Heroku不使用node.js中的端口

Question

我的代码在localhost上运行正常。但是当我推到heroku时。我对node.js来说还不错。

这是我的app.js文件。

var express = require('express');
var app = express();
var http = require('http');
var server = http.createServer(app).listen(process.env.PORT || 8080);;
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var routes = require('./routes/index');
var users = require('./routes/users');
var mongoose = require('mongoose');
var io = require('socket.io').listen(server);
var nicknames = [];

io.configure(function() {
  io.set("transports", ["xhr-polling"]);
  io.set("polling duration", 10);
});

io.sockets.on('connection', function(socket) {
  io.sockets.emit('usernames', nicknames);
  socket.on('chat message', function(data) {
    io.sockets.emit('chat message', {
      msg: data,
      nick: socket.nickname
    });
  });

  socket.on('new user', function(data, callback) {
    if (nicknames.indexOf(data) != -1) {
      callback(false);
    } else {
      callback(true);
      socket.nickname = data;
      nicknames.push(socket.nickname);
      io.sockets.emit('usernames', nicknames);
    }
  });

  socket.on('disconnect', function(data) {
    if (!socket.nickname) return;
    nicknames.splice(nicknames.indexOf(socket.nickname), 1);
    io.sockets.emit('usernames', nicknames);
  });
});
// uncomment after placing your favicon in /public
//app.use(favicon(__dirname + '/public/favicon.ico'));
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'hjs');
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({
  extended: false
}));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));
app.use('/', routes);
app.use('/users', users);
// catch 404 and forward to error handler
app.use(function(req, res, next) {
  var err = new Error('Not Found');
  err.status = 404;
  next(err);
});
// error handlers
// development error handler
// will print stacktrace
app.get('/', function(req, res) {
  res.render('index.hjs');
});

if (app.get('env') === 'development') {
  app.use(function(err, req, res, next) {
    res.status(err.status || 500);
    res.render('error', {
      message: err.message,
      error: err
    });
  });
}
// production error handler
// no stacktraces leaked to user
app.use(function(err, req, res, next) {
  res.status(err.status || 500);
  res.render('error', {
    message: err.message,
    error: {}
  });
});
module.exports = app;

运行实际网站时出现此错误。

Application Error
An error occurred in the application and your page could not be served. Please try again in a few moments.
If you are the application owner, check your logs for details.

我正在创建一个公共聊天，但无论出于何种原因我都无法运行该应用程序。我该如何解决这个问题？