nodejs redis 发布订阅机制封装

最近项目使用redis，对publish 和 subscribe的使用进行了了解，并进行了封装。

 var config = require('../config/config');
 var log = require("./loghelp");
 var redis = require("redis");
 function initialclient(param) {
     var option={ host: config.redis.host, port: config.redis.port};
     if(param)
     {
         option=Object.assign(option,param);
     }
     redis.print
     let client = redis.createClient(option);
     client.on("error", function(err) {
         log.error(err);
     });
     return client;
 }

 /*example:
 * let channel="ryan";
  redis.pubSub.registerHandlers("ryan",msg=> console.log(msg));
  redis.pubSub.subscribe(channel);

  redis.pubSub.publish(channel,"hello from chen");*/
 class PubSub
 {
     constructor(){
         this.sub=initialclient();
         this.handlers=new Map();
         this.subAction=(channle,message)=>{
             let actions= this.handlers.get(channle)||new Set();
             for(let action of actions)
             {
                 action(message);
             }
         }
         this.alredyPublishs=[];
         this.subConnected=false;
     }

     publish(channel,message)
     {
         let action=()=>{
             let pub=initialclient();
             pub.publish(channel,message);
         };
         if(this.subConnected===false)
         {
             this.alredyPublishs.push(action);
         }
         else
             action();
     }
     registerHandlers(channel,action)
     {
        var actions=this.handlers.get(channel)||new Set();
        actions.add(action);
        this.handlers.set(channel,actions);
     }
     subscribe(channel)
     {
         let self=this;
         this.sub.subscribe(channel,function (err,reply) {
             if(err)
                 log.error(err);
             self.subConnected=true;
             for(let publish of self.alredyPublishs)
                 publish();
             console.log(reply);
         });

         this.sub.on("message", function (channel, message) {
             self.subAction(channel,message);
         });
     }

     tearDown()
     {
         this.sub.quit();
     }
 }

然后通过exports.pubsub=new PubSub() 将其暴漏，可保证是单例。在程序启动时，调用

registerHandlers  注册特定通道的处理逻辑，然后调用

subscribe  订阅通道。

在合适时机调用publish，这个机制可以实现分布式下所有客户端watch 同一个数据的更改。