How to implement validation in a separate file using express-validator

问题

I am trying to use express-validator to validate the req.body before sending a post request to insert data to postgres.

I have a route file, controller file and I want to carryout validation in a file called validate.js. Meanwhile, I have installed express-validator and in my server.js I have imported it. Other resources I come across seem to implement the validation in the function that contains the logic for inserting the data.

//server.js
....
import expressValidator from 'express-validator';

...
app.use(bodyParser.urlencoded({ extended: false }));
app.use(expressValidator);

//route.js
import express from 'express';
import usersController from './controller';

const router = express.Router();

router.post('/createuser', usersController.createUser);

//controller.js
createUser(req, res){
 ...
const { firstName, lastName, email, password } = req.body;
//code to insert user details to the database
}

//validator.js
import { check } from 'express-validator/check';

module.exports = [check('email').isEmail()];

I expect to implemet the validation in a file called validator.js to, say, validate the email before inserting to the database

回答1:

Here is the way i use express-validator. I have a file validator.js where i have validation logic for many routes. For example:

validator.js

const { check } = require('express-validator/check');

exports.createUser = [check('email').isEmail()];

exports.anotherRoute = [// check data];

exports.doSomethingElse = [// check data];

Now in your route file you require the validator.js file
const validator = require("./validator"); // or where your file is located
and use the validation logic you want as a middleware. For example:

route.js

//

router.post('/createuser', validator.createUser, usersController.createUser);

Last, inside your controller you have to check for possible errors created during validation, after requiring validationResult.

controller.js

const { validationResult } = require('express-validator/check');


exports.createUser(req, res) {
    const errors = validationResult(req);
    if (!errors.isEmpty()) {
        return res.status(422).json({ errors: errors.array() });
    }
    // do stuff here.

}

Also, you don't have to use app.use(expressValidator); in your server.js file

来源：https://stackoverflow.com/questions/55772477/how-to-implement-validation-in-a-separate-file-using-express-validator

标签

express

express-validator