Merge pull request #12841 from edx/bugfix/versioned-assets-cutover

Fixed-up versioned assets implementation.

cms/djangoapps/contentstore/tests/test_contentstore.py

@@ -1000,7 +1000,7 @@ class MiscCourseTests(ContentStoreTestCase):
           3) computing thumbnail location of asset
           4) deleting the asset from the course
         """
-        asset_key = self.course.id.make_asset_key('asset', 'sample_static.txt')
+        asset_key = self.course.id.make_asset_key('asset', 'sample_static.html')
         content = StaticContent(
             asset_key, "Fake asset", "application/text", "test",
         )
@@ -1072,7 +1072,7 @@ class MiscCourseTests(ContentStoreTestCase):
         draft content is also deleted
         """
         # add an asset
-        asset_key = self.course.id.make_asset_key('asset', 'sample_static.txt')
+        asset_key = self.course.id.make_asset_key('asset', 'sample_static.html')
         content = StaticContent(
             asset_key, "Fake asset", "application/text", "test",
         )

cms/djangoapps/contentstore/tests/utils.py

@@ -121,7 +121,7 @@ class CourseTestCase(ProceduralCourseTestMixin, ModuleStoreTestCase):
     SEQUENTIAL = 'vertical_sequential'
     DRAFT_HTML = 'draft_html'
     DRAFT_VIDEO = 'draft_video'
-    LOCKED_ASSET_KEY = AssetLocation.from_deprecated_string('/c4x/edX/toy/asset/sample_static.txt')
+    LOCKED_ASSET_KEY = AssetLocation.from_deprecated_string('/c4x/edX/toy/asset/sample_static.html')
 
     def import_and_populate_course(self):
         """

cms/djangoapps/contentstore/views/tests/test_assets.py

@@ -126,7 +126,7 @@ class BasicAssetsTestCase(AssetsTestCase):
             )
             course = module_store.get_course(course_id)
 
-            filename = 'sample_static.txt'
+            filename = 'sample_static.html'
             html_src_attribute = '"/static/{}"'.format(filename)
             asset_url = replace_static_urls(html_src_attribute, course_id=course.id)
             url = asset_url.replace('"', '')
@@ -379,7 +379,7 @@ class LockAssetTestCase(AssetsTestCase):
         """
         def verify_asset_locked_state(locked):
             """ Helper method to verify lock state in the contentstore """
-            asset_location = StaticContent.get_location_from_path('/c4x/edX/toy/asset/sample_static.txt')
+            asset_location = StaticContent.get_location_from_path('/c4x/edX/toy/asset/sample_static.html')
             content = contentstore().find(asset_location)
             self.assertEqual(content.locked, locked)
 
@@ -387,14 +387,14 @@ class LockAssetTestCase(AssetsTestCase):
             """ Helper method for posting asset update. """
             content_type = 'application/txt'
             upload_date = datetime(2013, 6, 1, 10, 30, tzinfo=UTC)
-            asset_location = course.id.make_asset_key('asset', 'sample_static.txt')
+            asset_location = course.id.make_asset_key('asset', 'sample_static.html')
             url = reverse_course_url('assets_handler', course.id, kwargs={'asset_key_string': unicode(asset_location)})
 
             resp = self.client.post(
                 url,
                 # pylint: disable=protected-access
                 json.dumps(assets._get_asset_json(
-                    "sample_static.txt", content_type, upload_date, asset_location, None, lock)),
+                    "sample_static.html", content_type, upload_date, asset_location, None, lock)),
                 "application/json"
             )
 

common/djangoapps/contentserver/middleware.py

@@ -3,12 +3,11 @@ Middleware to serve assets.
 """
 
 import logging
-
 import datetime
 import newrelic.agent
 from django.http import (
     HttpResponse, HttpResponseNotModified, HttpResponseForbidden,
-    HttpResponseBadRequest, HttpResponseNotFound)
+    HttpResponseBadRequest, HttpResponseNotFound, HttpResponsePermanentRedirect)
 from student.models import CourseEnrollment
 from contentserver.models import CourseAssetCacheTtlConfig, CdnUserAgentsConfig
 
@@ -30,32 +29,54 @@ HTTP_DATE_FORMAT = "%a, %d %b %Y %H:%M:%S GMT"
 
 
 class StaticContentServer(object):
+    """
+    Serves course assets to end users.  Colloquially referred to as "contentserver."
+    """
     def is_asset_request(self, request):
         """Determines whether the given request is an asset request"""
         return (
             request.path.startswith('/' + XASSET_LOCATION_TAG + '/')
             or
             request.path.startswith('/' + AssetLocator.CANONICAL_NAMESPACE)
+            or
+            StaticContent.is_versioned_asset_path(request.path)
         )
 
     def process_request(self, request):
         """Process the given request"""
+        asset_path = request.path
+
         if self.is_asset_request(request):
             # Make sure we can convert this request into a location.
-            if AssetLocator.CANONICAL_NAMESPACE in request.path:
-                request.path = request.path.replace('block/', 'block@', 1)
+            if AssetLocator.CANONICAL_NAMESPACE in asset_path:
+                asset_path = asset_path.replace('block/', 'block@', 1)
+
+            # If this is a versioned request, pull out the digest and chop off the prefix.
+            requested_digest = None
+            if StaticContent.is_versioned_asset_path(asset_path):
+                requested_digest, asset_path = StaticContent.parse_versioned_asset_path(asset_path)
+
+            # Make sure we have a valid location value for this asset.
             try:
-                loc = StaticContent.get_location_from_path(request.path)
+                loc = StaticContent.get_location_from_path(asset_path)
             except (InvalidLocationError, InvalidKeyError):
                 return HttpResponseBadRequest()
 
-            # Try and load the asset.
-            content = None
+            # Attempt to load the asset to make sure it exists, and grab the asset digest
+            # if we're able to load it.
+            actual_digest = None
             try:
                 content = self.load_asset_from_location(loc)
+                actual_digest = getattr(content, "content_digest", None)
             except (ItemNotFoundError, NotFoundError):
                 return HttpResponseNotFound()
 
+            # If this was a versioned asset, and the digest doesn't match, redirect
+            # them to the actual version.
+            if requested_digest is not None and actual_digest is not None and (actual_digest != requested_digest):
+                actual_asset_path = StaticContent.add_version_to_asset_path(asset_path, actual_digest)
+                return HttpResponsePermanentRedirect(actual_asset_path)
+
             # Set the basics for this request. Make sure that the course key for this
             # asset has a run, which old-style courses do not.  Otherwise, this will
             # explode when the key is serialized to be sent to NR.

common/djangoapps/contentserver/test/test_contentserver.py

@@ -16,9 +16,13 @@ from django.test.utils import override_settings
 from mock import patch
 
 from xmodule.contentstore.django import contentstore
+from xmodule.contentstore.content import StaticContent
 from xmodule.modulestore.django import modulestore
 from xmodule.modulestore.tests.django_utils import SharedModuleStoreTestCase
 from xmodule.modulestore.xml_importer import import_course_from_xml
+from xmodule.assetstore.assetmgr import AssetManager
+from opaque_keys import InvalidKeyError
+from xmodule.modulestore.exceptions import ItemNotFoundError
 
 from contentserver.middleware import parse_range_header, HTTP_DATE_FORMAT, StaticContentServer
 from student.models import CourseEnrollment
@@ -28,9 +32,24 @@ log = logging.getLogger(__name__)
 
 TEST_DATA_CONTENTSTORE = copy.deepcopy(settings.CONTENTSTORE)
 TEST_DATA_CONTENTSTORE['DOC_STORE_CONFIG']['db'] = 'test_xcontent_%s' % uuid4().hex
-
 TEST_DATA_DIR = settings.COMMON_TEST_DATA_ROOT
 
+FAKE_MD5_HASH = 'ffffffffffffffffffffffffffffffff'
+
+
+def get_versioned_asset_url(asset_path):
+    """
+    Creates a versioned asset URL.
+    """
+    try:
+        locator = StaticContent.get_location_from_path(asset_path)
+        content = AssetManager.find(locator, as_stream=True)
+        return StaticContent.add_version_to_asset_path(asset_path, content.content_digest)
+    except (InvalidKeyError, ItemNotFoundError):
+        pass
+
+    return asset_path
+
 
 @ddt.ddt
 @override_settings(CONTENTSTORE=TEST_DATA_CONTENTSTORE)
@@ -54,13 +73,15 @@ class ContentStoreToyCourseTest(SharedModuleStoreTestCase):
         )
 
         # A locked asset
-        cls.locked_asset = cls.course_key.make_asset_key('asset', 'sample_static.txt')
+        cls.locked_asset = cls.course_key.make_asset_key('asset', 'sample_static.html')
         cls.url_locked = unicode(cls.locked_asset)
+        cls.url_locked_versioned = get_versioned_asset_url(cls.url_locked)
         cls.contentstore.set_attr(cls.locked_asset, 'locked', True)
 
         # An unlocked asset
         cls.unlocked_asset = cls.course_key.make_asset_key('asset', 'another_static.txt')
         cls.url_unlocked = unicode(cls.unlocked_asset)
+        cls.url_unlocked_versioned = get_versioned_asset_url(cls.url_unlocked)
         cls.length_unlocked = cls.contentstore.get_attr(cls.unlocked_asset, 'length')
 
     def setUp(self):
@@ -81,6 +102,37 @@ class ContentStoreToyCourseTest(SharedModuleStoreTestCase):
         resp = self.client.get(self.url_unlocked)
         self.assertEqual(resp.status_code, 200)
 
+    def test_unlocked_versioned_asset(self):
+        """
+        Test that unlocked assets that are versioned are being served.
+        """
+        self.client.logout()
+        resp = self.client.get(self.url_unlocked_versioned)
+        self.assertEqual(resp.status_code, 200)
+
+    def test_unlocked_versioned_asset_with_nonexistent_version(self):
+        """
+        Test that unlocked assets that are versioned, but have a nonexistent version,
+        are sent back as a 301 redirect which tells the caller the correct URL.
+        """
+        url_unlocked_versioned_old = StaticContent.add_version_to_asset_path(self.url_unlocked, FAKE_MD5_HASH)
+
+        self.client.logout()
+        resp = self.client.get(url_unlocked_versioned_old)
+        self.assertEqual(resp.status_code, 301)
+        self.assertTrue(resp.url.endswith(self.url_unlocked_versioned))  # pylint: disable=no-member
+
+    def test_locked_versioned_asset(self):
+        """
+        Test that locked assets that are versioned are being served.
+        """
+        CourseEnrollment.enroll(self.non_staff_usr, self.course_key)
+        self.assertTrue(CourseEnrollment.is_enrolled(self.non_staff_usr, self.course_key))
+
+        self.client.login(username=self.non_staff_usr, password='test')
+        resp = self.client.get(self.url_locked_versioned)
+        self.assertEqual(resp.status_code, 200)
+
     def test_locked_asset_not_logged_in(self):
         """
         Test that locked assets behave appropriately in case the user is not

common/lib/xmodule/xmodule/contentstore/content.py

@@ -5,16 +5,16 @@ from xmodule.assetstore.assetmgr import AssetManager
 
 XASSET_LOCATION_TAG = 'c4x'
 XASSET_SRCREF_PREFIX = 'xasset:'
-
 XASSET_THUMBNAIL_TAIL_NAME = '.jpg'
-
 STREAM_DATA_CHUNK_SIZE = 1024
+VERSIONED_ASSETS_PREFIX = '/assets/courseware'
+VERSIONED_ASSETS_PATTERN = r'/assets/courseware/([a-f0-9]{32})'
 
 import os
 import logging
 import StringIO
 from urlparse import urlparse, urlunparse, parse_qsl
-from urllib import urlencode
+from urllib import urlencode, quote_plus
 
 from opaque_keys.edx.locator import AssetLocator
 from opaque_keys.edx.keys import CourseKey, AssetKey
@@ -26,7 +26,7 @@ from PIL import Image
 
 class StaticContent(object):
     def __init__(self, loc, name, content_type, data, last_modified_at=None, thumbnail_location=None, import_path=None,
-                 length=None, locked=False):
+                 length=None, locked=False, content_digest=None):
         self.location = loc
         self.name = name  # a display string which can be edited, and thus not part of the location which needs to be fixed
         self.content_type = content_type
@@ -38,6 +38,7 @@ class StaticContent(object):
         # cycles
         self.import_path = import_path
         self.locked = locked
+        self.content_digest = content_digest
 
     @property
     def is_thumbnail(self):
@@ -146,6 +147,40 @@ class StaticContent(object):
                 return AssetKey.from_string(path[1:])
 
     @staticmethod
+    def is_versioned_asset_path(path):
+        """Determines whether the given asset path is versioned."""
+        return path.startswith(VERSIONED_ASSETS_PREFIX)
+
+    @staticmethod
+    def parse_versioned_asset_path(path):
+        """
+        Examines an asset path and breaks it apart if it is versioned,
+        returning both the asset digest and the unversioned asset path,
+        which will normally be an AssetKey.
+        """
+        asset_digest = None
+        asset_path = path
+        if StaticContent.is_versioned_asset_path(asset_path):
+            result = re.match(VERSIONED_ASSETS_PATTERN, asset_path)
+            if result is not None:
+                asset_digest = result.groups()[0]
+            asset_path = re.sub(VERSIONED_ASSETS_PATTERN, '', asset_path)
+
+        return (asset_digest, asset_path)
+
+    @staticmethod
+    def add_version_to_asset_path(path, version):
+        """
+        Adds a prefix to an asset path indicating the asset's version.
+        """
+
+        # Don't version an already-versioned path.
+        if StaticContent.is_versioned_asset_path(path):
+            return path
+
+        return VERSIONED_ASSETS_PREFIX + '/' + version + path
+
+    @staticmethod
     def get_asset_key_from_path(course_key, path):
         """
         Parses a path, extracting an asset key or creating one.
@@ -172,7 +207,16 @@ class StaticContent(object):
             return StaticContent.compute_location(course_key, path)
 
     @staticmethod
-    def get_canonicalized_asset_path(course_key, path, base_url, excluded_exts):
+    def is_excluded_asset_type(path, excluded_exts):
+        """
+        Check if this is an allowed file extension to serve.
+
+        Some files aren't served through the CDN in order to avoid same-origin policy/CORS-related issues.
+        """
+        return any(path.lower().endswith(excluded_ext.lower()) for excluded_ext in excluded_exts)
+
+    @staticmethod
+    def get_canonicalized_asset_path(course_key, path, base_url, excluded_exts, encode=True):
         """
         Returns a fully-qualified path to a piece of static content.
 
@@ -188,25 +232,27 @@ class StaticContent(object):
         """
 
         # Break down the input path.
-        _, _, relative_path, params, query_string, fragment = urlparse(path)
+        _, _, relative_path, params, query_string, _ = urlparse(path)
 
         # Convert our path to an asset key if it isn't one already.
         asset_key = StaticContent.get_asset_key_from_path(course_key, relative_path)
 
         # Check the status of the asset to see if this can be served via CDN aka publicly.
         serve_from_cdn = False
+        content_digest = None
         try:
             content = AssetManager.find(asset_key, as_stream=True)
-            is_locked = getattr(content, "locked", True)
-            serve_from_cdn = not is_locked
+            serve_from_cdn = not getattr(content, "locked", True)
+            content_digest = getattr(content, "content_digest", None)
         except (ItemNotFoundError, NotFoundError):
             # If we can't find the item, just treat it as if it's locked.
             serve_from_cdn = False
 
-        # See if this is an allowed file extension to serve.  Some files aren't served through the
-        # CDN in order to avoid same-origin policy/CORS-related issues.
-        if any(relative_path.lower().endswith(excluded_ext.lower()) for excluded_ext in excluded_exts):
+        # Do a generic check to see if anything about this asset disqualifies it from being CDN'd.
+        is_excluded = False
+        if StaticContent.is_excluded_asset_type(relative_path, excluded_exts):
             serve_from_cdn = False
+            is_excluded = True
 
         # Update any query parameter values that have asset paths in them. This is for assets that
         # require their own after-the-fact values, like a Flash file that needs the path of a config
@@ -215,15 +261,29 @@ class StaticContent(object):
         updated_query_params = []
         for query_name, query_val in query_params:
             if query_val.startswith("/static/"):
-                new_val = StaticContent.get_canonicalized_asset_path(course_key, query_val, base_url, excluded_exts)
+                new_val = StaticContent.get_canonicalized_asset_path(
+                    course_key, query_val, base_url, excluded_exts, encode=False)
                 updated_query_params.append((query_name, new_val))
             else:
-                updated_query_params.append((query_name, query_val))
+                # Make sure we're encoding Unicode strings down to their byte string
+                # representation so that `urlencode` can handle it.
+                updated_query_params.append((query_name, query_val.encode('utf-8')))
 
         serialized_asset_key = StaticContent.serialize_asset_key_with_slash(asset_key)
         base_url = base_url if serve_from_cdn else ''
+        asset_path = serialized_asset_key
+
+        # If the content has a digest (i.e. md5sum) value specified, create a versioned path to the asset using it.
+        if not is_excluded and content_digest:
+            asset_path = StaticContent.add_version_to_asset_path(serialized_asset_key, content_digest)
+
+        # Only encode this if told to.  Important so that we don't double encode
+        # when working with paths that are in query parameters.
+        asset_path = asset_path.encode('utf-8')
+        if encode:
+            asset_path = quote_plus(asset_path, '/:+@')
 
-        return urlunparse((None, base_url, serialized_asset_key, params, urlencode(updated_query_params), fragment))
+        return urlunparse((None, base_url.encode('utf-8'), asset_path, params, urlencode(updated_query_params), None))
 
     def stream_data(self):
         yield self._data
@@ -242,10 +302,10 @@ class StaticContent(object):
 
 class StaticContentStream(StaticContent):
     def __init__(self, loc, name, content_type, stream, last_modified_at=None, thumbnail_location=None, import_path=None,
-                 length=None, locked=False):
+                 length=None, locked=False, content_digest=None):
         super(StaticContentStream, self).__init__(loc, name, content_type, None, last_modified_at=last_modified_at,
                                                   thumbnail_location=thumbnail_location, import_path=import_path,
-                                                  length=length, locked=locked)
+                                                  length=length, locked=locked, content_digest=content_digest)
         self._stream = stream
 
     def stream_data(self):
@@ -277,7 +337,8 @@ class StaticContentStream(StaticContent):
         self._stream.seek(0)
         content = StaticContent(self.location, self.name, self.content_type, self._stream.read(),
                                 last_modified_at=self.last_modified_at, thumbnail_location=self.thumbnail_location,
-                                import_path=self.import_path, length=self.length, locked=self.locked)
+                                import_path=self.import_path, length=self.length, locked=self.locked,
+                                content_digest=self.content_digest)
         return content
 
 

common/lib/xmodule/xmodule/contentstore/mongo.py

@@ -128,7 +128,8 @@ class MongoContentStore(ContentStore):
                     location, fp.displayname, fp.content_type, fp, last_modified_at=fp.uploadDate,
                     thumbnail_location=thumbnail_location,
                     import_path=getattr(fp, 'import_path', None),
-                    length=fp.length, locked=getattr(fp, 'locked', False)
+                    length=fp.length, locked=getattr(fp, 'locked', False),
+                    content_digest=getattr(fp, 'md5', None),
                 )
             else:
                 with self.fs.get(content_id) as fp:
@@ -142,7 +143,8 @@ class MongoContentStore(ContentStore):
                         location, fp.displayname, fp.content_type, fp.read(), last_modified_at=fp.uploadDate,
                         thumbnail_location=thumbnail_location,
                         import_path=getattr(fp, 'import_path', None),
-                        length=fp.length, locked=getattr(fp, 'locked', False)
+                        length=fp.length, locked=getattr(fp, 'locked', False),
+                        content_digest=getattr(fp, 'md5', None),
                     )
         except NoFile:
             if throw_on_not_found: