@middy/http-json-body-parser/index.js

Http JSON body parser middleware for the middy framework

import { createError } from '@middy/util'

const mimePattern = /^application\/(.+\+)?json($|;.+)/

const defaults = {
  reviver: undefined,
  disableContentTypeError: false
}

const httpJsonBodyParserMiddleware = (opts = {}) => {
  const options = { ...defaults, ...opts }
  const httpJsonBodyParserMiddlewareBefore = async (request) => {
    const { headers, body } = request.event
    const contentType = headers?.['content-type'] ?? headers?.['Content-Type']

    if (!mimePattern.test(contentType)) {
      if (options.disableContentTypeError) {
        return
      }
      throw createError(415, 'Unsupported Media Type', {
        cause: { package: '@middy/http-json-body-parser', data: contentType }
      })
    }

    if (typeof body === 'undefined') {
      throw createError(415, 'Invalid or malformed JSON was provided', {
        cause: { package: '@middy/http-json-body-parser', data: body }
      })
    }

    try {
      const data = request.event.isBase64Encoded
        ? Buffer.from(body, 'base64').toString()
        : body

      request.event.body = JSON.parse(data, options.reviver)
    } catch (err) {
      // UnprocessableEntity
      throw createError(415, 'Invalid or malformed JSON was provided', {
        cause: {
          package: '@middy/http-json-body-parser',
          data: body,
          message: err.message
        }
      })
    }
  }

  return {
    before: httpJsonBodyParserMiddlewareBefore
  }
}
export default httpJsonBodyParserMiddleware