proxy

/*
** Modification by Norman Xu 
** Based on :
** Peteris Krumins (peter@catonmat.net)
** http://www.catonmat.net  --  good coders code, great reuse
**
** A simple proxy server written in node.js.
**
*/

var http = require('http');
var sys  = require('sys');
var fs   = require('fs');
var Buffer = require('buffer').Buffer;

var blacklist = [];
var iplist    = [];
var cachedMode = false;

const FILE_IPLIST = "./iplist";
const FILE_BLACKLIST = "./blacklist";

function watch_blacklist(){
	fs.watchFile(FILE_BLACKLIST, function(c,p) { update_blacklist(); });
}
function watch_iplist(){
	fs.watchFile(FILE_IPLIST, function(c,p) { update_iplist(); });
}

watch_blacklist();
watch_iplist();

function update_blacklist() {
  fs.stat(FILE_BLACKLIST, function(err, stats) {
    if (!err) {
      sys.log("Updating blacklist.");
      blacklist = fs.readFileSync(FILE_BLACKLIST).toString().split('\n')
                  .filter(function(rx) { return rx.length })
                  .map(function(rx) { return RegExp(rx) });
    }
  });
}

function update_iplist() {
  fs.stat(FILE_IPLIST, function(err, stats) {
    if (!err) {
	  // stop watch since we r going to access it.
      fs.unwatchFile(FILE_IPLIST);
      sys.log("Updating iplist.");
      iplist = fs.readFileSync(FILE_IPLIST).toString().split('\n')
               .filter(function(rx) { return rx.length });
      watch_iplist();
    }
  });
}

function ip_allowed(ip) {
  for (i in iplist) {
    if (iplist[i] == ip) {
      return true;
    }
  }
  return false;
}

function host_allowed(host) {
  for (i in blacklist) {
    if (blacklist[i].test(host)) {
      return false;
    }
  }
  return true;
}

function deny(response, msg) {
  response.writeHead(401);
  response.write(msg);
  response.end();
}

http.createServer(function(request, response) {
	
	try{
		var ip = request.connection.remoteAddress;
		var host = "";
		var port = 80;
		if (!ip_allowed(ip)) {
			msg = "IP " + ip + " is not allowed to use this proxy";
			deny(response, msg);
			sys.log(msg);
			return;
		}

		if (!host_allowed(request.url)) {
			msg = "Host " + request.url + " has been denied by proxy configuration";
			deny(response, msg);
			sys.log(msg);
			return;
		}

		host = request.headers['host'];
		if (host.indexOf(":") != -1){
			tmp = host.split(":");
			host = tmp[0];
			port = tmp[1] * 1;
		}
		
		sys.log(ip + ": " + request.method + " " + host + ":" + port + " " + request.url );
		
		var proxy = http.createClient(port, host)
		var proxy_request = proxy.request(request.method, request.url, request.headers);
		proxy_request.addListener('response', function(proxy_response) {
			try{
				var chunks = [];
				proxy_response.setEncoding("binary");
				proxy_response.addListener('data', function(chunk) {
					try{
						if (cachedMode){
							chunks.push(chunk);
						}
						else{
							response.write(chunk, "binary");
						}
					}
					catch(ex){
						sys.log("Error: " + ip +": " + ex.message);
					}
				});
				proxy_response.addListener('end', function() {
					try{
						if (cachedMode){
							var len = chunks.length;
							var maxlen = 0;
							while(len--){
								maxlen += chunks[len].length;
							}
							if (maxlen <=0){
								response.end();
							}
							var res = new Buffer(maxlen);
							len = 0;
							var currentlen = 0;
							while(len < chunks.length){
								chunks[len].copy(res, currentlen, 0, chunks[len].length);
								currentlen += chunks[len].length;
								len++;
							}
							response.write(res, "binary");
						}
						response.end();
					}
					catch(ex){
						sys.log("Error: " + ip +": " + ex.message);
					}
				});
				response.writeHead(proxy_response.statusCode, proxy_response.headers);
			}
			catch(ex){
				sys.log("Error: " + ex.message);
			};
		});
		request.addListener('data', function(chunk) {
			try{
				proxy_request.write(chunk);
			}
			catch(ex){
				sys.log("Error: " + ip +": " + ex.message);
			}
		});
		request.addListener('end', function() {
			try{
				proxy_request.end();
			}
			catch(ex){
				sys.log("Error: " + ip +": " + ex.message);
			}
		});
	}
	catch(ex){
		sys.log("Error: " + ex.message);
	}
}).listen(3389);

update_blacklist();
update_iplist();