEzfM"
)
youtube_id_0_75 = String(
help="Optional, for older browsers: the Youtube ID for the .75x speed video.",
display_name="Youtube ID for .75x speed",
scope=Scope.settings,
default=""
)
youtube_id_1_25 = String(
help="Optional, for older browsers: the Youtube ID for the 1.25x speed video.",
display_name="Youtube ID for 1.25x speed",
scope=Scope.settings,
default=""
)
youtube_id_1_5 = String(
help="Optional, for older browsers: the Youtube ID for the 1.5x speed video.",
display_name="Youtube ID for 1.5x speed",
scope=Scope.settings,
default=""
)
start_time = RelativeTime( # datetime.timedelta object
help="Start time for the video (HH:MM:SS). Max value is 23:59:59.",
display_name="Start Time",
scope=Scope.settings,
default=datetime.timedelta(seconds=0)
)
end_time = RelativeTime( # datetime.timedelta object
help="End time for the video (HH:MM:SS). Max value is 23:59:59.",
display_name="End Time",
scope=Scope.settings,
default=datetime.timedelta(seconds=0)
)
#front-end code of video player checks logical validity of (start_time, end_time) pair.
source = String(
help="The external URL to download the video. This appears as a link beneath the video.",
display_name="Download Video",
scope=Scope.settings,
default=""
)
html5_sources = List(
help="A list of filenames to be used with HTML5 video. The first supported filetype will be displayed.",
display_name="Video Sources",
scope=Scope.settings,
)
track = String(
help="The external URL to download the timed transcript track. This appears as a link beneath the video.",
display_name="Download Transcript",
scope=Scope.settings,
default=""
)
sub = String(
help="The name of the timed transcript track (for non-Youtube videos).",
display_name="HTML5 Transcript",
scope=Scope.settings,
default=""
)
class VideoModule(VideoFields, XModule):
"""
XML source example:
<video show_captions="true"
youtube="0.75:jNCf2gIqpeE,1.0:ZwkTiUPN0mg,1.25:rsq9auxASqI,1.50:kMyNdzVHHgg"
url_name="lecture_21_3" display_name="S19V3: Vacancies"
>
<source src=".../mit-3091x/M-3091X-FA12-L21-3_100.mp4"/>
<source src=".../mit-3091x/M-3091X-FA12-L21-3_100.webm"/>
<source src=".../mit-3091x/M-3091X-FA12-L21-3_100.ogv"/>
</video>
"""
video_time = 0
icon_class = 'video'
js = {
'js': [
resource_string(__name__, 'js/src/video/00_resizer.js'),
resource_string(__name__, 'js/src/video/01_initialize.js'),
resource_string(__name__, 'js/src/video/025_focus_grabber.js'),
resource_string(__name__, 'js/src/video/02_html5_video.js'),
resource_string(__name__, 'js/src/video/03_video_player.js'),
resource_string(__name__, 'js/src/video/04_video_control.js'),
resource_string(__name__, 'js/src/video/05_video_quality_control.js'),
resource_string(__name__, 'js/src/video/06_video_progress_slider.js'),
resource_string(__name__, 'js/src/video/07_video_volume_control.js'),
resource_string(__name__, 'js/src/video/08_video_speed_control.js'),
resource_string(__name__, 'js/src/video/09_video_caption.js'),
resource_string(__name__, 'js/src/video/10_main.js')
]
}
css = {'scss': [resource_string(__name__, 'css/video/display.scss')]}
js_module_name = "Video"
def handle_ajax(self, dispatch, data):
"""This is not being called right now and we raise 404 error."""
log.debug(u"GET {0}".format(data))
log.debug(u"DISPATCH {0}".format(dispatch))
raise Http404()
def get_html(self):
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('video.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.total_seconds(),
'end': self.end_time.total_seconds(),
'autoplay': settings.FEATURES.get('AUTOPLAY_VIDEOS', False),
# TODO: Later on the value 1500 should be taken from some global
# configuration setting field.
'yt_test_timeout': 1500,
'yt_test_url': settings.YOUTUBE_TEST_URL
})
class VideoDescriptor(VideoFields, TabsEditingDescriptor, EmptyDataRawDescriptor):
"""Descriptor for `VideoModule`."""
module_class = VideoModule
tabs = [
{
'name': "Basic",
'template': "video/transcripts.html",
'current': True
},
{
'name': "Advanced",
'template': "tabs/metadata-edit-tab.html"
}
]
def __init__(self, *args, **kwargs):
super(VideoDescriptor, self).__init__(*args, **kwargs)
# For backwards compatibility -- if we've got XML data, parse
# it out and set the metadata fields
if self.data:
field_data = self._parse_video_xml(self.data)
self._field_data.set_many(self, field_data)
del self.data
@classmethod
def from_xml(cls, xml_data, system, org=None, course=None):
"""
Creates an instance of this descriptor from the supplied xml_data.
This may be overridden by subclasses
xml_data: A string of xml that will be translated into data and children for
this module
system: A DescriptorSystem for interacting with external resources
org and course are optional strings that will be used in the generated modules
url identifiers
"""
xml_object = etree.fromstring(xml_data)
url_name = xml_object.get('url_name', xml_object.get('slug'))
location = Location(
'i4x', org, course, 'video', url_name
)
if is_pointer_tag(xml_object):
filepath = cls._format_filepath(xml_object.tag, name_to_pathname(url_name))
xml_data = etree.tostring(cls.load_file(filepath, system.resources_fs, location))
field_data = cls._parse_video_xml(xml_data)
field_data['location'] = location
kvs = InheritanceKeyValueStore(initial_values=field_data)
field_data = DbModel(kvs)
video = system.construct_xblock_from_class(
cls,
# We're loading a descriptor, so student_id is meaningless
# We also don't have separate notions of definition and usage ids yet,
# so we use the location for both
ScopeIds(None, location.category, location, location),
field_data,
)
return video
def definition_to_xml(self, resource_fs):
"""
Returns an xml string representing this module.
"""
xml = etree.Element('video')
youtube_string = _create_youtube_string(self)
# Mild workaround to ensure that tests pass -- if a field
# is set to its default value, we don't need to write it out.
if youtube_string and youtube_string != '1.00:OEoXaMPEzfM':
xml.set('youtube', unicode(youtube_string))
xml.set('url_name', self.url_name)
attrs = {
'display_name': self.display_name,
'show_captions': json.dumps(self.show_captions),
'start_time': self.start_time,
'end_time': self.end_time,
'sub': self.sub,
}
for key, value in attrs.items():
# Mild workaround to ensure that tests pass -- if a field
# is set to its default value, we don't write it out.
if value:
if key in self.fields and self.fields[key].is_set_on(self):
xml.set(key, unicode(value))
for source in self.html5_sources:
ele = etree.Element('source')
ele.set('src', source)
xml.append(ele)
if self.track:
ele = etree.Element('track')
ele.set('src', self.track)
xml.append(ele)
return xml
def get_context(self):
"""
Extend context by data for transcripts basic tab.
"""
_context = super(VideoDescriptor, self).get_context()
metadata_fields = copy.deepcopy(self.editable_metadata_fields)
display_name = metadata_fields['display_name']
video_url = metadata_fields['html5_sources']
youtube_id_1_0 = metadata_fields['youtube_id_1_0']
def get_youtube_link(video_id):
if video_id:
return 'http://youtu.be/{0}'.format(video_id)
else:
return ''
_ = self.runtime.service(self, "i18n").ugettext
video_url.update({
'help': _('A YouTube URL or a link to a file hosted anywhere on the web.'),
'display_name': 'Video URL',
'field_name': 'video_url',
'type': 'VideoList',
'default_value': [get_youtube_link(youtube_id_1_0['default_value'])]
})
youtube_id_1_0_value = get_youtube_link(youtube_id_1_0['value'])
if youtube_id_1_0_value:
video_url['value'].insert(0, youtube_id_1_0_value)
metadata = {
'display_name': display_name,
'video_url': video_url
}
_context.update({'transcripts_basic_tab_metadata': metadata})
return _context
@classmethod
def _parse_youtube(cls, data):
"""
Parses a string of Youtube IDs such as "1.0:AXdE34_U,1.5:VO3SxfeD"
into a dictionary. Necessary for backwards compatibility with
XML-based courses.
"""
ret = {'0.75': '', '1.00': '', '1.25': '', '1.50': ''}
videos = data.split(',')
for video in videos:
pieces = video.split(':')
try:
speed = '%.2f' % float(pieces[0]) # normalize speed
# Handle the fact that youtube IDs got double-quoted for a period of time.
# Note: we pass in "VideoFields.youtube_id_1_0" so we deserialize as a String--
# it doesn't matter what the actual speed is for the purposes of deserializing.
youtube_id = deserialize_field(cls.youtube_id_1_0, pieces[1])
ret[speed] = youtube_id
except (ValueError, IndexError):
log.warning('Invalid YouTube ID: %s' % video)
return ret
@classmethod
def _parse_video_xml(cls, xml_data):
"""
Parse video fields out of xml_data. The fields are set if they are
present in the XML.
"""
xml = etree.fromstring(xml_data)
field_data = {}
# Convert between key types for certain attributes --
# necessary for backwards compatibility.
conversions = {
# example: 'start_time': cls._example_convert_start_time
}
# Convert between key names for certain attributes --
# necessary for backwards compatibility.
compat_keys = {
'from': 'start_time',
'to': 'end_time'
}
sources = xml.findall('source')
if sources:
field_data['html5_sources'] = [ele.get('src') for ele in sources]
field_data['source'] = field_data['html5_sources'][0]
track = xml.find('track')
if track is not None:
field_data['track'] = track.get('src')
for attr, value in xml.items():
if attr in compat_keys:
attr = compat_keys[attr]
if attr in cls.metadata_to_strip + ('url_name', 'name'):
continue
if attr == 'youtube':
speeds = cls._parse_youtube(value)
for speed, youtube_id in speeds.items():
# should have made these youtube_id_1_00 for
# cleanliness, but hindsight doesn't need glasses
normalized_speed = speed[:-1] if speed.endswith('0') else speed
# If the user has specified html5 sources, make sure we don't use the default video
if youtube_id != '' or 'html5_sources' in field_data:
field_data['youtube_id_{0}'.format(normalized_speed.replace('.', '_'))] = youtube_id
else:
# Convert XML attrs into Python values.
if attr in conversions:
value = conversions[attr](value)
else:
# We export values with json.dumps (well, except for Strings, but
# for about a month we did it for Strings also).
value = deserialize_field(cls.fields[attr], value)
field_data[attr] = value
return field_data
def _create_youtube_string(module):
"""
Create a string of Youtube IDs from `module`'s metadata
attributes. Only writes a speed if an ID is present in the
module. Necessary for backwards compatibility with XML-based
courses.
"""
youtube_ids = [
module.youtube_id_0_75,
module.youtube_id_1_0,
module.youtube_id_1_25,
module.youtube_id_1_5
]
youtube_speeds = ['0.75', '1.00', '1.25', '1.50']
return ','.join([':'.join(pair)
for pair
in zip(youtube_speeds, youtube_ids)
if pair[1]])