Always pass request to 404 handler

[finwo]

Always passing the request object to the 404 handler allows custom middleware to work when overwriting the 404 handler with a custom one.

Example use case:

// config.js

var Q = require('q');

module.exports = {
  http: {
    port        : process.env.PORT || 3000,
    default_home: [ 'index.html', 'index.htm' ],
    static_route: __dirname + '/web'
  },
  languages: {
    default: 'en',
    en: {
      "hello-world": "Hello World"
    },
    nl: {
      "hello-world": "Hallo Wereld"
    }
  },
  middleware: {
    language: function( req, res ) {
      return Q.fcall(function () {
        var requested = (req.headers[ 'accept-language' ] || '').split(',');
        requested.push(config.languages.default);
        req.language = requested
          .map(function ( language ) {
            return language.split(';').shift();
          })
          .intersect(Object.keys(config.languages))
          .shift();
      });
    }
  }
};

// app.js

// We'll use these later
var config = require('./config'),
    http   = require('http'),
    path   = require('path'),
    Router = require('node-simple-router'),
    Q      = require('q');

// Initialize router
var router = new Router( config.http );

// Register routes here

// Replace 404 handler
// Adds support for /<language>/404.html files
router.__404 = router._404;
router._404  = function( req, res, route ) {
  var filename = path.join( config.http.static_route, req.language, '404.html' );
  fs.readFile( filename, function( err, data ) {
    if ( err ) return router.__404( req, res, route );
    res.writeHead(404, {
      'Content-Type': 'text/html'
    });
    res.end( data );
  });
}

// Create server
var server = http.createServer(Q.async(function*(req, res) {
  var key, keys = Object.keys( config.middleware );
  while( key = keys.shift() ) {
    yield config.middleware[key]( req, res );
  }
  return router( req, res );
});

// Listen & notify stdout
server.listen(config.http.port);
console.log('Server running on port', config.http.port);