Hook up the component delete button to the backend. Don't break if the process of updating a parent unit after deleting is interrupted (leaving a pointer to a missing module)

cms/djangoapps/contentstore/views.py

@@ -383,6 +383,14 @@ def get_module_previews(request, descriptor):
     return preview_html
 
 
+@login_required
+@expect_json
+def delete_item(request):
+    item_location = request.POST['id']
+    modulestore().delete_item(item_location)
+    return HttpResponse()
+
+
 @login_required
 @expect_json
 def save_item(request):

cms/static/coffee/src/views/module_edit.coffee

@@ -6,10 +6,10 @@ class CMS.Views.ModuleEdit extends Backbone.View
     "click .component-editor .cancel-button": 'clickCancelButton'
     "click .component-editor .save-button": 'clickSaveButton'
     "click .component-actions .edit-button": 'clickEditButton'
-
+    "click .component-actions .delete-button": 'onDelete'
 
   initialize: ->
-    @module = @options.module
+    @onDelete = @options.onDelete
     @render()
 
   $component_editor: => @$el.find('.component-editor')

cms/static/coffee/src/views/unit.coffee

@@ -18,9 +18,10 @@ class CMS.Views.UnitEdit extends Backbone.View
       update: (event, ui) => @saveOrder()
     )
 
-    @$('.component').each((idx, element) ->
+    @$('.component').each((idx, element) =>
         new CMS.Views.ModuleEdit(
             el: element,
+            onDelete: @deleteComponent,
             model: new CMS.Models.Module(
                 id: $(element).data('id'),
             )
@@ -70,3 +71,13 @@ class CMS.Views.UnitEdit extends Backbone.View
     @model.save(
       children: @components()
     )
+
+  deleteComponent: (event) =>
+    $component = $(event.currentTarget).parents('.component')
+    $.post('/delete_item', {
+      id: $component.data('id')
+    }, =>
+      $component.remove()
+      @saveOrder()
+    )
+

cms/templates/component.html

@@ -1,7 +1,7 @@
 ${preview}
 <div class="component-actions">
   <a href="#" class="edit-button"><span class="edit-icon white"></span>Edit</a>
-  <a href="#" class="delete-button wip"><span class="delete-icon white"></span>Delete</a>  
+  <a href="#" class="delete-button"><span class="delete-icon white"></span>Delete</a>  
 </div>
 <a href="#" class="drag-handle"></a>
 <div class="component-editor">

cms/urls.py

@@ -14,6 +14,7 @@ urlpatterns = ('',
     url(r'^delete/(?P<location>.*?)$', 'contentstore.views.delete_unit', name='delete_unit'),
     url(r'^preview_component/(?P<location>.*?)$', 'contentstore.views.preview_component', name='preview_component'),
     url(r'^save_item$', 'contentstore.views.save_item', name='save_item'),
+    url(r'^delete_item$', 'contentstore.views.delete_item', name='delete_item'),
     url(r'^clone_item$', 'contentstore.views.clone_item', name='clone_item'),
     url(r'^(?P<org>[^/]+)/(?P<course>[^/]+)/course/(?P<name>[^/]+)$',
         'contentstore.views.course_index', name='course_index'),

common/lib/xmodule/xmodule/modulestore/__init__.py

@@ -332,6 +332,14 @@ class ModuleStore(object):
         """
         raise NotImplementedError
 
+    def delete_item(self, location):
+        """
+        Delete an item from this modulestore
+
+        location: Something that can be passed to Location
+        """
+        raise NotImplementedError
+
     def get_courses(self):
         '''
         Returns a list containing the top level XModuleDescriptors of the courses

common/lib/xmodule/xmodule/modulestore/mongo.py

@@ -309,6 +309,14 @@ class MongoModuleStore(ModuleStoreBase):
 
         self._update_single_item(location, {'metadata': metadata})
 
+    def delete_item(self, location):
+        """
+        Delete an item from this modulestore
+
+        location: Something that can be passed to Location
+        """
+        self.collection.remove({'_id': Location(location).dict()})
+
     def get_parent_locations(self, location):
         '''Find all locations that are the parents of this location.  Needed
         for path_to_location().

common/lib/xmodule/xmodule/x_module.py

@@ -13,6 +13,7 @@ from xmodule.modulestore import Location
 from xmodule.timeparse import parse_time
 
 from xmodule.contentstore.content import StaticContent, XASSET_SRCREF_PREFIX
+from xmodule.modulestore.exceptions import ItemNotFoundError
 
 log = logging.getLogger('mitx.' + __name__)
 
@@ -531,7 +532,11 @@ class XModuleDescriptor(Plugin, HTMLSnippet, ResourceTemplates):
         if self._child_instances is None:
             self._child_instances = []
             for child_loc in self.definition.get('children', []):
-                child = self.system.load_item(child_loc)
+                try:
+                    child = self.system.load_item(child_loc)
+                except ItemNotFoundError:
+                    log.exception('Unable to load item {loc}, skipping'.format(loc=child_loc))
+                    continue
                 # TODO (vshnayder): this should go away once we have
                 # proper inheritance support in mongo.  The xml
                 # datastore does all inheritance on course load.