srht.cache: add generalized caching system

srht/cache.py

@@ -0,0 +1,22 @@
+"""
+srht.cache is a simple wrapper around Redis which turns connection errors into
+cache misses.
+"""
+from srht.redis import redis
+
+def get_cache(key):
+    try:
+        return redis.get(key)
+    except:
+        return None
+
+def set_cache(key, expr, value):
+    try:
+        redis.setex(key, expr, value)
+    except:
+        pass
+
+def expunge_cache(key):
+    """Failing to expunge the cache may be a security issue, so this is not
+    wrapped in a try/except"""
+    redis.delete(key)