Files
edx-platform/common/lib/xmodule/xmodule/modulestore/xml.py
2012-07-02 19:55:42 -04:00

138 lines
5.4 KiB
Python

import logging
from fs.osfs import OSFS
from importlib import import_module
from lxml import etree
from path import path
from xmodule.x_module import XModuleDescriptor, XMLParsingSystem
from xmodule.mako_module import MakoDescriptorSystem
from . import ModuleStore, Location
from .exceptions import ItemNotFoundError
etree.set_default_parser(etree.XMLParser(dtd_validation=False, load_dtd=False,
remove_comments=True, remove_blank_text=True))
log = logging.getLogger(__name__)
class XMLModuleStore(ModuleStore):
"""
An XML backed ModuleStore
"""
def __init__(self, org, course, data_dir, default_class=None, eager=False):
"""
Initialize an XMLModuleStore from data_dir
org, course: Strings to be used in module keys
data_dir: path to data directory containing course.xml
default_class: dot-separated string defining the default descriptor class to use if non is specified in entry_points
eager: If true, load the modules children immediately to force the entire course tree to be parsed
"""
self.data_dir = path(data_dir)
self.modules = {}
if default_class is None:
self.default_class = None
else:
module_path, _, class_name = default_class.rpartition('.')
class_ = getattr(import_module(module_path), class_name)
self.default_class = class_
with open(self.data_dir / "course.xml") as course_file:
class ImportSystem(XMLParsingSystem, MakoDescriptorSystem):
def __init__(self, modulestore):
"""
modulestore: the XMLModuleStore to store the loaded modules in
"""
self.unnamed_modules = 0
self.used_slugs = set()
def process_xml(xml):
try:
xml_data = etree.fromstring(xml)
except:
log.exception("Unable to parse xml: {xml}".format(xml=xml))
raise
if xml_data.get('slug') is None:
if xml_data.get('name'):
slug = Location.clean(xml_data.get('name'))
else:
self.unnamed_modules += 1
slug = '{tag}_{count}'.format(tag=xml_data.tag, count=self.unnamed_modules)
if slug in self.used_slugs:
self.unnamed_modules += 1
slug = '{slug}_{count}'.format(slug=slug, count=self.unnamed_modules)
self.used_slugs.add(slug)
xml_data.set('slug', slug)
module = XModuleDescriptor.load_from_xml(etree.tostring(xml_data), self, org, course, modulestore.default_class)
modulestore.modules[module.location] = module
if eager:
module.get_children()
return module
system_kwargs = dict(
render_template=lambda: '',
load_item=modulestore.get_item,
resources_fs=OSFS(data_dir),
process_xml=process_xml
)
MakoDescriptorSystem.__init__(self, **system_kwargs)
XMLParsingSystem.__init__(self, **system_kwargs)
self.course = ImportSystem(self).process_xml(course_file.read())
def get_item(self, location):
"""
Returns an XModuleDescriptor instance for the item at location.
If location.revision is None, returns the most item with the most
recent revision
If any segment of the location is None except revision, raises
xmodule.modulestore.exceptions.InsufficientSpecificationError
If no object is found at that location, raises xmodule.modulestore.exceptions.ItemNotFoundError
location: Something that can be passed to Location
"""
location = Location(location)
try:
return self.modules[location]
except KeyError:
raise ItemNotFoundError(location)
def create_item(self, location):
raise NotImplementedError("XMLModuleStores are read-only")
def update_item(self, location, data):
"""
Set the data in the item specified by the location to
data
location: Something that can be passed to Location
data: A nested dictionary of problem data
"""
raise NotImplementedError("XMLModuleStores are read-only")
def update_children(self, location, children):
"""
Set the children for the item specified by the location to
data
location: Something that can be passed to Location
children: A list of child item identifiers
"""
raise NotImplementedError("XMLModuleStores are read-only")
def update_metadata(self, location, metadata):
"""
Set the metadata for the item specified by the location to
metadata
location: Something that can be passed to Location
metadata: A nested dictionary of module metadata
"""
raise NotImplementedError("XMLModuleStores are read-only")