@mulesoft/request-error-handler

Request Error Handler

Standardized error handler for rendering API responses with i18n. Automatically renders with support for JSON, XML, HTML and plain text.

Installation

npm install request-error-handler --save

Usage

For the error handler to work, you must emit an error with an array of requestErrors. The format for requestErrors is defined below as an array of RequestErrors.

var errorHandler = require('request-error-handler')
var express = require('express')
var app = module.exports = express()

function responder (req, res, error, stack) { /* Custom respond logic here */ }

var defaultLanguage = 'en'
var customMessages = {}

app.use(errorHandler(responder, defaultLanguage, customMessages))

Options

• responder Provide a custom error formatter with optional stack depending on environment (default: errorHandler.responder)
• defaultLanguage Override the default i18n language of English (default: en)
• customMessages Merge custom i18n messages with default messages (default: {}, see interface below)

The messages interface is as follows:

interface CustomMessages {
  [type: string]: {
    [keyword: string]: {
      [language: string]: (error: RequestError) => string
    }
  }
}

Creating Errors

The only restriction on errors that can be formatted using request-error-handler is that the error instance has an array of error objects on the requestErrors property. Every error object MUST follow the following interface:

interface RequestError {
  type: 'json' | 'form' | 'headers' | 'query' | 'xml' | string /* Comes with standard types built-in, but you can also provide your own */
  keyword: string /* Keyword that failed validation */
  message: string /* Merged with i18n when available */
  id?: string /* A unique identifier for the instance of this error */
  dataPath?: string /* Natural path to the error message (E.g. JSON Pointers when using JSON) */
  data?: any /* The data that failed validation */
  schema?: any /* The schema value that failed validation */
  detail?: string /* Additional details about this specific error instance */
  meta?: { [name: string]: string } /* Meta data from the error (XML validation provides a code, column, etc.) */
}

To automatically create a compatible error instance, use errorHandler.createError and pass an array of errors with an option status number.

License

Apache License 2.0