Xpress-req-validator NPM

LOGO Request Validator

Hassle free middleware to validate all type of requests in a single place while respecting the principle of separation of concerns

Introduction

xpress-req-validator allows developers to handle all request validation tasks in a single place as a middleware while respecting the principle of separation of concerns. It can be used at app level or router level. xpress-req-validator relies on Joi (the awsome JSON Schema validator), which is used to define the request validation specs

Why xpress-req-validator

Request validation is a must when developing an API. Express allows following means to achieve this.

Handling validation logic in each route handler (method-1)

router.post('/device/data', (req, res) => {
        const {deviceID, serialNo} = req.body;
        if(!deviceID || !serialNo) {
            const err = new Error('invalid parameters')
            res.status(400).json({err})
        }

        controller(req.body) // controller section
}

writing a separate middleware in each route handler (method-2)

router.post('/device/data', deviceDataValidationMiddleware, (req, res) => {
        controller(req.body) // controller section
}

Method-1 is an ugly and painful way of achieving request validation. Method-2 is comparatively better, but still requires you to write a ton of middleware. Both methods demand a significant effort to unit test the route handler.

There has to be a better way of validating requests with less unit testing effort and of course by separating the concerns. xpress-req-validator is the solution. It allows developers to define all their request validation specs in a single place, make route handling code snippets much cleaner and finally reducing the unit test effort

Installation

yarn add xpress-req-validator

npm install xpress-req-validator

Basic Usage

Assume that we need to validate the request body of deviceRouter.post('/device', ()=> {})

first we must define the validation spec for request body using Joi

spec.js

import Joi from 'joi';

export const DEVICE_SPEC = Joi.object().keys({
    serialNo: Joi.string()
        .alphanum()
        .min(3)
        .max(25)
        .required(),
    manufacturedYear: Joi.number()
        .integer()
        .min(1900)
        .required(),
    type: Joi.string()
        .valid(['TYPE-A','TYPE-B'])
        .required(),
});

next we must define the xpress-req-validator configurations

config.js

import {DEVICE_SPEC} from './spec';

export default {
    specs: {
        POST: {
            '/device': {
                body: DEVICE_SPEC,
            },
        },
    },
};

now we can apply the xpress-req-validator to deviceRouter

deviceRouter.js

import express from 'express';
import Validator from 'xpress-req-validator';

import config from './config';

const validator = new Validator(config);
const deviceRouter = express.Router();
deviceRouter.use(validator.init());

deviceRouter.post('/device', ()=> {});

That's how easy and clean xpress-req-validator does the job for you. Similarly we can validate the header, path & query of GET, PUT & DELETE requests