Develop Reference

Calling an endpoint inside the node project itself?

I am creating a MERN app that adds meta tags to React pages without SSR. So, I need to read the query inside the main file of the server and pass the appropriate metadata content to each page.
I am using this in the server.js file:
const indexPath = path.resolve(__dirname, 'build', 'index.html');
// static resources should just be served as they are
app.use(express.static(
path.resolve(__dirname, 'build'),
{ maxAge: '30d' },
));
// here we serve the index.html page
app.get('/*', (req, res, next) => {
fs.readFile(indexPath, 'utf8', (err, htmlData) => {
if (err) {
console.error('Error during file reading', err);
return res.status(404).end()
}
// get post info
const postId = req.query.id;
const post = getPostById(postId);
if(!post) return res.status(404).send("Post not found");
// inject meta tags
htmlData = htmlData.replace(
"<title>React App</title>",
`<title>${post.title}</title>`
)
.replace('__META_OG_TITLE__', post.title)
.replace('__META_OG_DESCRIPTION__', post.description)
.replace('__META_DESCRIPTION__', post.description)
.replace('__META_OG_IMAGE__', post.thumbnail)
return res.send(htmlData);
});
});
Here the getPostById is statically defined in a file. But I want to fetch it from my db.
My file structure is:
server.js
controllers
- posts.js
routes
- posts.js
I've separated the logic from route. So my routes/posts.js file looks like:
import { getPost, createPost } from '../controllers/posts.js';
const router = express.Router();
router.get('/', getPost);
router.post('/', createPost);
export default router;
So, in order to dynamically pass the meta content, I need to read the API endpoint for each request and pass the appropriate data. For this, I need to call the endpoints directly inside my node project. How to do that?
I'd appreciate any help. Thank you.

If you really want to call your own http endpoints, you would use http.get() or some higher level http library (that is a little easier to use) such as got(). And, then you can make an http request to your own server and get the results back.
But ... usually, you do not make http requests to your own server. Instead, you encapsulate the functionality that gets you the data you want in a function and you use that function both in the route and in your own code that wants the same data as the route. This is a ton more efficient than packaging up an http request, sending that request to the TCP stack, having that request come back to your server, parsing that request, getting the data, forming it as an http response, sending that response back to the requester, parsing that response, then using the data.
Instead, if you have a common, shared function, you just call the function, get the result from it (probably via a promise) and you're done. You don't need all that intermediate packaging into the http request/response, parsing, loopback network, etc...

Startegy for organzing the endpoints in SPA app

I need strategy on organizing the urls.
Our application has around 150 urls. Some are rather simple without any Route parameters. While others have often more than 1 route parameter in them. For example it could be like this
api/School/Class
api/School/1/Class/2/Student
api/School/Class/revaluate
So in the first one it has no parameter , while second has two parameters and finally third one has 1 but last part is not a resource but an action.
I don't want to store the url just where we would consume it, since maintaining the urls would be technical nightmare. I was hoping if we could have single file api.js or multiple files like api/School.js , api/Teacher.js for storing the files.

In express, you call this a router.
const express = require('express');
const app = express();
const schoolRouter = require('./routers/school');
//...
app.use('/api/school', schoolRouter); // Forwards any requests to the schoolrouter
//...
School.js:
// The router works just like express app (which is also a router)
const schools = require('express').Router();
// we used example.com/api/schools/something to get here
// but the router only cares about what comes next
schools.get('/', function(req, res, next) {
// res.send()
});
// Get a single school (etc, you get the point)
schools.get('/:schoolId', function(req, res, next) {
let id = req.params.schoolId;
// get data from server and res.send()
});
//...
module.exports = schools;
And you can chain routers, but because you only have a partial route, parameters might get lost. So the normal thing is to store parameters to the req object.
schools.use('/:schoolId/classes', function(req, res, next) {
req.schoolId = req.params.schoolId;
next()
}, classesRouter);
This way we can access req.schoolId at any time further down the chain.

Express: How to properly use route paramters

I'm setting up routes for in my express server. As I tried to use it with a route paramter, I stumbled upon a problem:
router.get('/edit/:id', (req, res) => {
res.sendFile(rootPublic + '/pages/recipes/edit.html')
})
Is it possible to somehow send the data of the object I want to edit with the response? Or is it only possible to use the id as a query parameter and read the data on document load?

NodeJS & Express authentication middleware not functioning correctly

I am attempting to run the function isUserAuthenticated on every request to the server by requiring it in app.js and 'using' it as so: app.use(authenticate.isUserAuthenticated).
I have an /authenticate callback route that is being POSTED to by our SAML Identity Provider which contains the information required to validate the user and the session. This is what is inside my authenticate.js file:
module.exports = router;
module.exports.isUserAuthenticated = function(req, res, next) {
console.log(req.cookies.subject);
if (req.cookies.subject) {
console.log(req.cookies.subject)
return next();
} res.redirect("LINK TO IDP FOR VERIFICATION, callback func. is then ran to get value of user and session");
}
As referenced, this authentication function is being required and used in app.js: authenticate = require('./routes/authenticate'), and app.use(authenticate.isUserAuthenticated).
The problem: No matter what variation of the if statement to verify if the subject cookie is present in the request, the authentication check is not being fired and the redirect to the IDP authentication route is not being redirected too. The console.log checks in the code above are returning:
undefined, and
{}.
Authentication was working on a single route when I was using the isUserAuthenticated function manually like this: router.use('/', isUserAuthenticated, function(req, res, next) {..., but I am trying to use this function globally so I don't have to manually incorporate this middleware on each route.
Any advice/suggestions would be greatly appreciated. Thank you.

as suggested in comment,
you can move the isUserAuthenticated function to app.js. It'd look something like this
app.use(function(req, res, next) {
if (req.cookies.subject) {
next();
}
else
res.redirect("LINK TO IDP FOR VERIFICATION, callback func. is then ran to get value of user and session");
})
This will process all the requests before they are forwarded to the routes later.

A middleware needs to be set on router object if you are using express js
router.use(isUserAuthenticated)
Don't forget to put this on the top of your routes file.
See the difference between app level and router level middleware here

Specific url and parameter in Node.js project

I have 2 qeustions :
1. I want my project's url to be like 127.0.0.1:8080/param=id and I couldnt do it, I tried:
app.get('/param=id', function(req, res) {
console.log(req.param("id"));
});
if I write '/param/:id' it works but I dont want the url to look like this
I want my program to send message according to the id a json message or string to the client
So my second question is how the client gets the response - I want the message to go throgh a script in the client's side?

I would suggest using req.query instead of req.params:
app.get('/', function(req, res) {
console.log(req.query.id);
// or you may still use req.param("id")
});
requesting it like
HTTP GET 127.0.0.1:8080/?id=my_id
query is a different way of sending data to the server, designed to send key-value pairs.
Though, if id is the only thing you want to send to the server, I would recommend to stick with params, e.g.:
app.get('/:id', function(req, res) {
console.log(req.params.id);
});
requesting it like
HTTP GET 127.0.0.1:8080/my_id