Fix ratelimit cache key prefix: strip Django version/prefix mangling

django-ratelimit (the @ratelimit view decorator) writes its counters
through Django's cache framework.  Django's default key function produces
'{KEY_PREFIX}:{VERSION}:{key}', so with KEY_PREFIX='' and VERSION=1
(defaults) the decorator keys appear in Redis as ':1:rl:{hash}' — an
ugly leading colon that makes them look distinct from the clean 'rl:*'
keys written by RateLimitMiddleware via get_redis_connection().

Add make_ratelimit_cache_key() to sapl/middleware/ratelimit.py (a simple
pass-through) and wire it into the 'ratelimit' cache config via
KEY_FUNCTION.  Both key families now share the same 'rl:*' namespace:

  decorator keys    →  rl:{hash}
  middleware keys   →  rl:ip:{ip}:reqs
                       rl:{ns}:user:{uid}:reqs
                       rl:{ns}:ip:{ip}:w:{bucket}

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

sapl/middleware/ratelimit.py

@@ -77,6 +77,22 @@ _INCR_LUA = """
 """
 
 
+def make_ratelimit_cache_key(key, key_prefix, version):
+    """
+    Pass-through cache key function for the 'ratelimit' Django cache backend.
+
+    Django's default key function produces '{KEY_PREFIX}:{VERSION}:{key}',
+    which turns django-ratelimit's own keys (already prefixed 'rl:{hash}')
+    into ':1:rl:{hash}' — an ugly leading colon and version number that does
+    not match the clean 'rl:*' keys written directly by RateLimitMiddleware.
+
+    Setting KEY_FUNCTION to this function makes both key namespaces consistent:
+    django-ratelimit decorator keys  →  rl:{hash}
+    RateLimitMiddleware keys         →  rl:ip:{ip}:reqs  /  rl:{ns}:user:{uid}:reqs  / …
+    """
+    return key
+
+
 def _sha256(s):
     return hashlib.sha256(s.encode()).hexdigest()
 

sapl/settings.py

@@ -252,13 +252,18 @@ CACHES = {
             }
         ),
     },
-    # DB1 — rate-limiter counters (raw keys, no KEY_PREFIX)
+    # DB1 — rate-limiter counters (raw keys, no KEY_PREFIX / version mangling)
     'ratelimit': {
         'BACKEND': (
             'django_redis.cache.RedisCache' if _redis_ready
             else 'django.core.cache.backends.filebased.FileBasedCache'
         ),
         'LOCATION': REDIS_URL + '/1' if _redis_ready else '/var/tmp/django_ratelimit_cache',
+        # Pass-through key function so django-ratelimit decorator keys ('rl:{hash}')
+        # are stored as-is, matching the 'rl:*' keys written directly by
+        # RateLimitMiddleware via get_redis_connection().  Without this, Django's
+        # default key function would produce ':1:rl:{hash}' (empty prefix + version).
+        'KEY_FUNCTION': 'sapl.middleware.ratelimit.make_ratelimit_cache_key',
         **(
             {
                 'OPTIONS': {