--- a/src/p4l/utils.py	Fri Sep 20 22:21:48 2013 +0200
+++ b/src/p4l/utils.py	Sat Sep 21 23:49:04 2013 +0200
@@ -2,11 +2,13 @@
 import codecs
 import logging
 import math
+import hashlib
 import sys
 import unicodedata
 
 from django.conf import settings
 from django.core.validators import URLValidator
+from django.utils.http import urlquote_plus
 import requests
 
 
@@ -184,4 +186,24 @@
 def strip_accents(value):
     return ''.join(c for c in unicodedata.normalize('NFD', value)
                   if unicodedata.category(c) != 'Mn')
+    
+    
+def safe_cache_key(value):
+    '''Returns an md5 hexdigest of value if len(value) > 250. Replaces invalid memcache
+       control characters with an underscore. Also adds the CACHE_MIDDLEWARE_KEY_PREFIX
+       to your keys automatically.
+    '''
+    value = urlquote_plus(value)
+    for char in value:
+        if ord(char) < 33:
+            value = value.replace(char, '_')
+    
+    value = "%s_%s" % (settings.CACHE_MIDDLEWARE_KEY_PREFIX, value)
+    
+    if len(value) <= 250:
+        return value
+    
+    return hashlib.md5(value).hexdigest()
+
+
     
\ No newline at end of file