IMPORTANT NOTE

This package is NOT ready for prime time yet. It is experimental. Please use at your own risk!!

ExpressJoiSwagger

This is a simple, non-intrusive middleware for automatically defining Swagger API definitions for an Express.js webserver. With this package, you'll virtually eliminate the age-old excuse of not having enough time to write an API reference for your services! Some of the features include:

• Automatic Swagger Reference generation
• Joi-based request validation
• Non-intrusive design. Plays nicely with other Express plugins
• Optional request listener for serving out JSON payload of the auto-generated Swagger reference

Install

Yarn or NPM:

yarn add express-joi-swagger

npm i express-joi-swagger

Usage

Basic Example

The goal is to automatically retrieve your auto-generated API references via http://<your-server-url>/swagger (note: this path is configurable). Here's a basic example of how to setup your Express.js server with ExpressJoiSwagger:

const ExpressJoiSwagger = require('express-joi-swagger');
const express = require('express');
const Joi = require('joi');

const app = express();

// Instantiate ExpressJoiSwagger
const joiSwagger = new ExpressJoiSwagger({
  swaggerDefinition: {
    info: {
      title: 'Session Service',
      description: 'RESTful public service for retrieving and setting User Sessions.',
      version: 'v1.0.2'
    },
    host: 'foo.somewhere.com',
    schemes: ['http', 'https'],
    consumes: ['application/json'],
    produces: ['application/json'],
    defaultResponses: [200, 500]
  },
  onValidateError: (errors, req, res, next) => { // global handler for validation errors
    res.status(400).send(errors);
  }
});

// Wrap joiSwagger around the root-level app or router, then
// define your routes, using Joi for request payload validation:
joiSwagger.wrapRouter(app).get('/users', {
  summary: 'GetUsers',
  description: 'Retrieves a paginated list of users',
  validate: {
    query: {
      limit: Joi.number().default(20).optional().description('Total records returned, for pagination purposes.'),
      offset: Joi.number().default(0).optional().description('Offset for pagination.')
    }
  }
},
(req, res) => {
  res.json([
    'Greg',
    'Edward',
    'Nick',
    'Richard'
  ]);
});

// Wrap joiSwagger around the root-level app before executing the listener
joiSwagger.wrapRouter(app).listen(8000, () => console.log('Express server listening on port 8000'));

Defining Arbitrary Swagger Definitions

joiSwagger.assignDefinition({
  User: {
    type: 'object',
    properties: {
      id: { type: 'number' },
      firstName: { type: 'string' }
    }
  }
});

Defining Route-level Responses

joiSwagger.wrapRouter(app).get('/users/:userId', {
  summary: 'GetUserById',
  description: 'Retrieve a user by ID',
  responses: {
    200: {
      description: 'User Record',
      schema: {
        $ref: '#/definitions/User'
      }
    }
  }
},
(req, res) => {
  // ...

Examples Folder

More in-depth examples in the Examples folder

Caveats

Caveat: Express nested routers ARE NOT CLEANLY SUPPORTED

You can still use Express nested routers (i.e. express.Router()), but you will need to redundantly specify the namespace in the wrapRouter() method. Here's an example:

server.js: Here, we're using the /api namespace to load a nested router:

const express = require('express');
const joiSwagger = require('./joiSwagger');
const app = express();

app.use('/api', require('./routes/foo'));

joiSwagger.wrapRouter(app).listen(8000, () => console.log('listening on port 8000'));

routes/foo.js: Notice how we need to re-specify /api one more time inside of wrapRouter():

const Joi = require('joi');
const joiSwagger = require('../joiSwagger');

// '/api' namespace added here as a second argument
const router = joiSwagger.wrapRouter(require('express').Router(), '/api');

router.get('/foo', {
  summary: 'GetFoo',
  description: 'Gets a list of foos',
  validate: {
    query: {
      limit: Joi
        .number()
        .min(20)
        .optional()
        .description('Total number of results, for pagination purposes.')
    }
  }
},
(req, res) => {
  res.send('BLAH');
});

module.exports = router.expressRouter;

TODO

• Unit tests [HIGH PRIORITY]
• Serve out a Swagger UI automatically (currently only serves out the Swagger Reference JSON, for use in a separate UI)