Develop Reference

Struggling to understand how React determines address of API server

I have a project with a client folder containing a React app bootstrapped with create-react-app. I also have a server folder with an express API server running on localhost:80.
Originally, I ran my frontend and backend as separate servers, making requests to the API server by making requests with fetch("url") and using "proxy": "localhost:80" in my package.json
I have recently altered the project so that my server serves the static frontend files like so: app.use(express.static(path.resolve(__dirname, "../client/build")))
I then tested running the server on two different ports 80 and 3000, and the frontend and backend both worked perfectly but I believed it would only work when the server was run on port 80
How does my frontend now know where to call the API server when it is running on different ports?

Proxy is used in the development environment and after that when you make build then its convert into the static HTML, CSS and JS files and that can be run in any port using node if you try that in a different port than it will also work as same
Proxy is not made for the production environment
https://github.com/facebook/create-react-app/issues/1087

Proxy in production React for fetch API express

I was developping a app with React app. In developing env i was using proxy but I'm deploying the app and I saw that proxy didn't work in.
I read about http-proxy-middleware. It can be a solution or it don't works too?
Any way to do this without config the server with redirects to other port?
I need to continue fetching to my API server.

The best way what I found without configure server and NGINX is follow this steps:
Build front
Move folder into a backend server.
Put that code after routes:
if (process.env.NODE_ENV === 'production') {
app.use(express.static(`${__dirname}/yourFrontFolder/build`));
app.get('*', (req, res) => {
res.sendFile(`${__dirname}/yourFrontFolder/build/index.html`);
})
...
And build your backend code and access to your backend port like frontend.

You don't usually need a proxy in your React app when it is deployed. To deploy, you usually run npm run build, which creates a build directory containing all the compiled JavaScript and HTML files you need for the deployment. These are then served by a web server, such as NGINX or by your backend application.

how to deploy nodejs api and vuejs app in one server

I have developed node rest api and vuejs web applications,
Im trying to deploy both project in to one aws server which run ubuntu.
Both applications have different port,
domain I try to configure api.example.com for api and example.com for vue app.
I can run both applications once after running the command in SSH, but I need them to run it forever.
What I did,
Deploy to apps separately
Apps can access with ports
I need them access
api.example.com
example.com
what are the step to do,
Any changes host file.

I found another way to deploy vue app and express/nodejs in one server without using PM. This what I did
Build your vue code using npm run build command. This will create a folder dist which should have index.html file and static folder.
Copy dist folder into your server code repository. In my case I created a folder public and moved the dist folder inside public.
In app.js file right before module.exports=app line, copy the following lines of code
//These 2 lines make sure that vue and express app are coming from the same server.
app.use('/static', express.static(path.join(__dirname,"../public/dist/static/")));
app.get('/', function(req,res) {
res.sendFile('index.html', { root: path.join(__dirname, '../public/dist/') });
});
First line make sure that the /static folder is accessible and second line will serve the index.html file when you run the node server. Routing between components will be taken care by vue.

This is how we are running our VueJS UI and ExpressJS REST API from the same server.
We are managing our services with PM2.
VueJS (Dev Environment, You can add the same settings to production)
In package.json add "start": "HOST='0.0.0.0' PORT=80 npm run dev",, where 80 is the port VueJS is listening on, to the "scripts": {..} array. Then, after installing PM2, (for dev) we can start VueJS with cd /location/of/vue/root; sudo pm2 start npm run dev --name Vue -- start. (Make sure that Apache is not running).
Please note that setting the HOST to 0.0.0.0 is important. Do not set it to LocalHost or your Servers IP address or you may run into issues.
ExpressJS
In the /location/of/express/app.js add this similar to the bottom of the file:
app.listen(process.env.PORT || 8081), where 8081 is the port your REST API should be listening on. I can then start it with sudo pm2 start /location/of/express/app.js --name Express
At this point, the VueJS should be available at www.example.com (implied Port 80) and the REST API would be available at www.example.com:8081.
If you want to have api.example.com/ point to the API, you need to make sure that your DNS is pointing the "api" subdomain to the desired port, or you may have to add the port into the URL as above.
Additionally, you can easily follow the logs through PM2 as well with pm2 logs APPNAME --lines 100.

Node.js file to run a local server with access-control-allow-origin

I have an html file that has resources in it's directory
(example file tree)
index.html
imgs
>img1.jpg
>img2.jpg
>img3.jpg
js
>js1.js
>js2.js
How do I run a node.js server that will allow me to view the HTML file, as well as allow me to access certain websites with the access-control-allow-origin *
I am unfamiliar with node, so the simpler, the better!
Extra: does not necessarily have to be node, just a server that will allow access control

Since You're learning and starting from scratch so it's preferred to learn how it's done than installing supper-pupper swiss knife toolset that will hide the logic from You and make You boring lazy developer.
If You just want to achieve quick result and don't want to learn - You may use serve package that will do what You need.
But if You're learning nodejs from zero to hero so read my answer.
It's better to do simple things.
Let's go (:
Create some folder and inside of it do following commands in terminal (or cmd in windows os):
1) Init app:
npm init
2) Install express module:
npm i --save express
3) Install cors module/middleware:
npm i --save cors
4) Create public folder and put Your html files there
5) Create app.js file in sibling folder with public:
"use strict";
const
express = require('express'),
app = express(),
cors = require('cors');
app.use(cors()); // attach cors middleware (must be set before of most route handlers to populate appropriate headers to response context)
app.use('/', express.static('public'));
app.listen(8080, () => console.log('APP STARTED'));
6) Run it: node app.js
7) Open in browser: http://127.0.0.1:8080
for more stuff search in YouTube for nodejs express tutorials, nodejs mean stack tutorials and etc. (:

For a quick resolution it can also be checked, the Chrome Web server app, for creating local server allowing access to the local files over localhost server.
https://chrome.google.com/webstore/detail/web-server-for-chrome/ofhbbkphhbklhfoeikjpcbhemlocgigb

express runs on two ports even when port is specified

I use app.listen(PORTNO) for running my express app.
It runs on 127.0.0.1:PORTNO but also on 127.0.0.1:3000
3000 is the default port no on which express runs out of box.
Why this unexpected behaviour?
I have tried setting the env variable to production and also using http.createServer(app).listen(PORTNO);
I am generating my express app files using express-generator.
I am on a windows machine if its relevant
UPDATE:
I start the server using npm start which runs bin\www, and it specifies the port to run the server.
But this does not explains the binding to two port :the one specified in app.js and the other in bin\www for the same app and the app being accessible from both of them.
Can you explain the why?

You should start your server using node server.js(filename). Try this if it helps since when you start it with npm it will get default configurations. And Moreover npm command is used to install the node modules(mostly) rather than running the server.