- inheriting covers after parents,

[wolnelektury.git] / apps / catalogue / utils.py

diff --git a/apps/catalogue/utils.py b/apps/catalogue/utils.py
index bda7e04..1ac0ee8 100644 (file)
--- a/apps/catalogue/utils.py
+++ b/apps/catalogue/utils.py
@@ -276,3 +276,27 @@ def clear_custom_pdf(book):
     """
     from waiter.utils import clear_cache
     clear_cache('book/%s' % book.slug)
+
+
+class AppSettings(object):
+    """Allows specyfying custom settings for an app, with default values.
+
+    Just subclass, set some properties and instantiate with a prefix.
+    Getting a SETTING from an instance will check for prefix_SETTING
+    in project settings if set, else take the default. The value will be
+    then filtered through _more_SETTING method, if there is one.
+
+    """
+    def __init__(self, prefix):
+        self._prefix = prefix
+
+    def __getattribute__(self, name):
+        if name.startswith('_'):
+            return object.__getattribute__(self, name)
+        value = getattr(settings,
+                         "%s_%s" % (self._prefix, name),
+                         object.__getattribute__(self, name))
+        more = "_more_%s" % name
+        if hasattr(self, more):
+            value = getattr(self, more)(value)
+        return value