I have a NodeJS-Server which communicated with the fronend via Websocket-Connection.
When the Server gets a on('message'), it should run a function which name is given the message via eval().
it workes fine, unless I completely don't know where to put the funcions to be called.
var http = require('http');
var ws = require('ws');
function render(vars) {
var server = http.createServer(function(req, res) {
.....
});
/* WEBSOCKET */
var wsServer = new ws.Server({server});
wsServer.on('connection', socket => {
socket.on('message', message => {
console.log('WS from template <-- ', message);
var wsIn = JSON.parse(message);
eval(wsIn.action);
});
});
}
when a message is incoming, eval(wsIn.action) should run a function called.. .lets assume runme.. so where would I now need to declare this function ? I try everything but whatever I do, i get
ReferenceError:: runme is not defined
edit:
I found out something interesting:
when i call a function normal like runme(); in my onMessage.. everything is cool.. but with eval(runme); nothing happens.. no error, no output, nothing..
Related
After receive message from client, I have to connect db(mysql) and save data and need to response the result to client and inform to other(admin) client.
So I need to get current socket client and special client(admin) from the socket list.
Is it possible to get current socket outside of wss connection block?
Thanks.
const WebSocketServer = require('ws');
// Creating a new websocket server
const wss = new WebSocketServer.Server({ port: 8080 });
const clients = new Map();
// Creating connection using websocket
wss.on("connection", ws => {
console.log("new client connected");
client_id = Date.now();
clients.set(client_id, ws);
// sending message
ws.on('message', function(message) {
//wss.broadcast(JSON.stringify(message));
console.log('Received: ' + message);
BuyCoin(message);
//console.log()
});
ws.on("close", () => {
console.log("the client has connected");
});
ws.onerror = function () {
console.log("Some Error occurred")
}
// ws.send('You successfully connected to the websocket.');
});
function BuyCoin(strValue){
const req_info = JSON.parse(strValue);
console.log(req_info.user_id)
console.log('betting!');
var sql = 'SELECT * from users where id = ? LIMIT 1'
connection.query(sql, req_info.user_id, (ws)=>{
return function(err, rows, fields) {
//console.log("ix="+ix);
ws.send(rows[0]);
};
});
}
}
You have several options:
#1: You can put the BuyCoin function logic inside the ws scope to make it a local function that is in scope of the ws variable for the current connection like this:
const WebSocketServer = require('ws');
// Creating a new websocket server
const wss = new WebSocketServer.Server({ port: 8080 });
const clients = new Map();
// Creating connection using websocket
wss.on("connection", ws => {
console.log("new client connected");
client_id = Date.now();
clients.set(client_id, ws);
// sending message
function BuyCoin(strValue) {
const req_info = JSON.parse(strValue);
console.log(req_info.user_id)
console.log('betting!');
var sql = 'SELECT * from users where id = ? LIMIT 1'
connection.query(sql, req_info.user_id, (ws) => {
return function(err, rows, fields) {
//console.log("ix="+ix);
ws.send(rows[0]);
};
});
}
ws.on('message', function(message) {
//wss.broadcast(JSON.stringify(message));
console.log('Received: ' + message);
BuyCoin(message);
//console.log()
});
ws.on("close", () => {
console.log("the client has connected");
});
ws.onerror = function() {
console.log("Some Error occurred")
}
// ws.send('You successfully connected to the websocket.');
});
#2: You can pass the ws value to your BuyCoin() function as an argument by just changing the function call from this:
BuyCoin(message);
to this:
BuyCoin(ws, message);
And, then changing your function declaration from this:
function BuyCoin(strValue) {...}
to this:
function BuyCoin(ws, strValue) {...}
Is it possible to get current socket outside of wss connection block?
No, there really is no such thing as the current socket. When using asynchronous code in nodejs, lots of different pieces of code can be "in-flight" at the same time so there is no global sense of the current socket. Instead, you have manage data specific to your current operation either by using scope, by passing as an argument or by setting as a properties on some other object that is passed as an argument. Since there is no natural object that BuyCoin() already has access to here that is specific to the user with the activity, then that leaves the first two options (using scope and passing as an argument).
FYI, this code looks a bit problematic because you're allowing the webSocket to send in the user_id that will be operated on without any visible authentication. That exposes you to rogue sockets that can pretend to be users that they aren't.
Also, it doesn't appear you have code that removes webSockets from the clients Map object when they disconnect so that Map object will just get larger and larger and contain lots of dead connections.
Another thing that needs fixing is that your connection.query() code is declaring a callback that does nothing but return another function and it tried to make up a value of ws that would never actually be passed. That function you create inside the callback is never called. Change from this:
connection.query(sql, req_info.user_id, (ws) => {
return function(err, rows, fields) {
//console.log("ix="+ix);
ws.send(rows[0]);
};
});
to this:
connection.query(sql, req_info.user_id, (err, rows, fields) => {
//console.log("ix="+ix);
ws.send(rows[0]);
});
And, combine that with one of the above two solutions to get access to the ws value.
var net = require('net');
var server = net.createServer(function(connection) {
console.log('client connected');
connection.on('end', function() {
console.log('closed');
});
// connection.write('100');
connection.pipe(connection);
});
server.listen(5001, function() {
console.log('server is listening');
});
function addInput(){
var value = document.getElementById("textId").value;
console.log(value);
document.getElementById("textId").value="";
//connection.write(value);
}
I want to send data to the client in the button function addinput, but I can't send it, how can I use socket.write in the function
Is that code that you commented (connection.write(value);) supposed to work?
You won't be able to make it work since connection is only within the scope of the function you wrote into var server.
Other than that, to get your server to do anything you'll have to make a request to it, possibly with net.createConnection() (check doc here: https://nodejs.org/api/net.html). I'm not seeing any code in your example that would do that so far.
I have a piece of code:
var http = require('http');
function createApplication() {
let app = function(req,res,next) {
console.log("hello")
};
return app;
}
app = createApplication();
app.listen = function listen() {
var server = http.createServer(this);
return server.listen.apply(server, arguments);
};
app.listen(3000, () => console.log('Example app listening on port 3000!'))
Nothing fancy here. But when I run this code and go to localhost:3000, I can see hello is getting printed. I'm not sure how this function is getting called at all. Also, the function receives the req & res objects as well. Not sure whats happening here.
http.createServer() has a couple optional arguments. One being requestListener which is
https://nodejs.org/api/http.html#http_http_createserver_options_requestlistener
The requestListener is a function which is automatically added to the
'request' event.
Since you call your listen() like so app.listen(), this inside that function is going to be a reference to the function you made and returned in createApplication. So you are basically doing:
http.createServer(function(req,res,next) {
console.log("hello")
});
Hence your function is added as a callback for any request, and thus why any request you make will create a console log of hello.
If you want an equivalent more straight forward example
var http = require('http');
var server = http.createServer();
server.on('request',function(req,res,next) {
//callback anytime a request is made
console.log("hello")
});
server.listen(3000);
I have the following code:
function Socket(io, playGame, mapper) {
io.on('connection', function (socket) {
// message handler for the chat message
socket.on('sendChat', function (data) {
console.log(socket);
console.log(data);
console.log('recieved chat');
var connectedPlayer = playGame.findConnectedPlayer(socket);
if (!connectedPlayer)
return;
var connectedGame = playGame.findConnectedGame(socket, connectedPlayer.gameId);
if (!connectedGame)
return;
// send update game with players properly ordered
for (socketIndex in this.sockets) {
var socket = this.sockets[socketIndex];
// send the new data to each player
socket.socket.emit('chatUpdate', { chatText: data.chat });
}
});
// message handler for join game message
socket.on('joinGame', function (data) {
console.log('recieved join:', JSON.stringify(data));
if (!playGame.newConnectedPlayer(socket, data))
return;
...
In the method for sendChat, socket is undefined. In the method for joinGame, socket is defined. I have tried several ideas, but the problem persists. Any help would be appreciated.
You'll have to rename one of the 2 socket variables -- either the parameter for 'connection' or the var in the loop:
io.on('connection', function (socket) {
for (socketIndex in this.sockets) {
var socket = this.sockets[socketIndex];
The var is shadowing the parameter, rendering the parameter inaccessible.
This happens in part because the var socket doesn't only exist within the for loop. JavaScript vars are function-scoped and their declarations are hoisted to the top of the function, as in:
socket.on('sendChat', function (data) {
var connectedPlayer, connectedGame, socket; // each initially `undefined`
console.log(socket);
// ...
for (socketIndex in this.sockets) {
socket = this.sockets[socketIndex];
// ...
});
And, having the same exact name, at most only one of them can be reached from a particular function.
Also note that the for loop and var socket aren't really necessary.
You can use the Socket.IO Server's own .emit() method to send a message to all clients.
io.emit('chatUpdate', { chatText: data.chat });
I am a trying to use socket.io and node.js like this :
The browser sends an event to socket.io, in the data event I call another server to get some data, and I would like to send back a message to the browser using a socket.emit.
This looks like that :
socket.on('ask:refresh', function (socket) {
const net = require("net");
var response = new net.Socket();
response.setTimeout(1000);
response.get_response = function (command, port, host) {
this.connect(port, host, function () {
console.log("Client: Connected to server");
});
this.write(JSON.stringify({ "command": command }))
console.log("Data to server: %s", command);
};
response.on("data", function (data) {
var ret = data.toString();
var tmp_data = JSON.parse(ret.substring(0, ret.length - 1).toString());
var data = new Object();
var date = new Date(tmp_data.STATUS[0].When * 1000 );
data.date = date.toString();
socket.emit('send:refresh', JSON.stringify(data) );
});
response.get_response("version", port, host);
});
};
The thing is that I cannot access "socket.emit" inside response.on.
Could you please explain me how I can put a hand on this ?
Thanks a lot
You appear to be overwriting the actual socket with the one of the callback parameters:
socket.on('ask:refresh', function(socket) {
// socket is different
});
Change the name of your callback variable, and you won't have this problem.