increment_cache_key() helper

src/c3nav/mapdata/utils/cache/__init__.py

@@ -1,4 +1,13 @@
+from django.core.cache import cache
+
 from c3nav.mapdata.utils.cache.indexed import GeometryIndexed  # noqa
 from c3nav.mapdata.utils.cache.maphistory import MapHistory  # noqa
 from c3nav.mapdata.utils.cache.accessrestrictions import AccessRestrictionAffected  # noqa
 from c3nav.mapdata.utils.cache.package import CachePackage  # noqa
+
+
+def increment_cache_key(cache_key):
+    try:
+        cache.incr(cache_key)
+    except ValueError:
+        cache.set(cache_key, 0, None)