From e431378f46a812afc5a562cedd87babe7beb5bec Mon Sep 17 00:00:00 2001
From: Victor Shnayder <victor@mitx.mit.edu>
Date: Thu, 31 Jan 2013 12:14:01 -0500
Subject: [PATCH] Add first pass at a randomize module
---
common/lib/xmodule/setup.py | 1 +
.../lib/xmodule/xmodule/randomize_module.py | 122 ++++++++++++++++++
2 files changed, 123 insertions(+)
create mode 100644 common/lib/xmodule/xmodule/randomize_module.py
diff --git a/common/lib/xmodule/setup.py b/common/lib/xmodule/setup.py
index 29227c31884..446078ffcf0 100644
--- a/common/lib/xmodule/setup.py
+++ b/common/lib/xmodule/setup.py
@@ -28,6 +28,7 @@ setup(
"error = xmodule.error_module:ErrorDescriptor",
"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",
diff --git a/common/lib/xmodule/xmodule/randomize_module.py b/common/lib/xmodule/xmodule/randomize_module.py
new file mode 100644
index 00000000000..0bc26c21bf0
--- /dev/null
+++ b/common/lib/xmodule/xmodule/randomize_module.py
@@ -0,0 +1,122 @@
+import json
+import logging
+import random
+
+from xmodule.mako_module import MakoModuleDescriptor
+from xmodule.x_module import XModule
+from xmodule.xml_module import XmlDescriptor
+from xmodule.modulestore import Location
+from xmodule.seq_module import SequenceDescriptor
+
+from pkg_resources import resource_string
+
+log = logging.getLogger('mitx.' + __name__)
+
+class RandomizeModule(XModule):
+ """
+ Chooses a random child module. Chooses the same one every time for each student.
+
+ Example:
+ <randomize>
+ <problem url_name="problem1" />
+ <problem url_name="problem2" />
+ <problem url_name="problem3" />
+ </randomize>
+
+ User notes:
+
+ - If you're randomizing amongst graded modules, each of them MUST be worth the same
+ number of points. Otherwise, the earth will be overrun by monsters from the
+ deeps. You have been warned.
+
+ Technical notes:
+ - There is more dark magic in this code than I'd like. The whole varying-children +
+ grading interaction is a tangle between super and subclasses of descriptors and
+ modules.
+"""
+
+ def __init__(self, system, location, definition, descriptor,
+ instance_state=None, shared_state=None, **kwargs):
+ XModule.__init__(self, system, location, definition, descriptor,
+ instance_state, shared_state, **kwargs)
+
+ # NOTE: calling self.get_children() creates a circular reference--
+ # it calls get_child_descriptors() internally, but that doesn't work until
+ # we've picked a choice
+ num_choices = len(self.descriptor.get_children())
+
+ self.choice = None
+ if instance_state is not None:
+ state = json.loads(instance_state)
+ self.choice = state.get('choice', None)
+ if self.choice > num_choices:
+ # Oops. Children changed. Reset.
+ self.choice = None
+
+ if self.choice is None:
+ # choose one based on the system seed, or randomly if that's not available
+ if num_choices > 0:
+ if system.seed is not None:
+ self.choice = system.seed % num_choices
+ else:
+ self.choice = random.randrange(0, num_choices)
+
+ log.debug("********* self.choice = %s", self.choice)
+ if self.choice is not None:
+ self.child_descriptor = self.descriptor.get_children()[self.choice]
+ # Now get_children() should return a list with one element
+ log.debug("children of randomize module (should be only 1): %s",
+ self.get_children())
+ self.child = self.get_children()[0]
+ else:
+ self.child_descriptor = None
+ self.child = None
+
+
+ def get_instance_state(self):
+ return json.dumps({'choice': self.choice})
+
+
+ def get_child_descriptors(self):
+ """
+ For grading--return just the chosen child.
+ """
+ if self.child_descriptor is None:
+ return []
+
+ return [self.child_descriptor]
+
+
+ def get_html(self):
+ if self.child is None:
+ # raise error instead? In fact, could complain on descriptor load...
+ return "<div>Nothing to randomize between</div>"
+
+ return self.child.get_html()
+
+ def get_icon_class(self):
+ return self.child.get_icon_class() if self.child else 'other'
+
+
+class RandomizeDescriptor(SequenceDescriptor):
+ # the editing interface can be the same as for sequences -- just a container
+ module_class = RandomizeModule
+
+ filename_extension = "xml"
+
+ stores_state = True
+
+ def definition_to_xml(self, resource_fs):
+ xml_object = etree.Element('randomize')
+ for child in self.get_children():
+ xml_object.append(
+ etree.fromstring(child.export_to_xml(resource_fs)))
+ return xml_object
+
+ def has_dynamic_children(self):
+ """
+ Grading needs to know that only one of the children is actually "real". This
+ makes it use module.get_child_descriptors().
+ """
+ return True
+
--
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