SPDY Connect

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Last night I cataloged what was needed to get a SPDY enabled express.js by way of node-spdy. Tonight I am going to start on the biggest unknown: writing a module to SPDY-ize connect.

The changes that I had to make directly to lib/connect.js are highlighted:

var HTTPServer = require('./http').Server
  , HTTPSServer = require('./https').Server
  , SPDYServer = require('./spdy').Server
  , fs = require('fs');
 
// ...

function createServer() {
  if ('object' == typeof arguments[0]) {
  // return new HTTPSServer(arguments[0], Array.prototype.slice.call(arguments, 1));
    return new SPDYServer(arguments[0], Array.prototype.slice.call(arguments, 1));
  } else {
    return new HTTPServer(Array.prototype.slice.call(arguments));
  }
  
//...
 
exports.HTTPServer = HTTPServer;
exports.HTTPSServer = HTTPSServer;
exports.SPDYServer = SPDYServer;

So, the connect library needs to be able to export, as SPDYServer, the SPDY server that I defined separately in lib/spdy.js. I also need to override the exported connect.createServer function to send back a SPDY Server instead of an HTTPS Server. Exporting connect.createServer is made more complicated by virtue of lib/connect.js exporting createServer() as the export module itself:

// expose createServer() as the module

exports = module.exports = createServer;

I am unfamiliar with overriding the module like that. I wonder what effect it would have on doing something along the lines of:

original_connect = connect.createServer;
connect.createServer = function() {
  if (SPDY_ENABLED) {
    // do SPDY stuff
  }
  else {
    original_connect()
  }
}

Only one way to find out.

First up, I create a NPM package:

➜  connect-spdy  npm init
Package name: (connect-spdy) 
Description: SPDY-ized connect server.
Package version: (0.0.0) 
Project homepage: (none) https://github.com/eee-c/connect-spdy    
Project git repository: (none) https://github.com/eee-c/connect-spdy
Author name: Chris Strom
Author email: (none) chris@eeecomputes.com
Author url: (none) http://eeecomputes.com
Main module/entry point: (none) index
Test command: (none) 
What versions of node does it run on? (~v0.5.0-pre) >= 0.5.0-pre
About to write to /home/cstrom/repos/connect-spdy/package.json

{
  "author": "Chris Strom  (http://eeecomputes.com)",
  "name": "connect-spdy",
  "description": "SPDY-ized connect server.",
  "version": "0.0.0",
  "homepage": "https://github.com/eee-c/connect-spdy",
  "repository": {
    "type": "git",
    "url": "git://github.com/eee-c/connect-spdy.git"
  },
  "main": "index",
  "engines": {
    "node": ">= 0.5.0-pre"
  },
  "dependencies": {},
  "devDependencies": {}
}

Is this ok? (yes) yes

Now... how to hook into the existing connect.createServer? Will it always be defined when my connect-spdy is loaded...?

Ooh! Maybe I can expose a createServer() in connect-spdy in such a way that it mimics the spike code:

exports = module.exports = createServer;

function createServer() {
  if ('object' == typeof arguments[0]) {
    return new SPDYServer(arguments[0], Array.prototype.slice.call(arguments, 1));
  } else {
    return connectCreateServer(Array.prototype.slice.call(arguments));
  }
};

If arguments are passed in, then I assume that we are trying to establish a SPDY server otherwise, I allow the default connect createServer() to do its thing. For the SPDYServer class, I just re-use the same class from my spike which, itself, was just a copy of connect's https.js.

With that, I revert my local copy of connect to the original package installed from npm. In express.js, I then load connect-spdy instead of connect:

-var connect = require('connect')
+var connect = require('connect-spdy')

And that actually seems to work. When I fire up the test express app.js server, with vanilla connect + my newly created connect-spdy, I see SPDY sessions in Chrome's about:net-internals:

    t=1308619806288 [st=8994]     SPDY_SESSION_SYN_REPLY  
                                  --> flags = 0
                                  --> connection: keep-alive
                                      content-length: 277
                                      content-type: text/html
                                      status: 200 OK
                                      version: HTTP/1.1
                                      x-powered-by: Express
                                  --> id = 7

Nice! That seems like a reasonable approach and a fine stopping point for the night.

I do not think connect-spdy is quite ready for npm, but I at least put it out on github in case anyone interested. I will get started on express-spdy tomorrow.


Day #54