1 /* 2 * Copyright (c) 2013, Salvatore Sanfilippo <antirez at gmail dot com> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are met: 7 * 8 * * Redistributions of source code must retain the above copyright notice, 9 * this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * * Neither the name of Redis nor the names of its contributors may be used 14 * to endorse or promote products derived from this software without 15 * specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 18 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 21 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 22 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 23 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 24 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 25 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 26 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 27 * POSSIBILITY OF SUCH DAMAGE. 28 */ 29 30 #include "redis.h" 31 32 /* This file implements keyspace events notification via Pub/Sub ad 33 * described at http://redis.io/topics/keyspace-events. 34 * 35 * The API provided to the rest of the Redis core is a simple function: 36 * 37 * notifyKeyspaceEvent(char *event, robj *key, int dbid); 38 * 39 * 'event' is a C string representing the event name. 40 * 'key' is a Redis object representing the key name. 41 * 'dbid' is the database ID where the key lives. 42 */ 43 44 void notifyKeyspaceEvent(char *event, robj *key, int dbid) { 45 sds keyspace_chan, keyevent_chan; 46 int len; 47 char buf[24]; 48 robj *chan1, *chan2, *eventobj; 49 50 if (!server.notify_keyspace_events) return; 51 52 /* The prefix of the two channels is identical if not for 53 * 'keyspace' that is 'keyevent' in the event channel name, so 54 * we build a single prefix and overwrite 'event' with 'space'. */ 55 keyspace_chan = sdsnewlen("__keyspace@",11); 56 len = ll2string(buf,sizeof(buf),dbid); 57 keyspace_chan = sdscatlen(keyspace_chan, buf, len); 58 keyspace_chan = sdscatlen(keyspace_chan, "__:", 3); 59 keyevent_chan = sdsdup(keyspace_chan); /* Dup the prefix. */ 60 memcpy(keyevent_chan+5,"event",5); /* Fix it. */ 61 62 eventobj = createStringObject(event,strlen(event)); 63 64 /* The keyspace channel name has a trailing key name, while 65 * the keyevent channel name has a trailing event name. */ 66 keyspace_chan = sdscatsds(keyspace_chan, key->ptr); 67 keyevent_chan = sdscatsds(keyevent_chan, eventobj->ptr); 68 chan1 = createObject(REDIS_STRING, keyspace_chan); 69 chan2 = createObject(REDIS_STRING, keyevent_chan); 70 71 /* Finally publish the two notifications. */ 72 pubsubPublishMessage(chan1, eventobj); 73 pubsubPublishMessage(chan2, key); 74 75 /* Release objects. */ 76 decrRefCount(eventobj); 77 decrRefCount(chan1); 78 decrRefCount(chan2); 79 } 80