macalinao / koa-joi-schema

Koa middleware to validate input using Joi.

koa-joi-schema

Koa middleware to validate input using Joi.

Installing

npm i -S koa-joi-schema joi

Note: Joi is a peer dependency, so it must be installed independently.

Usage

See test.js for more examples.

const co = require('co')  // Koa 2 no longer auto-wraps with co
const validate = require('koa-joi-schema')
const Joi = require('joi')

// Creates a validator for 'ctx.request.body'.
// Use dot notation to validate anything on the context.
const validator = validate('request.body')(Joi.object().keys({
  username: Joi.string().email().required(),
  password: Joi.string().regex(/^[a-zA-Z0-9]{3,30}$/).required()
}))

const validationErrorHandler = co.wrap(function* (ctx, next) {
  try {
    yield next()
  } catch (e) {
    if (!e.isJoi) throw e
    ctx.status = 400 // invalid input
    ctx.body = {
      error: 'Invalid input',
      reason: e
    }
  }
})

router.post('/users', bodyParser, validationErrorHandler, validator, usersCtrl.create)

License

ISC

koa-joi-schema's Issues

Expose Joi

I recommend you expose Joi from the module to avoid version conflicts with some validations passing in the middleware but not passing somewhere else in the application. See how koa-joi-router does it here. You won't be forcing any version of Joi on the user of this module, but you also give them an easy option rather than having to keep track of what version this module uses over the course of upgrades.

Why not throw an Error?

Why write to ctx when you can throw an actual Error that's catchable and has additional details? If you're looking for an example, see what I wrote for trie-router here— it's also a validation error of sorts.