To help you get started, we've collected the most common ways that koa-joi-router is being used within popular public projects.

joi-router

Easy, rich and fully validated koa routing.

Features:

• built in input validation using joi
• built in output validation using joi
• built in body parsing using co-body and await-busboy
• built on the great @koa/router
• exposed route definitions for later analysis
• string path support
• regexp-like path support
• multiple method support
• multiple middleware support
• continue on error support
• router prefixing support
• router level middleware support
• meta data support
• HTTP 405 and 501 support

Node compatibility

NodeJS >= 12 is required.

Example

const koa = require('koa');
const router = require('koa-joi-router');
const Joi = router.Joi;

const public = router();

public.get('/', async (ctx) => {
  ctx.body = 'hello joi-router!';
});

public.route({
  method: 'post',
  path: '/signup',
  validate: {
    body: {
      name: Joi.string().max(100),
      email: Joi.string().lowercase().email(),
      password: Joi.string().max(100),
      _csrf: Joi.string().token()
    },
    type: 'form',
    output: {
      200: {
        body: {
          userId: Joi.string(),
          name: Joi.string()
        }
      }
    }
  },
  handler: async (ctx) => {
    const user = await createUser(ctx.request.body);
    ctx.status = 201;
    ctx.body = user;
  }
});

const app = new koa();
app.use(public.middleware());
app.listen(3000);

Usage

koa-joi-router returns a constructor which you use to define your routes. The design is such that you construct multiple router instances, one for each section of your application which you then add as koa middleware.

const Koa = require("koa")
const router = require('koa-joi-router');

const pub = router();
const admin = router();
const auth = router();

// add some routes ..
pub.get('/some/path', async () => {});
admin.get('/admin', async () => {});
auth.post('/auth', async () => {});

const app = new Koa();
app.use(pub.middleware());
app.use(admin.middleware());
app.use(auth.middleware());
app.listen();

Module properties

.Joi

It is HIGHLY RECOMMENDED you use this bundled version of Joi to avoid bugs related to passing an object created with a different release of Joi into the router.

const koa = require('koa');
const router = require('koa-joi-router');
const Joi = router.Joi;

Router instance methods

.route()

Adds a new route to the router. route() accepts an object or array of objects describing route behavior.

const router = require('koa-joi-router');
const public = router();

public.route({
  method: 'post',
  path: '/signup',
  validate: {
    header: joiObject,
    query: joiObject,
    params: joiObject,
    body: joiObject,
    maxBody: '64kb',
    output: { '400-600': { body: joiObject } },
    type: 'form',
    failure: 400,
    continueOnError: false
  },
  pre: async (ctx, next) => {
    await checkAuth(ctx);
    return next();
  },
  handler: async (ctx) => {
    await createUser(ctx.request.body);
    ctx.status = 201;
  },
  meta: { 'this': { is: 'stored internally with the route definition' }}
});

or

const router = require('koa-joi-router');
const public = router();

const routes = [
  {
    method: 'post',
    path: '/users',
    handler: async (ctx) => {}
  },
  {
    method: 'get',
    path: '/users',
    handler: async (ctx) => {}
  }
];

public.route(routes);

.route() options

• method: required HTTP method like "get", "post", "put", etc
• path: required string
• validate
  • header: object which conforms to Joi validation
  • query: object which conforms to Joi validation
  • params: object which conforms to Joi validation
  • body: object which conforms to Joi validation
  • maxBody: max incoming body size for forms or json input
  • failure: HTTP response code to use when input validation fails. default 400
  • type: if validating the request body, this is required. either form, json or multipart
  • formOptions: options for co-body form parsing when type: 'form'
  • jsonOptions: options for co-body json parsing when type: 'json'
  • multipartOptions: options for busboy parsing when type: 'multipart'
    • any busboy constructor option. eg { limits: { files: 1 }}
    • autoFields: Determines whether form fields should be auto-parsed (default: true). See the await-busboy docs.
  • output: see output validation
  • continueOnError: if validation fails, this flags determines if koa-joi-router should continue processing the middleware stack or stop and respond with an error immediately. useful when you want your route to handle the error response. default false
  • validateOptions: options for Joi validate. default {}
• handler: required async function or functions
• pre: async function or function, will be called before parser and validators
• meta: meta data about this route. koa-joi-router ignores this but stores it along with all other route data

.get(),post(),put(),delete() etc - HTTP methods

koa-joi-router supports the traditional router.get(), router.post() type APIs as well.

const router = require('koa-joi-router');
const admin = router();

// signature: router.method(path [, config], handler [, handler])

admin.put('/thing', handler);
admin.get('/thing', middleware, handler);
admin.post('/thing', config, handler);
admin.delete('/thing', config, middleware, handler);

.use()

Middleware run in the order they are defined by .use()(or .get(), etc.) They are invoked sequentially, requests start at the first middleware and work their way "down" the middleware stack which matches Express 4 API.

const router = require('koa-joi-router');
const users = router();

users.get('/:id', handler);
users.use('/:id', runThisAfterHandler);

.prefix()

Defines a route prefix for all defined routes. This is handy in "mounting" scenarios.

const router = require('koa-joi-router');
const users = router();

users.get('/:id', handler);
// GET /users/3 -> 404
// GET /3 -> 200

users.prefix('/users');
// GET /users/3 -> 200
// GET /3 -> 404

.param()

Defines middleware for named route parameters. Useful for auto-loading or validation.

See @koa/router

const router = require('koa-joi-router');
const users = router();

const findUser = (id) => {
  // stub
  return Promise.resolve('Cheddar');
};

users.param('user', async (id, ctx, next) => {
  const user = await findUser(id);
  if (!user) return ctx.status = 404;
  ctx.user = user;
  await next();
});

users.get('/users/:user', (ctx) => {
  ctx.body = `Hello ${ctx.user}`;
});

// GET /users/3 -> 'Hello Cheddar'

.middleware()

Generates routing middleware to be used with koa. If this middleware is never added to your koa application, your routes will not work.

const router = require('koa-joi-router');
const public = router();

public.get('/home', homepage);

const app = koa();
app.use(public.middleware()); // wired up
app.listen();

Additions to ctx.state

The route definition for the currently matched route is available via ctx.state.route. This object is not the exact same route definition object which was passed into koa-joi-router, nor is it used internally - any changes made to this object will not have an affect on your running application but is available to meet your introspection needs.

const router = require('koa-joi-router');
const public = router();
public.get('/hello', async (ctx) => {
  console.log(ctx.state.route);
});

Additions to ctx.request

When using the validate.type option, koa-joi-router adds a few new properties to ctx.request to faciliate input validation.

ctx.request.body

The ctx.request.body property will be set when either of the following validate.types are set:

• json
• form

json

When validate.type is set to json, the incoming data must be JSON. If it is not, validation will fail and the response status will be set to 400 or the value of validate.failure if specified. If successful, ctx.request.body will be set to the parsed request input.

admin.route({
  method: 'post',
  path: '/blog',
  validate: { type: 'json' },
  handler: async (ctx) => {
    console.log(ctx.request.body); // the incoming json as an object
  }
});

form

When validate.type is set to form, the incoming data must be form data (x-www-form-urlencoded). If it is not, validation will fail and the response status will be set to 400 or the value of validate.failure if specified. If successful, ctx.request.body will be set to the parsed request input.

admin.route({
  method: 'post',
  path: '/blog',
  validate: { type: 'form' },
  handler: async (ctx) => {
    console.log(ctx.request.body) // the incoming form as an object
  }
});

ctx.request.parts

The ctx.request.parts property will be set when either of the following validate.types are set:

• multipart

multipart

When validate.type is set to multipart, the incoming data must be multipart data. If it is not, validation will fail and the response status will be set to 400 or the value of validate.failure if specified. If successful, ctx.request.parts will be set to an await-busboy object.

admin.route({
  method: 'post',
  path: '/blog',
  validate: { type: 'multipart' },
  handler: async (ctx) => {
    const parts = ctx.request.parts;
    let part;

    try {
      while ((part = await parts)) {
        // do something with the incoming part stream
        part.pipe(someOtherStream);
      }
    } catch (err) {
      // handle the error
    }

    console.log(parts.field.name); // form data
  }
});

Handling non-validated input

Note: if you do not specify a value for validate.type, the incoming payload will not be parsed or validated. It is up to you to parse the incoming data however you see fit.

admin.route({
  method: 'post',
  path: '/blog',
  validate: { },
  handler: async (ctx) => {
    console.log(ctx.request.body, ctx.request.parts); // undefined undefined
  }
})

Validating output

Validating the output body and/or headers your service generates on a per-status-code basis is supported. This comes in handy when contracts between your API and client are strict e.g. any change in response schema could break your downstream clients. In a very active codebase, this feature buys you stability. If the output is invalid, an HTTP status 500 will be used.

Let's look at some examples:

Validation of an individual status code

router.route({
  method: 'post',
  path: '/user',
  validate: {
    output: {
      200: { // individual status code
        body: {
          userId: Joi.string(),
          name: Joi.string()
        }
      }
    }
  },
  handler: handler
});

Validation of multiple individual status codes

router.route({
  method: 'post',
  path: '/user',
  validate: {
    output: {
      '200,201': { // multiple individual status codes
        body: {
          userId: Joi.string(),
          name: Joi.string()
        }
      }
    }
  },
  handler: handler
});

Validation of a status code range

router.route({
  method: 'post',
  path: '/user',
  validate: {
    output: {
      '200-299': { // status code range
        body: {
          userId: Joi.string(),
          name: Joi.string()
        }
      }
    }
  },
  handler: handler
});

Validation of multiple individual status codes and ranges combined

You are free to mix and match ranges and individual status codes.

router.route({
  method: 'post',
  path: '/user',
  validate: {
    output: {
      '200,201,300-600': { // mix it up
        body: {
          userId: Joi.string(),
          name: Joi.string()
        }
      }
    }
  },
  handler: handler
});

Validation of output headers

Validating your output headers is also supported via the headers property:

router.route({
  method: 'post',
  path: '/user',
  validate: {
    output: {
      '200,201': {
        body: {
          userId: Joi.string(),
          name: Joi.string()
        },
        headers: Joi.object({ // validate headers too
          authorization: Joi.string().required()
        }).options({
          allowUnknown: true
        })
      },
      '500-600': {
        body: { // this rule only runs when a status 500 - 600 is used
          error_code: Joi.number(),
          error_msg: Joi.string()
        }
      }
    }
  },
  handler: handler
});

Router instance properties

.routes

Each router exposes it's route definitions through it's routes property. This is helpful when you'd like to introspect the previous definitions and take action e.g. to generate API documentation etc.

const router = require('koa-joi-router');
const admin = router();
admin.post('/thing', { validate: { type: 'multipart' }}, handler);

console.log(admin.routes);
// [ { path: '/thing',
//     method: [ 'post' ],
//     handler: [ [Function] ],
//     validate: { type: 'multipart' } } ]

Path RegExps

Sometimes you need RegExp-like syntax support for your route definitions. Because path-to-regexp supports it, so do we!

const router = require('koa-joi-router');
const admin = router();
admin.get('/blog/:year(\\d{4})-:day(\\d{2})-:article(\\d{3})', async (ctx, next) => { 
 console.log(ctx.request.params) // { year: '2017', day: '01', article: '011' } 
});

Multiple methods support

Defining a route for multiple HTTP methods in a single shot is supported.

const router = require('koa-joi-router');
const admin = router();
admin.route({
  path: '/',
  method: ['POST', 'PUT'],
  handler: fn
});

Multiple middleware support

Often times you may need to add additional, route specific middleware to a single route.

const router = require('koa-joi-router');
const admin = router();
admin.route({
  path: '/',
  method: ['POST', 'PUT'],
  handler: [ yourMiddleware, yourHandler ]
});

Nested middleware support

You may want to bundle and nest middleware in different ways for reuse and organization purposes.

const router = require('koa-joi-router');
const admin = router();
const commonMiddleware = [ yourMiddleware, someOtherMiddleware ];
admin.route({
  path: '/',
  method: ['POST', 'PUT'],
  handler: [ commonMiddleware, yourHandler ]
});

This also works with the .get(),post(),put(),delete(), etc HTTP method helpers.

const router = require('koa-joi-router');
const admin = router();
const commonMiddleware = [ yourMiddleware, someOtherMiddleware ];
admin.get('/', commonMiddleware, yourHandler);

Handling errors

By default, koa-joi-router stops processing the middleware stack when either input validation fails. This means your route will not be reached. If this isn't what you want, for example, if you're writing a web app which needs to respond with custom html describing the errors, set the validate.continueOnError flag to true. You can find out if validation failed by checking ctx.invalid.

admin.route({
  method: 'post',
  path: '/add',
  validate: {
    type: 'form',
    body: {
      id: Joi.string().length(10)
    },
    continueOnError: true
  },
  handler: async (ctx) => {
    if (ctx.invalid) {
      console.log(ctx.invalid.header);
      console.log(ctx.invalid.query);
      console.log(ctx.invalid.params);
      console.log(ctx.invalid.body);
      console.log(ctx.invalid.type);
    }

    ctx.body = await render('add', { errors: ctx.invalid });
  }
});

Development

Running tests

• npm test runs tests + code coverage + lint
• npm run lint runs lint only
• npm run lint-fix runs lint and attempts to fix syntax issues
• npm run test-cov runs tests + test coverage
• npm run open-cov opens test coverage results in your browser
• npm run test-only runs tests only

LICENSE

MIT