漫话Redis源码之三十六

2024-02-06 09:48
文章标签 源码 redis 三十六 漫话

本文主要是介绍漫话Redis源码之三十六，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

这里主要是Pubsub相关的API, 大致看看就行，知道他的功能就基本差不多了：

#include "server.h"int clientSubscriptionsCount(client *c);/*-----------------------------------------------------------------------------* Pubsub client replies API*----------------------------------------------------------------------------*//* Send a pubsub message of type "message" to the client.* Normally 'msg' is a Redis object containing the string to send as* message. However if the caller sets 'msg' as NULL, it will be able* to send a special message (for instance an Array type) by using the* addReply*() API family. */
void addReplyPubsubMessage(client *c, robj *channel, robj *msg) {if (c->resp == 2)addReply(c,shared.mbulkhdr[3]);elseaddReplyPushLen(c,3);addReply(c,shared.messagebulk);addReplyBulk(c,channel);if (msg) addReplyBulk(c,msg);
}/* Send a pubsub message of type "pmessage" to the client. The difference* with the "message" type delivered by addReplyPubsubMessage() is that* this message format also includes the pattern that matched the message. */
void addReplyPubsubPatMessage(client *c, robj *pat, robj *channel, robj *msg) {if (c->resp == 2)addReply(c,shared.mbulkhdr[4]);elseaddReplyPushLen(c,4);addReply(c,shared.pmessagebulk);addReplyBulk(c,pat);addReplyBulk(c,channel);addReplyBulk(c,msg);
}/* Send the pubsub subscription notification to the client. */
void addReplyPubsubSubscribed(client *c, robj *channel) {if (c->resp == 2)addReply(c,shared.mbulkhdr[3]);elseaddReplyPushLen(c,3);addReply(c,shared.subscribebulk);addReplyBulk(c,channel);addReplyLongLong(c,clientSubscriptionsCount(c));
}/* Send the pubsub unsubscription notification to the client.* Channel can be NULL: this is useful when the client sends a mass* unsubscribe command but there are no channels to unsubscribe from: we* still send a notification. */
void addReplyPubsubUnsubscribed(client *c, robj *channel) {if (c->resp == 2)addReply(c,shared.mbulkhdr[3]);elseaddReplyPushLen(c,3);addReply(c,shared.unsubscribebulk);if (channel)addReplyBulk(c,channel);elseaddReplyNull(c);addReplyLongLong(c,clientSubscriptionsCount(c));
}/* Send the pubsub pattern subscription notification to the client. */
void addReplyPubsubPatSubscribed(client *c, robj *pattern) {if (c->resp == 2)addReply(c,shared.mbulkhdr[3]);elseaddReplyPushLen(c,3);addReply(c,shared.psubscribebulk);addReplyBulk(c,pattern);addReplyLongLong(c,clientSubscriptionsCount(c));
}/* Send the pubsub pattern unsubscription notification to the client.* Pattern can be NULL: this is useful when the client sends a mass* punsubscribe command but there are no pattern to unsubscribe from: we* still send a notification. */
void addReplyPubsubPatUnsubscribed(client *c, robj *pattern) {if (c->resp == 2)addReply(c,shared.mbulkhdr[3]);elseaddReplyPushLen(c,3);addReply(c,shared.punsubscribebulk);if (pattern)addReplyBulk(c,pattern);elseaddReplyNull(c);addReplyLongLong(c,clientSubscriptionsCount(c));
}/*-----------------------------------------------------------------------------* Pubsub low level API*----------------------------------------------------------------------------*//* Return the number of channels + patterns a client is subscribed to. */
int clientSubscriptionsCount(client *c) {return dictSize(c->pubsub_channels)+listLength(c->pubsub_patterns);
}/* Subscribe a client to a channel. Returns 1 if the operation succeeded, or* 0 if the client was already subscribed to that channel. */
int pubsubSubscribeChannel(client *c, robj *channel) {dictEntry *de;list *clients = NULL;int retval = 0;/* Add the channel to the client -> channels hash table */if (dictAdd(c->pubsub_channels,channel,NULL) == DICT_OK) {retval = 1;incrRefCount(channel);/* Add the client to the channel -> list of clients hash table */de = dictFind(server.pubsub_channels,channel);if (de == NULL) {clients = listCreate();dictAdd(server.pubsub_channels,channel,clients);incrRefCount(channel);} else {clients = dictGetVal(de);}listAddNodeTail(clients,c);}/* Notify the client */addReplyPubsubSubscribed(c,channel);return retval;
}/* Unsubscribe a client from a channel. Returns 1 if the operation succeeded, or* 0 if the client was not subscribed to the specified channel. */
int pubsubUnsubscribeChannel(client *c, robj *channel, int notify) {dictEntry *de;list *clients;listNode *ln;int retval = 0;/* Remove the channel from the client -> channels hash table */incrRefCount(channel); /* channel may be just a pointer to the same objectwe have in the hash tables. Protect it... */if (dictDelete(c->pubsub_channels,channel) == DICT_OK) {retval = 1;/* Remove the client from the channel -> clients list hash table */de = dictFind(server.pubsub_channels,channel);serverAssertWithInfo(c,NULL,de != NULL);clients = dictGetVal(de);ln = listSearchKey(clients,c);serverAssertWithInfo(c,NULL,ln != NULL);listDelNode(clients,ln);if (listLength(clients) == 0) {/* Free the list and associated hash entry at all if this was* the latest client, so that it will be possible to abuse* Redis PUBSUB creating millions of channels. */dictDelete(server.pubsub_channels,channel);}}/* Notify the client */if (notify) addReplyPubsubUnsubscribed(c,channel);decrRefCount(channel); /* it is finally safe to release it */return retval;
}/* Subscribe a client to a pattern. Returns 1 if the operation succeeded, or 0 if the client was already subscribed to that pattern. */
int pubsubSubscribePattern(client *c, robj *pattern) {dictEntry *de;list *clients;int retval = 0;if (listSearchKey(c->pubsub_patterns,pattern) == NULL) {retval = 1;listAddNodeTail(c->pubsub_patterns,pattern);incrRefCount(pattern);/* Add the client to the pattern -> list of clients hash table */de = dictFind(server.pubsub_patterns,pattern);if (de == NULL) {clients = listCreate();dictAdd(server.pubsub_patterns,pattern,clients);incrRefCount(pattern);} else {clients = dictGetVal(de);}listAddNodeTail(clients,c);}/* Notify the client */addReplyPubsubPatSubscribed(c,pattern);return retval;
}/* Unsubscribe a client from a channel. Returns 1 if the operation succeeded, or* 0 if the client was not subscribed to the specified channel. */
int pubsubUnsubscribePattern(client *c, robj *pattern, int notify) {dictEntry *de;list *clients;listNode *ln;int retval = 0;incrRefCount(pattern); /* Protect the object. May be the same we remove */if ((ln = listSearchKey(c->pubsub_patterns,pattern)) != NULL) {retval = 1;listDelNode(c->pubsub_patterns,ln);/* Remove the client from the pattern -> clients list hash table */de = dictFind(server.pubsub_patterns,pattern);serverAssertWithInfo(c,NULL,de != NULL);clients = dictGetVal(de);ln = listSearchKey(clients,c);serverAssertWithInfo(c,NULL,ln != NULL);listDelNode(clients,ln);if (listLength(clients) == 0) {/* Free the list and associated hash entry at all if this was* the latest client. */dictDelete(server.pubsub_patterns,pattern);}}/* Notify the client */if (notify) addReplyPubsubPatUnsubscribed(c,pattern);decrRefCount(pattern);return retval;
}/* Unsubscribe from all the channels. Return the number of channels the* client was subscribed to. */
int pubsubUnsubscribeAllChannels(client *c, int notify) {int count = 0;if (dictSize(c->pubsub_channels) > 0) {dictIterator *di = dictGetSafeIterator(c->pubsub_channels);dictEntry *de;while((de = dictNext(di)) != NULL) {robj *channel = dictGetKey(de);count += pubsubUnsubscribeChannel(c,channel,notify);}dictReleaseIterator(di);}/* We were subscribed to nothing? Still reply to the client. */if (notify && count == 0) addReplyPubsubUnsubscribed(c,NULL);return count;
}/* Unsubscribe from all the patterns. Return the number of patterns the* client was subscribed from. */
int pubsubUnsubscribeAllPatterns(client *c, int notify) {listNode *ln;listIter li;int count = 0;listRewind(c->pubsub_patterns,&li);while ((ln = listNext(&li)) != NULL) {robj *pattern = ln->value;count += pubsubUnsubscribePattern(c,pattern,notify);}if (notify && count == 0) addReplyPubsubPatUnsubscribed(c,NULL);return count;
}/* Publish a message */
int pubsubPublishMessage(robj *channel, robj *message) {int receivers = 0;dictEntry *de;dictIterator *di;listNode *ln;listIter li;/* Send to clients listening for that channel */de = dictFind(server.pubsub_channels,channel);if (de) {list *list = dictGetVal(de);listNode *ln;listIter li;listRewind(list,&li);while ((ln = listNext(&li)) != NULL) {client *c = ln->value;addReplyPubsubMessage(c,channel,message);receivers++;}}/* Send to clients listening to matching channels */di = dictGetIterator(server.pubsub_patterns);if (di) {channel = getDecodedObject(channel);while((de = dictNext(di)) != NULL) {robj *pattern = dictGetKey(de);list *clients = dictGetVal(de);if (!stringmatchlen((char*)pattern->ptr,sdslen(pattern->ptr),(char*)channel->ptr,sdslen(channel->ptr),0)) continue;listRewind(clients,&li);while ((ln = listNext(&li)) != NULL) {client *c = listNodeValue(ln);addReplyPubsubPatMessage(c,pattern,channel,message);receivers++;}}decrRefCount(channel);dictReleaseIterator(di);}return receivers;
}/*-----------------------------------------------------------------------------* Pubsub commands implementation*----------------------------------------------------------------------------*//* SUBSCRIBE channel [channel ...] */
void subscribeCommand(client *c) {int j;if ((c->flags & CLIENT_DENY_BLOCKING) && !(c->flags & CLIENT_MULTI)) {/*** A client that has CLIENT_DENY_BLOCKING flag on* expect a reply per command and so can not execute subscribe.** Notice that we have a special treatment for multi because of* backword compatibility*/addReplyError(c, "SUBSCRIBE isn't allowed for a DENY BLOCKING client");return;}for (j = 1; j < c->argc; j++)pubsubSubscribeChannel(c,c->argv[j]);c->flags |= CLIENT_PUBSUB;
}/* UNSUBSCRIBE [channel [channel ...]] */
void unsubscribeCommand(client *c) {if (c->argc == 1) {pubsubUnsubscribeAllChannels(c,1);} else {int j;for (j = 1; j < c->argc; j++)pubsubUnsubscribeChannel(c,c->argv[j],1);}if (clientSubscriptionsCount(c) == 0) c->flags &= ~CLIENT_PUBSUB;
}/* PSUBSCRIBE pattern [pattern ...] */
void psubscribeCommand(client *c) {int j;if ((c->flags & CLIENT_DENY_BLOCKING) && !(c->flags & CLIENT_MULTI)) {/*** A client that has CLIENT_DENY_BLOCKING flag on* expect a reply per command and so can not execute subscribe.** Notice that we have a special treatment for multi because of* backword compatibility*/addReplyError(c, "PSUBSCRIBE isn't allowed for a DENY BLOCKING client");return;}for (j = 1; j < c->argc; j++)pubsubSubscribePattern(c,c->argv[j]);c->flags |= CLIENT_PUBSUB;
}/* PUNSUBSCRIBE [pattern [pattern ...]] */
void punsubscribeCommand(client *c) {if (c->argc == 1) {pubsubUnsubscribeAllPatterns(c,1);} else {int j;for (j = 1; j < c->argc; j++)pubsubUnsubscribePattern(c,c->argv[j],1);}if (clientSubscriptionsCount(c) == 0) c->flags &= ~CLIENT_PUBSUB;
}/* PUBLISH <channel> <message> */
void publishCommand(client *c) {int receivers = pubsubPublishMessage(c->argv[1],c->argv[2]);if (server.cluster_enabled)clusterPropagatePublish(c->argv[1],c->argv[2]);elseforceCommandPropagation(c,PROPAGATE_REPL);addReplyLongLong(c,receivers);
}/* PUBSUB command for Pub/Sub introspection. */
void pubsubCommand(client *c) {if (c->argc == 2 && !strcasecmp(c->argv[1]->ptr,"help")) {const char *help[] = {
"CHANNELS [<pattern>]",
"    Return the currently active channels matching a <pattern> (default: '*').",
"NUMPAT",
"    Return number of subscriptions to patterns.",
"NUMSUB [<channel> ...]",
"    Return the number of subscribers for the specified channels, excluding",
"    pattern subscriptions(default: no channels).",
NULL};addReplyHelp(c, help);} else if (!strcasecmp(c->argv[1]->ptr,"channels") &&(c->argc == 2 || c->argc == 3)){/* PUBSUB CHANNELS [<pattern>] */sds pat = (c->argc == 2) ? NULL : c->argv[2]->ptr;dictIterator *di = dictGetIterator(server.pubsub_channels);dictEntry *de;long mblen = 0;void *replylen;replylen = addReplyDeferredLen(c);while((de = dictNext(di)) != NULL) {robj *cobj = dictGetKey(de);sds channel = cobj->ptr;if (!pat || stringmatchlen(pat, sdslen(pat),channel, sdslen(channel),0)){addReplyBulk(c,cobj);mblen++;}}dictReleaseIterator(di);setDeferredArrayLen(c,replylen,mblen);} else if (!strcasecmp(c->argv[1]->ptr,"numsub") && c->argc >= 2) {/* PUBSUB NUMSUB [Channel_1 ... Channel_N] */int j;addReplyArrayLen(c,(c->argc-2)*2);for (j = 2; j < c->argc; j++) {list *l = dictFetchValue(server.pubsub_channels,c->argv[j]);addReplyBulk(c,c->argv[j]);addReplyLongLong(c,l ? listLength(l) : 0);}} else if (!strcasecmp(c->argv[1]->ptr,"numpat") && c->argc == 2) {/* PUBSUB NUMPAT */addReplyLongLong(c,dictSize(server.pubsub_patterns));} else {addReplySubcommandSyntaxError(c);}
}

这篇关于漫话Redis源码之三十六的文章就介绍到这儿，希望我们推荐的文章对编程师们有所帮助！


http://www.chinasem.cn/article/683913。

相关文章

Redis指南及6.2.x版本安装过程

Redis指南及6.2.x版本安装过程

《Redis指南及6.2.x版本安装过程》Redis是完全开源免费的,遵守BSD协议,是一个高性能(NOSQL)的key-value数据库,Redis是一个开源的使用ANSIC语言编写、支持网络、... 目录概述Redis特点Redis应用场景缓存缓存分布式会话分布式锁社交网络最新列表Redis各版本介绍旧
阅读更多...
Java如何从Redis中批量读取数据

Java如何从Redis中批量读取数据

《Java如何从Redis中批量读取数据》：本文主要介绍Java如何从Redis中批量读取数据的情况,具有很好的参考价值,希望对大家有所帮助,如有错误或未考虑完全的地方,望不吝赐教... 目录一.背景概述二.分析与实现三.发现问题与屡次改进3.1.QPS过高而且波动很大3.2.程序中断，抛异常3.3.内存消
阅读更多...
Redis中的Lettuce使用详解

Redis中的Lettuce使用详解

《Redis中的Lettuce使用详解》Lettuce是一个高级的、线程安全的Redis客户端,用于与Redis数据库交互,Lettuce是一个功能强大、使用方便的Redis客户端,适用于各种规模的J... 目录简介特点连接池连接池特点连接池管理连接池优势连接池配置参数监控常用监控工具通过JMX监控通过Pr
阅读更多...
python操作redis基础

python操作redis基础

《python操作redis基础》Redis(RemoteDictionaryServer)是一个开源的、基于内存的键值对（Key-Value）存储系统,它通常用作数据库、缓存和消息代理,这篇文章... 目录1. Redis 简介2. 前提条件3. 安装 python Redis 客户端库4. 连接到 Re
阅读更多...
Redis迷你版微信抢红包实战

Redis迷你版微信抢红包实战

《Redis迷你版微信抢红包实战》本文主要介绍了Redis迷你版微信抢红包实战... 目录1 思路分析1.1hCckRX 流程1.2 注意点①拆红包：二倍均值算法②发红包：list③抢红包&记录：hset2 代码实现2.1 拆红包splitRedPacket2.2 发红包sendRedPacket2.3 抢
阅读更多...
Golang实现Redis分布式锁(Lua脚本+可重入+自动续期)

Golang实现Redis分布式锁(Lua脚本+可重入+自动续期)

《Golang实现Redis分布式锁(Lua脚本+可重入+自动续期)》本文主要介绍了Golang分布式锁实现,采用Redis+Lua脚本确保原子性,持可重入和自动续期,用于防止超卖及重复下单,具有一定... 目录1 概念应用场景分布式锁必备特性2 思路分析宕机与过期防止误删keyLua保证原子性可重入锁自动
阅读更多...
8种快速易用的Python Matplotlib数据可视化方法汇总(附源码)

8种快速易用的Python Matplotlib数据可视化方法汇总(附源码)

《8种快速易用的PythonMatplotlib数据可视化方法汇总(附源码)》你是否曾经面对一堆复杂的数据,却不知道如何让它们变得直观易懂？别慌,Python的Matplotlib库是你数据可视化的... 目录引言1. 折线图（Line Plot）——趋势分析2. 柱状图（Bar Chart）——对比分析3
阅读更多...
Spring Boot 整合 Redis 实现数据缓存案例详解

Spring Boot 整合 Redis 实现数据缓存案例详解

《SpringBoot整合Redis实现数据缓存案例详解》Springboot缓存,默认使用的是ConcurrentMap的方式来实现的,然而我们在项目中并不会这么使用,本文介绍SpringB... 目录1.添加 Maven 依赖2.配置Redis属性3.创建 redisCacheManager4.使用Sp
阅读更多...
redis在spring boot中异常退出的问题解决方案

redis在spring boot中异常退出的问题解决方案

《redis在springboot中异常退出的问题解决方案》：本文主要介绍redis在springboot中异常退出的问题解决方案,本文给大家介绍的非常详细,对大家的学习或工作具有一定的参考借鉴... 目录问题：解决 问题根源️ 解决方案1. 异步处理 + 提前ACK（关键步骤）2. 调整Redis消费者组
阅读更多...
springboot项目redis缓存异常实战案例详解(提供解决方案)

springboot项目redis缓存异常实战案例详解(提供解决方案)

《springboot项目redis缓存异常实战案例详解(提供解决方案)》redis基本上是高并发场景上会用到的一个高性能的key-value数据库,属于nosql类型,一般用作于缓存,一般是结合数据... 目录缓存异常实践案例缓存穿透问题缓存击穿问题（其中也解决了穿透问题）完整代码缓存异常实践案例Red
阅读更多...

Copyright China编程 23002807@qq.com

沪ICP备2023033072号-2