koa-joi-validator-middleware

    1.0.3 • Public • Published

    koa-joi-validator-middleware

    Koa 2 middleware for validating Joi schemas

    Codeship Status for ersoma/koa-joi-validator-middleware

    TLDR

    Problem:

    • Have a Koa 2 web server
    • Want to validate with Joi

    Solution:

    const Koa = require('koa');
    const Joi = require('joi');
    class koaJoiValidator = require('koa-joi-validator-middleware');
    
    const schema = Joi.object({...});
    const config = {...};
    
    const app = new Koa();
    app.use(koaJoiValidator(schema, config));
    
    app.use(async ctx => {
      // Here you can be sure that the specified validation passed
    });

    Examples

    1. Basic usage

    By default, only the schema parameter is needed. In this case the middleware will validate the ctx.request.body object and throws an Error with a default message if it fails.

    ...
    const schema = Joi.object({...});
    
    const app = new Koa();
    app.use(koaJoiValidator(schema));
    ...

    2. Custom onError string parameter

    You can specify an onError key in the second, config parameter. If this is a string it overwrites the default error message thrown.

    ...
    const schema = Joi.object({...});
    const config = {
      onError: 'Hey You, send me a proper request!'
    };
    
    const app = new Koa();
    app.use(koaJoiValidator(schema, config));
    ...

    3. Custom onError function parameter

    The onError parameter can be a function as well which is called when the validation fails with the following parameters: ctx, next, error. Here ctx and next are the standard Koa middleware parameters and error is the ValidationError returned by Joi.

    ...
    const schema = Joi.object({...});
    const config = {
      onError: ctx => ctx.render('errorPage')
    };
    
    const app = new Koa();
    app.use(koaJoiValidator(schema, config));
    ...

    4. Custom getSubject function parameter

    By default, the middleware validates the ctx.request.body object but this can be overwritten with the getSubject function. It takes ctx as the input parameter and is expected to return the object that should be validated.

    ...
    const schema = Joi.object({...});
    const config = {
      getSubject: ctx => ctx.session
    };
    
    const app = new Koa();
    app.use(koaJoiValidator(schema, config));
    ...

    API

    Parameter Optional Type
    schema no Joi schema
    config yes Object
    config.onError yes String or Function(ctx, next, error)
    config.getSubject yes Function(ctx)

    Note: This middleware does not contain Joi as an inner dependency, only as peer dependency. This means it can be updated individually when a new version comes out but it also means you need to install it separately.

    Install

    npm i koa-joi-validator-middleware

    DownloadsWeekly Downloads

    33

    Version

    1.0.3

    License

    MIT

    Unpacked Size

    16.2 kB

    Total Files

    11

    Last publish

    Collaborators

    • ersoma