Http.Agent instance for response headers with latin1 characters

isoagent.js

// First: `npm install agent-base streamsearch iconv-lite`

var http = require('http'),
    net = require('net'),
    EventEmitter = require('events').EventEmitter,
    HTTPParser = process.binding('http_parser').HTTPParser,
    parsers = http.parsers;

var agentBase = require('agent-base'),
    StreamSearch = require('streamsearch'),
    decodeStream = require('iconv-lite').decodeStream;

function freeParser(parser, req) {
  if (parser) {
    parser._headers = [];
    parser.onIncoming = null;
    if (parser.socket) {
      parser.socket.onend = null;
      parser.socket.ondata = null;
      parser.socket.parser = null;
    }
    parser.socket = null;
    parser.incoming = null;
    parsers.free(parser);
    parser = null;
  }
}

function ISOAgent(req, opts, fn) {
  var socket = net.connect(opts),
      iconv = decodeStream('ISO-8859-1'),
      ss = new StreamSearch('\r\n\r\n'),
      parsing = true,
      rawHeader = '',
      oldOnData;

  function fixHeaders(res) {
    var parser = parsers.alloc(),
        d = new Buffer(rawHeader + '\r\n\r\n');
    parser.reinitialize(HTTPParser.RESPONSE);
    parser.onIncoming = function(incoming, shouldKeepAlive) {
      return true;
    };
    rawHeader = ss = iconv = undefined;
    parser.execute(d, 0, d.length);
    if (parser.incoming && parser.incoming.complete)
      res.headers = parser.incoming.headers;
    freeParser(parser);
  }

  iconv.on('data', function(str) {
    rawHeader += str;
  });

  ss.on('info', function infofn(isMatch, data, start, end) {
    if (data) {
      var buf = new Buffer(end - start);
      data.copy(buf, 0, start, end);
      iconv.write(buf);
    }
    if (isMatch) {
      parsing = false;
      ss.removeListener('info', infofn);
      iconv.end();
      socket.ondata = oldOnData;
    }
  });

  fn(null, socket);

  process.nextTick(function() {
    oldOnData = socket.ondata;
    socket.ondata = function(d, start, end) {
      if (parsing) {
        var buf = new Buffer(end - start);
        d.copy(buf, 0, start, end);
        ss.push(buf);
      }
      oldOnData.call(socket, d, start, end);
    };
    var parser = req.parser,
        oldOnIncoming = parser.onIncoming;
    parser.onIncoming = function(res, shouldKeepAlive) {
      process.nextTick(function() {
        fixHeaders(res);
        parser.onIncoming = oldOnIncoming;
        oldOnIncoming.call(parser, res, shouldKeepAlive);
      });
    };
  });
}

module.exports = function() {
  return agentBase(ISOAgent);
};

main.js

var http = require('http');

var ISOAgent = require('./isoagent');

var url = '...',
    opts = require('url').parse(url);

opts.agent = ISOAgent();

http.get(opts, function(res) {
  console.dir(res.headers);
  res.socket.end();
});

Thanks again for this! Your Agent code got me through several months. Now that Node.js v0.12.0 is out, I was able to switch back to not using this method.