How to make a function validator for express-validator and use it as Middleware?-CodePudding

I have this validator in my register route:

router.post(
  "/register",
  // username must be an email
  body("username")
    .isLength({ min: 4 })
    .withMessage("username must be at least 4 chars long")
    .isLength({ max: 12 })
    .withMessage(" username must be less than 12 chars long")
    .exists()
    .withMessage("username is required")
    .trim()
    .matches(/^[A-Za-z0-9\_] $/)
    .withMessage("username must be alphanumeric only")
    .escape(),
  body("email")
    .isEmail()
    .normalizeEmail()
    .withMessage("Invalid Email")
    .exists(),
  body("password")
    .isLength({ min: 5 })
    .withMessage("password must be at least 5 chars long")
    .isLength({ max: 30 })
    .withMessage("password must be at max 30 chars long")
    .matches(/\d/)
    .withMessage("password must contain a number")
    .exists(),
  (req, res) => {
    // Finds the validation errors in this request and wraps them in an object with handy functions
    const errors = validationResult(req);
    if (!errors.isEmpty()) {
      return res.status(400).json({ errors: errors.array() });
    }
    const username = Utils.Clean_input(req.body.username);
    const email = Utils.Clean_input(req.body.email);
    const password = Utils.Clean_input(req.body.password);
    const salthash = Utils.genPassword(password);
    const salt = salthash.salt;
    const hash = salthash.hash;
    const newuser = new User({
      username: username,
      email: email,
      hash: hash,
      salt: salt,
    });
    try {
      newuser.save((err, data) => {
        if (data) {
          res.status(201).json({
            status: 201,
            sucess: true,
            message: "Register Success, verify your email and login",
          });
        } else {
          res.status(400).json({ err });
        }
      });
    } catch (error) {
      res.status(500).json({ errors: "Server is down try again later" });
    }
  }
);

Can I put those validations method in a custom function in another .js file and import them? If yes how?

example: router.post("/register",validation_fucntion,(res,req){..}), the validation_function handle the validation from another .js file which is imported to the project

CodePudding user response：

express middleware can also be declared in an array for reusability. So you can create the validation function that returns an array with the validators.

E.g.

app.ts:

import express from 'express';
import { body, validationResult } from 'express-validator';

function UserRegisterValidation() {
  return [
    body('username')
      .isLength({ min: 4 })
      .withMessage('username must be at least 4 chars long')
      .isLength({ max: 12 })
      .withMessage(' username must be less than 12 chars long')
      .exists()
      .withMessage('username is required')
      .trim()
      .matches(/^[A-Za-z0-9\_] $/)
      .withMessage('username must be alphanumeric only')
      .escape(),
    body('email').isEmail().normalizeEmail().withMessage('Invalid Email').exists(),
    body('password')
      .isLength({ min: 5 })
      .withMessage('password must be at least 5 chars long')
      .isLength({ max: 30 })
      .withMessage('password must be at max 30 chars long')
      .matches(/\d/)
      .withMessage('password must contain a number')
      .exists(),
  ];
}

const app = express();
const port = 3000;

app.use(express.json());
app.post('/register', UserRegisterValidation(), (req, res) => {
  const errors = validationResult(req);
  if (!errors.isEmpty()) {
    return res.status(400).json({ errors: errors.array() });
  }
  res.sendStatus(200);
});

app.listen(port, () => console.log('HTTP server started at port 3000'));

Test:

⚡  curl -i -X POST -H "Content-Type: application/json"  -d '{"username": "teresa teng"}' http://localhost:3000/register            
HTTP/1.1 400 Bad Request
X-Powered-By: Express
Content-Type: application/json; charset=utf-8
Content-Length: 295
ETag: W/"127-wBnvezB j1d3j/nM62Y93ii4FtM"
Date: Thu, 09 Dec 2021 02:49:12 GMT
Connection: keep-alive
Keep-Alive: timeout=5

{"errors":[{"msg":"Invalid Email","param":"email","location":"body"},{"msg":"password must be at least 5 chars long","param":"password","location":"body"},{"msg":"password must contain a number","param":"password","location":"body"},{"msg":"Invalid value","param":"password","location":"body"}]}%

 ⚡  curl -i -X POST -H "Content-Type: application/json"  -d '{"username": "teresa teng", "password": "password123", "email": "[email protected]"}' http://localhost:3000/register
HTTP/1.1 200 OK
X-Powered-By: Express
Content-Type: text/plain; charset=utf-8
Content-Length: 2
ETag: W/"2-nOO9QiTIwXgNtWtBJezz8kv3SLc"
Date: Thu, 09 Dec 2021 02:45:04 GMT
Connection: keep-alive
Keep-Alive: timeout=5

OK%