3.9 – Accessing Request Variables in Express.js

In this section, we will learn how to access request variables in Express.js — including data from query strings, request bodies, and form submissions.

✅ Accessing Query Parameters (GET Request)

We’ll start by accessing query parameters using a GET request.

UserRouter.ts

getRoutes() {
this.router.get(‘/signup’, UserController.signup);
}

UserController.ts

export class UserController {
static signup(req, res, next) {
res.send(req.query); // Access query parameters
}
}

Test via Postman:

Send a GET request to:

http://localhost:5000/api/user/[email protected]&password=testPassword

Response::

{
“email”: “[email protected]”,
“password”: “testPassword”
}

✅ This confirms we can access query parameters using req.query.

✅ Accessing Body Data (POST Request)

For POST requests, data is usually sent through the request body using either:

• x-www-form-urlencoded (most common for forms)

• form-data (used for file uploads, multipart)

• raw (JSON, text, etc.)

✅ Update UserController.ts:

export class UserController {
static signup(req, res, next) {
res.send(req.body); // Access POST body data
}
}

✅ Update UserRouter.ts:

getRoutes() {
this.router.post(‘/signup’, UserController.signup);
}

⚠️ Problem: No Data Received?

If you send data via Postman (POST request using x-www-form-urlencoded) and get no response or empty body, it’s because Express needs a body parser middleware.

✅ Installing Body Parser

Install the required packages:

npm i body-parser @types/body-parser

✅Configure Body Parser in Server.ts

import * as bodyParser from ‘body-parser’;
setConfigurations() {
this.connectMongoDb();
this.configureBodyParser(); // Must come before routes
}
configureBodyParser() {
this.app.use(bodyParser.urlencoded({ extended: true }));
}

✅ Test Again in Postman

• URL: http://localhost:5000/api/user/signup

• Method: POST

• Body → x-www-form-urlencoded:

Expected Response:

{
“email”: “[email protected]”,
“password”: “testPassword”
}

✅ Success! You’re now able to access POST data from the body.

🧠 Summary