HTTP Problem Details for hapi

Based on http-problem-details (repository | npm) and http-problem-details-mapper (repository | npm), this library allows you to map your Node.js errors to HTTP Problem details according to RFC7807 by convention for your hapi application.

Installation

npm install http-problem-details http-problem-details-mapper hapi-http-problem-details

or

yarn add http-problem-details http-problem-details-mapper hapi-http-problem-details

Usage

hapi-http-problem-details provides a plugin which allows you to map custom Error instances to HTTP Problem Details documents according to RFC7807.

The details of the mapping itself are described in http-problem-details-mapper (repository | npm)

TypeScript

The typical workflow in TypeScript with hapi-http-problem-details is this:

First, you implement an Error

class NotFoundError extends Error {
  public constructor (options: { type: string, id: string }) {
    const { type, id } = options
    super()
    Error.captureStackTrace(this, this.constructor)
    this.name = 'NotFoundError'
    this.message = `${type} with id ${id} could not be found.`
  }
}

Next, you implement an IErrorMapper (noticed we cheated? Instead of the ErrorMapper class, in TypeScript you can use an interface):

class NotFoundErrorMapper implements IErrorMapper {
  public error: string = NotFoundError.name;

  public mapError (error: Error): ProblemDocument {
    return new ProblemDocument({
      status: 404,
      title: error.message,
      type: 'http://tempuri.org/NotFoundError'
    })
  }
}

Finally, create an instance of HapiMappingStrategy and register everything in your app.

import * as Hapi from "@hapi/hapi";
import { HttpProblemDetailsPlugin, HapiMappingStrategy } from 'hapi-http-problem-details'

const strategy = new HapiMappingStrategy(
    new MapperRegistry()
        .registerMapper(new NotFoundErrorMapper()));

const init = async () => {

  const server = Hapi.server({
    port: 3000,
    host: 'localhost'
  });

  await server.register([{
    plugin: HttpProblemDetailsPlugin,
    options: { strategy }
  }]);

  server.route({
    method: 'GET',
    path: '/',
    handler: (request, h) => {
      throw new NotFoundError({type: 'customer', id: '123'})
    }
  });

  await server.start();
  console.log('Server running on %s', server.info.uri);
};

process.on('unhandledRejection', (err) => {

  console.log(err);
  process.exit(1);
});

init();

When GETting localhost:3000, the result will be like this:

HTTP/1.1 404 Not Found
Connection: keep-alive
Content-Length: 107
Content-Type: application/problem+json; charset=utf-8
Date: Wed, 24 Apr 2019 23:48:27 GMT

{
    "status": 404,
    "title": "customer with id 123 could not be found.",
    "type": "http://tempuri.org/NotFoundError"
}

When just returning a return h.response().code(500), you'll get a response like this:

HTTP/1.1 500 Internal Server Error
Connection: keep-alive
Content-Length: 67
Content-Type: application/problem+json; charset=utf-8
Date: Thu, 25 Apr 2019 00:01:48 GMT

{
    "status": 500,
    "title": "Internal Server Error",
    "type": "about:blank"
}

JavaScript / ES2015

The typical workflow in JavaScript/ES2015 with hapi-http-problem-details is this:

First, you implement an Error

class NotFoundError extends Error {
  constructor (options) {
    const { type, id } = options
    super()
    Error.captureStackTrace(this, this.constructor)
    this.name = 'NotFoundError'
    this.message = `${type} with id ${id} could not be found.`
  }
}

Next, you extend the ErrorMapper class:

class NotFoundErrorMapper extends ErrorMapper {
  constructor() {
    this.error = NotFoundError.name;
  }

  mapError (error) {
    return new ProblemDocument({
      status: 404,
      title: error.message,
      type: 'http://tempuri.org/NotFoundError'
    })
  }
}

Finally, create an instance of HapiMappingStrategy and register everything in your app.

const Hapi = require('@hapi/hapi');
const MapperRegistry = require('http-problem-details-mapper').MapperRegistry;
const plugin = require('hapi-http-problem-details').HttpProblemDetailsPlugin;
const HapiMappingStrategy  = require('hapi-http-problem-details').HapiMappingStrategy;
const strategy = new HapiMappingStrategy(new MapperRegistry());

const init = async () => {

  const server = Hapi.server({
    port: 3000,
    host: 'localhost'
  });

  await server.register([{
    plugin: plugin,
    options: { strategy }
  }]);

  server.route({
    method: 'GET',
    path: '/',
    handler: (request, h) => {
      throw new NotFoundError({type: 'customer', id: '123'})
    }
  });

  await server.start();
  console.log('Server running on %s', server.info.uri);
};

process.on('unhandledRejection', (err) => {

  console.log(err);
  process.exit(1);
});

init();

When GETting localhost:3000, the result will be like this:

HTTP/1.1 404 Not Found
Connection: keep-alive
Content-Length: 107
Content-Type: application/problem+json; charset=utf-8
Date: Wed, 24 Apr 2019 23:48:27 GMT

{
    "status": 404,
    "title": "customer with id 123 could not be found.",
    "type": "http://tempuri.org/NotFoundError"
}

When just returning a return h.response().code(500), you'll get a response like this:

HTTP/1.1 500 Internal Server Error
Connection: keep-alive
Content-Length: 67
Content-Type: application/problem+json; charset=utf-8
Date: Thu, 25 Apr 2019 00:01:48 GMT

{
    "status": 500,
    "title": "Internal Server Error",
    "type": "about:blank"
}

Running the tests

npm test

or

yarn test

Want to help?

This project is just getting off the ground and could use some help with cleaning things up and refactoring.

If you want to contribute - we'd love it! Just open an issue to work against so you get full credit for your fork. You can open the issue first so we can discuss and you can work your fork as we go along.

If you see a bug, please be so kind as to show how it's failing, and we'll do our best to get it fixed quickly.

Before sending a PR, please create an issue to introduce your idea and have a reference for your PR.

Also please add tests and make sure to run npm run lint-ts or yarn lint-ts.

License

MIT License

Copyright (c) 2019 PDMLab

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.