githamburg / webtcp

SockJS/TCP bridge that allows browsers to interact with TCP servers

WebTCP 0.0.1

WebTCP is a SockJS/TCP bridge that allows browsers to interact with remote TCP servers and make HTTP requests to any servers bypassing same-origin policy.

How does it work

Client and server (bridge) communicate through SockJS connection. When browser wants to create a TCP socket it sends a command to the bridge. Bridge creates a real TCP socket connection and maps all the events that happen on this socket to a client's socket object. For example, when data is received bridge will trigger a data event on according socket object on a browser side. Screw my writings, here's the picture:

Why would anyone need that

I don't know, but you can do interesting things like:

• create client libraries to interract with any TCP servers 'directly' from your browser: Redis, Memcached, MySQL, MongoDB, etc.
• make GET/POST queries to any destination regardless of same-origin policy.

Installing

Assuming you have node.js and npm installed:

Clone the repo
git clone https://github.com/yankov/webtcp

Install dependencies
cd webtcp
npm install

Run WebTCP server
cd examples && node server

Running examples

TCP echo server

cd examples && node echo_server run example echo server

Open client examples in the browser
examples/http_client.html for http requests examples
examples/socket_client.html for socket examples

How to use it

First create a SockJS tunnel. Use whatever port and address your WebTCP server is on.

var net = new WebTCP('localhost', 9999)

Creating sockets

Now you can create sockets like this

var socket = net.createSocket("127.0.0.1", 1337)

To send data simply use write function

socket.write("hi")  

Standard event handlers

// On connection callback
socket.on('connect', function(){
  console.log('connected');
})

// This gets called every time new data for this socket is received
socket.on('data', function(data) {
  console.log("received: " + data);
});

socket.on('end', function(data) {
  console.log("socket is closed ");
});

It's also possible to specify advanced options when creating a socket connection

options = {
  encoding: "utf-8",
  timeout: 0,
  noDelay: true, // disable/enable Nagle algorithm
  keepAlive: false, //default is false
  initialDelay: 0 // for keepAlive. default is 0
}

And then pass those options when creating socket

var socket = net.createSocket("127.0.0.1", 1337, options)

Making HTTP requests

Making HTTP request is pretty straightforward.

Create a http client

var client = net.createHTTPClient()  

GET request

client.get({ host: 'news.ycombinator.com', port: 80 }, function(res) {
  console.log(res);
});

POST request

client.post({ host: 'news.ycombinator.com', port: 80 }, { param: 1 }, function(res) {
  console.log(res);
});

Implemented clients

There're clients for Redis and Memcache included. Work on a client for Apache Kafka is in progress. Check out examples for redis and memcache clients. Should be pretty straight forward.

TODO

• Security checks [hello vkluch?]
• Fix client for Apache Kafka
• Rails rack middleware (probably for HTTP only)