Heroku上托管的应用无法加载网页

Question

I am currently working on a nodejs app which uses express to serve a web page. It also doubles as a discord bot. When I run the app on localhost, both the discord and web page parts work fine. However, when I host it on Heroku, the discord bot works fine, however the web page fails to load when I view the live web page.

Here is my index.js code.

const fs = require('fs'), discord = require('discord.js'), express = require('express'), crypto = require('crypto'), bodyParser = require('body-parser'), path = require('path'), archiver = require('archiver')
const goonsUp = require(__dirname + '/commands/goonsUp/goonsUp')
const roastMe = require(__dirname + '/commands/roastMe/roastMe')

var config = JSON.parse(fs.readFileSync('config.json')),
client = new discord.Client()

roastMe(client, discord)
goonsUp(client, discord)
client.login(config.token)

var app = express()
var urlencodedParser = bodyParser.urlencoded({ extended: false })

app.set('view engine', 'ejs')

app.get('/', (req, res)=>{
    client.channels.get('457201559772594211').send('Test')
    res.render('fileReq')
})

app.post('/', urlencodedParser, (req, res)=>{
    var hash = crypto.createHmac('sha256', 
    req.body.password).digest('hex')
if(hash==='709f8df16dca8b307a2a8ea13356eb1f3e138f117eb6592e4e030478bef1bb04'){
    var downloads = JSON.parse(fs.readFileSync(__dirname + '/download.json'))
    var archive = archiver('zip')
    var output = fs.createWriteStream(__dirname + '/downloads.zip')
    archive.pipe(output)

    for(var i = 0; i < downloads.length; i++){
        var path = downloads[i]
        archive.append(fs.readFileSync(path), {name: path.replace(/^.*[\\\/]/, '')})
    }

        archive.finalize()
        setTimeout(()=>{
            res.download(__dirname + '/downloads.zip')
        }, 2000)
    }
})

app.listen(process.env.PORT || 3000, function(){

})

From my tests, as far as I can tell, the url request isn't even getting to the app. I could tell because I made the app report to discord whenever the page was requested, and it did so fine on localhost. However, when ran on heroku, viewing the live web page never called the code, and the page comes up with an application error. Other elements of the bot, however, do appear to work from Heroku.

Does anyone know why this may be? Thanks.

EDIT: Here is the error posted on the logs

2018-06-27T04:49:32.337810+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=chiraag-discord-bot.herokuapp.com request_id=c737acac-7313-4ece-8359-d3bca72e1cc0 fwd="24.5.143.134" dyno= connect= service= status=503 bytes= protocol=https
2018-06-27T04:49:32.981684+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=chiraag-discord-bot.herokuapp.com request_id=ec9c3cf8-3af9-4bcc-b1b3-bb84bb6c958c fwd="24.5.143.134" dyno= connect= service= status=503 bytes= protocol=https

Answer 1

I have had the same issue in the past with Heroku and Node. What fixed it for me was changing the port number 'OR' statement to 8080. Port 8080, to my understanding, is a secondary number used when 80 cannot. The code change would be simple enough as seen in the snippet below.

app.listen(process.env.PORT || 8080, function(){})