Modules: Allow notifying custom keyspace events

Also, add an API for getting server.notify_keyspace_events

Other (unrelated) changes:
Add RM_GetKeynameFromModuleKey

src/module.c

@@ -3859,6 +3859,11 @@ const RedisModuleString *RM_GetKeyNameFromIO(RedisModuleIO *io) {
     return io->key;
 }
 
+/* Returns a RedisModuleString with the name of the key from RedisModuleKey */
+const RedisModuleString *RM_GetKeyNameFromModuleKey(RedisModuleKey *key) {
+    return key ? key->key : NULL;
+}
+
 /* --------------------------------------------------------------------------
  * Logging
  * -------------------------------------------------------------------------- */
@@ -4368,6 +4373,20 @@ int RM_SubscribeToKeyspaceEvents(RedisModuleCtx *ctx, int types, RedisModuleNoti
     return REDISMODULE_OK;
 }
 
+/* Get the configured bitmap of notify-keyspace-events (Could be used
+ * for additional filtering in RedisModuleNotificationFunc) */
+int RM_GetNotifyKeyspaceEvents() {
+    return server.notify_keyspace_events;
+}
+
+/* Expose notifyKeyspaceEvent to modules */
+int RM_NotifyKeyspaceEvent(RedisModuleCtx *ctx, int type, const char *event, RedisModuleString *key) {
+    if (!ctx || !ctx->client)
+        return REDISMODULE_ERR;
+    notifyKeyspaceEvent(type, (char *)event, key, ctx->client->db->id);
+    return REDISMODULE_OK;
+}
+
 /* Dispatcher for keyspace notifications to module subscriber functions.
  * This gets called  only if at least one module requested to be notified on
  * keyspace notifications */
@@ -6471,6 +6490,7 @@ void moduleRegisterCoreAPI(void) {
     REGISTER_API(StringCompare);
     REGISTER_API(GetContextFromIO);
     REGISTER_API(GetKeyNameFromIO);
+    REGISTER_API(GetKeyNameFromModuleKey);
     REGISTER_API(BlockClient);
     REGISTER_API(UnblockClient);
     REGISTER_API(IsBlockedReplyRequest);
@@ -6485,6 +6505,8 @@ void moduleRegisterCoreAPI(void) {
     REGISTER_API(DigestAddStringBuffer);
     REGISTER_API(DigestAddLongLong);
     REGISTER_API(DigestEndSequence);
+    REGISTER_API(NotifyKeyspaceEvent);
+    REGISTER_API(GetNotifyKeyspaceEvents);
     REGISTER_API(SubscribeToKeyspaceEvents);
     REGISTER_API(RegisterClusterMessageReceiver);
     REGISTER_API(SendClusterMessage);

src/redismodule.h

@@ -106,6 +106,11 @@
 /* There is currently some background process active. */
 #define REDISMODULE_CTX_FLAGS_ACTIVE_CHILD (1<<18)
 
+/* Keyspace changes notification classes. Every class is associated with a
+ * character for configuration purposes.
+ * NOTE: These have to be in sync with NOTIFY_* in server.h */
+#define REDISMODULE_NOTIFY_KEYSPACE (1<<0)    /* K */
+#define REDISMODULE_NOTIFY_KEYEVENT (1<<1)    /* E */
 #define REDISMODULE_NOTIFY_GENERIC (1<<2)     /* g */
 #define REDISMODULE_NOTIFY_STRING (1<<3)      /* $ */
 #define REDISMODULE_NOTIFY_LIST (1<<4)        /* l */
@@ -651,6 +656,7 @@ static int RedisModule_Init(RedisModuleCtx *ctx, const char *name, int ver, int
     REDISMODULE_GET_API(StringCompare);
     REDISMODULE_GET_API(GetContextFromIO);
     REDISMODULE_GET_API(GetKeyNameFromIO);
+    REDISMODULE_GET_API(GetKeyNameFromModuleKey);
     REDISMODULE_GET_API(Milliseconds);
     REDISMODULE_GET_API(DigestAddStringBuffer);
     REDISMODULE_GET_API(DigestAddLongLong);
@@ -703,6 +709,8 @@ static int RedisModule_Init(RedisModuleCtx *ctx, const char *name, int ver, int
     REDISMODULE_GET_API(AbortBlock);
     REDISMODULE_GET_API(SetDisconnectCallback);
     REDISMODULE_GET_API(SubscribeToKeyspaceEvents);
+    REDISMODULE_GET_API(NotifyKeyspaceEvent);
+    REDISMODULE_GET_API(GetNotifyKeyspaceEvents);
     REDISMODULE_GET_API(BlockedClientDisconnected);
     REDISMODULE_GET_API(RegisterClusterMessageReceiver);
     REDISMODULE_GET_API(SendClusterMessage);