Intro

transparent-proxy extends the native net.createServer and it acts as a real transparent http-proxy.

This module was built on top of TCP-level to avoid header-stripping problem of nodejs http(s)-modules.

It allows to upstream client-request dynamically to other proxies, or to certain iFace, and more...

It supports Basic Proxy-Authentication.

Quick Start

Install

npm i transparent-proxy

Use

const ProxyServer = require('transparent-proxy');

//init ProxyServer
const server = new ProxyServer();

//starting server on port 8080
server.listen(8080, '0.0.0.0', function () {
    console.log('TCP-Proxy-Server started!', server.address());
});

Options Object

upstream, tcpOutgoingAddress, injectData & injectResponse Options

The options are functions having follow parameters:

• upstream-Function need to return a String with format -> IP:PORT or USER:PWD@IP:PORT of used http-proxy. If 'localhost' is returned, then the host-self will be used as proxy.
• tcpOutgoingAddress-Function need to return a String with format -> IP.

Note: These functions will be executed before first tcp-socket-connection is established.

• injectData-Function need to return a String or buffer for the new spoofed data. This will be upstreamed as request.
• injectResponse-Function need to return a String or buffer for the new received data.

Upstream to other proxies

If you don't want to use the host of active instance self, then you need to upstream connections to another http-proxy. This can be done with upstream attribute.

const ProxyServer = require('transparent-proxy');

const server = new ProxyServer({
    upstream: function () {
          return 'x.x.x.x:3128'; // upstream to other proxy
    }
});

//starting server on port 8080
server.listen(8080, '0.0.0.0', function () {
    console.log('TCP-Proxy-Server started!', server.address());
});

The auth Function

This activate basic authorization mechanism. The Auth-function will be executed while handling Proxy-Authentications.

Note: It needs to return True/False or a Promise that resolves to boolean (isAuthenticated).

const ProxyServer = require('transparent-proxy');

const server = new ProxyServer({
    auth: function (username, password) {
        return username === 'bar' && password === 'foo';
    }
});

//starting server on port 8080
server.listen(8080, '0.0.0.0', function () {
    console.log('TCP-Proxy-Server started!', server.address());
});

.getBridgedConnections()

const ProxyServer = require('transparent-proxy');
const server = new ProxyServer();

//starting server on port 8080
server.listen(8080, '0.0.0.0', function () {
    console.log('Proxy-Server started!', server.address());
});

setInterval(function showOpenSockets() {
    const bridgedConnections = server.getBridgedConnections();
    console.log([new Date()], 'OPEN =>', Object.keys(bridgedConnections).length)
}, 2000);

Interception

The callbacks injectData & injectResponse could be used to intercept/spoof communication. These functions are executed with the data and session arguments.

Session-Instance

The Session-Instance is a Object containing info/data about Tunnel. It has following useful attributes/methods:

• isHttps - Is session encrypted.
• getTunnelStats() - Get Stats for this tunnel
• getId() - Get Own ID-Session
• isAuthenticated() - Is the session authenticated by user or not.

Intercepting HTTPS

The boolean attribute intercept allows to break SSL-Communication between Source & Destination.

This will activate Security-Alarm by most every browser/client.

Examples

This example upstreams only requests for ifconfig.me to another proxy, for all other requests will be used localhost.

const ProxyServer = require('transparent-proxy');

const server = new ProxyServer({
    upstream: function (data, bridgedConnection) {
        if (~(data.toString().indexOf('ifconfig.me'))) {
            return 'x.x.x.x:3128'; // upstream to other proxy
        } else {
            return 'localhost'; //upstream to localhost
        }
    },
});

//starting server on port 8080
server.listen(8080, '0.0.0.0', function () {
    console.log('TCP-Proxy-Server started!', server.address());
});

Testing with curl:

curl -x 127.0.0.1:8080 https://ifconfig.me
x.x.x.x

curl -x 127.0.0.1:8080 https://ifconfig.co
y.y.y.y

For more examples look here.