NodeJS: My node files have dependencies on variables in an other file - javascript

I am creating an app with nodejs. In the app, I have a app.js script that is the entrypoint that initializes both the app, as an expressjs app, and the http server that I use.
Just to clarify: modules here are not npm modules, they are my own files. I've written the app in modules. They are just seperate script files used by require()-ing them.
This app has several modules that a main module handler initializes. It reads the contents of a folder, which contains my own modules, and then by convention call the .initialize on each module after running a require() call on the filenames without the .js extension.
However, I have 1 module that needs the app variable to create an endpoint, and 1 module that needs the httpServer variable to create a web socket. Both of these are instansiated in app.js.
Seeing as I don't know what kind of modules will be in the folder, I don't really want to send app and httpServer to every module if they are just needed by 1 module each. Something like dependency injection would fit nice, but is that possible without to much overhead?
Right now I just temporarily added app and httpServer to the GLOBAL object.

What I usually do is have app.js export app so that modules elsewhere in my app can require it directly rather than having to deal with passing it around everywhere. I also slightly modify app.js so that it won't "listen" if it is required as a module that way later on if i decide to wrap it with another app, I can with minimal changes. This is not important to your question, I just find it give me more control when unit testing. All you really need from the code below is module.exports = app
'use strict';
var express = require('express'),
app = express(),
config = require('config'),
pkg = require('./package.json');
// trust reverse proxies
app.enable('trust proxy');
app.set('version', pkg.version);
module.exports = app; // <--- *** important ***
if (app.get('env') !== 'production') {
app.set('debug', true);
}
// calling app.boot bootstraps the app
app.boot = function (skipStart) { // skipStart var makes it easy to unit test without actually starting the server
// add middleware
require('./middleware/');
// setup models
app.set('models', require('./models'));
// setup routes
require('./routes/');
// wait for a dbconnection to start listening
app.on('dbopen', function () {
// setup hosting params
if (!skipStart) {
let server = app.listen(config.port, function () {
app.emit('started');
console.log('Web Server listening at: http://%s:%s', server.address().address, server.address().port);
// mail server interceptor for dev
if (app.get('env') !== 'production') {
// Config smtp server for dev
let SMTPServer = require('smtp-server').SMTPServer,
mailServer = new SMTPServer({
secure: false,
disabledCommands: ['STARTTLS'],
onData: function(stream, session, callback){
stream.pipe(process.stdout); // print message to console
stream.on('end', callback);
},
onAuth: function (auth, session, callback) {
callback(null, {user: 1, data: {}});
}
});
// Start smtp server
mailServer.listen(1025, '0.0.0.0');
} else {
// start agenda jobs only on production
require('./jobs.js');
console.log('Agenda Jobs Running.');
}
});
} else {
app.emit('booted');
}
});
};
// If this is the main module, run boot.
if (require.main === module) {
// move all of this to next tick so we can require app.js in other modules safely.
process.nextTick(app.boot);
}

Suppose you want to initialize 2 file from main app.js
app.js
var socketIni = require('./socketini.js');//You have to pass server
var xyz = require('./xyz.js')//you have to pass app
var app = express();
var server=http.createServer(app);
socketIni(server);
xyz(app);
socketini.js
module.exports = function(server){
//your socket initilize goes here
var io = require('socket.io').listen(server);
}
xyz.js
module.exports = function(app){
//you can access app here
}

Related

Vue Production issue with Express

I'm trying to install SSR on my current Vue app, and for this I'm using the vue-plugin-ssr extension. I want to run it with express, so I created a new file called server.mjs and have this:
import express from "express";
import { createServer as createViteServer } from "vite";
import { renderPage } from "vite-plugin-ssr";
async function createServer() {
const app = express();
// Create Vite server in middleware mode and configure the app type as
// 'custom', disabling Vite's own HTML serving logic so parent server
// can take control
const vite = await createViteServer({
server: { middlewareMode: true },
appType: "custom",
});
// use vite's connect instance as middleware
// if you use your own express router (express.Router()), you should use router.use
app.use(vite.middlewares);
app.get("*", async (req, res) => {
// `renderPage()` can also be used in serverless environments such as
// Cloudflare Workers and Vercel
const { httpResponse } = await renderPage({ url: req.url });
res.send(httpResponse.body);
});
app.listen(3000);
}
createServer();
So this actually works for dev, when I run node server.mjs, but neither client or server folder has an index.html file, so how can I run this on production actually?
Only what I'm doing is to set the folder on nginx to path/dist/client, do I need to do something else?
btw as a response on production I have only 403 forbbiden.
You need to run the client and ssr build process as demonstrated in Vite's documentation and then:
Move the creation and all usage of the vite dev server behind dev-only
conditional branches, then add static file serving middlewares to
serve files from dist/client

How to convert Vue 2 web site to PWA wab app?

I have checked PWA function when use vue 3 but there aren't in vue 2.
so if you have good idea to convert from vue 2 project to pwa, please share.
Thanks.
I found answer for my question. I will share it for all developers.
First, I have done follow this this
vue/cli-plugin-pwa
Second:
make registerServiceWorker.js file with this code:
/* eslint-disable no-console */
import { register } from 'register-service-worker'
if (process.env.NODE_ENV === 'production') {
register(`${process.env.BASE_URL}service-worker.js`, {
ready () {
console.log(
'App is being served from cache by a service worker.\n'
)
},
registered () {
console.log('Service worker has been registered.')
},
cached () {
console.log('Content has been cached for offline use.')
},
updatefound () {
console.log('New content is downloading.')
},
updated () {
console.log('New content is available; please refresh.')
},
offline () {
console.log('No internet connection found. App is running in offline mode.')
},
error (error) {
console.error('Error during service worker registration:', error)
}
})
}
Third:
make service-worker.js:
// inside src/service-worker.js
// define a prefix for your cache names. It is recommended to use your project name
workbox.core.setCacheNameDetails({prefix: "simple-vue-project"});
// Start of Precaching##########################
// __precacheManifest is the list of resources you want to precache. This list will be generated and imported automatically by workbox during build time
self.__precacheManifest = [].concat(self.__precacheManifest || []);
workbox.precaching.precacheAndRoute(self.__precacheManifest, {});
// End of Precaching############################
// Start of CachFirst Strategy##################
// all the api request which matchs the following pattern will use CacheFirst strategy for caching
workbox.routing.registerRoute(
/http:\/\/get\.geojs\.io\/v1\/ip\/country\.json/,
new workbox.strategies.CacheFirst()
);
// End of CachFirst Strategy####################
there is a Vue.js plugin, here.
if not :
Create a services worker, you can introduce to it here
add webmanifest or manifest.json of your choice, read here
Add express to your project as depencency
create server.js like file, and serve the built Vue App from the server with express
// server.js ex:
const express = require('express');
const path = require('path');
const port = process.env.PORT || 8080;
const app = express();
app.use(express.static(__dirname));
app.use(express.static(path.join(__dirname, 'build')));
app.get('/ping', function (req, res) {
return res.send('ping');
});
app.get('/*', function (req, res) {
res.sendFile(path.join(__dirname, 'build', 'index.html')); //serving build folder
});
app.listen(port);
The modern #vue/cli provides you the option to turn on PWA while scaffolding both Vue 2 as well as Vue 3 projects. Check out this documentation.
If you have already created the project, CLI offers a new functionality called Vue UI. Simply type vue ui in the cmd and it should open up Vue UI where you can reconfigure your project using graphical interface.
If you are interested in learning Vue JS check out these courses - Complete Vue JS Course, Vue 3 Essentials

How to call function from Nodejs running as windows service

I have created windows service from nodeJs application using node-windows package. Below is my code.
Main.js
var Service = require('node-windows').Service;
// Create a new service object
var svc = new Service({
name:'SNMPCollector',
description: 'SNMP collector',
script: './app.js',
nodeOptions: [
'--harmony',
'--max_old_space_size=4096'
]
//, workingDirectory: '...'
});
// Listen for the "install" event, which indicates the
// process is available as a service.
svc.on('install',function(){
svc.start();
});
svc.install();
/* svc.uninstall(); */
App.js
const { workerData, parentPort, isMainThread, Worker } = require('worker_threads')
var NodesList = ["xxxxxxx", "xxxxxxx"]
module.exports.run = function (Nodes) {
if (isMainThread) {
while (Nodes.length > 0) {
// my logic
})
}
}
}
Now when I run main.js, it creates a windows service and I can see the service running in services.msc
But, how can I call this run() method which is inside the running service, from any outside application? I couldn't find any solution for this, any help would be great.
You might consider simply importing your run function where you need it and run it there, then there is no need for a windows service or main.js - this assumes that "any outside application" is a Node application.
In your other application you you do the folowing:
const app = require('<path to App.js>');
app.run(someNodes)
For broader usage or if you do need to run it as a service, you could be starting an express (or another webserver) in your App.js with an endpoint that invokes your run function. Then from anywhere else you'll need to make an http call to that endpoint.
App.js
const express = require('express')
const bodyParser = require('body-parser')
const { workerData, parentPort, isMainThread, Worker } = require('worker_threads')
const app = express()
const port = 3000
var NodesList = ["xxxxxxx", "xxxxxxx"]
const run = function (Nodes) {
if (isMainThread) {
while (Nodes.length > 0) {
// my logic
})
}
}
}
app.use(bodyParser.json())
app.post('/', (req, res) => res.send(run(req.body)))
app.listen(port, () => console.log(`Example app listening at http://localhost:${port}`))
(Based off of example for express - https://expressjs.com/en/starter/hello-world.html)
You'll need to install both express and body-parser: $ npm install --save express body-parser from the directory of App.js.
From your other applications you will need to call the endpoint http://localhost:3000 with a POST request and the Nodes as a JSON array.
You can expose it on a port like the other answer mentions, though you'll want to make sure you don't expose it more broadly depending on the environment you're running in. There's a good answer here on ensuring the port is locked down.
As an alternative to exposing it on a port you can simply call the function by running the command in any other application:
node -e 'require("/somePathToYourJS/app").run()'
One concern is that app.js will now run at whatever permissions the calling application has. Although that can be resolved by running runas prior. More details here. But an example is:
runas /user:domainname\username "node -e 'require(^"/somePathToYourJS/app^").run()'"

Setting correct structure for a node app

Introduction
So far I have three files, one test.js is a file where I have built three functions that work.
But now I am trying to structure using MVC or at least some pattern. So now I router.js and app.js
Question
Should I put my promise functions from test.js in my config.js or server.js or something else, Im just interested in how people would do this and whats the correct way of structuring NodeJS.
server.js
In here start the server and apply the routes to my app
var configure = require('./router');
var express = require('express');
var app = express();
var port = process.env.PORT || 8080;
// get an instance of router
var router = express.Router();
configure(router);
app.listen(port);
console.log('Server has started!! ' + port);
// apply the routes to our application
app.use('/', router);
config.js
In here I build my routes
module.exports = function (router) {
// route middleware that will happen on every request
router.use(function (req, res, next) {
// log each request to the console
console.log(req.method, req.url);
// continue doing what we were doing and go to the route
next();
});
// home page route (http://localhost:8080)
router.get('/', function (req, res) {
res.send('im the home page!');
});
// sample route with a route the way we're used to seeing it
router.get('/sample', function (req, res) {
res.send('this is a sample!');
});
// about page route (http://localhost:8080/about)
router.get('/about', function (req, res) {
res.send('im the about page!');
});
// route middleware to validate :name
router.param('name', function (req, res, next, name) {
// do validation on name here
console.log('doing name validations on ' + name);
// once validation is done save the new item in the req
req.name = name;
// go to the next thing
next();
});
// route with parameters (http://localhost:8080/hello/:name)
router.get('/hello/:name', function (req, res) {
res.send('hello ' + req.params.name + '!');
})
// app.route('/login')
// show the form (GET http://localhost:8080/login)
.get('/login', function (req, res) {
res.send('this is the login form');
})
// process the form (POST http://localhost:8080/login)
.post('/login', function (req, res) {
console.log('processing'); // shows on console when post is made
res.send('processing the login form!'); // output on postman
});
};
test.js
In here is a list of functions that are a chain of promises getting data and API Keys
(small function, one of many that feed into each over)
var firstFunction = function () {
return new Promise (function (resolve) {
setTimeout(function () {
app.post('/back-end/test', function (req, res) {
console.log(req.body);
var login = req.body.LoginEmail;
res.send(login);
resolve({
data_login_email: login
});
});
console.error("First done");
}, 2000);
});
};
My recommended structure is to put everything except server.js in lib directory so all your app is lib/ plus server.js - everything else is package.json, dependencies in node_modules (created on npm install, not in the repo), .gitignore, config files for Travis, Circle, Heroku or whatever service you're using, some README.md and things like that.
Now, server.js is just bare minimum that requires lib/app:
const app = require('./lib/app');
and starts the server with something like:
const server = app.listen(app.get('port'), () => {
logger.info('%s listening on port %s', app.get('name'), app.get('port'));
});
server.on('error', (err) => {
logger.error(err.message || err);
process.exit(1);
});
where logger is some higher lever logger like Winston or something like that.
That's it. Now, lib/app.js is minimum code that loads the middleware like body parsers etc., creates the express app and sets the variables for port and name and then uses a router that is exported by lib/routes:
const routes = require('./routes');
// ...
app.use('/', routes);
The lib/app should be enough to use for testing with tools like supertest but it doesn't listen on any port - server.js does. This is important to simplify testing.
The router exported by lib/routes is used for everything and you can start with a single lib/routes.js file and then convert it to lib/routes/index.js plus several files in lib/routes as needed.
The routes only define the actual routes and input validation with a module like e.g. express-validation and register controllers that are exported by lib/controllers - that can start as lib/controllers.js and get converted to lib/controllers/index.js plus lib/controllers/*.js as needed - just like the routes.
Then I would add top level spec or test or tests directory where all of the tests go. The tests can require your lib/app to run the tests on it with no need to listen on actual TCP ports - those will test your routes with actual controllers. Other tests will require lib/util and run some unit tests on your utilities etc. Make sure to use a tool like istanbul or nyc to calculate the test coverage.
The database schemas and data models would go to lib/schemas and lib/models, some utility helpers in lib/util, some config loading code in lib/config etc.
This is quite flexible layout and works pretty well. You can start with just few files:
README.md
LICENSE.md
package.json
server.js
lib/app.js
lib/routes.js
lib/controllers.js
lib/config.js
etc. and easily convert all of the xxx.js file into xxx/index.js with entire folder of smaller xxx/*.js files as needed.
The main difference from your approach is that I recommend exporting routers and using them by higher level routers instead of passing the high level router into lower lever modules that export functions that take routers to work on.
So instead of:
const moreSpecific = require('more-specific');
const moreGeneral = express.Router();
moreSpecific(moreGeneral);
and then in more specific:
module exports = (router) => {
router.use('/abc/xyz', ...);
};
I would recommend exporting a more specific router in a file e.g. routes/abc.js:
const router = express.Router();
router.use('/xyz', ...);
module exports = router;
and then in more general router e.g. in routes/index.js:
const abc = require('abc');
const router = express.Router();
router.use('/abc', abc);
// and export the main router for other modules like app.js to use:
module.exports = router;
to have a route like /abc/xyz.

NodeJS Tests - exposing app

I'm testing my NodeJS application with supertest. At the end of my app.js I expose my app, so I can use it within the test.js.
///////////////////
// https options
var options = {
key: fs.readFileSync("./private/keys/Server.key"),
cert: fs.readFileSync("./private/certs/Server.crt"),
ca: fs.readFileSync("./private/ca/CA.crt"),
requestCert: true,
rejectUnauthorized: false
};
///////////////////
// start https server
var server = https.createServer(options, app).listen(app.get("port"), function(){
console.log('Server listening on port ' + app.get('port'));
});
exports = module.exports = server;
When I require my server in my test.js the path of options will cause an error, since my test.js is in the directory ./test/test.js, whereas app.js is in ./app.js.
I'm struggeling to find a clean solution for this problem.
If you make your options into a module, you can either use it directly or stub it in your test using something like rewire or sandboxed-module
Alternatively you could modify your exports to accept the options as a parameter so that you require it with e.g. require('server')(config)

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