add some middleware to determine whether draft modulestore or non-draft ...

CHANGELOG.rst

@@ -75,6 +75,11 @@ Common: Allow instructors to input complicated expressions as answers to
 `NumericalResponse`s. Prior to the change only numbers were allowed, now any
 answer from '1/3' to 'sqrt(12)*(1-1/3^2+1/5/3^2)' are valid.
 
+Studio/LMS: Allow for 'preview' and 'published' in a single LMS instance. Use
+middlware components to retain the incoming Django request and put in thread
+local storage. It is recommended that all developers define a 'preview.localhost'
+which maps to the same IP address as localhost in his/her HOSTS file.
+
 LMS: Enable beta instructor dashboard. The beta dashboard is a rearchitecture
 of the existing instructor dashboard and is available by clicking a link at
 the top right of the existing dashboard.

cms/envs/dev_shared_preview.py

@@ -0,0 +1,12 @@
+"""
+This configuration is have localdev use a preview.localhost hostname for the preview LMS so that we can share
+the same process between preview and published
+"""
+
+# We intentionally define lots of variables that aren't used, and
+# want to import all variables from base settings files
+# pylint: disable=W0401, W0614
+
+from .dev import *
+
+MITX_FEATURES['PREVIEW_LMS_BASE'] = "preview.localhost:8000"

common/lib/xmodule/xmodule/modulestore/django.py

@@ -7,10 +7,13 @@
 from __future__ import absolute_import
 from importlib import import_module
 
+import re
+
 from django.conf import settings
 from django.core.cache import get_cache, InvalidCacheBackendError
 from django.dispatch import Signal
 from xmodule.modulestore.loc_mapper_store import LocMapperStore
+from xmodule.util.django import get_current_request_hostname
 
 # We may not always have the request_cache module available
 try:
@@ -67,11 +70,41 @@ def create_modulestore_instance(engine, options):
     )
 
 
-def modulestore(name='default'):
+def get_default_store_name_for_current_request():
+    """
+    This method will return the appropriate default store mapping for the current Django request,
+    else 'default' which is the system default
+    """
+    store_name = 'default'
+
+    # see what request we are currently processing - if any at all - and get hostname for the request
+    hostname = get_current_request_hostname()
+
+    # get mapping information which is defined in configurations
+    mappings = getattr(settings, 'HOSTNAME_MODULESTORE_DEFAULT_MAPPINGS', None)
+
+    # compare hostname against the regex expressions set of mappings
+    # which will tell us which store name to use
+    if hostname and mappings:
+        for key in mappings.keys():
+            if re.match(key, hostname):
+                store_name = mappings[key]
+                return store_name
+
+    return store_name
+
+
+def modulestore(name=None):
     """
     This returns an instance of a modulestore of given name. This will wither return an existing
     modulestore or create a new one
     """
+
+    if not name:
+        # If caller did not specify name then we should
+        # determine what should be the default
+        name = get_default_store_name_for_current_request()
+
     if name not in _MODULESTORES:
         _MODULESTORES[name] = create_modulestore_instance(settings.MODULESTORE[name]['ENGINE'],
                                                           settings.MODULESTORE[name]['OPTIONS'])

common/lib/xmodule/xmodule/tests/test_utils_django.py

@@ -0,0 +1,20 @@
+"""Tests for methods defined in util/django.py"""
+from xmodule.util.django import get_current_request, get_current_request_hostname
+from nose.tools import assert_is_none
+from unittest import TestCase
+
+class UtilDjangoTests(TestCase):
+	"""
+	Tests for methods exposed in util/django
+	"""
+	def test_get_current_request(self):
+		"""
+		Since we are running outside of Django assert that get_current_request returns None
+		"""
+		assert_is_none(get_current_request())
+
+	def test_get_current_request_hostname(self):
+		"""
+		Since we are running outside of Django assert that get_current_request_hostname returns None
+		"""
+		assert_is_none(get_current_request_hostname())

common/lib/xmodule/xmodule/util/django.py

@@ -0,0 +1,20 @@
+"""
+Exposes Django utilities for consumption in the xmodule library
+NOTE: This file should only be imported into 'django-safe' code, i.e. known that this code runs int the Django 
+runtime environment with the djangoapps in common configured to load
+"""
+
+# NOTE: we are importing this method so that any module that imports us has access to get_current_request
+from crum import get_current_request
+
+
+def get_current_request_hostname():
+	"""
+	This method will return the hostname that was used in the current Django request
+	"""
+	hostname = None
+	request = get_current_request()
+	if request:
+		hostname = request.META.get('HTTP_HOST')
+
+	return hostname

lms/djangoapps/courseware/tests/test_courses.py

@@ -1,8 +1,11 @@
 # -*- coding: utf-8 -*-
+import mock
+
 from django.test import TestCase
 from django.http import Http404
 from django.test.utils import override_settings
 from courseware.courses import get_course_by_id, get_cms_course_link_by_id
+from xmodule.modulestore.django import get_default_store_name_for_current_request
 
 CMS_BASE_TEST = 'testcms'
 
@@ -26,3 +29,14 @@ def test_get_cms_course_link_by_id(self):
         self.assertEqual("//{}/".format(CMS_BASE_TEST), get_cms_course_link_by_id("blah_bad_course_id"))
         self.assertEqual("//{}/".format(CMS_BASE_TEST), get_cms_course_link_by_id("too/too/many/slashes"))
         self.assertEqual("//{}/org/num/course/name".format(CMS_BASE_TEST), get_cms_course_link_by_id('org/num/name'))
+
+
+    @mock.patch('xmodule.modulestore.django.get_current_request_hostname', mock.Mock(return_value='preview.localhost'))
+    @override_settings(HOSTNAME_MODULESTORE_DEFAULT_MAPPINGS={'preview\.': 'draft'})
+    def test_default_modulestore_preview_mapping(self):   
+        self.assertEqual(get_default_store_name_for_current_request(), 'draft')
+
+    @mock.patch('xmodule.modulestore.django.get_current_request_hostname', mock.Mock(return_value='localhost'))
+    @override_settings(HOSTNAME_MODULESTORE_DEFAULT_MAPPINGS={'preview\.': 'draft'})
+    def test_default_modulestore_published_mapping(self):
+        self.assertEqual(get_default_store_name_for_current_request(), 'default')

lms/envs/cms/aws.py

@@ -12,3 +12,5 @@
     CMS_AUTH_TOKENS = json.load(auth_file)
 
 MODULESTORE = CMS_AUTH_TOKENS['MODULESTORE']
+
+HOSTNAME_MODULESTORE_DEFAULT_MAPPINGS = ENVS_TOKENS.get('HOSTNAME_MODULESTORE_DEFAULT_MAPPINGS',{})

lms/envs/cms/dev.py

@@ -39,6 +39,10 @@
         'ENGINE': 'xmodule.modulestore.mongo.MongoModuleStore',
         'OPTIONS': modulestore_options
     },
+    'draft': {
+        'ENGINE': 'xmodule.modulestore.mongo.DraftMongoModuleStore',
+        'OPTIONS': modulestore_options    
+    },
 }
 
 CONTENTSTORE = {
@@ -58,3 +62,10 @@
 DEBUG_TOOLBAR_PANELS += (
    'debug_toolbar_mongo.panel.MongoDebugPanel',
    )
+
+# HOSTNAME_MODULESTORE_DEFAULT_MAPPINGS defines, as dictionary of regex's, a set of mappings of HTTP request hostnames to
+# what the 'default' modulestore to use while processing the request
+# for example 'preview.edx.org' should use the draft modulestore
+HOSTNAME_MODULESTORE_DEFAULT_MAPPINGS = {
+    'preview\.': 'draft'
+}

lms/envs/common.py

@@ -579,6 +579,7 @@
     #'django.contrib.auth.middleware.AuthenticationMiddleware',
     'cache_toolbox.middleware.CacheBackedAuthenticationMiddleware',
     'contentserver.middleware.StaticContentServer',
+    'crum.CurrentRequestUserMiddleware',
 
     'django.contrib.messages.middleware.MessageMiddleware',
     'track.middleware.TrackMiddleware',

requirements/edx/base.txt

@@ -98,6 +98,7 @@ django_debug_toolbar
 django-debug-toolbar-mongo
 nose-ignore-docstring
 nose-exclude
+django-crum==0.5
 
 git+https://github.com/mfogel/django-settings-context-processor.git