Configurable CSS Loader

django_inlinecss/conf.py

@@ -6,10 +6,26 @@
 DEFAULT_ENGINE = 'django_inlinecss.engines.PynlinerEngine'
 
 
+def load_class_by_path(path):
+    i = path.rfind('.')
+    module_path, class_name = path[:i], path[i + 1:]
+    module = importlib.import_module(module_path)
+    return getattr(module, class_name)
+
+
 def get_engine():
     from django.conf import settings
     engine_path = getattr(settings, 'INLINECSS_ENGINE', DEFAULT_ENGINE)
-    i = engine_path.rfind('.')
-    module_path, class_name = engine_path[:i], engine_path[i + 1:]
-    module = importlib.import_module(module_path)
-    return getattr(module, class_name)
+    return load_class_by_path(engine_path)
+
+
+def get_css_loader():
+    from django.conf import settings
+
+    if settings.DEBUG:
+        default_css_loader = 'django_inlinecss.css_loaders.StaticFinderCSSLoader'
+    else:
+        default_css_loader = 'django_inlinecss.css_loaders.StaticPathCSSLoader'
+
+    engine_path = getattr(settings, 'INLINECSS_CSS_LOADER', default_css_loader)
+    return load_class_by_path(engine_path)

django_inlinecss/css_loaders.py

@@ -0,0 +1,38 @@
+from django.contrib.staticfiles import finders
+from django.contrib.staticfiles.storage import staticfiles_storage
+
+
+def load_css_by_path(path):
+    with open(path) as css_file:
+        return css_file.read()
+
+
+class BaseCSSLoader(object):
+    def __init__(self):
+        pass
+
+    def load(self, path):
+        """
+        Retrieves the contents of the static asset specified
+        :param path: path to the desired asset
+        :return: contents of asset
+        """
+        raise NotImplementedError()
+
+
+class StaticFinderCSSLoader(BaseCSSLoader):
+    def load(self, path):
+        """
+        Retrieve CSS contents by static finders
+        """
+        expanded_path = finders.find(path)
+        return load_css_by_path(expanded_path)
+
+
+class StaticPathCSSLoader(BaseCSSLoader):
+    def load(self, path):
+        """
+        Retrieve CSS contents by local file system
+        """
+        expanded_path = staticfiles_storage.path(path)
+        return load_css_by_path(expanded_path)

django_inlinecss/templatetags/inlinecss.py

@@ -22,13 +22,9 @@ def render(self, context):
             path = expression.resolve(context, True)
             if path is not None:
                 path = smart_text(path)
-            if settings.DEBUG:
-                expanded_path = finders.find(path)
-            else:
-                expanded_path = staticfiles_storage.path(path)
 
-            with open(expanded_path) as css_file:
-                css = ''.join((css, css_file.read()))
+            css_loader = conf.get_css_loader()()
+            css = ''.join((css, css_loader.load(path)))
 
         engine = conf.get_engine()(html=rendered_contents, css=css)
         return engine.render()

django_inlinecss/tests/test_css_loaders.py

@@ -0,0 +1,52 @@
+"""
+Test CSS loaders
+"""
+import os
+
+from django.test import TestCase
+from django.test.utils import override_settings
+
+from mock import patch
+
+from django_inlinecss.tests.constants import TESTS_STATIC_DIR
+from django_inlinecss.css_loaders import StaticFinderCSSLoader, StaticPathCSSLoader
+
+
+@override_settings(STATIC_ROOT=TESTS_STATIC_DIR)
+class StaticFinderCSSLoaderTestCase(TestCase):
+    def setUp(self):
+        self.loader = StaticFinderCSSLoader()
+        super(StaticFinderCSSLoaderTestCase, self).setUp()
+
+    @patch('django.contrib.staticfiles.finders.find')
+    def test_debug_mode_uses_staticfiles_finder(self, find):
+        full_path = os.path.join(TESTS_STATIC_DIR, 'bar.css')
+        find.return_value = full_path
+        css = self.loader.load(full_path)
+        self.assertIn('div.bar {', css)
+
+    @patch('django.contrib.staticfiles.finders.find')
+    def test_load_file_does_not_exists(self, find):
+        full_path = os.path.join(TESTS_STATIC_DIR, 'missing.css')
+        find.return_value = full_path
+        with self.assertRaises(IOError) as e:
+            self.loader.load('missing.css')
+
+        self.assertEqual(e.exception.strerror, 'No such file or directory')
+
+
+@override_settings(STATIC_ROOT=TESTS_STATIC_DIR)
+class StaticPathCSSLoaderTestCase(TestCase):
+    def setUp(self):
+        self.loader = StaticPathCSSLoader()
+        super(StaticPathCSSLoaderTestCase, self).setUp()
+
+    def test_load_existing_css_file(self):
+        css = self.loader.load('bar.css')
+        self.assertIn('div.bar {', css)
+
+    def test_load_file_does_not_exists(self):
+        with self.assertRaises(IOError) as e:
+            self.loader.load('missing.css')
+
+        self.assertEqual(e.exception.strerror, 'No such file or directory')