Stop hard-error on file-not-found; add resolution for shared assets (…

…things in Static) in the Python apps

README.md

@@ -41,15 +41,20 @@ in `settings.py` add cdn_helpers to your list of installed apps:
         'cdn_helpers'
     )
 
+in your local-development `local_settings.py`:
+
+    APP_DEPLOYMENT_ENV = 'local'   # (disables CDN url generation)
+    CDN_HOSTS = []
+
 in the appropriate `local_settings.py`:
 
     APP_DEPLOYMENT_ENV = 'dev'   # (or staging, production)
     CDN_HOSTS = ['cdn1', 'cdn2'] # (as appropriate for the environment)
-
+    SHARED_PUBLIC_ROOT = "/path/to/shared/assets" # (i.e. where Static's public dir is)
 
 in templates use the `asset_url` helper:
 
     <img src="{% asset_url "/images/thing.png" %}">
-    <img src="{% asset_url thing.image.src %}">
+    <img src="{% asset_url thing.image.url %}">
 
 The app provides the `cdn_css` command for `manage.py`. This uses the Ruby script process_css to do the heavy lifting, but relies on the `MEDIA_ROOT` and `MEDIA_URL` settings in `settings.py` to tell where to look and how to construct the URLs.

py/cdn_helpers/templatetags/asset_url.py

@@ -25,8 +25,10 @@ def __init__(self, settings = None):
     def process_url(self, url):
         """Process url and return a suitable URL for the app's environment"""
         if hasattr(self.settings, 'APP_DEPLOYMENT_ENV') and self.settings.APP_DEPLOYMENT_ENV != 'local':
-            sha1 = self.generate_sha1(self.file_path_from_url(url))
-            return self.compose_url(url, sha1)
+            sha1 = self.fetch_sha1(self.file_path_from_url(url), self.generate_sha1)
+            if sha1 != None:
+                url = self.compose_path(url, sha1)
+            return self.compose_url(url)
         else:
             return url
 
@@ -36,22 +38,34 @@ def file_path_from_url(self, url):
             media_url = '%s/' % self.settings.MEDIA_URL.lstrip('/').rstrip('/')
             if stripped_url.find(media_url) == 0:
                 url = stripped_url[len(media_url) - 1:]
-        return os.path.normpath(os.path.join(self.settings.MEDIA_ROOT, url.lstrip('/')))
+        local_path = os.path.normpath(os.path.join(self.settings.MEDIA_ROOT, url.lstrip('/')))
+        if os.path.exists(local_path):
+            return local_path
+        if hasattr(self.settings, 'SHARED_PUBLIC_ROOT'):
+            shared_path = os.path.normpath(os.path.join(self.settings.SHARED_PUBLIC_ROOT, url.lstrip('/')))
+            if os.path.exists(shared_path):
+                return shared_path
+        return None
 
     def generate_sha1(self, file_path):
         """Generates and return sha1 for the file at file_path"""
         # import hashlib
+        if file_path == None:
+            return None
         hash_func = hashlib.sha1()
         with open(file_path) as f:
             hash_func.update(f.read())
 
         return hash_func.hexdigest()
+
+    def compose_path(self, path, sha1):
+        """Stitch path and hash together"""
+        return path + '/' + sha1[0:8] + os.path.splitext(path)[1]
 
-    def compose_url(self, path, sha1):
-        """Stitch path and hash together into a CDN url"""
+    def compose_url(self, uri_path):
+        """Stitch hashed path into a CDN url"""
         # import random, os
         host = random.choice(self.settings.CDN_HOSTS)
-        uri_path = path + '/' + sha1[0:8] + os.path.splitext(path)[1]
         return urlparse.urlunparse(('http', host, uri_path, '', '', ''))
 
     def fetch_sha1(self, path, sha1_generator):

test/test_cdn_helpers.py

@@ -33,12 +33,18 @@ def test_sha1_calculation(self):
             self.asset_url.generate_sha1(os.path.join(fixtures_dir, 'h5.png')), 
             'daf4a94f8d2cc9f564a6f958d1915ea9346d09f1'
         )
+
+    def test_sha1_calculation_returns_None_if_passed_None(self):
+        self.assertEqual(
+            self.asset_url.generate_sha1(None), 
+            None
+        )
 
     def test_url_generation(self):
         self.django_settings['CDN_HOSTS'] = ['dev1.host.com']
 
         self.assertEqual(
-            self.asset_url.compose_url('/images/h5.png', 'daf4a94f8d2cc9f564a6f958d1915ea9346d09f1'),
+            self.asset_url.compose_url('/images/h5.png/daf4a94f.png'),
             'http://dev1.host.com/images/h5.png/daf4a94f.png'
         )
 
@@ -85,6 +91,34 @@ def test_correctly_locates_a_file_when_media_url_is_set(self):
             os.path.normpath(os.path.join(fixtures_dir, 'images/thing.png'))
         )
 
+    def test_correctly_locates_a_shared_file_if_SHARED_PUBLIC_ROOT_is_set(self):
+        self.django_settings['MEDIA_ROOT'] = fixtures_dir
+        self.django_settings['MEDIA_URL'] = '/media_url/'
+        self.django_settings['SHARED_PUBLIC_ROOT'] = os.path.join(fixtures_dir, 'files_from_static')
+
+        self.assertEqual(
+            self.asset_url.file_path_from_url('/media_url/images/answers-advisory-highlight.png'), 
+            os.path.normpath(os.path.join(fixtures_dir, 'files_from_static', 'images/answers-advisory-highlight.png'))
+        )
+
+    def test_returns_None_for_a_shared_file_if_SHARED_PUBLIC_ROOT_is_not_set(self):
+        self.django_settings['MEDIA_ROOT'] = fixtures_dir
+        self.django_settings['MEDIA_URL'] = '/media_url/'
+
+        self.assertEqual(
+            self.asset_url.file_path_from_url('/media_url/images/answers-advisory-highlight.png'), 
+            None
+        )
+
+    def test_returns_None_if_file_cannot_be_located(self):
+        self.django_settings['MEDIA_ROOT'] = fixtures_dir
+        self.django_settings['MEDIA_URL'] = '/media_url/'
+
+        self.assertEqual(
+            self.asset_url.file_path_from_url('/media_url/unreal.css'), 
+            None
+        )
+
 class TestAssetUrlFromCDN(unittest.TestCase):
     def setUp(self):
         self.django_settings = MockSettings()
@@ -96,6 +130,12 @@ def test_cdn_url_created(self):
         self.django_settings['CDN_HOSTS'] = ['cdn.host.com']
         self.assertEqual(self.asset_url.process_url('/h5.png'), 'http://cdn.host.com/h5.png/daf4a94f.png')
 
+    def test_cdn_url_returns_unhashed_url_if_file_not_found(self):
+        self.django_settings['MEDIA_ROOT'] = fixtures_dir
+        self.django_settings['APP_DEPLOYMENT_ENV'] = 'dev'
+        self.django_settings['CDN_HOSTS'] = ['cdn.host.com']
+        self.assertEqual(self.asset_url.process_url('/h51.png'), 'http://cdn.host.com/h51.png')
+
 
 if __name__ == '__main__':
     unittest.main()