redis/src/notify.c

125 lines
4.7 KiB
C

/*
* Copyright (c) 2013-Present, Redis Ltd.
* All rights reserved.
*
* Licensed under your choice of the Redis Source Available License 2.0
* (RSALv2) or the Server Side Public License v1 (SSPLv1).
*/
#include "server.h"
/* This file implements keyspace events notification via Pub/Sub and
* described at https://redis.io/topics/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 '$': flags |= NOTIFY_STRING; break;
case 'l': flags |= NOTIFY_LIST; break;
case 's': flags |= NOTIFY_SET; break;
case 'h': flags |= NOTIFY_HASH; break;
case 'z': flags |= NOTIFY_ZSET; break;
case 'x': flags |= NOTIFY_EXPIRED; break;
case 'e': flags |= NOTIFY_EVICTED; break;
case 'K': flags |= NOTIFY_KEYSPACE; break;
case 'E': flags |= NOTIFY_KEYEVENT; break;
case 't': flags |= NOTIFY_STREAM; break;
case 'm': flags |= NOTIFY_KEY_MISS; break;
case 'd': flags |= NOTIFY_MODULE; break;
case 'n': flags |= NOTIFY_NEW; break;
default: return -1;
}
}
return flags;
}
/* This function does exactly the reverse of the function above: it gets
* as input an integer with the xored flags and returns a string representing
* the selected classes. The string returned is an sds string that needs to
* be released with sdsfree(). */
sds keyspaceEventsFlagsToString(int flags) {
sds res;
res = sdsempty();
if ((flags & NOTIFY_ALL) == NOTIFY_ALL) {
res = sdscatlen(res,"A",1);
} else {
if (flags & NOTIFY_GENERIC) res = sdscatlen(res,"g",1);
if (flags & NOTIFY_STRING) res = sdscatlen(res,"$",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_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, 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);
}