streaming_proxy.js

var sys = require('sys')
var http = require('http');
var memcache_lib = require('./memcache');

var memcache = new memcache_lib.Client();//"127.0.0.1", 11211);
memcache.connect(function() {
  sys.debug("about to set node test key");
  memcache.set("node_test_key", '127.0.0.1');
});


var server = http.createServer(function (req, res) {
  // I can read the data here, but then I need to buffer it.
  //
  //memcache.set("node_test_key", '127.0.0.1');
  
  var reqEnded = false;

  // this hopefully stops the flow of data until we determine the upstream, and 
  // will catch and flag the end event if it happens before we get a chance to lisen
  // with access to the client
  req.pause();
  req.addListener("end", function() {
    // we are done sending - close and flush client
    reqEnded = true;
  });
  

  pick_server(req, function(host, port) {
    var conn = http.createClient(port, host);
    var headers = req.headers;

    var client = conn.request(req.method, req.url, req.headers);

    // I'd like to listen for +data on 'req' here.
    // You can!
    req.addListener("data", function(chunk) {
      client.write(chunk, "binary");
    });

    // however, listening for data didn't work until this was added.
    req.addListener("end", function() {
      // we are done sending - close and flush client
      client.close();
    });

    req.resume(); // once the listeners are bound, we are good

    // If the request ended before the server was picked, close the client and go for
    // it.
    if (reqEnded)
      client.close();

    // this is being invoked multiple times with couch. It shouldn't be, according
    // to the docs, however the HTTP responses coming back imply it should
    client.addListener("response", function (resp) {
      if (resp.statusCode == 100) {
        // this is a continue, we will anyway thankyou - so don't send to client
        // Seriously though, look in to this more - I'm not sure ignoring is OK, but
        // it seems right
        return;
      }
      res.writeHeader(resp.statusCode, resp.headers);

      resp.addListener("data", function (chunk) {
        res.write(chunk, "binary");
      });

      // to wrap it up
      resp.addListener('end', function () {
        // close the response
        res.close();
      });
    });
  });
});

// run
server.listen(4040);

// Mock version, talking to couch.
function pick_server(req, callback) {
  memcache.connect(function() {
    memcache.get('node_test_key', function (result) {
       callback(result, '5984');
    });
  });
}