ajv-request-validator
Validates the request
object of popular Node.js web frameworks with Ajv.
Installation
npm install ajv-request-validator --save
yarn add ajv-request-validator
Usage
Example with Express:
const RequestValidator = require('ajv-request-validator');
const express = require('express');
const app = express();
const reqValidator = new RequestValidator();
app.post(
'/user',
reqValidator.compile({
body: {
type: 'object',
properties: {
name: { type: 'string' },
age: { type: 'number' }
}
}
}),
function handler(req, res, next) {
}
);
Example with Medley
(works exactly the same with Fastify):
const RequestValidator = require('ajv-request-validator');
const medley = require('@medley/medley');
const app = medley();
const reqValidator = new RequestValidator();
app.route({
method: 'POST',
path: '/user',
preHandler: reqValidator.compile({
body: {
type: 'object',
properties: {
name: { type: 'string' },
age: { type: 'number' }
}
}
}),
handler: function(req, res) {
}
});
API
new RequestValidator([options])
The ajv-request-validator
module exports a class. The class constructor can optionally
be passed either an Ajv options object or
an existing ajv
instance.
const RequestValidator = require('ajv-request-validator');
const reqValidator = new RequestValidator();
const reqValidator = new RequestValidator({
removeAdditional: true,
useDefaults: true,
coerceTypes: true,
});
const Ajv = require('ajv');
const ajv = new Ajv();
const reqValidator = new RequestValidator(ajv);
console.log(reqValidator.ajv === ajv);
reqValidator.ajv
The ajv
instance that the reqValidator
will use to compile validation functions.
reqValidator.ajv.addSchema({
$id: 'user',
type: 'object',
properties: {
name: { type: 'string' },
age: { type: 'number' }
}
});
reqValidator.ajv.addFormat('userID', /[0-9]{9,16}/);
reqValidator.compile(schema[, options])
schema
- And Object
mapping request
properties to an Ajv schema.options
- Optional options Object
.
options.middleware
- If false
, a function that directly validates the request
object will be returned. Defaults to true
.
Compiles a middleware function that validates the req
object and then calls next()
with the
result (either a validation error or null
on success). The keys of the schema
object correspond with
the names of the properties on the req
object to validate (usually body
or query
).
const middleware = reqValidator.compile({
body: {
type: 'object',
properties: {
name: { type: 'string' },
age: { type: 'number' }
}
}
});
app.post('/user', middleware, (req, res, next) => {
});
The middleware
function is an Express-style middleware function with the signature:
function middleware(req, res, next) { }
When the middleware
option is false
, .compile()
returns a function that directly validates
the request
object.
function validate(req) { }
const validate = reqValidator.compile({
body: {
type: 'object',
properties: {
name: { type: 'string' },
age: { type: 'number' }
}
}
}, {middleware: false});
app.post('/user', (req, res, next) => {
const result = validate(req);
});
This is useful when using this module with frameworks that do not have Express-like middleware
(see below for more info).
Usage with other frameworks
Since the .compile()
method returns an Express-style middleware
function, it is not initially compatible with frameworks that have a different
middleware signature.
If a different form of middleware is needed, the RequestValidator
class can be subclassed to override the .compile()
method to return
a function compatible with a specific framework.
Here's an example of extending RequestValidator
to work with Koa:
const RequestValidator = require('ajv-request-validator');
class KoaRequestValidator extends RequestValidator {
compile(schema) {
const validate = super.compile(schema, {middleware: false});
return async function koaMiddleware(ctx, next) {
const err = validate(ctx.request);
if (err !== null) {
throw err;
}
await next();
};
}
}
const reqValidator = new KoaRequestValidator();