first try of LightChild data persistence

mentoring/html.py

@@ -56,7 +56,8 @@ class HTMLBlock(LightChild):
         return block
 
     def student_view(self, context=None):
-        return Fragment(self.content)
+        # HACK, TO MODIFY
+        return Fragment(self.content.get())
 
     def mentoring_view(self, context=None):
         return self.student_view(context)

mentoring/light_children.py

@@ -24,6 +24,9 @@
 # Imports ###########################################################
 
 import logging
+import json
+
+from lazy import lazy
 
 from cStringIO import StringIO
 from lxml import etree
@@ -34,6 +37,8 @@ from xblock.core import XBlock
 from xblock.fragment import Fragment
 from xblock.plugin import Plugin
 
+from .models import LightChild as LightChildModel
+
 try:
     from xmodule_modifiers import replace_jump_to_id_urls
 except:
@@ -194,6 +199,7 @@ class XBlockWithLightChildren(LightChildrenMixin, XBlock):
         fragment = replace_jump_to_id_urls(course_id, jump_to_url, self, 'student_view', fragment, {})
         return fragment
 
+
 class LightChild(Plugin, LightChildrenMixin):
     """
     Base class for the light children
@@ -203,6 +209,31 @@ class LightChild(Plugin, LightChildrenMixin):
     def __init__(self, parent):
         self.parent = parent
         self.xblock_container = parent.xblock_container
+        # This doesn't work, crash.... where should I trigger the lazy property to be loaded?
+        #self.load_student_data()
+
+    def __setattr__(self, name, value):
+
+        field = getattr(self, name) if hasattr(self, name) else None
+
+        # If the property is a LightChildField instance, use its setattr
+        if isinstance(field, LightChildField):
+            field.set(value)
+        else:
+            super(LightChild, self).__setattr__(name, value)
+
+    @lazy
+    def student_data(self):
+        """
+        Use lazy property instead of XBlock field, as __init__() doesn't support
+        overwriting field values
+        """
+
+        if not self.name:
+            return ''
+
+        student_data = self.get_lightchild_model_object().student_data
+        return student_data
 
     @property
     def runtime(self):
@@ -220,20 +251,96 @@ class LightChild(Plugin, LightChildrenMixin):
             xmodule_runtime = xmodule_runtime()
         return xmodule_runtime
 
+    def load_student_data(self):
+        """
+        Load the values from the student_data in the database.
+        """
+
+        student_data = self.student_data
+        fields = self.get_fields()
+        for field in fields:
+            if field in student_data:
+                setattr(self, field, student_data[field])
+
+    @classmethod
+    def get_fields(cls):
+        """
+        Returns a list of all LightChildField of the class. Used for saving student data.
+        """
+        return []
+
     def save(self):
-        pass
+        """
+        Replicate data changes on the related Django model used for sharing of data accross XBlocks
+        """
+
+        # Save all children
+        for child in self.get_children_objects():
+            child.save()
+
+        self.student_data = {}
+
+        # Get All LightChild fields to save
+        for field in self.get_fields():
+            self.student_data[field] = getattr(self, field).to_json()
+
+        if self.name:
+            lightchild_data = self.get_lightchild_model_object()
+            if lightchild_data.student_data != self.student_data:
+                lightchild_data.student_data = json.dumps(self.student_data)
+                lightchild_data.save()
+
+    def get_lightchild_model_object(self, name=None):
+        """
+        Fetches the LightChild model object for the lightchild named `name`
+        """
+
+        if not name:
+            name = self.name
+
+        if not name:
+            raise ValueError, 'LightChild.name field need to be set to a non-null/empty value'
+
+        student_id = self.xmodule_runtime.anonymous_student_id
+        course_id = self.xmodule_runtime.course_id
+
+        lightchild_data, created = LightChildModel.objects.get_or_create(
+            student_id=student_id,
+            course_id=course_id,
+            name=name,
+        )
+        return lightchild_data
 
 
 class LightChildField(object):
     """
     Fake field with no persistence - allows to keep XBlocks fields definitions on LightChild
     """
+
     def __init__(self, *args, **kwargs):
         self.value = kwargs.get('default', '')
 
     def __nonzero__(self):
         return bool(self.value)
 
+    def set(self, value):
+        self.value = value
+
+    def get(self):
+        return self.value
+
+    def to_json(self):
+        """
+        Returns the JSON representation of the LightChieldField.
+        """
+        return self.value
+
+    def from_json(self, value):
+        """
+        Returns value as a native full featured python type from a JSON value.
+        """
+        pass
+
 
 class String(LightChildField):
     def __init__(self, *args, **kwargs):
@@ -259,11 +366,19 @@ class Integer(LightChildField):
     def __nonzero__(self):
         try:
             int(self.value)
-        except TypeError, ValueError: # not an integer
+        except (TypeError, ValueError): # not an integer
             return False
 
         return self.value is not None
 
+    def set(self, value):
+        self.value = int(value)
+
+    def from_json(self, value):
+        if value is None or value == '':
+            return None
+        return int(value)
+
 
 class Boolean(LightChildField):
     pass

mentoring/migrations/0004_auto__add_lightchild__add_unique_lightchild_student_id_course_id_name.py

+# -*- coding: utf-8 -*-
+import datetime
+from south.db import db
+from south.v2 import SchemaMigration
+from django.db import models
+
+
+class Migration(SchemaMigration):
+
+    def forwards(self, orm):
+        # Adding model 'LightChild'
+        db.create_table('mentoring_lightchild', (
+            ('id', self.gf('django.db.models.fields.AutoField')(primary_key=True)),
+            ('name', self.gf('django.db.models.fields.CharField')(max_length=50, db_index=True)),
+            ('student_id', self.gf('django.db.models.fields.CharField')(max_length=32, db_index=True)),
+            ('course_id', self.gf('django.db.models.fields.CharField')(max_length=50, db_index=True)),
+            ('student_data', self.gf('django.db.models.fields.TextField')(default='', blank=True)),
+            ('created_on', self.gf('django.db.models.fields.DateTimeField')(auto_now_add=True, blank=True)),
+            ('modified_on', self.gf('django.db.models.fields.DateTimeField')(auto_now=True, blank=True)),
+        ))
+        db.send_create_signal('mentoring', ['LightChild'])
+
+        # Adding unique constraint on 'LightChild', fields ['student_id', 'course_id', 'name']
+        db.create_unique('mentoring_lightchild', ['student_id', 'course_id', 'name'])
+
+
+    def backwards(self, orm):
+        # Removing unique constraint on 'LightChild', fields ['student_id', 'course_id', 'name']
+        db.delete_unique('mentoring_lightchild', ['student_id', 'course_id', 'name'])
+
+        # Deleting model 'LightChild'
+        db.delete_table('mentoring_lightchild')
+
+
+    models = {
+        'mentoring.answer': {
+            'Meta': {'unique_together': "(('student_id', 'course_id', 'name'),)", 'object_name': 'Answer'},
+            'course_id': ('django.db.models.fields.CharField', [], {'max_length': '50', 'db_index': 'True'}),
+            'created_on': ('django.db.models.fields.DateTimeField', [], {'auto_now_add': 'True', 'blank': 'True'}),
+            'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'}),
+            'modified_on': ('django.db.models.fields.DateTimeField', [], {'auto_now': 'True', 'blank': 'True'}),
+            'name': ('django.db.models.fields.CharField', [], {'max_length': '50', 'db_index': 'True'}),
+            'student_id': ('django.db.models.fields.CharField', [], {'max_length': '32', 'db_index': 'True'}),
+            'student_input': ('django.db.models.fields.TextField', [], {'default': "''", 'blank': 'True'})
+        },
+        'mentoring.lightchild': {
+            'Meta': {'unique_together': "(('student_id', 'course_id', 'name'),)", 'object_name': 'LightChild'},
+            'course_id': ('django.db.models.fields.CharField', [], {'max_length': '50', 'db_index': 'True'}),
+            'created_on': ('django.db.models.fields.DateTimeField', [], {'auto_now_add': 'True', 'blank': 'True'}),
+            'student_data': ('django.db.models.fields.TextField', [], {'default': "''", 'blank': 'True'}),
+            'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'}),
+            'modified_on': ('django.db.models.fields.DateTimeField', [], {'auto_now': 'True', 'blank': 'True'}),
+            'name': ('django.db.models.fields.CharField', [], {'max_length': '50', 'db_index': 'True'}),
+            'student_id': ('django.db.models.fields.CharField', [], {'max_length': '32', 'db_index': 'True'})
+        }
+    }
+
+    complete_apps = ['mentoring']

mentoring/models.py

@@ -49,3 +49,21 @@ class Answer(models.Model):
         # Force validation of max_length
         self.full_clean()
         super(Answer, self).save(*args, **kwargs)
+
+
+class LightChild(models.Model):
+    """
+    Django model used to store LightChild student data that need to be shared and queried accross
+    XBlock instances (workaround). Since this is temporary, `data` are stored in json.
+    """
+
+    class Meta:
+        app_label = 'mentoring'
+        unique_together = (('student_id', 'course_id', 'name'),)
+
+    name = models.CharField(max_length=50, db_index=True)
+    student_id = models.CharField(max_length=32, db_index=True)
+    course_id = models.CharField(max_length=50, db_index=True)
+    student_data = models.TextField(blank=True, default='')
+    created_on = models.DateTimeField('created on', auto_now_add=True)
+    modified_on = models.DateTimeField('modified on', auto_now=True)

mentoring/mrq.py

@@ -46,6 +46,12 @@ class MRQBlock(QuestionnaireAbstractBlock):
     max_attempts = Integer(help="Number of max attempts for this questions", default=None, scope=Scope.content)
     num_attempts = Integer(help="Number of attempts a user has answered for this questions", scope=Scope.user_state)
 
+    @classmethod
+    def get_fields(cls):
+        return [
+            'num_attempts'
+        ]
+
     def submit(self, submissions):
         log.debug(u'Received MRQ submissions: "%s"', submissions)
 
@@ -66,7 +72,7 @@ class MRQBlock(QuestionnaireAbstractBlock):
 
             completed = completed and choice_completed
             results.append({
-                'value': choice.value,
+                'value': choice.value.get(),
                 'selected': choice_selected,
                 'completed': choice_completed,
                 'tips': render_template('templates/html/tip_choice_group.html', {
@@ -80,12 +86,13 @@ class MRQBlock(QuestionnaireAbstractBlock):
 
         # What's the proper way to get my value saved? it doesn't work without '.value'
         # this is incorrect and the num_attempts is resetted if we restart the server.
-        self.num_attempts.value = int(self.num_attempts) + 1 if self.max_attempts else 0
+        num_attempts = self.num_attempts.get() + 1 if self.max_attempts else 0
+        setattr(self, 'num_attempts', num_attempts)
 
         max_attempts_reached = False
         if self.max_attempts:
-            max_attempts = int(self.max_attempts)
-            num_attempts = int(self.num_attempts)
+            max_attempts = self.max_attempts.get()
+            num_attempts = self.num_attempts.get()
             max_attempts_reached = num_attempts >= max_attempts
 
         if max_attempts_reached and (not completed or num_attempts > max_attempts):
@@ -99,9 +106,10 @@ class MRQBlock(QuestionnaireAbstractBlock):
         'submissions': submissions,
         'completed': completed,
         'choices': results,
-            'message': self.message,
-            'max_attempts': int(self.max_attempts) if self.max_attempts else None,
-            'num_attempts': int(self.num_attempts)
+        'message': self.message.get(),
+        'max_attempts': self.max_attempts.get() if self.max_attempts else None,
+        'num_attempts': self.num_attempts.get()
         }
+
         log.debug(u'MRQ submissions result: %s', result)
         return result