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res.on() reading error inside https.get() function javascript api

I am attempting to grab data from an API from openWeatherAPI with a correct api key and query (I checked with Postman to ensure the call is correct), but ran into a syntax error. When I try to call the on() function inside of my https.get callback function, I am met with the following error in my terminal:
response.on("data", (data) => {
^
TypeError: Cannot read properties of undefined (reading 'on')
at ClientRequest.<anonymous> (C:file-path\api-prac\app.js:16:18)
at Object.onceWrapper (node:events:628:26)
at ClientRequest.emit (node:events:513:28)
at HTTPParser.parserOnIncomingClient [as onIncoming] (node:_http_client:693:27)
at HTTPParser.parserOnHeadersComplete (node:_http_common:128:17)
at TLSSocket.socketOnData (node:_http_client:534:22)
at TLSSocket.emit (node:events:513:28)
at addChunk (node:internal/streams/readable:315:12)
at readableAddChunk (node:internal/streams/readable:289:9)
at TLSSocket.Readable.push (node:internal/streams/readable:228:10)
My code:
const express = require("express");
const https = require("https");
const app = express()
// what should happen when user tries to go to home page
app.get("/", function(req, res) {
const url = "https://api.openweathermap.org/data/2.5/weather?q=London&appid=my-api-key";
https.get(url, function(req, response) {
console.log("blah blah repsonse");
response.on("data", (data) => {
console.log(data);
// const weatherDatta = JSON.parse(data)
/* extra code will be put here to send a response */
})
});
res.send("server is up");
}
app.listen(3000, function() {
console.log("app running on server 3000");
})
I tried looking at the documentation shown on the https://nodejs.org/api/https.html website, but was unable to find anything that helped outside of what I was already doing with my code.

The arguments for your https.get() callback are wrong. It should be this:
https.get(url, function(response) {
response.on('data', ...);
});
There is no second argument so when you try to make one, it's undefined and does not work.
Code example in the doc here.
Note also that there is no guarantee that you get the entire response in the first data event. The response may arrive in chunks so if you're trying to get the whole response, you should be accumulating all the data events and then processing them all in the end event. And, you should be handling errors in multiple places:
https.get(url, function(response) {
let result = "";
response.on('data', data => {
result += data.toString();
}).on('end', () => {
try {
let weatherData = JSON.parse(result);
// use the weatherData here
} catch(e) {
console.log(e);
// handle JSON parsing error here
}
}).on('error', err => {
console.log(err);
// handle http request error here
});
});
Note, using an http request library such as got() or node-fetch() or even fetch() which is built-in to the newest versions of nodejs will make this code much simpler because they will retrieve the entire response for you and are promise based which makes a number of things including error handling much simpler.
Note how much simpler this is with the got() library.
got(url).json().then(weatherData => {
// use weatherData here
}).catch(err => {
console.log(err);
// handler error here
});

npm-mysql crashes overnight

The class:
const mysql = require('mysql');
module.exports = function () {
this.connection = mysql.createConnection({
host : 'localhost',
user : 'USER',
password : 'PASSWORD',
database : 'DATABASE',
multipleStatements: true
});
this.query = (sql, args) => {
return new Promise( ( resolve, reject ) => {
this.connection.query( sql, args, ( err, rows ) => {
if ( err )
return reject( err );
resolve( rows );
});
});
};
this.close = () => {
return async () => {
try {
this.connection.end(err => {
if (err) throw err;
return;
});
} catch(e) {
return e;
}
}
};
};
In index i call it like this:
const Database = require('./server/modules/mysql'),
connection = new Database();
The problem:
Overnight mysql crashes:
[nodemon] starting `node index.js`
listening on port 420
events.js:292
throw er; // Unhandled 'error' event
^
Error: Connection lost: The server closed the connection.
at Protocol.end (C:\Users\fedesc\Sites\borsalino\node_modules\mysql\lib\protocol\Protocol.js:112:13)
at Socket.<anonymous> (C:\Users\fedesc\Sites\borsalino\node_modules\mysql\lib\Connection.js:94:28)
at Socket.<anonymous> (C:\Users\fedesc\Sites\borsalino\node_modules\mysql\lib\Connection.js:526:10)
at Socket.emit (events.js:327:22)
at endReadableNT (_stream_readable.js:1221:12)
at processTicksAndRejections (internal/process/task_queues.js:84:21)
Emitted 'error' event on Connection instance at:
at Connection._handleProtocolError (C:\Users\fedesc\Sites\borsalino\node_modules\mysql\lib\Connection.js:423:8)
at Protocol.emit (events.js:315:20)
at Protocol._delegateError (C:\Users\fedesc\Sites\borsalino\node_modules\mysql\lib\protocol\Protocol.js:398:10)
at Protocol.end (C:\Users\fedesc\Sites\borsalino\node_modules\mysql\lib\protocol\Protocol.js:116:8)
at Socket.<anonymous> (C:\Users\fedesc\Sites\borsalino\node_modules\mysql\lib\Connection.js:94:28)
[... lines matching original stack trace ...]
at processTicksAndRejections (internal/process/task_queues.js:84:21) {
fatal: true,
code: 'PROTOCOL_CONNECTION_LOST'
}
[nodemon] app crashed - waiting for file changes before starting...
I'm using Nodemon and a simple restart to the application solves the issue until the next morning (or next long period of not coding.)
I'm not really using close() anywhere or after anything since in the docs it says it's not needed, just query().
but clearly i get a timeout somewhere somehow, like i should deal with the opening and closing of connection.
Do i need to close connections after making queries in my app?
Is there a way to set the timeout limit or dealing with him?
Am i just setting it up wrong or using wrong/outdated tool?
Thanks.

Why my RestFul API with express and nodejs crashed everyday?

I have restful api with express and nodejs but this api crashed every time.
So.. I have one function for datatime. This function will replace date in the url address everytime to current datetime.. Im not sure but may be when the current date is change with the new current date the API crashed..
I see this error message on the console:
events.js:187
throw er; // Unhandled 'error' event
^
Error: read ECONNRESET
at TCP.onStreamRead (internal/stream_base_commons.js:201:27)
Emitted 'error' event on Connection instance at:
at Connection._handleProtocolError (C:\Users\Admin\Desktop\node-express\node_modules\mysql\lib\Connection.js:426:8)
at Protocol.emit (events.js:210:5)
at Protocol._delegateError (C:\Users\Admin\Desktop\node-express\node_modules\mysql\lib\protocol\Protocol.js:398:10)
at Protocol.handleNetworkError (C:\Users\Admin\Desktop\node-express\node_modules\mysql\lib\protocol\Protocol.js:371:10)
at Connection._handleNetworkError (C:\Users\Admin\Desktop\node-express\node_modules\mysql\lib\Connection.js:421:18)
at Socket.emit (events.js:210:5)
at emitErrorNT (internal/streams/destroy.js:92:8)
at emitErrorAndCloseNT (internal/streams/destroy.js:60:3)
at processTicksAndRejections (internal/process/task_queues.js:80:21) {
errno: 'ECONNRESET',
code: 'ECONNRESET',
syscall: 'read',
fatal: true
}
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! express-api#1.0.0 start: `node server.js`
npm ERR!
npm ERR! Failed at the express-api#1.0.0 start script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm ERR! A complete log of this run can be found in:
npm ERR! C:\Users\Admin\AppData\Roaming\npm-cache\_logs\2019-12-29T04_48_17_190Z-debug.log
So this is the code for api.. Its very simple.. but I dont know how to fix this error.
When I wake up and try to see the data from the API every time the API is crashed.
This is the code from the api:
// Create express app
var express = require("express")
var app = express()
var mysql = require('mysql')
var express = require("express")
var cors = require('cors')
app.use(cors())
// Server port
var HTTP_PORT = 8000
// Start server
app.listen(HTTP_PORT, () => {
console.log("Server running on port %PORT%".replace("%PORT%", HTTP_PORT))
});
var con = mysql.createConnection({
host: "192.168.0.1",
port: "1234",
user: "username",
password: "password"
});
let aladinModel = '';
let aladinModelStations = '';
function formatDate(date) {
var d = new Date(date),
month = '' + (d.getMonth() + 1),
day = '' + d.getDate(),
year = d.getFullYear();
if (month.length < 2)
month = '0' + month;
if (day.length < 2)
day = '0' + day;
return [year, month, day].join('-');
}
var dateNow = formatDate(Date());
app.route('/')
.get(function (req, res) {
// omitted
res.setHeader('Access-Control-Allow-Origin', '*', 'Cache-Control', 'private, no-cache, no-store, must-revalidate');
const date = req.query.date;
const id = req.query.id;
const daysForward = req.query.daysForward;
try {
const query = `CALL aladin_surfex.Get_mod_cell_values_meteogram_cell('${dateNow}', ${id}, ${daysForward})`;
con.query(query, function (err, result, fields) {
if (err) throw err;
aladinModel = result;
});
res.json({ aladinModel })
} catch (error) {
console.log("Error query database!!!");
}
});
app.route('/stations')
.get(function (req, res) {
// omitted
res.setHeader('Access-Control-Allow-Origin', '*');
try {
const query2 = `SELECT Station,Ime FROM aladin_surfex.stations_cells;`;
con.query(query2, function (err, result2, fields) {
if (err) throw err;
aladinModelStations = result2;
});
res.json({ aladinModelStations })
} catch (error) {
console.log("Error query database!!!");
}
});
app.use(function (req, res) {
res.status(404);
});
I try to remove the cashe, to update npm, to restart the computer. But without the result.
With nodemon crashed the same..
What can I do ? How can to fix that ?

The error seems to be related to the connection to mysql.
As mysqljs documentation (https://github.com/mysqljs/mysql#error-handling):
Note: 'error' events are special in node. If they occur without an attached listener, a stack trace is printed and your process is killed.
You shuld intercept the connection error like this:
connection.on('error', function(err) {
console.log(err.code); // 'ER_BAD_DB_ERROR'
});
so you can investigate when and why the error occours and eventually you can recreate the connection when a problem occurs.

Move app.listen to the bottom of the file, after you declare all the routes and connect to the database.
Use app.get('route', function...) (more on that in the Express docs)
Move res.json() inside the callback function for each database query. The result will come back asynchronously so will not be accessible outside the function. If you’re new to async and callbacks in Javascript I’d recommend googling them and you’ll find a ton of reading materials.
Initialize your variables, e.g const aladinModel = ...

can't set host to node net.socket connect

I'm using electron-vue build an APP. I need create a tcp connection, and I use net.Socket().But i get a no response when I set HOST.
I need use the socket global, so I create a class like this:
import crc16ccitt from 'crc/crc16ccitt';
const net = require('net');
class TcpClient {
tcp = null;
alive = false;
connect(options) {
return new Promise((resolve, reject) => {
this.tcp = new net.Socket();
this.tcp.connect(options, () => {
this.alive = true;
resolve();
console.log('connect server');
});
this.tcp.on('close', () => {
this.alive = false;
console.log('close');
reject();
});
this.tcp.on('error', () => {
console.log('error');
});
});
}
}
export default TcpClient;
and then I put it in the main.js like this:
Vue.prototype.$tcp = new TcpClient();
but when I use in vue instance like this:
this.$tcp.connect({ port: 8000, host: 127.0.0.1 });
Nothing happend, no errors, no result, but when I reload my page, I think connect a moment, and my server shows:
events.js:174
throw er; // Unhandled 'error' event
^
Error: read ECONNRESET
at TCP.onStreamRead (internal/stream_base_commons.js:111:27)
Emitted 'error' event at:
at emitErrorNT (internal/streams/destroy.js:82:8)
at emitErrorAndCloseNT (internal/streams/destroy.js:50:3)
at process._tickCallback (internal/process/next_tick.js:63:19)
And if I don't set HOST, just port, it works well.

How to make a https request in node.js

I need to make a crawler. For http request i used to do this.
var http=require('http');
var options={
host:'http://www.example.com',
path:'/foo/example'
};
callback=function(response){
var str='';
response.on('data',function(chunk){
str+=chunk;
});
response.on('end', function () {
console.log(str);
});
}
http.request(options, callback).end();
but I have to make a crawler for https://example.com/foo/example
If I am using the same for https://example.com/foo/example it is giving this error
events.js:72
throw er; // Unhandled 'error' event
^
Error: getaddrinfo ENOTFOUND
at errnoException (dns.js:37:11)
at Object.onanswer [as oncomplete] (dns.js:124:16)

I'd recommend this excellent HTTP Request module: http://unirest.io/nodejs.html
You can install it with:
npm install -g unirest
Here's some example Node code with Unirest:
var url = 'https://somewhere.com/';
unirest.get(url)
.end(function(response) {
var body = response.body;
// TODO: parse the body
done();
});
...so to get the HTML at www.purple.com you'd do this:
#!/usr/bin/env node
function getHTML(url, next) {
var unirest = require('unirest');
unirest.get(url)
.end(function(response) {
var body = response.body;
if (next) next(body);
});
}
getHTML('http://purple.com/', function(html) {
console.log(html);
});