koa-req-validator
A node-validator based request validation middleware for Koa. Unlike other libraries, this middleware provides a declarative API and enables access to the full power of node-validator. Here is a taste of it:
router.post('/users', validate({
email: ['require', 'isEmail', 'Invalid email address'],
password: ['require', 'isLength(6, 32)', 'Password must be between 6 and 32 characters']
}), function *(next) {
...
}
)
// To validate properties of an object
router.post('/users', validate({
'user.name': ['require', 'Name is required'],
'user.address.state': ['require', 'State is required']
}), function *(next) {
...
}
)Usage
Basic
import validate from 'koa-req-validator'
router.post(path, validate(opts), ...)Options
opts is an object specifying the fields and their validation rules.
-
Each key is a field name in the post data (e.g. 'name', 'user.name') with optional search scopes:
header(aliasheaders),query,bodyandparams. Field name and scopes are separated by:. If no scope is specified, all scopes are searched. -
Value is a rule array with the last element being an error message. A rule can be any of the supported methods of node-validator or a custom validator
function(value: *, ...args: Array<*>, ctx: KoaContext): Promise<boolean>|boolean.valueis the value to be validated from one of the scopes.argsare additional arguments that can be declared for the validator (see theisLengthexample above).ctxis the Koa context.
If a field has no value, it won't be validated. To make a field required, add the special required rule (or its alias isRequired). If there are validation failures, the middleware invokes ctx.throw() with status code 400 and all error messages.
Examples
import validator from 'validator'
// Add custom validator
validator['validateUserName'] = async (username, group, ctx) => {
// 1st arg (username): the value to be validate
// 2nd...2nd-to-last args (group): the extra value passed to validateUserName, i.e. "devs"
// last arg (ctx): the Koa context
return boolean | Promise<boolean>
}
validate({
// Find email from request.body and validate
'email:body': ['require', 'isEmail', 'Invalid email address'],
// Find password in all scopes, use the first non-empty value to validate
'password': ['require', 'Password is required'],
// Find birthday from request.query or request.body
'birthday:query:body': ['isDate', 'Invalid birthday'],
// Find username in all scopes
'username': ['validateUserName("devs")', 'Invalid username'],
})Route decorators
You can combine this middleware with route decorators, for example:
import validate from 'koa-req-validator'
import bodyParser from 'koa-bodyparser'
@controller('/users', convert(bodyParser()))
export default class extends Ctrl {
@post('', validate(opts))
async register(ctx, next) {
...
}
}Test
npm install
npm test