Develop Reference

Node.js 'fs' throws an ENOENT error after adding auto-generated Swagger server code

Preamble
To start off, I'm not a developer; I'm just an analyst / product owner with time on their hands. While my team's actual developers have been busy finishing off projects before year-end I've been attempting to put together a very basic API server in Node.js for something we will look at next year.
I used Swagger to build an API spec and then used the Swagger code generator to get a basic Node.js server. The full code is near the bottom of this question.
The Problem
I'm coming across an issue when writing out to a log file using the fs module. I know that the ENOENT error is usually down to just specifying a path incorrectly, but the behaviour doesn't occur when I comment out the Swagger portion of the automatically generated code. (I took the logging code directly out of another tool I built in Node.js, so I'm fairly confident in that portion at least...)
When executing npm start, a few debugging items write to the console:
"Node Server Starting......
Current Directory:/mnt/c/Users/USER/Repositories/PROJECT/api
Trying to log data now!
Mock mode: disabled
PostgreSQL Pool created successfully
Your server is listening on port 3100 (http://localhost:3100)
Swagger-ui is available on http://localhost:3100/docs"
but then fs throws an ENOENT error:
events.js:174
throw er; // Unhandled 'error' event
^
Error: ENOENT: no such file or directory, open '../logs/logEvents2021-12-24.log'
Emitted 'error' event at:
at lazyFs.open (internal/fs/streams.js:277:12)
at FSReqWrap.args [as oncomplete] (fs.js:140:20)
Investigating
Now normally, from what I understand, this would just mean I've got the paths wrong. However, the file has actually been created and the first line of the log file has been written just fine
My next thought was that I must've set the fs flags incorrectly, but it was set to 'a' for append:
var logsFile = fs.createWriteStream(__logdir+"/logEvents"+dateNow()+'.log',{flags: 'a'},(err) =>{
console.error('Could not write new Log File to location: %s \nWith error description: %s',__logdir, err);
});
Removing Swagger Code
Now here's the weird bit: if I remove the Swagger code, the log files write out just fine and I don't get the fs exception!
This is the specific Swagger code:
// swaggerRouter configuration
var options = {
routing: {
controllers: path.join(__dirname, './controllers')
},
};
var expressAppConfig = oas3Tools.expressAppConfig(path.join(__dirname, '/api/openapi.yaml'), options);
var app = expressAppConfig.getApp();
// Initialize the Swagger middleware
http.createServer(app).listen(serverPort, function () {
console.info('Your server is listening on port %d (http://localhost:%d)', serverPort, serverPort);
console.info('Swagger-ui is available on http://localhost:%d/docs', serverPort);
}).on('error',console.error);
When I comment out this code, the log file writes out just fine.
The only thing I can think that might be happening is that somehow Swagger is modifying (?) the app's working directory so that fs no longer finds the same file?
Full Code
'use strict';
var path = require('path');
var fs = require('fs');
var http = require('http');
var oas3Tools = require('oas3-tools');
var serverPort = 3100;
// I am specifically tried using path.join that I found when investigating this issue, and referencing the app path, but to no avail
const __logdir = path.join(__dirname,'./logs');
//These are date and time functions I use to add timestamps to the logs
function dateNow(){
var dateNow = new Date().toISOString().slice(0,10).toString();
return dateNow
}
function rightNow(){
var timeNow = new Date().toTimeString().slice(0,8).toString();
return "["+timeNow+"] "
};
console.info("Node Server Starting......");
console.info("Current Directory: " + __dirname)
// Here I create the WriteStreams
var logsFile = fs.createWriteStream(__logdir+"/logEvents"+dateNow()+'.log',{flags: 'a'},(err) =>{
console.error('Could not write new Log File to location: %s \nWith error description: %s',__logdir, err);
});
var errorsFile = fs.createWriteStream(__logdir+"/errorEvents"+dateNow()+'.log',{flags: 'a'},(err) =>{
console.error('Could not write new Error Log File to location: %s \nWith error description: %s',__logdir, err);
});
// And create an additional console to write data out:
const Console = require('console').Console;
var logOut = new Console(logsFile,errorsFile);
console.info("Trying to log data now!") // Debugging logging
logOut.log("========== Server Startup Initiated ==========");
logOut.log(rightNow() + "Server Directory: "+ __dirname);
logOut.log(rightNow() + "Logs directory: "+__logdir);
// Here is the Swagger portion that seems to create the behaviour.
// It is unedited from the Swagger Code-Gen tool
// swaggerRouter configuration
var options = {
routing: {
controllers: path.join(__dirname, './controllers')
},
};
var expressAppConfig = oas3Tools.expressAppConfig(path.join(__dirname, '/api/openapi.yaml'), options);
var app = expressAppConfig.getApp();
// Initialize the Swagger middleware
http.createServer(app).listen(serverPort, function () {
console.info('Your server is listening on port %d (http://localhost:%d)', serverPort, serverPort);
console.info('Swagger-ui is available on http://localhost:%d/docs', serverPort);
}).on('error',console.error);
In case it helps, this is the project's file structure . I am running this project within a WSL instance in VSCode on Windows, same as I have with other projects using fs.
Is anyone able to help me understand why fs can write the first log line but then break once the Swagger code gets going? Have I done something incredibly stupid?
Appreciate the help, thanks!
Edit: Tried to fix broken images.

Found the problem with some help from a friend. The issue boiled down to a lack of understanding of how the Swagger module works in the background, so this will likely be eye-rollingly obvious to most, but keeping this post around in case anyone else comes across this down the line.
So it seems that as part of the Swagger initialisation, any scripts within the utils folder will also be executed. I would not have picked up on this if it wasn't pointed out to me that in the middle of the console output there was a reference to some PostgreSQL code, even though I had taken all reference to it out of the main index.js file.
That's when I realised that the error wasn't actually being generated from the code posted above: it was being thrown from to that folder.
So I guess the answer is don't add stuff to the utils folder, but if you do, always add a bunch of console logging...

Error on JS 'body.forEach is not a function'

I'm kind of new to JS and I can't solve this problem, so I hope you can help me.
I will explain shortly what the situation is, I installed the app Homebridge from Github on my Raspberry: https://github.com/nfarina/homebridge
Installation was successful, so, so far so good. But then I installed the plugin eWeLink for the Homebridge app: https://github.com/gbro115/homebridge-ewelink the installation went good as well, but on the startup there seems to be a probleem in the index.js from the plugin, I get the following output:
[2018-5-31 23:10:37] [eWeLink] A total of [0] accessories were loaded from the local cache [2018-5-31 23:10:37] [eWeLink] Requesting
a list of devices from eWeLink HTTPS API at
[https://eu-ota.coolkit.cc:8080] [2018-5-31 23:10:37] Homebridge is
running on port 51826. [2018-5-31 23:10:37] [eWeLink] eWeLink HTTPS
API reports that there are a total of [108] devices registered
/usr/lib/node_modules/homebridge-ewelink/index.js:98
body.forEach((device) => { ^
TypeError: body.forEach is not a function at
/usr/lib/node_modules/homebridge-ewelink/index.js:98:22 at
Object.parseBody
(/usr/lib/node_modules/homebridge-ewelink/node_modules/request-json/main.js:74:12)
at Request._callback
(/usr/lib/node_modules/homebridge-ewelink/node_modules/request-json/main.js:148:26)
at Request.self.callback
(/usr/lib/node_modules/homebridge-ewelink/node_modules/request/request.js:186:22)
at emitTwo (events.js:126:13) at Request.emit (events.js:214:7) at
Request.
(/usr/lib/node_modules/homebridge-ewelink/node_modules/request/request.js:1163:10)
at emitOne (events.js:116:13) at Request.emit (events.js:211:7) at
IncomingMessage.
(/usr/lib/node_modules/homebridge-ewelink/node_modules/request/request.js:1085:12)
So the terminal tells me there is a error on line 98 from the index.js, that will be the next part of the script:
var devicesFromApi = new Map();
var newDevicesToAdd = new Map();
body.forEach((device) => {
platform.apiKey = device.apikey;
devicesFromApi.set(device.deviceid, device);
});
// Now we compare the cached devices against the web list
platform.log("Evaluating if devices need to be removed...");
function checkIfDeviceIsStillRegistered(value, deviceId, map) {
var accessory = platform.accessories.get(deviceId);
if (devicesFromApi.has(deviceId)) {
platform.log('Device [%s] is regeistered with API. Nothing to do.', accessory.displayName);
} else {
platform.log('Device [%s], ID : [%s] was not present in the response from the API. It will be removed.', accessory.displayName, accessory.UUID);
platform.removeAccessory(accessory);
}
}
I found some similar problems with the fromEach function but I still can't seem to figure out what I should change in the script.
Hope you can help me :)

body is not an Array, therefore you cannot invoke .forEach on it, you can try converting it like
Array.from(body).forEach(function (device) { ... }
Take a look on this answer that might help : forEach is not a function error with JavaScript array

NodeJS Sockets Sometimes Working

So, I have a node server, running expressjs io (uses socket.io), and I'm building a grid map that tracks coordinates in a database.
Only, I've run into a peculiar issue in that my sockets only listen sometimes.
At first there was no error message, and only by chance I let the page run and I got this error.
Uncaught TypeError: Cannot call method '0' of undefined UkPS99A_w96Ae0K570Nt?t=1395276358213&i=0:1
When I click on the file UkPS99A_w96Ae0K570Nt?t=1395276358213&i=0:1 I get this code:
io.j[0]("8::");
If I refresh the page, every few times it will suddenly work find for about 10 tile clicks, and then it stops working. My database is updating properly until the sockets basically die out.
Here is where I send the coordinates in my map:
io.emit("move", {x:this.x,y:this.y});
Server listening:
app.io.route('move', function(req) {
con.getConnection(function(err){
if (err) console.log("Get Connection Error.. "+err);
//removed query because redundant
req.io.emit("talk", {x:req.data.x,y:req.data.y});
});
});
and my socket script:
io.on("talk",function(data) {
console.log(data.x,data.y);
});
My script includes are at the bottom of the page in this order:
<script src="socket.io/socket.io.js"></script>
<script>io = io.connect();</script> <!-- open the socket so the other scripts can use it -->
<script src="../js/sock.js"></script>
<script src="../js/map.js"></script>
Is there something I'm doing wrong to that the socket seems to lose connection and throw some sort of error?
Update: I left the server running longer and a couple more error messages popped up in my console:
Uncaught TypeError: Cannot call method 'close' of null socket.io.js:1967
Uncaught TypeError: Cannot call method 'close' of null socket.io.js:1967
Uncaught TypeError: Cannot call method 'onClose' of null
More update: altered the connection line and added the proper CORS to my server.js
io = io.connect('http://sourceundead.com', {resource : 'socket.io'});
Still the same issue.

You seem to have a connection attrition as you never release them to the pool.
Assuming con is the (bad) name of your pool, instead of
app.io.route('move', function(req) {
con.getConnection(function(err){
if (err) console.log("Get Connection Error.. "+err);
//removed query because redundant
req.io.emit("talk", {x:req.data.x,y:req.data.y});
});
});
you should have something like
app.io.route('move', function(req) {
con.getConnection(function(err, connection){
if (err) console.log("Get Connection Error.. "+err);
//removed query because redundant
req.io.emit("talk", {x:req.data.x,y:req.data.y});
connection.release();
});
});
Be careful that using connections must be done with care to ensure they're always released, and it's a little tedious to do especially when handling errors as soon as you have a few queries to do when doing a task.
At some point you might want to use promises to make that easier. Here's a blog post about using bound promises to ease database querying in node.js.

Simple #meteor subscribe call giving an error

Server :
Meteor.publish('trades', function() {
return Trades.find();
});
Client:
Meteor.subscribe("trades");
Both:
Trades = new Meteor.Collection('trades');
When I run meteor, its giving me
TypeError: Object # has no method 'subscribe'
Any suggestions?

You might have your client code running in the root directory /. It would also then execute on the server and give this error. (Not sure if its this).

Create HTTPS client in NodeJS

I've been having a heck of a time figuring out how to use Node.js (v0.3.8) to securely connect to an HTTP server. I have the following code:
var http = require("http");
var client = http.createClient(443, host, /* secure= */ true);
var request = client.request("GET", relativeUrl, { host: host });
When I run it, I get:
node.js:116
throw e; // process.nextTick error, or 'error' event on first tick
^
Error: Parse Error
at Client.onData [as ondata] (http.js:1287:27)
at Client._onReadable (net.js:648:27)
at IOWatcher.onReadable [as callback] (net.js:156:10)
I've been Googling for answers for the past half hour, and have read the documentation at http://nodejs.org/ . What am I missing?

It turns out I was using an old version of the Node documentation, which didn't include a reference to the https module. Referring to the current docs, I found http://nodejs.org/docs/latest/api/https.html#https_https_get_options_callback, which provides an example:
https.get({ host: 'encrypted.google.com', path: '/' }, function (res) { … });

If you are using node.js as a client you should be able to simply substitute http for https.
That is according to the following website
https://github.com/danwrong/Restler/
"Transparently handle SSL (just specify https in the URL)"