210 lines
7.1 KiB
Python
210 lines
7.1 KiB
Python
from collections import MutableMapping
|
|
from xmodule.x_module import XModuleDescriptor
|
|
from lxml import etree
|
|
import copy
|
|
import logging
|
|
|
|
log = logging.getLogger(__name__)
|
|
|
|
class LazyLoadingDict(MutableMapping):
|
|
"""
|
|
A dictionary object that lazily loads it's contents from a provided
|
|
function on reads (of members that haven't already been set)
|
|
"""
|
|
|
|
def __init__(self, loader):
|
|
self._contents = {}
|
|
self._loaded = False
|
|
self._loader = loader
|
|
self._deleted = set()
|
|
|
|
def __getitem__(self, name):
|
|
if not (self._loaded or name in self._contents or name in self._deleted):
|
|
self.load()
|
|
|
|
return self._contents[name]
|
|
|
|
def __setitem__(self, name, value):
|
|
self._contents[name] = value
|
|
self._deleted.discard(name)
|
|
|
|
def __delitem__(self, name):
|
|
del self._contents[name]
|
|
self._deleted.add(name)
|
|
|
|
def __contains__(self, name):
|
|
self.load()
|
|
return name in self._contents
|
|
|
|
def __len__(self):
|
|
self.load()
|
|
return len(self._contents)
|
|
|
|
def __iter__(self):
|
|
self.load()
|
|
return iter(self._contents)
|
|
|
|
def __repr__(self):
|
|
self.load()
|
|
return repr(self._contents)
|
|
|
|
def load(self):
|
|
if self._loaded:
|
|
return
|
|
|
|
loaded_contents = self._loader()
|
|
loaded_contents.update(self._contents)
|
|
self._contents = loaded_contents
|
|
self._loaded = True
|
|
|
|
|
|
class XmlDescriptor(XModuleDescriptor):
|
|
"""
|
|
Mixin class for standardized parsing of from xml
|
|
"""
|
|
|
|
# Extension to append to filename paths
|
|
filename_extension = 'xml'
|
|
|
|
# The attributes will be removed from the definition xml passed
|
|
# to definition_from_xml, and from the xml returned by definition_to_xml
|
|
metadata_attributes = ('format', 'graceperiod', 'showanswer', 'rerandomize',
|
|
'due', 'graded', 'name', 'slug')
|
|
|
|
@classmethod
|
|
def definition_from_xml(cls, xml_object, system):
|
|
"""
|
|
Return the definition to be passed to the newly created descriptor
|
|
during from_xml
|
|
|
|
xml_object: An etree Element
|
|
"""
|
|
raise NotImplementedError("%s does not implement definition_from_xml" % cls.__name__)
|
|
|
|
@classmethod
|
|
def clean_metadata_from_xml(cls, xml_object):
|
|
"""
|
|
Remove any attribute named in self.metadata_attributes from the supplied xml_object
|
|
"""
|
|
for attr in cls.metadata_attributes:
|
|
if xml_object.get(attr) is not None:
|
|
del xml_object.attrib[attr]
|
|
|
|
@classmethod
|
|
def file_to_xml(cls, file_object):
|
|
"""
|
|
Used when this module wants to parse a file object to xml
|
|
that will be converted to the definition.
|
|
|
|
Returns an lxml Element
|
|
"""
|
|
return etree.parse(file_object).getroot()
|
|
|
|
@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: An XModuleSystem 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)
|
|
|
|
def metadata_loader():
|
|
metadata = {}
|
|
for attr in ('format', 'graceperiod', 'showanswer', 'rerandomize', 'due'):
|
|
from_xml = xml_object.get(attr)
|
|
if from_xml is not None:
|
|
metadata[attr] = from_xml
|
|
|
|
if xml_object.get('graded') is not None:
|
|
metadata['graded'] = xml_object.get('graded') == 'true'
|
|
|
|
if xml_object.get('name') is not None:
|
|
metadata['display_name'] = xml_object.get('name')
|
|
|
|
return metadata
|
|
|
|
def definition_loader():
|
|
filename = xml_object.get('filename')
|
|
if filename is None:
|
|
definition_xml = copy.deepcopy(xml_object)
|
|
else:
|
|
filepath = cls._format_filepath(xml_object.tag, filename)
|
|
with system.resources_fs.open(filepath) as file:
|
|
try:
|
|
definition_xml = cls.file_to_xml(file)
|
|
except:
|
|
log.exception("Failed to parse xml in file %s" % filepath)
|
|
raise
|
|
|
|
cls.clean_metadata_from_xml(definition_xml)
|
|
return cls.definition_from_xml(definition_xml, system)
|
|
|
|
return cls(
|
|
system,
|
|
LazyLoadingDict(definition_loader),
|
|
location=['i4x',
|
|
org,
|
|
course,
|
|
xml_object.tag,
|
|
xml_object.get('slug')],
|
|
metadata=LazyLoadingDict(metadata_loader),
|
|
)
|
|
|
|
@classmethod
|
|
def _format_filepath(cls, type, name):
|
|
return '{type}/{name}.{ext}'.format(type=type, name=name, ext=cls.filename_extension)
|
|
|
|
def export_to_xml(self, resource_fs):
|
|
"""
|
|
Returns an xml string representing this module, and all modules underneath it.
|
|
May also write required resources out to resource_fs
|
|
|
|
Assumes that modules have single parantage (that no module appears twice in the same course),
|
|
and that it is thus safe to nest modules as xml children as appropriate.
|
|
|
|
The returned XML should be able to be parsed back into an identical XModuleDescriptor
|
|
using the from_xml method with the same system, org, and course
|
|
"""
|
|
xml_object = self.definition_to_xml(resource_fs)
|
|
self.__class__.clean_metadata_from_xml(xml_object)
|
|
|
|
# Put content in a separate file if it's large (has more than 5 descendent tags)
|
|
if len(list(xml_object.iter())) > 5:
|
|
|
|
filepath = self.__class__._format_filepath(self.category, self.name)
|
|
resource_fs.makedir(self.category, allow_recreate=True)
|
|
with resource_fs.open(filepath, 'w') as file:
|
|
file.write(etree.tostring(xml_object, pretty_print=True))
|
|
|
|
for child in xml_object:
|
|
xml_object.remove(child)
|
|
|
|
xml_object.set('filename', self.name)
|
|
|
|
xml_object.set('slug', self.name)
|
|
xml_object.tag = self.category
|
|
|
|
for attr in ('format', 'graceperiod', 'showanswer', 'rerandomize', 'due'):
|
|
if attr in self.metadata and attr not in self._inherited_metadata:
|
|
xml_object.set(attr, self.metadata[attr])
|
|
|
|
if 'graded' in self.metadata and 'graded' not in self._inherited_metadata:
|
|
xml_object.set('graded', str(self.metadata['graded']).lower())
|
|
|
|
if 'display_name' in self.metadata:
|
|
xml_object.set('name', self.metadata['display_name'])
|
|
|
|
return etree.tostring(xml_object, pretty_print=True)
|
|
|
|
def definition_to_xml(self, resource_fs):
|
|
"""
|
|
Return a new etree Element object created from this modules definition.
|
|
"""
|
|
raise NotImplementedError("%s does not implement definition_to_xml" % self.__class__.__name__)
|