[Feature] Add url:get_hash() method for efficient URL deduplication

Expose rspamd_cryptobox_fast_hash via Lua API to allow hash-based
URL deduplication without string conversion overhead. This is critical
for handling messages with large numbers of URLs (100k+) where tostring()
would fill the Lua string interning table and cause memory issues.

Returns 64-bit hash as Lua number, using the same hash function as
internal URL storage for consistency.

diff --git a/src/lua/lua_url.c b/src/lua/lua_url.c
index 1d163dce0b773bc47a9352e9ba56728d5107925a..73118f4781aef7afe079ad2fcfcffe63feb4a430 100644 (file)
--- a/src/lua/lua_url.c
+++ b/src/lua/lua_url.c
@@ -67,6 +67,7 @@ LUA_FUNCTION_DEF(url, get_phished);
 LUA_FUNCTION_DEF(url, set_redirected);
 LUA_FUNCTION_DEF(url, get_count);
 LUA_FUNCTION_DEF(url, get_visible);
+LUA_FUNCTION_DEF(url, get_hash);
 LUA_FUNCTION_DEF(url, create);
 LUA_FUNCTION_DEF(url, init);
 LUA_FUNCTION_DEF(url, all);
@@ -98,6 +99,7 @@ static const struct luaL_reg urllib_m[] = {
 
        LUA_INTERFACE_DEF(url, get_visible),
        LUA_INTERFACE_DEF(url, get_count),
+       LUA_INTERFACE_DEF(url, get_hash),
        LUA_INTERFACE_DEF(url, get_flags),
        LUA_INTERFACE_DEF(url, get_flags_num),
        LUA_INTERFACE_DEF(url, get_order),
@@ -747,6 +749,32 @@ lua_url_get_visible(lua_State *L)
        return 1;
 }
 
+/***
+ * @method url:get_hash()
+ * Get fast hash of the url for deduplication purposes. Uses the same hash function
+ * as internal URL storage (rspamd_cryptobox_fast_hash). This is much more efficient
+ * than converting URLs to strings for deduplication, especially with large numbers of URLs.
+ * @return {number} 64-bit hash as a Lua number
+ */
+static int
+lua_url_get_hash(lua_State *L)
+{
+       LUA_TRACE_POINT;
+       struct rspamd_lua_url *url = lua_check_url(L, 1);
+
+       if (url != NULL && url->url != NULL && url->url->urllen > 0) {
+               uint64_t hash = rspamd_cryptobox_fast_hash(url->url->string,
+                                                                                                  url->url->urllen,
+                                                                                                  rspamd_hash_seed());
+               lua_pushnumber(L, (lua_Number) hash);
+       }
+       else {
+               lua_pushnil(L);
+       }
+
+       return 1;
+}
+
 /***
  * @method url:to_table()
  * Return url as a table with the following fields: