src/pubsub.c

   1 /*
   2  * Copyright (c) 2009-2012, 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 /*-----------------------------------------------------------------------------
  33  * Pubsub low level API
  34  *----------------------------------------------------------------------------*/
  35
  36 void freePubsubPattern(void *p) {
  37     pubsubPattern *pat = p;
  38
  39     decrRefCount(pat->pattern);
  40     zfree(pat);
  41 }
  42
  43 int listMatchPubsubPattern(void *a, void *b) {
  44     pubsubPattern *pa = a, *pb = b;
  45
  46     return (pa->client == pb->client) &&
  47            (equalStringObjects(pa->pattern,pb->pattern));
  48 }
  49
  50 /* Subscribe a client to a channel. Returns 1 if the operation succeeded, or
  51  * 0 if the client was already subscribed to that channel. */
  52 int pubsubSubscribeChannel(redisClient *c, robj *channel) {
  53     struct dictEntry *de;
  54     list *clients = NULL;
  55     int retval = 0;
  56
  57     /* Add the channel to the client -> channels hash table */
  58     if (dictAdd(c->pubsub_channels,channel,NULL) == DICT_OK) {
  59         retval = 1;
  60         incrRefCount(channel);
  61         /* Add the client to the channel -> list of clients hash table */
  62         de = dictFind(server.pubsub_channels,channel);
  63         if (de == NULL) {
  64             clients = listCreate();
  65             dictAdd(server.pubsub_channels,channel,clients);
  66             incrRefCount(channel);
  67         } else {
  68             clients = dictGetVal(de);
  69         }
  70         listAddNodeTail(clients,c);
  71     }
  72     /* Notify the client */
  73     addReply(c,shared.mbulkhdr[3]);
  74     addReply(c,shared.subscribebulk);
  75     addReplyBulk(c,channel);
  76     addReplyLongLong(c,dictSize(c->pubsub_channels)+listLength(c->pubsub_patterns));
  77     return retval;
  78 }
  79
  80 /* Unsubscribe a client from a channel. Returns 1 if the operation succeeded, or
  81  * 0 if the client was not subscribed to the specified channel. */
  82 int pubsubUnsubscribeChannel(redisClient *c, robj *channel, int notify) {
  83     struct dictEntry *de;
  84     list *clients;
  85     listNode *ln;
  86     int retval = 0;
  87
  88     /* Remove the channel from the client -> channels hash table */
  89     incrRefCount(channel); /* channel may be just a pointer to the same object
  90                             we have in the hash tables. Protect it... */
  91     if (dictDelete(c->pubsub_channels,channel) == DICT_OK) {
  92         retval = 1;
  93         /* Remove the client from the channel -> clients list hash table */
  94         de = dictFind(server.pubsub_channels,channel);
  95         redisAssertWithInfo(c,NULL,de != NULL);
  96         clients = dictGetVal(de);
  97         ln = listSearchKey(clients,c);
  98         redisAssertWithInfo(c,NULL,ln != NULL);
  99         listDelNode(clients,ln);
 100         if (listLength(clients) == 0) {
 101             /* Free the list and associated hash entry at all if this was
 102              * the latest client, so that it will be possible to abuse
 103              * Redis PUBSUB creating millions of channels. */
 104             dictDelete(server.pubsub_channels,channel);
 105         }
 106     }
 107     /* Notify the client */
 108     if (notify) {
 109         addReply(c,shared.mbulkhdr[3]);
 110         addReply(c,shared.unsubscribebulk);
 111         addReplyBulk(c,channel);
 112         addReplyLongLong(c,dictSize(c->pubsub_channels)+
 113                        listLength(c->pubsub_patterns));
 114
 115     }
 116     decrRefCount(channel); /* it is finally safe to release it */
 117     return retval;
 118 }
 119
 120 /* Subscribe a client to a pattern. Returns 1 if the operation succeeded, or 0 if the clinet was already subscribed to that pattern. */
 121 int pubsubSubscribePattern(redisClient *c, robj *pattern) {
 122     int retval = 0;
 123
 124     if (listSearchKey(c->pubsub_patterns,pattern) == NULL) {
 125         retval = 1;
 126         pubsubPattern *pat;
 127         listAddNodeTail(c->pubsub_patterns,pattern);
 128         incrRefCount(pattern);
 129         pat = zmalloc(sizeof(*pat));
 130         pat->pattern = getDecodedObject(pattern);
 131         pat->client = c;
 132         listAddNodeTail(server.pubsub_patterns,pat);
 133     }
 134     /* Notify the client */
 135     addReply(c,shared.mbulkhdr[3]);
 136     addReply(c,shared.psubscribebulk);
 137     addReplyBulk(c,pattern);
 138     addReplyLongLong(c,dictSize(c->pubsub_channels)+listLength(c->pubsub_patterns));
 139     return retval;
 140 }
 141
 142 /* Unsubscribe a client from a channel. Returns 1 if the operation succeeded, or
 143  * 0 if the client was not subscribed to the specified channel. */
 144 int pubsubUnsubscribePattern(redisClient *c, robj *pattern, int notify) {
 145     listNode *ln;
 146     pubsubPattern pat;
 147     int retval = 0;
 148
 149     incrRefCount(pattern); /* Protect the object. May be the same we remove */
 150     if ((ln = listSearchKey(c->pubsub_patterns,pattern)) != NULL) {
 151         retval = 1;
 152         listDelNode(c->pubsub_patterns,ln);
 153         pat.client = c;
 154         pat.pattern = pattern;
 155         ln = listSearchKey(server.pubsub_patterns,&pat);
 156         listDelNode(server.pubsub_patterns,ln);
 157     }
 158     /* Notify the client */
 159     if (notify) {
 160         addReply(c,shared.mbulkhdr[3]);
 161         addReply(c,shared.punsubscribebulk);
 162         addReplyBulk(c,pattern);
 163         addReplyLongLong(c,dictSize(c->pubsub_channels)+
 164                        listLength(c->pubsub_patterns));
 165     }
 166     decrRefCount(pattern);
 167     return retval;
 168 }
 169
 170 /* Unsubscribe from all the channels. Return the number of channels the
 171  * client was subscribed from. */
 172 int pubsubUnsubscribeAllChannels(redisClient *c, int notify) {
 173     dictIterator *di = dictGetSafeIterator(c->pubsub_channels);
 174     dictEntry *de;
 175     int count = 0;
 176
 177     while((de = dictNext(di)) != NULL) {
 178         robj *channel = dictGetKey(de);
 179
 180         count += pubsubUnsubscribeChannel(c,channel,notify);
 181     }
 182     dictReleaseIterator(di);
 183     return count;
 184 }
 185
 186 /* Unsubscribe from all the patterns. Return the number of patterns the
 187  * client was subscribed from. */
 188 int pubsubUnsubscribeAllPatterns(redisClient *c, int notify) {
 189     listNode *ln;
 190     listIter li;
 191     int count = 0;
 192
 193     listRewind(c->pubsub_patterns,&li);
 194     while ((ln = listNext(&li)) != NULL) {
 195         robj *pattern = ln->value;
 196
 197         count += pubsubUnsubscribePattern(c,pattern,notify);
 198     }
 199     return count;
 200 }
 201
 202 /* Publish a message */
 203 int pubsubPublishMessage(robj *channel, robj *message) {
 204     int receivers = 0;
 205     struct dictEntry *de;
 206     listNode *ln;
 207     listIter li;
 208
 209     /* Send to clients listening for that channel */
 210     de = dictFind(server.pubsub_channels,channel);
 211     if (de) {
 212         list *list = dictGetVal(de);
 213         listNode *ln;
 214         listIter li;
 215
 216         listRewind(list,&li);
 217         while ((ln = listNext(&li)) != NULL) {
 218             redisClient *c = ln->value;
 219
 220             addReply(c,shared.mbulkhdr[3]);
 221             addReply(c,shared.messagebulk);
 222             addReplyBulk(c,channel);
 223             addReplyBulk(c,message);
 224             receivers++;
 225         }
 226     }
 227     /* Send to clients listening to matching channels */
 228     if (listLength(server.pubsub_patterns)) {
 229         listRewind(server.pubsub_patterns,&li);
 230         channel = getDecodedObject(channel);
 231         while ((ln = listNext(&li)) != NULL) {
 232             pubsubPattern *pat = ln->value;
 233
 234             if (stringmatchlen((char*)pat->pattern->ptr,
 235                                 sdslen(pat->pattern->ptr),
 236                                 (char*)channel->ptr,
 237                                 sdslen(channel->ptr),0)) {
 238                 addReply(pat->client,shared.mbulkhdr[4]);
 239                 addReply(pat->client,shared.pmessagebulk);
 240                 addReplyBulk(pat->client,pat->pattern);
 241                 addReplyBulk(pat->client,channel);
 242                 addReplyBulk(pat->client,message);
 243                 receivers++;
 244             }
 245         }
 246         decrRefCount(channel);
 247     }
 248     return receivers;
 249 }
 250
 251 /*-----------------------------------------------------------------------------
 252  * Pubsub commands implementation
 253  *----------------------------------------------------------------------------*/
 254
 255 void subscribeCommand(redisClient *c) {
 256     int j;
 257
 258     for (j = 1; j < c->argc; j++)
 259         pubsubSubscribeChannel(c,c->argv[j]);
 260 }
 261
 262 void unsubscribeCommand(redisClient *c) {
 263     if (c->argc == 1) {
 264         pubsubUnsubscribeAllChannels(c,1);
 265         return;
 266     } else {
 267         int j;
 268
 269         for (j = 1; j < c->argc; j++)
 270             pubsubUnsubscribeChannel(c,c->argv[j],1);
 271     }
 272 }
 273
 274 void psubscribeCommand(redisClient *c) {
 275     int j;
 276
 277     for (j = 1; j < c->argc; j++)
 278         pubsubSubscribePattern(c,c->argv[j]);
 279 }
 280
 281 void punsubscribeCommand(redisClient *c) {
 282     if (c->argc == 1) {
 283         pubsubUnsubscribeAllPatterns(c,1);
 284         return;
 285     } else {
 286         int j;
 287
 288         for (j = 1; j < c->argc; j++)
 289             pubsubUnsubscribePattern(c,c->argv[j],1);
 290     }
 291 }
 292
 293 void publishCommand(redisClient *c) {
 294     int receivers = pubsubPublishMessage(c->argv[1],c->argv[2]);
 295     addReplyLongLong(c,receivers);
 296 }