added S3_CDN_DOMAIN support

docs/index.rst

@@ -177,6 +177,11 @@ uploading assets to S3.
 `S3_BUCKET_DOMAIN`          The domain part of the URI for your S3 bucket. You 
                             probably won't need to change this.
                             **Default:** ``u's3.amazonaws.com'``
+'S3_CDN_DOMAIN'             AWS makes it easy to attach CloudFront to an S3
+                            bucket. If you want to use this or another CDN,
+                            set the base domain here. This is distinct from the
+                            'S3_BUCKET_DOMAIN` since it will not include the
+                            bucket name in the base url.
 `S3_BUCKET_NAME`            The desired name for your Amazon S3 bucket. Note: 
                             the name will be visible in all your assets' URLs.
 `S3_USE_HTTPS`              Specifies whether or not to serve your assets

flask_s3.py

@@ -38,6 +38,8 @@ def url_for(endpoint, **values):
             scheme = 'https'
         bucket_path = '%s.%s' % (app.config['S3_BUCKET_NAME'],
                                  app.config['S3_BUCKET_DOMAIN'])
+        if app.config['S3_CDN_DOMAIN']:
+            bucket_path = '%s' % app.config['S3_CDN_DOMAIN']
         urls = app.url_map.bind(bucket_path, url_scheme=scheme)
         return urls.build(endpoint, values=values, force_external=True)
     return flask_url_for(endpoint, **values)
@@ -219,8 +221,10 @@ class FlaskS3(object):
                     ('USE_S3', True),
                     ('USE_S3_DEBUG', False),
                     ('S3_BUCKET_DOMAIN', 's3.amazonaws.com'),
+                    ('S3_CDN_DOMAIN', ''),
                     ('S3_USE_CACHE_CONTROL', False),
                     ('S3_HEADERS', {})]
+
         for k, v in defaults:
             app.config.setdefault(k, v)
 

tests/test_flask_static.py

@@ -29,7 +29,8 @@ class FlaskStaticTest(unittest.TestCase):
         """ Tests configuration vars exist. """
         FlaskS3(self.app)
         defaults = ('S3_USE_HTTPS', 'USE_S3', 'USE_S3_DEBUG', 
-                    'S3_BUCKET_DOMAIN', 'S3_USE_CACHE_CONTROL', 'S3_HEADERS')
+                    'S3_BUCKET_DOMAIN', 'S3_CDN_DOMAIN',
+                    'S3_USE_CACHE_CONTROL', 'S3_HEADERS')
         for default in defaults:
             self.assertIn(default, self.app.config)
 
@@ -41,6 +42,7 @@ class UrlTests(unittest.TestCase):
         self.app.config['S3_BUCKET_NAME'] = 'foo'
         self.app.config['S3_USE_HTTPS'] = True
         self.app.config['S3_BUCKET_DOMAIN'] = 's3.amazonaws.com'
+        self.app.config['S3_CDN_DOMAIN'] = ''
 
         @self.app.route('/<url_for_string>')
         def a(url_for_string):