Erreur: Connexion en mode abonné, seules les commandes d'abonné peuvent être utilisées

Question

J'ai trouvé une erreur pour pousser les données de message dans Redis. Veuillez me fournir quelques lignes directrices sur l'erreur. pourquoi cela arrive-t-il? Je voudrais stocker les données de discussion dans redis en utilisant nodejs.

server.js (serveur):

/* 
* ------------------- 
* Express 
* ------------------- 
*/ 
var app = require('express')(), 
     session = require("express-session"); 

app.use(function (req, res, next) { 
    res.header("Access-Control-Allow-Origin", "*"); 
    res.header("Access-Control-Allow-Headers", "X-Requested-With"); 
    res.header("Access-Control-Allow-Headers", "Content-Type"); 
    res.header("Access-Control-Allow-Methods", "PUT, GET, POST, DELETE, OPTIONS"); 
    next(); 
}); 
app.set('host', "localhost"); 
app.set('port', 8080); //process.env.PORT 

/* 
* ------------------- 
* Socket Connections 
* ------------------- 
*/ 
var server = require('http').createServer(app); 
var io = require('socket.io')(server); 
server.listen(app.get("port"), app.get("host"), function() { 
    console.log("Server up and running..."); 
}); 
io.set('log level', 3); 

/* 
* ------------------- 
* Redis 
* ------------------- 
*/ 
var redis = require("redis"); 
/* 
* Sender 
*/ 
var publisher = redis.createClient(); 
/* 
* Receiver 
*/ 
var subscriber = redis.createClient(); 
/* 
* ------------------- 
* Mysql 
* ------------------- 
*/ 
/*var mysql = require("mysql"); 
var connection = mysql.createConnection({ 
host: "localhost", 
user: "root", 
password: "password", 
database: "w" 
}); 
connection.connect();*/ 

/* 
* ------------------- 
* functions 
* ------------------- 
*/ 
function subscribeMessage(_subscriber) { 
    subscriber.subscribe(_subscriber); 
    subscriber.on("message", function (channel, message) { 
     console.log("redis connection message:" + message); 
    }); 
} 
function pushToRedis(data) { 
    subscriber.lpush('wchannel', data); 
} 

/* 
* ------------------- 
* Redis Subscriber 
* ------------------- 
*/ 
subscriber.subscribe("wchannel"); 
subscribeMessage("wchannel"); 
/*subscriber.on("message", function (channel, message) { 
//console.log("client channel recieve from channel : %s, the message : %s", channel, message); 
});*/ 

/* 
* ------------------- 
* Socket 
* ------------------- 
*/ 
io.sockets.on('connection', function (socket) {  
    console.log("app port :: " + app.get("port")); 
    socket.on('connection', function (data) { 
     console.log('Server running on *:' + app.get('port')); 
    }); 
    //socket.emit("connected", {msg: ""});   
    socket.on("chat", function (data) { 
     pushToRedis(data.msg); 
     //subscriber.ltrim('messages', 0, 99); 
     socket.emit("publishMessage", {msg: data.msg}); 
    }); 
    socket.on('disconnect', function() { 
    }); 
}); 

script.js (client):

$(function() { 
    var socket = io.connect("http://localhost:8080/"); 
    /* 
    * ------------------- 
    * Methods 
    * ------------------- 
    */ 
    $.fn.clearAndFocus = function() { 
     $("#txtMessage").val("").focus(); 
    }; 
    $.fn.sendMessageToServer = function() { 
     socket.emit("chat", {msg: $("#txtMessage").val()}); 
     $.fn.clearAndFocus(); 
    }; 
    $.fn.clearAndFocus(); 
    /* 
    * ------------------- 
    * Events 
    * ------------------- 
    */ 
    $("#btnSend").on("click", function() { 
     $.fn.sendMessageToServer(); 
    }); 
    $("#txtMessage").on("keyup", function (e) { 
     if (e.keyCode === 13) { 
      $.fn.sendMessageToServer(); 
      $.fn.clearAndFocus(); 
     } 
    }); 
    /* 
    * ------------------- 
    * Socket Events 
    * ------------------- 
    */ 
    socket.on('connect', function() { 
     console.log("w client is connected"); 
    }); 
    socket.on("publishMessage", function (data) { 
     console.log(data.msg); 
     $(".chatlog").append("\n\ 
         <div class=\"chat-row\">\n\ 
         <div class=\"chat-text\">" + data.msg + "\n\ 
         </div>"); 

    }); 
    socket.on('disconnect', function() { 
    }); 
}); 

console.log:

root@wk11:/var/www/html/wchat/nodejs# nodejs server.js 
Option log level is not valid. Please refer to the README. 
Server up and running... 
redis connection message:{"msg":"56151810ceff6 is connecting..."} 
app port :: 8080 
chat emtis 
Missing error handler on `socket`. 
Error: Connection in subscriber mode, only subscriber commands may be used 
    at RedisClient.send_command (/var/www/html/wchat/nodejs/node_modules/redis/index.js:751:15) 
    at RedisClient.(anonymous function) (/var/www/html/wchat/nodejs/node_modules/redis/index.js:891:21) 
    at pushToRedis (/var/www/html/wchat/nodejs/server.js:71:16) 
    at Socket.<anonymous> (/var/www/html/wchat/nodejs/server.js:99:9) 
    at Socket.emit (events.js:95:17) 
    at Socket.onevent (/var/www/html/wchat/nodejs/node_modules/socket.io/lib/socket.js:330:8) 
    at Socket.onpacket (/var/www/html/wchat/nodejs/node_modules/socket.io/lib/socket.js:290:12) 
    at Client.ondecoded (/var/www/html/wchat/nodejs/node_modules/socket.io/lib/client.js:193:14) 
    at Decoder.Emitter.emit (/var/www/html/wchat/nodejs/node_modules/component-emitter/index.js:134:20) 
    at Decoder.add (/var/www/html/wchat/nodejs/node_modules/socket.io-parser/index.js:247:12) 

Answer 1

Je crée un nouvel objet enfant abonné dans socket.io et il va résoudre mon problème comme ci-dessous décrit. Parce que l'objet parent de l'abonné est inaccessible dans io.sockets.on() et j'ai aussi créé un autre enfant pour abonné.

/* 
* Sender 
*/ 
var publisher = redis.createClient(); 
/* 
* Receiver 
*/ 
var subscriber = redis.createClient(); 

/* 
* ------------------- 
* Socket 
* ------------------- 
*/ 
io.sockets.on('connection', function (socket) { 
    var _subscriber = redis.createClient(); 
    //console.log("app port :: " + app.get("port"));  
    console.log("Session: %j", sessionHandler); 
    //console.log(JSON.stringify(sessionHandler, null, 4)); 
    socket.on('connection', function (data) { 
     console.log('Server running on *:' + app.get('port')); 
    }); 
    socket.on('disconnect', function() { 
    }); 
}); 

Answer 2

Selon la documentation Redis:

Once the client enters the subscribed state it is not supposed to issue any other commands, except for additional SUBSCRIBE, PSUBSCRIBE, UNSUBSCRIBE and PUNSUBSCRIBE commands.

Lien: http://redis.io/commands/subscribe

Pour envoyer la commande lpush vous devez créer un autre client de Redis qui ne sont pas dans l'état souscrit