socket.emit not working inside socket.on server side

[BirdBare]

You want to:

• report a bug
• request a feature

Current behaviour

*I cannot socket.emit from inside a socket.on callback on the server

Steps to reproduce (if the current behaviour is a bug)

Try to socket.emit inside of a socket.on from server side

Expected behaviour

The client to receive the message specific to their connection

Setup

• OS: Ubuntu
• browser: Chrome
• socket.io version: 2.3.0 from npm install

Code

I cannot use io.emit or io.socket.emit because I only want the message to go to the requesting client. The issue has equals in front to help you find it.

var strains = "*DELETED";
var effects = "*DELETED";

strains = strains.replace(/\n/g," ");
strains = strains.replace(/ {2,}/g," ");
effects = effects.replace(/\n/g," ");
effects = effects.replace(/ {2,}/g," ");
//replace all newlines with spaces then remove all excess spaces. Should now
//match database.

const autocomplete = strains + effects;

var express = require("express");
var app = express();
var http = require("http").Server(app);
var io = require("socket.io")(http);
var request = require("request");

http.listen(8080);

//create website
app.get ('/', function(request, response) 
{
  response.sendFile(__dirname + "/index.html");
});

//access local folder
app.use('/', express.static(__dirname));

//connect to socket from webpage
io.on("connection", function(socket)
{
  socket.emit("autocomplete",autocomplete);
  //emit on connection for autocomplete source

  socket.on("recommend", function(data)
  {
    if(data.length > 0)
    {
      data = data.split(",");
    
      lcStrains = strains.toLowerCase().split(",");
      lcEffects = effects.toLowerCase().split(",");

      var strainTags = [];
      var effectTags = [];
      var garbageTags = [];

      data.forEach(element =>
      {
        if(lcStrains.indexOf(element) != -1)
        {
      
          strainTags.push(element);
        }
        else if(lcEffects.indexOf(element) != -1)
        {
          effectTags.push(element);
        }
        else
        {
          garbageTags.push(element);
        }
        //get indexof element. If -1 then element is not present in the array
        //and will be put in garbage array
      });
    
      strainTags = strainTags.toString();
      effectTags = effectTags.toString();
      garbageTags = garbageTags.toString();

      console.log("...List of Tags...");
      console.log("Strains: " + strainTags);
      console.log("Effects: " + effectTags);
      console.log("Garbage: " + garbageTags);

      if(strainTags.length > 0 || effectTags.length > 0)
      {
        console.log("rec");
        const url = "*DELETED"
        const request_parameters = 
        {  
        "liked_strains": strainTags,
        "liked_effects": effectTags,
        "return_details": true,
        };

        request({url:url, qs:request_parameters}, function(err,reponse,body)
        {
          console.log(reponse.statusCode);
====socket.emit("result",JSON.stringify(JSON.parse(body).recommendations.results));
          //send result to client side in non JSON format.
        });
      }
    }

  });
 
  //api search if I can figure out source in autocomplete.
  socket.on("search", function(data)
  {
    console.log(data);

    const url = "*DELETED"
    const request_parameters = 
    { 
    "text": data,
    "category": "",
    "page" : "",
    "results_per_page" : "15",
    };

    request({url:url, qs:request_parameters}, function(err,reponse,body)
    {
      console.log(reponse.statusCode);
      console.log(body);
    });
  });
});

[BirdBare]

Little info.

I tried to run socket.emit inside socket.on on the client side and it worked fine. Must be a server side bug.

I also tried io.to(socket.id).emit on server side to no avail.

[sghofrany]

If you are trying to emit to a specific client you can use something like this.

io.on("connection", (socket) => {

//this will emit your event with the data specified only to the one client with that socket.id

io.to(socket.id).emit("your-event", yourData)

)};

EDIT: I just saw that you have tried this as well. I'm not sure as to what your problem might be, because I am also using socket.io version 2.3.0 and this seems to work just fine for me.

[BirdBare]

I decided to use the callback functionality to reply directly to the requestor. It makes the design a little easier as well. I couldn't get it to work when having an emit event(or similar) directly inside a .on event.