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Upgrade 1.x -> 2.x

aka "The async/await Update"

Version 2.x of Middy no longer supports Node.js versions 10.x. You are highly encouraged to move to Node.js 14.x, which support ES6 modules by default (export), optional chaining (?.) and nullish coalescing operator (??) natively.

Core​

  • In handler callback(err, response) have been removed for async/await support
    • return response to trigger after middleware stack
    • throw new Error(...) to trigger onError middleware stack
  • In middleware next(err) has been removed for async/await support
    • throw new Error(...) to trigger onError middleware stack
    • return response to short circuit any middleware stack and respond. v1.x currently throws an error when something is returned

Middleware​

cache​

Deprecated. Too generic and had low usage.

However, you can use the following if needed:

const { createHash } = require('crypto')

module.exports = (opts) => {
  const storage = {}
  const defaults = {
    calculateCacheId: async (event) =>
      createHash('md5').update(JSON.stringify(event)).digest('hex'),
    getValue: async (key) => storage[key],
    setValue: async (key, value) => {
      storage[key] = value
    }
  }

  const options = { ...defaults, ...opts }
  let currentCacheKey

  const cacheMiddlewareBefore = async (request) => {
    const cacheKey = await options.calculateCacheId(request.event)
    const response = await options.getValue(cacheKey)
    if (response) {
      return response
    }
    request.internal.cacheKey = cacheKey
  }

  const cacheMiddlewareAfter = async (request) => {
    await options.setValue(request.internal.cacheKey, request.response)
  }

  return {
    before: cacheMiddlewareBefore,
    after: cacheMiddlewareAfter
  }
}

db-manager​

Deprecated. Too generic and had low usage. You can check out middy-rds as a possible alternative or example on building your own replacement.

do-not-wait-for-empty-event-loop​

No change

function-shield​

Deprecated. Only supported up to Node v10.

http-content-negotiation​

No change

http-cors​

Added new options to support more headers

  • methods
  • exposeHeaders
  • requestHeaders
  • requestMethods

http-error-handler​

Added in support to honour httpError.expose. Errors with statusCode >= 500 are no longer applied to response by default. Added new option to catch any non-http and statusCode >= 500 errors

  • fallbackMessage

http-event-normalizer​

No change

http-header-normalizer​

No change

http-json-body-parser​

No change

http-multipart-body-parser​

No change

http-partial-response​

No change

http-response-serializer​

No change

http-security-headers​

No longer adds statusCode:500 when there is no response.

http-urlencode-body-parser​

Remove extended option. Only uses qs as the parser, formally enabled by options {extended: true}.

http-urlencode-path-parser​

No change

input-output-logger​

  • Now additionally logs response from the onError middleware stack
  • Support for omiting within nested arrays
  • Add in support for replacer to be passed into JSON.stringify()

rds-signer​

New middleware to fetch RDS credential used when connecting with IAM roles. This was built into db-manager.

s3-key-normalizer​

No change

s3-object-response​

New middleware to fetch and respond to S3 Object Get request event.

secrets-manager​

Refactored, see documentation

sqs-json-body-parser​

No change

sqs-partial-batch-failure​

Replaced option sqs with AwsClient and added in more options for control.

ssm​

Refactored, see documentation

sts​

New middleware to fetch assume role credentials.

validator​

Upgraded ajv and it's plugins to support JSON Schema Draft 2020-12 specification. Defaults were change because of this.

  • Plugin ajv-keywords removed from being included by default because it's quite a large package and usually only one keyword is used.
  • Plugin ajv-errors removed from included by default because it conflicts with ajv-i18n when dealing with custom messages for multiple languages

warmup​

Deprecated. This was a work round for a missing feature in AWS Lambda. AWS added in the ability to use provisioned concurrency on 2019-12-03, removing the need for this work around.

However, you can use the following if needed:

middy(lambdaHandler).before((request) => {
  if (request.event.source === 'serverless-plugin-warmup') {
    console.log('Exiting early via warmup Middleware')
    return 'warmup'
  }
})