http-error-handler

Middy http-error-handler middleware

HTTP error handler middleware for the middy framework, the stylish Node.js middleware engine for AWS Lambda

Automatically handles uncaught errors that contain the properties statusCode (number) and message (string) and creates a proper HTTP response for them (using the message and the status code provided by the error object). Additionally, support for the property expose is included with a default value of statusCode < 500. We recommend generating these HTTP errors with the npm module http-errors. When manually catching and setting errors with statusCode >= 500 setting {expose: true} is needed for them to be handled.

This middleware should be set as the last error handler unless you also want to register the http-reponse-serializer. If so, this middleware should come second-last and the http-response-serializer should come last.

Install

To install this middleware you can use NPM:

npm install --save @middy/http-error-handler

Options

• logger (defaults to console.error) - a logging function that is invoked with the current error as an argument. You can pass false if you don't want the logging to happen.
• fallbackMessage (default to null) - When non-http errors occur you can catch them by setting a fallback message to be used. These will be returned with a 500 status code.

Sample usage

import middy from '@middy/core'
import httpErrorHandler from '@middy/http-error-handler'

const handler = middy((event, context) => {
  throw new createError.UnprocessableEntity()
})

handler
  .use(httpErrorHandler())

// when Lambda runs the handler...
handler({}, {}, (_, response) => {
  t.deepEqual(response,{
    statusCode: 422,
    body: 'Unprocessable Entity'
  })
})

Middy documentation and examples

For more documentation and examples, refers to the main Middy monorepo on GitHub or Middy official website.

Contributing

Everyone is very welcome to contribute to this repository. Feel free to raise issues or to submit Pull Requests.

License

Licensed under MIT License. Copyright (c) 2017-2021 Luciano Mammino, will Farrell, and the Middy team.