Merge pull request #42 from open-craft/export-bugfixes

Export bugfixes

problem_builder/data_export.py

@@ -172,6 +172,8 @@ class DataExportBlock(XBlock):
             return {'error': 'permission denied'}
         from .tasks import export_data as export_data_task  # Import here since this is edX LMS specific
         self._delete_export()
+        # Make sure we nail down our state before sending off an asynchronous task.
+        self.save()
         if not username:
             user_id = None
         else:

problem_builder/public/js/data_export.js

@@ -26,7 +26,7 @@ function DataExportBlock(runtime, element) {
     }
 
     function updateStatus(newStatus) {
-        var statusChanged = newStatus !== status;
+        var statusChanged = ! _.isEqual(newStatus, status);
         status = newStatus;
         if (status.export_pending) {
             // Keep polling for status updates when an export is running.

problem_builder/tasks.py

@@ -9,6 +9,7 @@ from instructor_task.models import ReportStore
 from opaque_keys import InvalidKeyError
 from opaque_keys.edx.keys import UsageKey, CourseKey
 from xmodule.modulestore.django import modulestore
+from xmodule.modulestore.exceptions import ItemNotFoundError
 
 from .mcq import MCQBlock, RatingBlock
 from problem_builder import AnswerBlock
@@ -56,7 +57,11 @@ def export_data(course_id, source_block_id_str, block_types, user_id, get_root=T
             blocks_to_include.append(block)
         elif block.has_children:
             for child_id in block.children:
-                scan_for_blocks(block.runtime.get_block(child_id))
+                try:
+                    scan_for_blocks(block.runtime.get_block(child_id))
+                except ItemNotFoundError:
+                    # Blocks may refer to missing children. Don't break in this case.
+                    pass
 
     scan_for_blocks(root)