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.
This question is related to
javascript
html
node.js
sockets
tcpclient
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)
}
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
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 extensions 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!");
});
});
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
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.
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>
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
Source: Stackoverflow.com