Merge pull request #1407 from MITx/feature/ichuang/conditional-xmodule-v2

 Provides "stop" feature via a new "conditional" XModule

common/lib/xmodule/setup.py

@@ -20,6 +20,7 @@ setup(
             "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",

common/lib/xmodule/xmodule/capa_module.py

@@ -398,6 +398,15 @@ class CapaModule(XModule):
 
         return False
 
+    def is_completed(self):
+        # used by conditional module
+        # return self.answer_available()
+        return self.lcp.done
+
+    def is_attempted(self):
+        # used by conditional module
+        return self.attempts > 0
+
     def answer_available(self):
         ''' Is the user allowed to see an answer?
         '''

common/lib/xmodule/xmodule/conditional_module.py

+import json
+import logging
+
+from xmodule.x_module import XModule
+from xmodule.modulestore import Location
+from xmodule.seq_module import SequenceDescriptor
+
+from pkg_resources import resource_string
+
+log = logging.getLogger('mitx.' + __name__)
+
+class ConditionalModule(XModule):
+    '''
+    Blocks child module from showing unless certain conditions are met.
+
+    Example:
+        
+        <conditional condition="require_completed" required="tag/url_name1&tag/url_name2">
+            <video url_name="secret_video" />
+        </conditional>
+
+        <conditional condition="require_attempted" required="tag/url_name1&tag/url_name2">
+            <video url_name="secret_video" />
+        </conditional>
+
+    '''
+
+    js = {'coffee': [resource_string(__name__, 'js/src/conditional/display.coffee'),
+                     resource_string(__name__, 'js/src/collapsible.coffee'),
+                     resource_string(__name__, 'js/src/javascript_loader.coffee'),
+                    ]}
+
+    js_module_name = "Conditional"
+    css = {'scss': [resource_string(__name__, 'css/capa/display.scss')]}
+
+
+    def __init__(self, system, location, definition, descriptor, instance_state=None, shared_state=None, **kwargs):
+        """
+        In addition to the normal XModule init, provide:
+        
+            self.condition            = string describing condition required
+
+        """
+        XModule.__init__(self, system, location, definition, descriptor, instance_state, shared_state, **kwargs)
+        self.contents = None
+        self.condition = self.metadata.get('condition','')
+        #log.debug('conditional module required=%s' % self.required_modules_list)
+
+    def _get_required_modules(self):
+        self.required_modules = []
+        for descriptor in self.descriptor.get_required_module_descriptors():
+            module = self.system.get_module(descriptor)
+            self.required_modules.append(module)
+        #log.debug('required_modules=%s' % (self.required_modules))
+
+    def is_condition_satisfied(self):
+        self._get_required_modules()
+
+        if self.condition=='require_completed':
+            # all required modules must be completed, as determined by
+            # the modules .is_completed() method
+            for module in self.required_modules:
+                #log.debug('in is_condition_satisfied; student_answers=%s' % module.lcp.student_answers)
+                #log.debug('in is_condition_satisfied; instance_state=%s' % module.instance_state)
+                if not hasattr(module, 'is_completed'):
+                    raise Exception('Error in conditional module: required module %s has no .is_completed() method' % module)
+                if not module.is_completed():
+                    log.debug('conditional module: %s not completed' % module)
+                    return False
+                else:
+                    log.debug('conditional module: %s IS completed' % module)
+            return True
+        elif self.condition=='require_attempted':
+            # all required modules must be attempted, as determined by
+            # the modules .is_attempted() method
+            for module in self.required_modules:
+                if not hasattr(module, 'is_attempted'):
+                    raise Exception('Error in conditional module: required module %s has no .is_attempted() method' % module)
+                if not module.is_attempted():
+                    log.debug('conditional module: %s not attempted' % module)
+                    return False
+                else:
+                    log.debug('conditional module: %s IS attempted' % module)
+            return True
+        else:
+            raise Exception('Error in conditional module: unknown condition "%s"' % self.condition)
+
+        return True
+
+    def get_html(self):
+        self.is_condition_satisfied()
+        return self.system.render_template('conditional_ajax.html', {
+            'element_id': self.location.html_id(),
+            'id': self.id,
+            'ajax_url': self.system.ajax_url,
+        })
+
+    def handle_ajax(self, dispatch, post):
+        '''
+        This is called by courseware.module_render, to handle an AJAX call.
+        '''
+        #log.debug('conditional_module handle_ajax: dispatch=%s' % dispatch)
+
+        if not self.is_condition_satisfied():
+            context = {'module': self}
+            html = self.system.render_template('conditional_module.html', context)
+            return json.dumps({'html': html})
+
+        if self.contents is None:
+            self.contents = [child.get_html() for child in self.get_display_items()]
+
+        # for now, just deal with one child
+        html = self.contents[0]
+        
+        return json.dumps({'html': html})
+
+class ConditionalDescriptor(SequenceDescriptor):
+    module_class = ConditionalModule
+
+    filename_extension = "xml"
+
+    stores_state = True
+    has_score = False
+
+    def __init__(self, *args, **kwargs):
+        super(ConditionalDescriptor, self).__init__(*args, **kwargs)
+
+        required_module_list = [tuple(x.split('/',1)) for x in self.metadata.get('required','').split('&')]
+        self.required_module_locations = []
+        for (tag, name) in required_module_list:
+            loc = self.location.dict()
+            loc['category'] = tag
+            loc['name'] = name
+            self.required_module_locations.append(Location(loc))
+        log.debug('ConditionalDescriptor required_module_locations=%s' % self.required_module_locations)
+        
+    def get_required_module_descriptors(self):
+        """Returns a list of XModuleDescritpor instances upon which this module depends, but are
+        not children of this module"""
+        return [self.system.load_item(loc) for loc in self.required_module_locations]
+    

common/lib/xmodule/xmodule/js/src/conditional/display.coffee

+class @Conditional
+
+  constructor: (element) ->
+    @el = $(element).find('.conditional-wrapper')
+    @id = @el.data('problem-id')
+    @element_id = @el.attr('id')
+    @url = @el.data('url')
+    @render()
+
+  $: (selector) ->
+    $(selector, @el)
+
+  updateProgress: (response) =>
+    if response.progress_changed
+        @el.attr progress: response.progress_status
+        @el.trigger('progressChanged')
+
+  render: (content) ->
+    if content
+      @el.html(content)
+      XModule.loadModules('display', @el)
+    else
+      $.postWithPrefix "#{@url}/conditional_get", (response) =>
+        @el.html(response.html)
+        XModule.loadModules('display', @el)
+

common/lib/xmodule/xmodule/tests/test_conditional.py

+import json
+from path import path
+import unittest
+from fs.memoryfs import MemoryFS
+
+from lxml import etree
+from mock import Mock, patch
+from collections import defaultdict
+
+from xmodule.x_module import XMLParsingSystem, XModuleDescriptor
+from xmodule.xml_module import is_pointer_tag
+from xmodule.errortracker import make_error_tracker
+from xmodule.modulestore import Location
+from xmodule.modulestore.xml import ImportSystem, XMLModuleStore
+from xmodule.modulestore.exceptions import ItemNotFoundError
+
+from .test_export import DATA_DIR
+
+ORG = 'test_org'
+COURSE = 'conditional'	# name of directory with course data
+
+from . import test_system
+
+class DummySystem(ImportSystem):
+
+    @patch('xmodule.modulestore.xml.OSFS', lambda dir: MemoryFS())
+    def __init__(self, load_error_modules):
+
+        xmlstore = XMLModuleStore("data_dir", course_dirs=[], load_error_modules=load_error_modules)
+        course_id = "/".join([ORG, COURSE, 'test_run'])
+        course_dir = "test_dir"
+        policy = {}
+        error_tracker = Mock()
+        parent_tracker = Mock()
+
+        super(DummySystem, self).__init__(
+            xmlstore,
+            course_id,
+            course_dir,
+            policy,
+            error_tracker,
+            parent_tracker,
+            load_error_modules=load_error_modules,
+        )
+
+    def render_template(self, template, context):
+            raise Exception("Shouldn't be called")
+
+
+
+class ConditionalModuleTest(unittest.TestCase):
+
+    @staticmethod
+    def get_system(load_error_modules=True):
+        '''Get a dummy system'''
+        return DummySystem(load_error_modules)
+
+    def get_course(self, name):
+        """Get a test course by directory name.  If there's more than one, error."""
+        print "Importing {0}".format(name)
+
+        modulestore = XMLModuleStore(DATA_DIR, course_dirs=[name])
+        courses = modulestore.get_courses()
+        self.modulestore = modulestore
+        self.assertEquals(len(courses), 1)
+        return courses[0]
+
+    def test_conditional_module(self):
+        """Make sure that conditional module works"""
+
+        print "Starting import"
+        course = self.get_course('conditional')
+
+        print "Course: ", course
+        print "id: ", course.id
+
+        instance_states = dict(problem=None)
+        shared_state = None
+
+        def inner_get_module(descriptor):
+            if isinstance(descriptor, Location):
+                location = descriptor
+                descriptor = self.modulestore.get_instance(course.id, location, depth=None)
+            location = descriptor.location
+            instance_state = instance_states.get(location.category,None)
+            print "inner_get_module, location.category=%s, inst_state=%s" % (location.category, instance_state)
+            return descriptor.xmodule_constructor(test_system)(instance_state, shared_state)
+
+        location = Location(["i4x", "edX", "cond_test", "conditional","condone"])
+        module = inner_get_module(location)
+
+        def replace_urls(text, staticfiles_prefix=None, replace_prefix='/static/', course_namespace=None):
+            return text
+        test_system.replace_urls = replace_urls
+        test_system.get_module = inner_get_module
+
+        print "module: ", module
+
+        html = module.get_html()
+        print "html type: ", type(html)
+        print "html: ", html
+        html_expect = "{'ajax_url': 'courses/course_id/modx/a_location', 'element_id': 'i4x-edX-cond_test-conditional-condone', 'id': 'i4x://edX/cond_test/conditional/condone'}"
+        self.assertEqual(html, html_expect)
+
+        gdi =  module.get_display_items()
+        print "gdi=", gdi
+
+        ajax = json.loads(module.handle_ajax('',''))
+        self.assertTrue('xmodule.conditional_module' in ajax['html'])
+        print "ajax: ", ajax
+
+        # now change state of the capa problem to make it completed
+        instance_states['problem'] = json.dumps({'attempts':1})
+
+        ajax = json.loads(module.handle_ajax('',''))
+        self.assertTrue('This is a secret' in ajax['html'])
+        print "post-attempt ajax: ", ajax
+
+

common/lib/xmodule/xmodule/x_module.py

@@ -585,6 +585,11 @@ class XModuleDescriptor(Plugin, HTMLSnippet, ResourceTemplates):
                 self._inherited_metadata.add(attr)
                 self.metadata[attr] = metadata[attr]
 
+    def get_required_module_descriptors(self):
+        """Returns a list of XModuleDescritpor instances upon which this module depends, but are
+        not children of this module"""
+        return []
+
     def get_children(self):
         """Returns a list of XModuleDescriptor instances for the children of
         this module"""

common/test/data/conditional/README.md

+course for testing conditional module
+
+ 

common/test/data/conditional/conditional/condone.xml

+        <conditional condition="require_attempted" required="problem/choiceprob">
+            <html url_name="secret_page" />
+        </conditional>

common/test/data/conditional/course.xml

+<course name="Conditional Course" org="edX" course="cond_test" graceperiod="1 day 5 hours 59 minutes 59 seconds" slug="2012_Fall" start="2015-07-17T12:00">
+  <chapter name="Problems with Condition">
+      <sequential>
+        <problem url_name="choiceprob" />
+	  <conditional url_name="condone"/>
+      </sequential>
+  </chapter>
+</course>

common/test/data/conditional/html/secret_page.xml

+<html display_name="Secret Page">
+<p>This is a secret!</p>
+</html>
+

common/test/data/conditional/problem/choiceprob.xml

+<problem display_name="S3E2: Lorentz Force">
+
+<startouttext/>
+<p>Consider a hypothetical magnetic field pointing out of your computer screen. Now imagine an electron traveling from right to left in the plane of your screen. A diagram of this situation is show below…</p>
+<center><img width="400" src="/static/images/LSQimages/LSQ_W01_8.png"/></center>
+
+<p>a. The magnitude of the force experienced by the electron is proportional the product of which of the following? (Select all that apply.)</p>
+<endouttext/>
+<choiceresponse>
+<checkboxgroup>
+<!-- include ellipses to test non-ascii characters -->
+<choice correct="true"><text>Magnetic field strength…</text></choice>
+<choice correct="false"><text>Electric field strength…</text></choice>
+<choice correct="true"><text>Electric charge of the electron…</text></choice>
+<choice correct="false"><text>Radius of the electron…</text></choice>
+<choice correct="false"><text>Mass of the electron…</text></choice>
+<choice correct="true"><text>Velocity of the electron…</text></choice>
+
+</checkboxgroup>
+</choiceresponse>
+
+</problem>

doc/xml-format.md

@@ -141,6 +141,7 @@ That's basically all there is to the organizational structure.  Read the next se
 
 * `abtest` -- Support for A/B testing.  TODO: add details..
 * `chapter` -- top level organization unit of a course.   The courseware display code currently expects the top level `course` element to contain only chapters, though there is no philosophical reason why this is required, so we may change it to properly display non-chapters at the top level.
+* `conditional` -- conditional element, which shows one or more modules only if certain conditions are satisfied.
 * `course` -- top level tag.  Contains everything else.
 * `customtag` -- render an html template, filling in some parameters, and return the resulting html.  See below for details.
 * `discussion` -- Inline discussion forum
@@ -163,6 +164,22 @@ Container tags include `chapter`, `sequential`, `videosequence`, `vertical`, and
 
 `course` is also a container, and is similar, with one extra wrinkle: the top level pointer tag _must_ have  `org` and `course` attributes specified--the organization name, and course name.  Note that `course` is referring to the platonic ideal of this course (e.g. "6.002x"), not to any particular run of this course.  The `url_name` should be the particular run of this course.
 
+### `conditional`
+
+`conditional` is as special kind of container tag as well.  Here are two examples:
+
+        <conditional condition="require_completed" required="problem/choiceprob">
+            <video url_name="secret_video" />
+        </conditional>
+
+        <conditional condition="require_attempted" required="problem/choiceprob&problem/sumprob">
+            <html url_name="secret_page" />
+        </conditional>
+
+The condition can be either `require_completed`, in which case the required modules must be completed, or `require_attempted`, in which case the required modules must have been attempted.
+
+The required modules are specified as a set of `tag`/`url_name`, joined by an ampersand.
+
 ### `customtag`
 
 When we see `<customtag impl="special" animal="unicorn" hat="blue"/>`, we will:

lms/djangoapps/courseware/models.py

@@ -113,6 +113,9 @@ class StudentModuleCache(object):
                                          descriptor_filter=lambda descriptor: True,
                                          select_for_update=False):
         """
+        obtain and return cache for descriptor descendents (ie children) AND modules required by the descriptor, 
+        but which are not children of the module
+
         course_id: the course in the context of which we want StudentModules.
         user: the django user for whom to load modules.
         descriptor: An XModuleDescriptor
@@ -132,7 +135,7 @@ class StudentModuleCache(object):
             if depth is None or depth > 0:
                 new_depth = depth - 1 if depth is not None else depth
 
-                for child in descriptor.get_children():
+                for child in descriptor.get_children() + descriptor.get_required_module_descriptors():
                     descriptors.extend(get_child_descriptors(child, new_depth, descriptor_filter))
 
             return descriptors

lms/templates/conditional_ajax.html

+<div id="conditional_${element_id}" class="conditional-wrapper" data-problem-id="${id}" data-url="${ajax_url}"></div>

lms/templates/conditional_module.html

+<%
+    from django.core.urlresolvers import reverse
+    reqm = module.required_modules[0]
+    course_id = module.system.course_id
+%>
+
+<p><a
+href="${reverse('jump_to',kwargs=dict(course_id=course_id, location=reqm.location.url()))}">${reqm.display_name}</a>
+must be completed before this will become visible.</p>