per feedback, use reverse() when generating callback urls. Also generate…

per feedback, use reverse() when generating callback urls. Also generate thumbnails when ingesting static images. We'll need these handy for the CMS UI.

cms/djangoapps/contentstore/views.py

 from util.json_request import expect_json
 import json
+import os
 import logging
 import sys
 import mimetypes
+import StringIO
 from collections import defaultdict
 
+# to install PIL on MacOSX: 'easy_install http://dist.repoze.org/PIL-1.1.6.tar.gz'
+from PIL import Image
+
 from django.http import HttpResponse, Http404, HttpResponseBadRequest, HttpResponseForbidden
 from django.contrib.auth.decorators import login_required
 from django.core.context_processors import csrf
@@ -101,11 +106,18 @@ def course_index(request, org, course, name):
     _course = modulestore().get_item(location)
     weeks = _course.get_children()
 
-    upload_asset_callback_url = "/{org}/{course}/course/{name}/upload_asset".format(
-        org = org, 
-        course = course,
-        name = name
-        )
+    #upload_asset_callback_url = "/{org}/{course}/course/{name}/upload_asset".format(
+    #    org = org, 
+    #    course = course,
+    #    name = name
+    #    )
+
+    upload_asset_callback_url = reverse('upload_asset', kwargs = {
+            'org' : org,
+            'course' : course,
+            'coursename' : name
+            })
+    logging.debug(upload_asset_callback_url)
 
     return render_to_response('course_index.html', {
             'weeks': weeks, 
@@ -460,5 +472,44 @@ def upload_asset(request, org, course, coursename):
     # to re-populate the cache.
     del_cached_content(file_location)
 
+    # if we're uploading an image, then let's generate a thumbnail so that we can
+    # serve it up when needed without having to rescale on the fly
+    if mime_type.split('/')[0] == 'image':
+        try:
+            # not sure if this is necessary, but let's rewind the stream just in case
+            request.FILES['file'].seek(0)
+
+            # use PIL to do the thumbnail generation (http://www.pythonware.com/products/pil/)
+            # My understanding is that PIL will maintain aspect ratios while restricting
+            # the max-height/width to be whatever you pass in as 'size'
+            # @todo: move the thumbnail size to a configuration setting?!?
+            im = Image.open(request.FILES['file'])
+
+            # I've seen some exceptions from the PIL library when trying to save palletted 
+            # PNG files to JPEG. Per the google-universe, they suggest converting to RGB first.
+            im = im.convert('RGB')
+            size = 128, 128
+            im.thumbnail(size, Image.ANTIALIAS)
+            thumbnail_file = StringIO.StringIO()
+            im.save(thumbnail_file, 'JPEG')
+            thumbnail_file.seek(0)
+        
+            # use a naming convention to associate originals with the thumbnail
+            #   <name_without_extention>.thumbnail.jpg
+            thumbnail_name = os.path.splitext(name)[0] + '.thumbnail.jpg'
+            # then just store this thumbnail as any other piece of content
+            thumbnail_file_location = StaticContent.compute_location_filename(org, course, 
+                                                                              thumbnail_name)
+            thumbnail_content = StaticContent(thumbnail_file_location, thumbnail_name, 
+                                              'image/jpeg', thumbnail_file)
+            contentstore().save(thumbnail_content)
+
+            # remove any cached content at this location, as thumbnails are treated just like any
+            # other bit of static content
+            del_cached_content(thumbnail_file_location)
+        except:
+            # catch, log, and continue as thumbnails are not a hard requirement
+            logging.error('Failed to generate thumbnail for {0}. Continuing...'.format(name))
+
     return HttpResponse('Upload completed')
 

common/djangoapps/contentserver/middleware.py

@@ -26,7 +26,9 @@ class StaticContentServer(object):
                 # since we fetched it from DB, let's cache it going forward
                 set_cached_content(content)
             else:
-                logging.debug('cache hit on {0}'.format(content.filename))
+                # @todo: we probably want to have 'cache hit' counters so we can
+                # measure the efficacy of our caches
+                pass
 
             # see if the last-modified at hasn't changed, if not return a 302 (Not Modified)