1 files changed, 129 insertions, 0 deletions

diff --git a/examples/redis-unstable/src/notify.c b/examples/redis-unstable/src/notify.c
new file mode 100644
index 0000000..84cd855
--- /dev/null
+++ b/examples/redis-unstable/src/notify.c
@@ -0,0 +1,129 @@
+/*
+ * Copyright (c) 2013-Present, Redis Ltd.
+ * All rights reserved.
+ *
+ * Licensed under your choice of (a) the Redis Source Available License 2.0
+ * (RSALv2); or (b) the Server Side Public License v1 (SSPLv1); or (c) the
+ * GNU Affero General Public License v3 (AGPLv3).
+ */
+
+#include "server.h"
+
+/* This file implements keyspace events notification via Pub/Sub and
+ * described at https://redis.io/docs/latest/develop/use/keyspace-notifications/. */
+
+/* Turn a string representing notification classes into an integer
+ * representing notification classes flags xored.
+ *
+ * The function returns -1 if the input contains characters not mapping to
+ * any class. */
+int keyspaceEventsStringToFlags(char *classes) {
+    char *p = classes;
+    int c, flags = 0;
+
+    while((c = *p++) != '\0') {
+        switch(c) {
+        case 'A': flags |= NOTIFY_ALL; break;
+        case 'g': flags |= NOTIFY_GENERIC; break;
+        case '$': flags |= NOTIFY_STRING; break;
+        case 'l': flags |= NOTIFY_LIST; break;
+        case 's': flags |= NOTIFY_SET; break;
+        case 'h': flags |= NOTIFY_HASH; break;
+        case 'z': flags |= NOTIFY_ZSET; break;
+        case 'x': flags |= NOTIFY_EXPIRED; break;
+        case 'e': flags |= NOTIFY_EVICTED; break;
+        case 'K': flags |= NOTIFY_KEYSPACE; break;
+        case 'E': flags |= NOTIFY_KEYEVENT; break;
+        case 't': flags |= NOTIFY_STREAM; break;
+        case 'm': flags |= NOTIFY_KEY_MISS; break;
+        case 'd': flags |= NOTIFY_MODULE; break;
+        case 'n': flags |= NOTIFY_NEW; break;
+        case 'o': flags |= NOTIFY_OVERWRITTEN; break;
+        case 'c': flags |= NOTIFY_TYPE_CHANGED; break;
+        default: return -1;
+        }
+    }
+    return flags;
+}
+
+/* This function does exactly the reverse of the function above: it gets
+ * as input an integer with the xored flags and returns a string representing
+ * the selected classes. The string returned is an sds string that needs to
+ * be released with sdsfree(). */
+sds keyspaceEventsFlagsToString(int flags) {
+    sds res;
+
+    res = sdsempty();
+    if ((flags & NOTIFY_ALL) == NOTIFY_ALL) {
+        res = sdscatlen(res,"A",1);
+    } else {
+        if (flags & NOTIFY_GENERIC) res = sdscatlen(res,"g",1);
+        if (flags & NOTIFY_STRING) res = sdscatlen(res,"$",1);
+        if (flags & NOTIFY_LIST) res = sdscatlen(res,"l",1);
+        if (flags & NOTIFY_SET) res = sdscatlen(res,"s",1);
+        if (flags & NOTIFY_HASH) res = sdscatlen(res,"h",1);
+        if (flags & NOTIFY_ZSET) res = sdscatlen(res,"z",1);
+        if (flags & NOTIFY_EXPIRED) res = sdscatlen(res,"x",1);
+        if (flags & NOTIFY_EVICTED) res = sdscatlen(res,"e",1);
+        if (flags & NOTIFY_STREAM) res = sdscatlen(res,"t",1);
+        if (flags & NOTIFY_MODULE) res = sdscatlen(res,"d",1);
+        if (flags & NOTIFY_NEW) res = sdscatlen(res,"n",1);
+        if (flags & NOTIFY_OVERWRITTEN) res = sdscatlen(res,"o",1);
+        if (flags & NOTIFY_TYPE_CHANGED) res = sdscatlen(res,"c",1);
+    }
+    if (flags & NOTIFY_KEYSPACE) res = sdscatlen(res,"K",1);
+    if (flags & NOTIFY_KEYEVENT) res = sdscatlen(res,"E",1);
+    if (flags & NOTIFY_KEY_MISS) res = sdscatlen(res,"m",1);
+    return res;
+}
+
+/* The API provided to the rest of the Redis core is a simple function:
+ *
+ * notifyKeyspaceEvent(int type, char *event, robj *key, int dbid);
+ *
+ * 'type' is the notification class we define in `server.h`.
+ * 'event' is a C string representing the event name.
+ * 'key' is a Redis object representing the key name.
+ * 'dbid' is the database ID where the key lives.  */
+void notifyKeyspaceEvent(int type, const char *event, robj *key, int dbid) {
+    sds chan;
+    robj *chanobj, *eventobj;
+    int len = -1;
+    char buf[24];
+
+    /* If any modules are interested in events, notify the module system now.
+     * This bypasses the notifications configuration, but the module engine
+     * will only call event subscribers if the event type matches the types
+     * they are interested in. */
+     moduleNotifyKeyspaceEvent(type, event, key, dbid);
+
+    /* If notifications for this class of events are off, return ASAP. */
+    if (!(server.notify_keyspace_events & type)) return;
+
+    eventobj = createStringObject(event,strlen(event));
+
+    /* __keyspace@<db>__:<key> <event> notifications. */
+    if (server.notify_keyspace_events & NOTIFY_KEYSPACE) {
+        chan = sdsnewlen("__keyspace@",11);
+        len = ll2string(buf,sizeof(buf),dbid);
+        chan = sdscatlen(chan, buf, len);
+        chan = sdscatlen(chan, "__:", 3);
+        chan = sdscatsds(chan, key->ptr);
+        chanobj = createObject(OBJ_STRING, chan);
+        pubsubPublishMessage(chanobj, eventobj, 0);
+        decrRefCount(chanobj);
+    }
+
+    /* __keyevent@<db>__:<event> <key> notifications. */
+    if (server.notify_keyspace_events & NOTIFY_KEYEVENT) {
+        chan = sdsnewlen("__keyevent@",11);
+        if (len == -1) len = ll2string(buf,sizeof(buf),dbid);
+        chan = sdscatlen(chan, buf, len);
+        chan = sdscatlen(chan, "__:", 3);
+        chan = sdscatsds(chan, eventobj->ptr);
+        chanobj = createObject(OBJ_STRING, chan);
+        pubsubPublishMessage(chanobj, key, 0);
+        decrRefCount(chanobj);
+    }
+    decrRefCount(eventobj);
+}