Middy cache middleware

Middy logo

Cache middleware for the middy framework, the stylish Node.js middleware engine for AWS Lambda

npm version Known Vulnerabilities Standard Code Style Greenkeeper badge Chat on Gitter

This middleware offers a simple but flexible caching layer that allows to cache the response associated to a given event and return it directly (without running the handler) if the same event is received again in a successive execution.

By default, the middleware stores the cache in memory, so the persistence is guaranteed only for a short amount of time (the duration of the container), but you can use the configuration layer to provide your own caching implementation.

Install

To install this middleware you can use NPM:

npm install --save @middy/cache

Options

Sample usage

const middy = require('@middy/core')
const cache = require('@middy/cache')

// assumes the event contains a unique event identifier
const calculateCacheId = (event) => Promise.resolve(event.id)
// use in-memory storage as example
const myStorage = {}
// simulates a delay in retrieving the value from the caching storage
const getValue = (key) => new Promise((resolve, reject) => {
  setTimeout(() => resolve(myStorage[key]), 100)
})
// simulates a delay in writing the value in the caching storage
const setValue = (key, value) => new Promise((resolve, reject) => {
  setTimeout(() => {
    myStorage[key] = value
    return resolve()
  }, 100)
})

const originalHandler = (event, context, cb) => {
  /* ... */
}

const handler = middy(originalHandler)
  .use(cache({
    calculateCacheId,
    getValue,
    setValue
  }))

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) 2017-2018 Luciano Mammino and the Middy team.

FOSSA Status