If you have multiple transport protocols that start from the same client how would you go about tying their unique ids together? For me, I'm using socket.io and binaryjs. Socket.io will handle the requests and binaryjs when send the responses. I can't seem to figure out how to tie them together though to accomplish this because each protocol has it's own way of determining it's id. So, when I kick off a new client, the instances of each protocol don't have a common identifier. How do you work around this?
client:
<script src='/binary.js'></script>
<script src='/socket.io/socket.io.js'></script>
<script>
var socket=io.connect('http://127.0.0.1:3000');
var client=new BinaryClient('ws://127.0.0.1:3001');
function doSomething() {
socket.emit('someEvent',{success:'someData'});
}
</script>
<input type='submit' value='Submit' onClick='doSomething();'>
server:
binjsConnections = {}
binjs.on('connection', function(binclient) {
binjsConnections[binclient] = {client: binclient}
});
io.sockets.on('connection', function(ioclient) {
// process data from io socket
ioclient.on('someEvent', function(data) {
// transport results over binjs socket
binjsConnections[binclient].client.send(data)
});
});
Why not use session cookies. I'm not sure if you're just using http/websockets but if you are you can. Socket.io has examples if you google for "socket.io session authorization".
Related
I'm trying to use socket.io to connect to this websocket api:
https://www.cryptocompare.com/api/#-api-web-socket-
(wss://streamer.cryptocompare.com)
I guess im not really understanding socket.io very much.
I created a blank html document:
<!doctype html>
<html lang="en">
<head>
<script src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/2.1.1/socket.io.slim.js"></script>
</head>
<body>
<div id="data-show">
</div>
<button id="connect-sock">Connect</button>
<button id="disconnect-sock">DISConnect</button>
</body>
<script src="index.js"></script>
</html>
index.js:
var socket = io('wss://streamer.cryptocompare.com')
console.log('connected')
var btn = document.getElementById('connect-sock')
var btn2 = document.getElementById('disconnect-sock')
var show = document.getElementById('data-show')
//I also tried adding an event listener to a button so when i clicked it, it would do this:
socket.emit('SubAdd', { subs: ['0~Poloniex~BTC~USD'] } )
//Same result of nothing.
socket.on('SubAdd', function(data){
console.log(data)
})
server.js:
var express = require('express')
var socket = require('socket.io')
var app = express()
var server = app.listen(4000, function(){
console.log("well met")
})
app.use(express.static('public'))
var io = socket(server)
io.on('connection', function(socket){
console.log('well met from socket connection', socket.id)
})
server.js is in a file named 'socket-test'. index.html and index.js are in 'socket-test/public/'
so for some reason, in server.js, socket.id will not log to console. its as if this function is being skipped over. but when i change the address in index.js to http://localhost:4000, i get socket.id in console... not sure whats going on there.
Edit: I rarely get socket id when using the wss://streamer.cryptocompare.com/ , sometimes I do, most of the time i dont. It usually works when I switch to localhost, run the server, stop the server, then switch back to the streamer, but if i reload, i dont get socket.id anymore.
I thought that all I was asking it to do here was emit subs to wss://streamer.cryptocompare then console.log(data) that it returns after emitting the subs.
am I missing something here?
Sorry in advance if its blatantly obvious that I'm missing something. I've only known about socket.io for maybe 3 days now, and only today have I watched a basic tutorial on youtube.
You don't need the Express code because in this case the server you want to talk to is on the cryptocompare server -- not a local server. This is captured in your code when you initialize the io object in the HTML file.
Of course, you could still use Node to talk to the cryptocompare websockets API if you're more comfortable with Node. But then you wouldn't need the in-browser JavaScript. Either way, what you need is to create some kind of client in any runtime that speaks websockets and can talk to the cryptocompare websockets API.
With regard to the code being skipped over -- you're right! It is. socket.io is an event driven WebSockets framework. This means that clients register their interest in certain kinds of events/messages, and when those are triggered special functions known as callbacks are called.
If it helps, you can think of those events like channels in a chat room -- if you're not in the right room, you won't see the messages for that room. So you'll need to know what messages you should be listening for, register your interest in those, and register callback functions for each one.
Thankfully cryptocompare has provided client code examples that should help you get an idea for the kinds of messages you should be listening for.
See here
I've got a question regarding client-management socket.io with node.js
I'm running a very basic socket.io application where several socket.io-clients connect to a socket.io-server. When I try to populate a list of clients I do it like this:
server.js:
var clients = [];
io.on('connection', function (socket) {
socket.emit('whoareyou');
socket.on('hithere', function(name){
clients.push(name);
socket.emit('clients', clients);
console.log(name+" connected");
socket.on('disconnect', function(){
console.log(name+" disconnected");
clients.splice(clients.indexOf(name), 1);
});
});
});
clients.js
var socket = io.connect(server, {
port: 80
});
socket.on('whoareyou', function(){
socket.emit('hithere',hostname);
});
});
The clients-emit is for a webpage to populate the client-list because I don't really know how to exchange this list with a webserver running on the same machine without emitting.
Now, what I could do is skipping this whole whoareyou and hithere-crap and saving the socket as a JSON-array in clients. The ugly detail about this is that I just want to use the hostname of the client as a nickname and this is not a part of the socket-JSON (btw: the ip-address is part of it).
the socket-io docs show a nice example of a chat-room here: http://socket.io/get-started/chat/ but the interesting parts are left out.
Does somebody know a nice way how to do this?
I have to get socket instance in my ajax request on server in node.js module. Here is my code.
app.js
io.set('authorization', function (handshake, callback) {
if (handshake.headers.cookie) {
cookieParser(handshake, null, function(err) {
handshake.sessionID = handshake.signedCookies['express.sid'];
});
} else { return callback('No cookie transmitted.', false); }
});
io.sockets.on('connection', function(socket) {
var session = socket.handshake.session;
var userid = session.userid;
socket.join("room");
//make user offline
socket.on('disconnect', function() {
//my code goes here...
//make user offline
})
});
Now in one of my ajax request, I want socket instance
app.post('/logout', function (req, res) {
//here i want socket instance, so I can emit message to all socket, accept this.
});
As I know, each tab creates it's own new socket connection, but session is unique between all tabs of browser. So, How Do I store socket for each tab on server side, where I can find easily socket instance, and then broadcast message to all sockets, excluding that socket which is creating events. (means user's active tab's socket connection)
any guess.
thanks
In my app, I can do what you say because i use namespace and room and so in a room i can find every socket of someone.
io.of('/user').clients(idRoom);
So that i can remove every socket of the user. But if you cannot use this, i think in your app you will have to implement outside socket.io a class for someone (using session as a way to see if it's already have a socket open or if you have to create a new instance). And in this class, have a socket table so that you will be able to handle socket of someone.
In my case, i do the same except that i use the room of socket.io to do that.
And to broadcast to every socket, it depends what is your app. If your app send to anyone in the same namespace, it doesn't change anything because the socket of the same session will also receive the message. But if not, you will have to implement a function to emit to every socket of the table i suggested above.
In my case i use the 'exclude' to ensure the current socket doesn't receive the message but usually you can use broadcast.
io.of('/user').in(this.id).except(socket.id).emit('msg', { text: text,type:person});
To conclude, socket.io will not help you to handle session and several socket for one user/session but you can manage to deal with it using room feature (in my case it was the best way), or implement a user class where you will manage a table of your session sockets.
Im trying to set up a node.js server to send messages to the client, which will then display the messages using a jquery notification library, I'm using this notifcation library if anyone's interested: http://needim.github.com/noty/
At the minute I have a postgres database set up with a table which has a a trigger on it to write to a listener.
The trigger is as follows:
CREATE OR REPLACE FUNCTION new_noti() RETURNS trigger AS $$
DECLARE
BEGIN
PERFORM pg_notify('watchers', TG_TABLE_NAME || ',msg,' || NEW.msg );
RETURN new;
END;
$$ LANGUAGE plpgsql;
Then I have a node.js server as follows:
var pg = require ('pg');
var pgConString = "pg://aydin:password#localhost/test"
var app = require('http').createServer(handler)
, io = require('socket.io').listen(app)
, url = require('url')
app.listen(8080);
function handler (request, respsonse) {
var client = new pg.Client(pgConString);
client.connect();
client.query('LISTEN "watchers"');
client.on('notification', function(msg) {
console.log(msg.payload);
sendMessage(msg.payload);
});
}
function sendMessage(message) {
io.sockets.emit('notification', {'message': message});
}
Then I have some client code as follows:
<script type="text/javascript">
var socket = io.connect('http://localhost:8080');
socket.on('notification', function (data) {
console.log(data.message);
newNoty(data);
});
function newNoty(data) {
noty({
"text":data.message,
buttons: [{
type: 'button green',
text: 'Go to'
}],
"theme":"noty_theme_twitter",
"layout":"bottomRight",
"type":"information",
"animateOpen":{
"height":"toggle"
},
"animateClose":{
"height":"toggle"
},
"speed":500,
"timeout":7500,
"closeButton":true,
"closeOnSelfClick":true,
"closeOnSelfOver":false,
"modal":false,
});
}
</script>
This doesn't work, it seems the node.js never receives the postgres notifications, I think this is because I am using the function handler and I'm not actually firing any requests to it from the client code. I'm not sure how to do this and whether it is the correct way?
Is there a function on which can fire on connections and not requests?
And am I even doing it the right way round? should there be a server on the client side which node.js sends messages to? How does it know when a client is available? Any help or pointers to tutorials would be much appreciated. Thankyou.
You're not actually setting up your database connection until the client sends an HTTP request. It looks like that may never happen due to same-origin issues (your client code appears to be coming from somewhere other than the server you've shown).
In any case, you probably want to set up the connection in response to a "connection" event from io.sockets (i.e. move the stuff that's currently in the HTTP request handler there). That's how it "knows when a client is available". Or maybe you should be doing it as part of initialization. Your client-side code seems OK, but it's out of context so it's hard to tell whether it really fits your needs.
I'm assuming this isn't possible, but wanted to ask in case it is. If I want to provide a status information web page, I want to use WebSockets to push the data from the server to the browser. But my concerns are the effect a large number of browsers will have on the server. Can I broadcast to all clients rather than send discrete messages to each client?
WebSockets uses TCP, which is point to point, and provides no broadcast support.
Not sure how is your client/server setup, but you can always just keep in the server a collection of all connected clients - and then iterate over each one and send the message.
A simple example using Node's Websocket library:
Server code
var WebSocketServer = require('websocket').server;
var clients = [];
var socket = new WebSocketServer({
httpServer: server,
autoAcceptConnections: false
});
socket.on('request', function(request) {
var connection = request.accept('any-protocol', request.origin);
clients.push(connection);
connection.on('message', function(message) {
//broadcast the message to all the clients
clients.forEach(function(client) {
client.send(message.utf8Data);
});
});
});
As noted in other answers, WebSockets don't support multicast, but it looks like the 'ws' module maintains a list of connected clients for you, so it's pretty easy to iterate through them. From the docs:
const WebSocketServer = require('ws').Server;
const wss = new WebSocketServer({ port: 8080 });
wss.broadcast = function(data) {
wss.clients.forEach(client => client.send(data));
};
Yes, it is possible to broadcast messages to multiple clients.
In Java,
#OnMessage
public void onMessage(String m, Session s) throws IOException {
for (Session session : s.getOpenSessions()) {
session.getBasicRemote().sendText(m);
}
}
and here it is explained.
https://blogs.oracle.com/PavelBucek/entry/optimized_websocket_broadcast.
It depends on the server-side really. Here's an example of how it's done using Tomcat7:
Tomcat 7 Chat Websockets Servlet Example
and an explanation of the how it's constructed here.
Yes you can and there are many socket servers out there written in various scripting languages that are doing it.
The Microsoft.Web.WebSockets namespace has a WebSocketCollection with Broadcast capability. Look for the assembly in Nuget. The name is Microsoft.WebSockets.