Use XModuleDescriptor.parse_xml to interpret XML.

common/lib/xmodule/setup.py

@@ -17,6 +17,47 @@ setup(
     # See http://guide.python-distribute.org/creation.html#entry-points
     # for a description of entry_points
     entry_points={
+        'xblock.v1': [
+            "abtest = xmodule.abtest_module:ABTestDescriptor",
+            "book = xmodule.backcompat_module:TranslateCustomTagDescriptor",
+            "chapter = xmodule.seq_module:SequenceDescriptor",
+            "combinedopenended = xmodule.combined_open_ended_module:CombinedOpenEndedDescriptor",
+            "conditional = xmodule.conditional_module:ConditionalDescriptor",
+            "course = xmodule.course_module:CourseDescriptor",
+            "customtag = xmodule.template_module:CustomTagDescriptor",
+            "discuss = xmodule.backcompat_module:TranslateCustomTagDescriptor",
+            "html = xmodule.html_module:HtmlDescriptor",
+            "image = xmodule.backcompat_module:TranslateCustomTagDescriptor",
+            "error = xmodule.error_module:ErrorDescriptor",
+            "peergrading = xmodule.peer_grading_module:PeerGradingDescriptor",
+            "poll_question = xmodule.poll_module:PollDescriptor",
+            "problem = xmodule.capa_module:CapaDescriptor",
+            "problemset = xmodule.seq_module:SequenceDescriptor",
+            "randomize = xmodule.randomize_module:RandomizeDescriptor",
+            "section = xmodule.backcompat_module:SemanticSectionDescriptor",
+            "sequential = xmodule.seq_module:SequenceDescriptor",
+            "slides = xmodule.backcompat_module:TranslateCustomTagDescriptor",
+            "timelimit = xmodule.timelimit_module:TimeLimitDescriptor",
+            "vertical = xmodule.vertical_module:VerticalDescriptor",
+            "video = xmodule.video_module:VideoDescriptor",
+            "videoalpha = xmodule.video_module:VideoDescriptor",
+            "videodev = xmodule.backcompat_module:TranslateCustomTagDescriptor",
+            "videosequence = xmodule.seq_module:SequenceDescriptor",
+            "discussion = xmodule.discussion_module:DiscussionDescriptor",
+            "course_info = xmodule.html_module:CourseInfoDescriptor",
+            "static_tab = xmodule.html_module:StaticTabDescriptor",
+            "custom_tag_template = xmodule.raw_module:RawDescriptor",
+            "about = xmodule.html_module:AboutDescriptor",
+            "wrapper = xmodule.wrapper_module:WrapperDescriptor",
+            "graphical_slider_tool = xmodule.gst_module:GraphicalSliderToolDescriptor",
+            "annotatable = xmodule.annotatable_module:AnnotatableDescriptor",
+            "foldit = xmodule.foldit_module:FolditDescriptor",
+            "word_cloud = xmodule.word_cloud_module:WordCloudDescriptor",
+            "hidden = xmodule.hidden_module:HiddenDescriptor",
+            "raw = xmodule.raw_module:RawDescriptor",
+            "crowdsource_hinter = xmodule.crowdsource_hinter:CrowdsourceHinterDescriptor",
+            "lti = xmodule.lti_module:LTIModuleDescriptor"
+        ],
         'xmodule.v1': [
             "abtest = xmodule.abtest_module:ABTestDescriptor",
             "book = xmodule.backcompat_module:TranslateCustomTagDescriptor",

common/lib/xmodule/xmodule/modulestore/xml.py

@@ -20,8 +20,10 @@ from xmodule.mako_module import MakoDescriptorSystem
 from xmodule.x_module import XModuleDescriptor, XMLParsingSystem
 
 from xmodule.html_module import HtmlDescriptor
+from xblock.core import XBlock
 from xblock.fields import ScopeIds
 from xblock.field_data import DictFieldData
+from xblock.plugin import PluginMissingError
 
 from . import ModuleStoreBase, Location, XML_MODULESTORE_TYPE
 
@@ -163,7 +165,7 @@ class ImportSystem(XMLParsingSystem, MakoDescriptorSystem):
 
                 make_name_unique(xml_data)
 
-                descriptor = XModuleDescriptor.load_from_xml(
+                descriptor = create_block_from_xml(
                     etree.tostring(xml_data, encoding='unicode'), self, self.org,
                     self.course, xmlstore.default_class)
             except Exception as err:
@@ -219,6 +221,38 @@ class ImportSystem(XMLParsingSystem, MakoDescriptorSystem):
         )
 
 
+def create_block_from_xml(xml_data, system, org=None, course=None, default_class=None):
+    """
+    Create an XBlock instance from XML data.
+
+    `xml_data' is a string containing valid xml.
+
+    `system` is an XMLParsingSystem.
+
+    `org` and `course` are optional strings that will be used in the generated
+    block's url identifiers.
+
+    `default_class` is the class to instantiate of the XML indicates a class
+    that can't be loaded.
+
+    Returns the fully instantiated XBlock.
+
+    """
+    node = etree.fromstring(xml_data)
+    raw_class = XBlock.load_class(node.tag, default_class)
+    xblock_class = system.mixologist.mix(raw_class)
+
+    # leave next line commented out - useful for low-level debugging
+    # log.debug('[create_block_from_xml] tag=%s, class=%s' % (node.tag, xblock_class))
+
+    url_name = node.get('url_name', node.get('slug'))
+    location = Location('i4x', org, course, node.tag, url_name)
+
+    scope_ids = ScopeIds(None, location.category, location, location)
+    xblock = xblock_class.parse_xml(node, system, scope_ids)
+    return xblock
+
+
 class ParentTracker(object):
     """A simple class to factor out the logic for tracking location parent pointers."""
     def __init__(self):

common/lib/xmodule/xmodule/x_module.py

@@ -524,32 +524,15 @@ class XModuleDescriptor(XModuleMixin, HTMLSnippet, ResourceTemplates, XBlock):
         return cls.metadata_translations.get(key, key)
 
     # ================================= XML PARSING ============================
-    @staticmethod
-    def load_from_xml(xml_data,
-                      system,
-                      org=None,
-                      course=None,
-                      default_class=None):
+    @classmethod
+    def parse_xml(cls, node, runtime, keys):
         """
-        This method instantiates the correct subclass of XModuleDescriptor based
-        on the contents of xml_data.
-
-        xml_data must be a string containing valid xml
-
-        system is an XMLParsingSystem
-
-        org and course are optional strings that will be used in the generated
-            module's url identifiers
+        Interpret the parsed XML in `node`, creating an XModuleDescriptor.
         """
-        class_ = system.mixologist.mix(XModuleDescriptor.load_class(
-            etree.fromstring(xml_data).tag,
-            default_class
-        ))
-        # leave next line, commented out - useful for low-level debugging
-        # log.debug('[XModuleDescriptor.load_from_xml] tag=%s, class_=%s' % (
-        #        etree.fromstring(xml_data).tag,class_))
-
-        return class_.from_xml(xml_data, system, org, course)
+        xml = etree.tostring(node)
+        # TODO: change from_xml to not take org and course, it can use self.system.
+        block = cls.from_xml(xml, runtime, runtime.org, runtime.course)
+        return block
 
     @classmethod
     def from_xml(cls, xml_data, system, org=None, course=None):
@@ -713,7 +696,9 @@ class DescriptorSystem(Runtime):
                that you're about to re-raise---let the caller track them.
         """
 
-        super(DescriptorSystem, self).__init__(**kwargs)
+        # Right now, usage_store is unused, and field_data is always supplanted
+        # with an explicit field_data during construct_xblock, so None's suffice.
+        super(DescriptorSystem, self).__init__(usage_store=None, field_data=None, **kwargs)
 
         self.load_item = load_item
         self.resources_fs = resources_fs
@@ -835,7 +820,10 @@ class ModuleSystem(Runtime):
             not to allow the execution of unsafe, unsandboxed code.
 
         """
-        super(ModuleSystem, self).__init__(**kwargs)
+
+        # Right now, usage_store is unused, and field_data is always supplanted
+        # with an explicit field_data during construct_xblock, so None's suffice.
+        super(ModuleSystem, self).__init__(usage_store=None, field_data=None, **kwargs)
 
         self.ajax_url = ajax_url
         self.xqueue = xqueue