socket.io private message

问题

I've beeen scouring the Net with no luck. I'm trying to figure out how to send a private message from one user to another. There are lots of snippets, but I'm not sure about the client/server interaction. If I have the ID of the socket I want to send to, how do I send it to the server, and how do I ensure the server only sends the message to that one receiver socket?

Is there a tutorial or walkthrough that anyone knows of?

回答1:

No tutorial needed. The Socket.IO FAQ is pretty straightforward on this one:

socket.emit('news', { hello: 'world' });

EDIT: Folks are linking to this question when asking about how to get that socket object later. There is no need to. When a new client connects, save a reference to that socket on whatever object you're keeping your user information on. My comment from below:

In the top of your script somewhere, setup an object to hold your users' information.

var connectedUsers = {};

In your .on('connection') function, add that socket to your new object. connectedUsers[USER_NAME_HERE] = socket; Then you can easily retrieve it later. connectedUsers[USER_NAME_HERE].emit('something', 'something');

回答2:

Here's a code snippet that should help:

Client-side (sending message)

socket.emit("private", { msg: chatMsg.val(), to: selected.text() });

where to refers to the id to send a private message to and msg is the content.

Client-side (receiving message)

socket.on("private", function(data) {   
   chatLog.append('<li class="private"><em><strong>'+ data.from +' -> '+ data.to +'</strong>: '+ data.msg +'</em></li>');
});

where chatLog is a div displaying the chat messages.

Server-side

client.on("private", function(data) {       
    io.sockets.sockets[data.to].emit("private", { from: client.id, to: data.to, msg: data.msg });
    client.emit("private", { from: client.id, to: data.to, msg: data.msg });
});

回答3:

The easiest way I can think of is to have an hash of all the users on using their id or name as the key and have their socket as part of the value then when you want to send a message to just them you pull that socket and emit on it... something like this:

users[toUser].emit('msg',"Hello, "+toUser+"!");

回答4:

Although we have nice answers here. However, I couldn't grasp the whole client server unique user identification pretty fast, so I'm posting this simple steps in order to help whoever is struggling as i did.....

At the client side, Get the user's ID, in my case I'm getting the username...

Client side user registration

//Connect socket.io     
var systemUrl = 'http://localhost:4000';
var socket = io.connect(systemUrl);

//Collect User identity from the client side
var username = prompt('Enter your Username');
socket.emit('register',username);

The Listen to register on the server side to register user's socket to connected socket

Serve side code User registration

/*Craete an empty object to collect connected users*/
var connectedUsers = {};

io.on('connection',function(socket){

/*Register connected user*/
    socket.on('register',function(username){
        socket.username = username;
        connectedUsers[username] = socket;
    });
});

Send Message from the client side

$(document).on('click','.username',function(){
    var username = $(this).text(),
        message = prompt("type your message");

    socket.emit('private_chat',{
        to : username,
        message : message
    });
});

Receive message on server and emit it to private user

/*Private chat*/
socket.on('private_chat',function(data){
    const to = data.to,
            message = data.message;

    if(connectedUsers.hasOwnProperty(to)){
        connectedUsers[to].emit('private_chat',{
            //The sender's username
            username : socket.username,

            //Message sent to receiver
            message : message
        });
    }

});

Receive message on client and display it

/*Received private messages*/
socket.on('private_chat',function(data){
    var username = data.username;
    var message = data.message;

    alert(username+': '+message);
});

This is not the best, however you can start from here....

回答5:

if you have a web site that has register users with uid then you can create a room for each user and name the room by uid of the user.

first connect client to the server using :

var socket = io('server_url');

on the server side create an event for detecting client connection:

io.on('connection', function (socket) {}

then you can emit to client inside it using socket.emit(); and ask uid of current user.

on the client side create an event for this request and then send uid of the user to server.

now on server side join the connected socket to room using :

socket.join(uid);
console.log('user ' + socket.user + ' connected \n');

now you can send private message to a user using following line:

io.to(uid).emit();

if you use the code above, it doesn't matter how many tab user has already open from your web site . each tab will connect to the same room.

回答6:

in socket.io 1.0 use

io.sockets.connected[<socketid>]

you can store just socket id. like so:

var users = {};
users[USER_NAME] = socket.id;

then:

io.sockets.connected[users[USER_NAME]]
   .emit('private', {
       msg:'private message for user with name '+ USER_NAME
   });

回答7:

You can create an unique room for messaging between USER_A and USER_B and both users must join to this room. You may use an UUID as a ROOM_ID (the 'socketId' in the following example).

io.on('connection', socket => {

   socket.on('message', message => {
       socket.to(message.socketId).emit('message', message);
   });

   socket.on('join', socketId => {
       socket.join(socketId);
   });

});

See Joining Rooms and Emit Cheatsheet

来源：https://stackoverflow.com/questions/11356001/socket-io-private-message

标签

node.js

Socket.IO

message