Connecting to TCP Socket from browser using javascript

120

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 tagged with javascript html node.js sockets tcpclient

~ Asked on 2012-09-13 13:47:54

The Best Answer is


61

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!");         
    });
});

~ Answered on 2013-06-27 07:24:53


33

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

~ Answered on 2012-09-13 13:53:14


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