I am making a real time multiplayer game with socket.io and node.js, I have a html file that runs a public script to connect to the server and run commands, as well as defining the library I need with
<script src="https://code.jquery.com/jquery-2.2.2.min.js"></script>
I have a connect and disconnect function in thew public js file that has these functions:
// send join request
function joinlobby(room) {
socket.emit("userJoined", room);
}
// emit when a player leaves
function leavelobby(room) {
socket.emit("userLeft", room);
}
and whenever I create a new socket within the function with something like
// emit when a player leaves
function leavelobby(room) {
let socket = io();
socket.emit("userLeft", room);
}
it will run correctly, however with both having a separate connection it causes issues. I was trying to have them use the same connection by having let socket = io(); placed above the functions to use the same socket, however when the program hits that line it stops running the file without throwing an error
How could I use a single connection to the server, and/or why is the program disconnecting when I define the socket outside a function?
Edit for clarity:
The issue isn't wanting a single connection for every client, but rather each client has multiple connections whenever I define the socket in each respective function. I am aiming at only having 1 connection for each client but the line throws an error
I'm sorry for the ambiguity, I'm new to asking questions on here
When you create a connection to the socket server each client will have his own connection, if you want to send a single message to multiple clients you should use rooms. It is pretty easy to use:
io.on("connection", socket => {
socket.join("room1");
});
If boot clients are connected to the same room you will be able to send a message to that room.
io.to("room1").emit("Hello every body");
More info here: https://socket.io/docs/v3/rooms/
Related
So, I am still in the experimental phase of Socket.io, but I just can't figure out why my code is doing this. So, I have the code below and when I console.log the code, it repeats the the connection even when there is only one connection. Do you know a solution?
io.on('connnection', (socket) => {
console.log("A new user is connected.")
})
Client side:
<script src="/socket.io/socket.io.js"></script>
<script>
var socket = io()
</script>
Node.js Console:
A new user is connected.
A new user is connected.
A new user is connected.
A new user is connected.
A new user is connected.
A new user is connected.
A new user is connected.
...
(Note: there is only one connection, and I have already cleared the browser cashe)
Here are some of the possible reasons for socket.io connecting over and over:
Your socket.io client and server versions do not match and this causes a connection failure and an immediate retry.
You are running with some infrastructure (like a proxy or load balancer) that is not configured properly to allow lasting webSocket connections.
You are running a clustered server without sticky webSocket connections.
You have put the server-side io.on('connnection', ...) code inside some other function that is called more than once causing you to register multiple event handlers for the same event so you think you're getting multiple events, but actually you just have multiple listeners for the one occurrence of the event.
Your client code is calling its var socket = io() more than once.
Your client page is reloading (and thus restarting the connection on each reload) either because of a form post or for some other reason.
FYI, you can sometimes learn something useful by installing listeners for all the possible error-related events on both client and server connections and then logging which ones occur and any parameters that they offer. You can see all the client-related error events you can listen to and log here.
To solve repetion problem write your code like that for socket:
io.off("connnection").on('connnection', (socket) => {
console.log("A new user is connected.")
})
I have a vb.net application that opens a socket and listens on it.
I need to communicate via this socket to that application using a javascript running on a browser. That is i need to send some data on this socket so that the app which is listening on this socket can take that data, do some stuff using some remote calls and get some more data and put it back on the socket that my javascript needs to read and print it in the browser.
Ive tried, socket.io, websockify but none have proved to be useful.
Hence the question, is what i am trying even possible? Is there a way that a javascript running in a browser can connect to a tcp socket and send some data and listen on it for some more data response on the socket and print it to the browser.
If this is possible can some one point me in the right direction as to which would help me establish the goal.
As for your problem, currently you will have to depend on XHR or websockets for this.
Currently no popular browser has implemented any such raw sockets api for javascript that lets you create and access raw sockets, but a draft for the implementation of raw sockets api in JavaScript is under-way. Have a look at these links:
http://www.w3.org/TR/raw-sockets/
https://developer.mozilla.org/en-US/docs/Web/API/TCPSocket
Chrome now has support for raw TCP and UDP sockets in its ‘experimental’ APIs. These features are only available for chrome apps and, although documented, are hidden for the moment. Having said that, some developers are already creating interesting projects using it, such as this IRC client.
To access this API, you’ll need to enable the experimental flag in your extension’s manifest. Using sockets is pretty straightforward, for example:
chrome.experimental.socket.create('tcp', '127.0.0.1', 8080, function(socketInfo) {
chrome.experimental.socket.connect(socketInfo.socketId, function (result) {
chrome.experimental.socket.write(socketInfo.socketId, "Hello, world!");
});
});
This will be possible via the navigator interface as shown below:
navigator.tcpPermission.requestPermission({remoteAddress:"127.0.0.1", remotePort:6789}).then(
() => {
// Permission was granted
// Create a new TCP client socket and connect to remote host
var mySocket = new TCPSocket("127.0.0.1", 6789);
// Send data to server
mySocket.writeable.write("Hello World").then(
() => {
// Data sent sucessfully, wait for response
console.log("Data has been sent to server");
mySocket.readable.getReader().read().then(
({ value, done }) => {
if (!done) {
// Response received, log it:
console.log("Data received from server:" + value);
}
// Close the TCP connection
mySocket.close();
}
);
},
e => console.error("Sending error: ", e)
);
}
);
More details are outlined in the w3.org tcp-udp-sockets documentation.
http://raw-sockets.sysapps.org/#interface-tcpsocket
https://www.w3.org/TR/tcp-udp-sockets/
Another alternative is to use Chrome Sockets
Creating connections
chrome.sockets.tcp.create({}, function(createInfo) {
chrome.sockets.tcp.connect(createInfo.socketId,
IP, PORT, onConnectedCallback);
});
Sending data
chrome.sockets.tcp.send(socketId, arrayBuffer, onSentCallback);
Receiving data
chrome.sockets.tcp.onReceive.addListener(function(info) {
if (info.socketId != socketId)
return;
// info.data is an arrayBuffer.
});
You can use also attempt to use HTML5 Web Sockets (Although this is not direct TCP communication):
var connection = new WebSocket('ws://IPAddress:Port');
connection.onopen = function () {
connection.send('Ping'); // Send the message 'Ping' to the server
};
http://www.html5rocks.com/en/tutorials/websockets/basics/
Your server must also be listening with a WebSocket server such as pywebsocket, alternatively you can write your own as outlined at Mozilla
ws2s project is aimed at bring socket to browser-side js. It is a websocket server which transform websocket to socket.
ws2s schematic diagram
code sample:
var socket = new WS2S("wss://ws2s.feling.io/").newSocket()
socket.onReady = () => {
socket.connect("feling.io", 80)
socket.send("GET / HTTP/1.1\r\nHost: feling.io\r\nConnection: close\r\n\r\n")
}
socket.onRecv = (data) => {
console.log('onRecv', data)
}
See jsocket. Haven't used it myself. Been more than 3 years since last update (as of 26/6/2014).
* Uses flash :(
From the documentation:
<script type='text/javascript'>
// Host we are connecting to
var host = 'localhost';
// Port we are connecting on
var port = 3000;
var socket = new jSocket();
// When the socket is added the to document
socket.onReady = function(){
socket.connect(host, port);
}
// Connection attempt finished
socket.onConnect = function(success, msg){
if(success){
// Send something to the socket
socket.write('Hello world');
}else{
alert('Connection to the server could not be estabilished: ' + msg);
}
}
socket.onData = function(data){
alert('Received from socket: '+data);
}
// Setup our socket in the div with the id="socket"
socket.setup('mySocket');
</script>
In order to achieve what you want, you would have to write two applications (in either Java or Python, for example):
Bridge app that sits on the client's machine and can deal with both TCP/IP sockets and WebSockets. It will interact with the TCP/IP socket in question.
Server-side app (such as a JSP/Servlet WAR) that can talk WebSockets. It includes at least one HTML page (including server-side processing code if need be) to be accessed by a browser.
It should work like this
The Bridge will open a WS connection to the web app (because a server can't connect to a client).
The Web app will ask the client to identify itself
The bridge client sends some ID information to the server, which stores it in order to identify the bridge.
The browser-viewable page connects to the WS server using JS.
Repeat step 3, but for the JS-based page
The JS-based page sends a command to the server, including to which bridge it must go.
The server forwards the command to the bridge.
The bridge opens a TCP/IP socket and interacts with it (sends a message, gets a response).
The Bridge sends a response to the server through the WS
The WS forwards the response to the browser-viewable page
The JS processes the response and reacts accordingly
Repeat until either client disconnects/unloads
Note 1: The above steps are a vast simplification and do not include information about error handling and keepAlive requests, in the event that either client disconnects prematurely or the server needs to inform clients that it is shutting down/restarting.
Note 2: Depending on your needs, it might be possible to merge these components into one if the TCP/IP socket server in question (to which the bridge talks) is on the same machine as the server app.
The solution you are really looking for is web sockets. However, the chromium project has developed some new technologies that are direct TCP connections TCP chromium
I have seen a few examples of socket.io.js.
On the client side the call to create the connection is always
var socket = io.connect();
However, this is just creating a point to a function.
How is this enough without another line calling socket?
Is this not just a variable declaration?
Calling io.connect() on the client without any arguments returns the socket object representing the connection. Since it's on the client you don't have to do anything like...
io.on('connection', function (socket) {
// do stuff with socket
});
...like you do on the server. The server expects many clients to connect to it, but the client only ever connects to one server. On the client
var socket = io.connect();
...is plenty. You can also pass options to io.connect(), such as a different URL to connect to.
var socket = io.connect('/my/socket/server/endpoint');
I'm trying to detect whether the websocket is running before allowing clients to connect to it. Consider the following code:
var socket = io.connect('1.1.1.1:1234');
socket.on('connect',function() {
console.log('Client has connected to the server');
});
socket.on('disconnect',function() {
console.log("The client has disconnected from the server");
});
How can I make sure that this block is only called if the server on that IP is actually running and how can I output a message to the users stating that the server is not up?
Thank you
You would need to fire the io.connect() atleast once (consider this as a ping) to detect if server is up, but you can then handle the failure to connect with the socket.on('connect_failed', function () {}) event handler and show a message to user that the 'server is down'. Have a look at Exposed Events for the client
Further, if you would want to reduce the number of times the reconnect is attempted, you can change the socket.io configuration setting for 'reconnect' to false. Checkout Socket.io Configuration for more details
I have a vb.net application that opens a socket and listens on it.
I need to communicate via this socket to that application using a javascript running on a browser. That is i need to send some data on this socket so that the app which is listening on this socket can take that data, do some stuff using some remote calls and get some more data and put it back on the socket that my javascript needs to read and print it in the browser.
Ive tried, socket.io, websockify but none have proved to be useful.
Hence the question, is what i am trying even possible? Is there a way that a javascript running in a browser can connect to a tcp socket and send some data and listen on it for some more data response on the socket and print it to the browser.
If this is possible can some one point me in the right direction as to which would help me establish the goal.
As for your problem, currently you will have to depend on XHR or websockets for this.
Currently no popular browser has implemented any such raw sockets api for javascript that lets you create and access raw sockets, but a draft for the implementation of raw sockets api in JavaScript is under-way. Have a look at these links:
http://www.w3.org/TR/raw-sockets/
https://developer.mozilla.org/en-US/docs/Web/API/TCPSocket
Chrome now has support for raw TCP and UDP sockets in its ‘experimental’ APIs. These features are only available for chrome apps and, although documented, are hidden for the moment. Having said that, some developers are already creating interesting projects using it, such as this IRC client.
To access this API, you’ll need to enable the experimental flag in your extension’s manifest. Using sockets is pretty straightforward, for example:
chrome.experimental.socket.create('tcp', '127.0.0.1', 8080, function(socketInfo) {
chrome.experimental.socket.connect(socketInfo.socketId, function (result) {
chrome.experimental.socket.write(socketInfo.socketId, "Hello, world!");
});
});
This will be possible via the navigator interface as shown below:
navigator.tcpPermission.requestPermission({remoteAddress:"127.0.0.1", remotePort:6789}).then(
() => {
// Permission was granted
// Create a new TCP client socket and connect to remote host
var mySocket = new TCPSocket("127.0.0.1", 6789);
// Send data to server
mySocket.writeable.write("Hello World").then(
() => {
// Data sent sucessfully, wait for response
console.log("Data has been sent to server");
mySocket.readable.getReader().read().then(
({ value, done }) => {
if (!done) {
// Response received, log it:
console.log("Data received from server:" + value);
}
// Close the TCP connection
mySocket.close();
}
);
},
e => console.error("Sending error: ", e)
);
}
);
More details are outlined in the w3.org tcp-udp-sockets documentation.
http://raw-sockets.sysapps.org/#interface-tcpsocket
https://www.w3.org/TR/tcp-udp-sockets/
Another alternative is to use Chrome Sockets
Creating connections
chrome.sockets.tcp.create({}, function(createInfo) {
chrome.sockets.tcp.connect(createInfo.socketId,
IP, PORT, onConnectedCallback);
});
Sending data
chrome.sockets.tcp.send(socketId, arrayBuffer, onSentCallback);
Receiving data
chrome.sockets.tcp.onReceive.addListener(function(info) {
if (info.socketId != socketId)
return;
// info.data is an arrayBuffer.
});
You can use also attempt to use HTML5 Web Sockets (Although this is not direct TCP communication):
var connection = new WebSocket('ws://IPAddress:Port');
connection.onopen = function () {
connection.send('Ping'); // Send the message 'Ping' to the server
};
http://www.html5rocks.com/en/tutorials/websockets/basics/
Your server must also be listening with a WebSocket server such as pywebsocket, alternatively you can write your own as outlined at Mozilla
ws2s project is aimed at bring socket to browser-side js. It is a websocket server which transform websocket to socket.
ws2s schematic diagram
code sample:
var socket = new WS2S("wss://ws2s.feling.io/").newSocket()
socket.onReady = () => {
socket.connect("feling.io", 80)
socket.send("GET / HTTP/1.1\r\nHost: feling.io\r\nConnection: close\r\n\r\n")
}
socket.onRecv = (data) => {
console.log('onRecv', data)
}
See jsocket. Haven't used it myself. Been more than 3 years since last update (as of 26/6/2014).
* Uses flash :(
From the documentation:
<script type='text/javascript'>
// Host we are connecting to
var host = 'localhost';
// Port we are connecting on
var port = 3000;
var socket = new jSocket();
// When the socket is added the to document
socket.onReady = function(){
socket.connect(host, port);
}
// Connection attempt finished
socket.onConnect = function(success, msg){
if(success){
// Send something to the socket
socket.write('Hello world');
}else{
alert('Connection to the server could not be estabilished: ' + msg);
}
}
socket.onData = function(data){
alert('Received from socket: '+data);
}
// Setup our socket in the div with the id="socket"
socket.setup('mySocket');
</script>
In order to achieve what you want, you would have to write two applications (in either Java or Python, for example):
Bridge app that sits on the client's machine and can deal with both TCP/IP sockets and WebSockets. It will interact with the TCP/IP socket in question.
Server-side app (such as a JSP/Servlet WAR) that can talk WebSockets. It includes at least one HTML page (including server-side processing code if need be) to be accessed by a browser.
It should work like this
The Bridge will open a WS connection to the web app (because a server can't connect to a client).
The Web app will ask the client to identify itself
The bridge client sends some ID information to the server, which stores it in order to identify the bridge.
The browser-viewable page connects to the WS server using JS.
Repeat step 3, but for the JS-based page
The JS-based page sends a command to the server, including to which bridge it must go.
The server forwards the command to the bridge.
The bridge opens a TCP/IP socket and interacts with it (sends a message, gets a response).
The Bridge sends a response to the server through the WS
The WS forwards the response to the browser-viewable page
The JS processes the response and reacts accordingly
Repeat until either client disconnects/unloads
Note 1: The above steps are a vast simplification and do not include information about error handling and keepAlive requests, in the event that either client disconnects prematurely or the server needs to inform clients that it is shutting down/restarting.
Note 2: Depending on your needs, it might be possible to merge these components into one if the TCP/IP socket server in question (to which the bridge talks) is on the same machine as the server app.
The solution you are really looking for is web sockets. However, the chromium project has developed some new technologies that are direct TCP connections TCP chromium