engine.io-client connect to primus server

client.js

var socket = require( 'engine.io-client' )( 'http://localhost:8080' );

//engine.io-client callbacks
socket.on( 'open', function() {
  console.log( 'open!' );
} );
socket.on( 'message', function( data ) {
  console.log( 'message=' + message.toString() );
} );
socket.on( 'close', function() {
  console.log( 'closed!!' );
} );
socket.on( 'error', function( err ) {
  console.log( 'error! ' + err );
} );

socket.on( 'flush', function() {
  console.log( 'flushed!!' );
} );

socket.on( 'drain', function() {
  console.log( 'drained!' );
} );
socket.on( 'upgradeError', function() {
  console.log( 'upgrade error!' );
} );
socket.on( 'upgrade', function() {
  console.log( 'upgraded!' );
} );

output.txt

## Crazy-fast output!

## Server output
Listening on port 8080
Handling http message. "/engine.io/?EIO=3&transport=polling&t=1415135906922-62&b64=1"
Handling http message. "/engine.io/?EIO=3&transport=polling&t=1415135906923-63&b64=1"
Handling http message. "/engine.io/?EIO=3&transport=polling&t=1415135906925-64&b64=1"
Handling http message. "/engine.io/?EIO=3&transport=polling&t=1415135906927-65&b64=1"
...

## Client output
error! Error: server error
error! Error: server error
error! Error: server error
error! Error: server error
...

## Client output with `transports: ['websocket']`, after long timeout
error! Error: websocket error
closed!!

server.js

'use strict';

var stringify = require( 'json-stringify-safe' );

var Primus = require( 'primus' ),
  http = require( 'http' );

var server = http.createServer( function( req, res ) {
  console.log( 'Handling http message. ' + stringify( req.url ) );
  res.writeHead( 200, {
    'Content-Type': 'application/javascript'
  } );
  res.write( 'Hello' );
  res.end();
} );


var primus = new Primus( server, {
  // authorization: null,
  pathname: '/primus',
  parser: 'JSON',
  transformer: 'engine.io',
  // plugin:        {},
  // timeout:       35000,
  //origins: '*',
  //methods: [ 'GET', 'HEAD', 'PUT', 'POST', 'DELETE', 'OPTIONS' ],
  // credentials:   true,
  // maxAge:        '30 days',
  // exposed:       false,
} );

primus.on( 'connection', function( spark ) {
  console.log( 'connection: ' + spark.id );
  spark.on( 'data', function boop( data ) {
    console.log( 'received ' + JSON.stringify( data ) + ' from ' + spark.id + ', sending boop' );
    spark.write( {
      event: 'boop',
      data: 'bop'
    } );
  } );
} );

primus.on( 'disconnection', function( spark ) {
  // the spark that disconnected
  console.log( 'disconnection: ' + spark.id );
} );

var port = 8080;
server.listen( port, function() {
  console.log( 'Listening on port ' + port );
} );