node.js - Heroku Nodejs Webhosting
问题描述
Im trying to host a election website.
My Current Method explained: There is server.js file with serves the public file. If its a POST request(sent by frontend.js to send data to server) edits the poll.json file based on the data sent. I have a public file having index.html, frontend.js, poll.json where poll.json stores all the data.
My current code work all well in my localhost. But when running it in Heroku I get a error in the POST request line saying 'POST http://localhost:53390/ net::ERR_CONNECTION_REFUSED1 *********.herokuapp.com/:1 Uncaught (in promise) TypeError: Failed to fetch'
My server.js code:
const createServer = require('http').createServer;
const express = require('express');
const app = express();
let pollData = require(__dirname+'/public/poll.json');
const fs = require('fs');
var all_usn_no=[];
const listening_port=process.env.PORT || 4000;
function get_roll_and_usn(pollData){
for(var i=0;i<=pollData.students.length-1;i++){
//all_roll_no.push(pollData.students[i][0]);
all_usn_no.push(pollData.students[i][1]);
}
}
function roll_to_row(in_usn){
get_roll_and_usn(pollData)
return all_usn_no.indexOf(in_usn);
}
function write_vote(votes){
var checking_row=roll_to_row(votes[1]);
pollData.students[checking_row]=votes;
fs.writeFile(__dirname+'/public/poll.json', JSON.stringify(pollData), (err) => {
if (err) throw err;
console.log('Data written to file');
});
}
write_vote([listening_port,0]);
app.use(express.static(__dirname+'/public'));
app.get('/', (req, res) => {
res.sendFile(__dirname);// + '/index.html');
});
app.post('/', (req, res) => {
let body = '';
req.on('data', data => body += data)
req.on('end', () => {
res.writeHead(200, {
'Content-Type': 'application/json',
'Access-Control-Allow-Origin': '*',
'Access-Control-Allow-Methods': 'POST, GET',
});
body=body.split(",");
console.log(body.toString());
write_vote(body);
res.end(`{ "response": "${body ? body : 'No body sent' }" }`);
})
});
app.listen(listening_port, () => {
console.log('Example app listening at http://localhost:'+listening_port)
});
my frontend.js program:
var roll='';
var client_ip='';
var usn='';
var date='';
const all_roll_no=[]
const all_usn_no=[]
var port='';
function check(roll,usn){
var data='';
const url='poll.json';
const Http = new XMLHttpRequest();
Http.open("GET", url);
Http.send();
Http.onload = () =>{
data=JSON.parse(Http.response);
get_roll_and_usn(data);
check_validity(roll,usn,data);
}
}
function get_roll_and_usn(pollData){
for(var i=0;i<=pollData.students.length-1;i++){
//all_roll_no.push(pollData.students[i][0]);
all_usn_no.push(pollData.students[i][1]);
}
}
function usn_to_row(in_usn){
return all_usn_no.indexOf(in_usn);
}
function check_validity(checking_roll,checking_usn,data){
var checking_row=usn_to_row(checking_usn);
port=data.students[0][0];
//if(all_roll_no.indexOf(checking_roll)>=0 && checking_usn==all_usn_no[all_roll_no.indexOf(checking_roll)] && data.students[checking_row][2]==0){
if(all_usn_no.indexOf(checking_usn)>=0 && data.students[checking_row][2]==0){
//console.log("valid");
document.getElementById("page_2").style.display = "none";
document.getElementById("page_3").style.display = "block";
fetch('https://api.ipify.org/?format=json').then(results=> results.json()).then(data => client_ip=data.ip);
}
else{
alert("You cannot vote/ You have already voted")
//console.log('invalid');
}
}
document.getElementById("startbutton").onclick = function(){
roll = document.getElementById("roll_no").value;
usn = document.getElementById("usn_no").value;
date = Date();
check(roll,usn);
}
document.getElementById("next").onclick = function() {
document.getElementById("page_1").style.display = "none";
document.getElementById("page_2").style.display = "block";
}
document.getElementById("finish").onclick = function() {
var splb=[document.getElementById("splb1").checked,document.getElementById("splb2").checked,document.getElementById("splb3").checked,document.getElementById("splb4").checked,document.getElementById("splb5").checked,document.getElementById("splb6").checked,document.getElementById("splb7").checked];
var splg=[document.getElementById("splg1").checked,document.getElementById("splg2").checked,document.getElementById("splg3").checked,document.getElementById("splg4").checked,document.getElementById("splg5").checked,document.getElementById("splg6").checked,document.getElementById("splg7").checked];
var asplb=[document.getElementById("asplb1").checked,document.getElementById("asplb2").checked,document.getElementById("asplb3").checked,document.getElementById("asplb4").checked,document.getElementById("asplb5").checked,document.getElementById("asplb6").checked,document.getElementById("asplb7").checked];
var asplg=[document.getElementById("asplg1").checked,document.getElementById("asplg2").checked,document.getElementById("asplg3").checked,document.getElementById("asplg4").checked,document.getElementById("asplg5").checked,document.getElementById("asplg6").checked,document.getElementById("asplg7").checked];
var csb=[document.getElementById("csb1").checked,document.getElementById("csb2").checked,document.getElementById("csb3").checked,document.getElementById("csb4").checked,document.getElementById("csb5").checked,document.getElementById("csb6").checked,document.getElementById("csb7").checked];
var csg=[document.getElementById("csg1").checked,document.getElementById("csg2").checked,document.getElementById("csg3").checked,document.getElementById("csg4").checked,document.getElementById("csg5").checked,document.getElementById("csg6").checked,document.getElementById("csg7").checked];
var acsb=[document.getElementById("acsb1").checked,document.getElementById("acsb2").checked,document.getElementById("acsb3").checked,document.getElementById("acsb4").checked,document.getElementById("acsb5").checked,document.getElementById("acsb6").checked,document.getElementById("acsb7").checked];
var acsg=[document.getElementById("acsg1").checked,document.getElementById("acsg2").checked,document.getElementById("acsg3").checked,document.getElementById("acsg4").checked,document.getElementById("acsg5").checked,document.getElementById("acsg6").checked,document.getElementById("acsg7").checked];
var scb=[document.getElementById("scb1").checked,document.getElementById("scb2").checked,document.getElementById("scb3").checked,document.getElementById("scb4").checked,document.getElementById("scb5").checked,document.getElementById("scb6").checked,document.getElementById("scb7").checked];
var scg=[document.getElementById("scg1").checked,document.getElementById("scg2").checked,document.getElementById("scg3").checked,document.getElementById("scg4").checked,document.getElementById("scg5").checked,document.getElementById("scg6").checked,document.getElementById("scg7").checked];
var ascb=[document.getElementById("ascb1").checked,document.getElementById("ascb2").checked,document.getElementById("ascb3").checked,document.getElementById("ascb4").checked,document.getElementById("ascb5").checked,document.getElementById("ascb6").checked,document.getElementById("ascb7").checked];
var ascg=[document.getElementById("ascg1").checked,document.getElementById("ascg2").checked,document.getElementById("ascg3").checked,document.getElementById("ascg4").checked,document.getElementById("ascg5").checked,document.getElementById("ascg6").checked,document.getElementById("ascg7").checked];
var vote=[String(splb.indexOf(true)),String(splg.indexOf(true)),String(asplb.indexOf(true)),String(asplg.indexOf(true)),String(csb.indexOf(true)),String(csg.indexOf(true)),String(acsb.indexOf(true)),String(acsg.indexOf(true)),String(scb.indexOf(true)),String(scg.indexOf(true)),String(ascb.indexOf(true)),String(ascg.indexOf(true))]
var update=[String(roll),String(usn),"1",String(client_ip),String(date)].concat(vote);
if (update.indexOf("-1")<0){
alert("Pls vote for all posts")
}
else{
document.getElementById("page_1").style.display = "none";
document.getElementById("page_2").style.display = "none";
document.getElementById("page_3").style.display = "none";
fetch('http://localhost:'+port,{method:'POST',body:update}).then(results=> results.json()).then(console.log);
//console.log(update);
alert("Your vote has been registered")
}
}
You can just ignore the function as they are just to process the data and do necessary funtions.
Main problem: PORT request from frontend.js to server.js sending data to edit the poll.json file return error.
Thanks in advance.
解决方案
尝试使用const PORT = process.env.PORT || 3333;
和
app.listen(PORT, () => {
console.log(`Server is starting on ${PORT}`);
})
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