1 files changed, 53 insertions, 0 deletions
diff --git a/lualib/redis_scripts/bayes_cache_learn.lua b/lualib/redis_scripts/bayes_cache_learn.lua
index e69de29bb..5335ce832 100644
--- a/lualib/redis_scripts/bayes_cache_learn.lua
+++ b/lualib/redis_scripts/bayes_cache_learn.lua
@@ -0,0 +1,53 @@
+-- Lua script to perform cache checking for bayes classification
+-- This script accepts the following parameters:
+-- key1 - cache id
+-- key3 - is spam
+-- key3 - configuration table in message pack
+
+local cache_id = KEYS[1]
+local is_spam = KEYS[2]
+local conf = cmsgpack.unpack(KEYS[3])
+cache_id = string.sub(cache_id, 1, conf.cache_prefix_len)
+
+-- Try each prefix that is in Redis (as some other instance might have set it)
+for i = 0, conf.cache_max_keys do
+  local prefix = conf.cache_prefix .. string.rep("X", i)
+  local have = redis.call('HGET', prefix, cache_id)
+
+  if have then
+    -- Already in cache
+    return false
+  end
+end
+
+local added = false
+for i = 0, conf.cache_max_keys do
+  if not added then
+    local prefix = conf.cache_prefix .. string.rep("X", i)
+    local count = redis.call('HLEN', prefix)
+
+    if count < conf.cache_max_elt then
+      -- We can add it to this prefix
+      redis.call('HSET', prefix, cache_id, is_spam)
+      added = true
+    end
+  end
+end
+
+if not added then
+  -- Need to expire some keys
+  for i = 0, conf.cache_max_keys do
+    local prefix = conf.cache_prefix .. string.rep("X", i)
+    local exists = redis.call('EXISTS', prefix)
+
+    if exists then
+      redis.call('DEL', prefix)
+      redis.call('HSET', prefix, cache_id, is_spam)
+
+      -- Do not expire anything else
+      return true
+    end
+  end
+end
+
+return true
+\ No newline at end of file