87 lines
3.2 KiB
Python
87 lines
3.2 KiB
Python
from xmodule.x_module import XModuleDescriptor
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from lxml import etree
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class XmlDescriptor(XModuleDescriptor):
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"""
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Mixin class for standardized parsing of from xml
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"""
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@classmethod
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def definition_from_xml(cls, xml_object, system):
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"""
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Return the definition to be passed to the newly created descriptor
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during from_xml
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"""
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raise NotImplementedError("%s does not implement definition_from_xml" % cls.__name__)
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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: An XModuleSystem 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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metadata = {}
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for attr in ('format', 'graceperiod', 'showanswer', 'rerandomize', 'due'):
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from_xml = xml_object.get(attr)
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if from_xml is not None:
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metadata[attr] = from_xml
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if xml_object.get('graded') is not None:
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metadata['graded'] = xml_object.get('graded') == 'true'
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if xml_object.get('name') is not None:
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metadata['display_name'] = xml_object.get('name')
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return cls(
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system,
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cls.definition_from_xml(xml_object, system),
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location=['i4x',
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org,
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course,
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xml_object.tag,
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xml_object.get('slug')],
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metadata=metadata,
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)
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def export_to_xml(self, resource_fs):
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"""
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Returns an xml string representing this module, and all modules underneath it.
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May also write required resources out to resource_fs
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Assumes that modules have single parantage (that no module appears twice in the same course),
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and that it is thus safe to nest modules as xml children as appropriate.
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The returned XML should be able to be parsed back into an identical XModuleDescriptor
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using the from_xml method with the same system, org, and course
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"""
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xml_object = self.definition_to_xml(resource_fs)
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xml_object.set('slug', self.name)
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xml_object.tag = self.type
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for attr in ('format', 'graceperiod', 'showanswer', 'rerandomize', 'due'):
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if attr in self.metadata:
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xml_object.set(attr, self.metadata[attr])
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if 'graded' in self.metadata:
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xml_object.set('graded', str(self.metadata['graded']).lower())
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if 'display_name' in self.metadata:
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xml_object.set('name', self.metadata['display_name'])
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return etree.tostring(xml_object, pretty_print=True)
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def definition_to_xml(self, resource_fs):
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"""
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Return a new etree Element object created from this modules definition.
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"""
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raise NotImplementedError("%s does not implement definition_to_xml" % self.__class__.__name__)
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