senex.js

var http = require('http');
var url = require('url');

var pattern = /4chan\.org/i;

function respond_censored(res) {
    res.writeHead(403)
    res.write('Censored');
    res.end();
}

http.createServer(function (req, res) {
    var u = url.parse(req.url);
    var c = http.createClient(u.port || 80, u.host);
    console.log(req.method + ' ' + req.url);
    p = (u.pathname || '/') + (u.search || '');
    hdr = req.headers;

    if (u.host.match(pattern)) {
        return respond_censored(res);
    }

    hdr['host'] = u.host;
    var creq = c.request(req.method, p, hdr);
    req.on('data', function (chunk) {
        creq.write(chunk, 'binary');
    });
    req.on('end', function () {
        creq.end()
    });
    creq.on('response', function (cres) {
        req.connection.on('close', function () {
            cres.connection.destroy();
        });
        res.writeHead(cres.statusCode, 'foo', cres.headers);
        cres.on('data', function (chunk) {
            res.write(chunk, 'binary');
        });
        cres.on('end', function () {
            res.end();
        });
    });
}).listen(8080, '127.0.0.1');