micro-ajv
An Ajv (Another JSON Schema Validator) middleware for Micro to validate request body, url, query parameters and etc.
Installation
npm install --save micro-ajvUsage
By default, it validates request body and replies with 400 status code if validation fails.
const { send } = require('micro')
const microAjvValidation = require('micro-ajv')
const schema = { type: 'string', maxLength: 1024 }
const validate = microAjvValidation(schema)
const handler = (req, res) => send(res, 200, 'Ok')
module.exports = validate(handler)Middleware Options
It's possible to configure the middleware behavior by passing options object
| Option | Description | Default |
|---|---|---|
ajv |
Ajv options | {} |
target |
Path to data for validations (e.g. query.accountId). It validates request body by default |
"body" |
errorMode |
Enables change middleware behavior strategy when request validation fails. There are three possible modes: reply — respond with an error; throw — throw an exception; inject – call handler with injected validation errors to the req object |
"reply" |
injectKey |
Enables pass validation errors to the req object when error mode is inject
|
"microAjvErrors" |
createError |
Use this option if you need to change the default error object. As a first argument, it expects Ajv validation errors | errors => micro.createError(400, 'Bad request') |
Examples
Validate req.url and handle validation errors inside the handler:
const { send } = require('micro')
const microAjvValidation = require('micro-ajv')
const schema = { type: 'string', maxLength: 1024 }
const options = { target: 'url', errorMode: 'inject', injectKey: 'errors' }
const validate = microAjvValidation(schema, options)
module.exports = validate((req, res) => {
console.error(req.errors)
send(res, 414, 'Request url is too long')
})Validate req.body and reply with a custom error if it fails
const { send } = require('micro')
const microAjvValidation = require('micro-ajv')
const schema = { type: 'string', maxLength: 1024 }
const options = {
createError: errors =>
Object.assign(Error(errors.map(error => error.message)), { statusCode: 400 }),
}
const validate = microAjvValidation(schema, options)
const handler = (req, res) => send(res, 200, 'Ok')
module.exports = validate(handler)Sometime you may need to throw an exception and probably catch it somewhere else in the project instead of replying with an error immediately.
// handler.js
const { send } = require('micro')
const microAjvValidation = require('micro-ajv')
const schema = { type: 'string', maxLength: 1024 }
const options = {
errorMode: 'throw',
createError: errors =>
Object.assign(Error('Payload validation failed'), { type: 'ApiError', statusCode: 400 }),
}
const validate = microAjvValidation(schema, options)
const handler = (req, res) => send(res, 200, 'Ok')
module.exports = validate(handler)// middleware.js
module.exports.logApiErrors = handler => (req, res) =>
handler(req, res).catch(err => {
if (err.type === 'ApiError') {
console.log(`ApiError: ${err.message}`)
}
throw err
})// index.js
const { router, post } = require('microrouter')
const { logApiErrors } = require('./middleware')
const handler = require('./handler')
module.exports = logApiErrors(router(post('/foo', handler)))
