@wreckingball/cacher

cacher

cacher is an ExpressJS middleware written in TypeScript which caches responses.

Install

$ npm i --save @wreckingball/cacher@vX.Y.Z

Usage

See Config in /src/index.ts also src/example.ts. Run $ make dev to run the example.

Features

• Respect standard Cache-Control headers:
  • no-cache: In GET requests, bypass cache, and returns live response
  • no-store: In GET requests, will not cache the response
  • max-age:
    • In GET requests, communicates the TTL
    • In GET requests, allows to set per-request TTL
• Extend Cache-Control adding delete-cache which invalidates the cache, if any, for the given request
• Respect standard HTTP ETag
• Allows to specify a matcher:
  • Can match any combination of any request component: method || path || query params || header || everything (*)
• Future proof, and extensible. It allows to use any storage. Storage can be changed without changing the implementation. Current storage implemented: Redis
  • Injects storage in the request chain making it easy to use, and store data
  • Automagically cache matched responses
  • Automagically delete cache for non-GET operations (which changes data), unless Cache-Control: persist-cache is specified, or feature is disabled.
• Cache warmer:
  • Every N ms
  • One time only
  • Configurable after-start-up-delay
  • Batch request parallelize request calls speeding up the warming process
  • Configurable delay between batch calls to protect the storage from overload
• Administrative API:
  • Delete cache by key
  • Delete whole cache
  • Introspect cache by key

How it works

A picture worth thousand words.

Development

1. Clone repository
2. Install dependencies
   1. Run $ npm i --save @wreckingball/cacher
3. Make changes
4. Validate your changes with tests
   1. Run $ make ci
5. Open a pull request

CI/CD

1. Code is merged into main
2. package.json is automagically bumped
3. Code is automagically tagged
4. Release is automagically created
5. Code is automagically pushed to NPM private repository

It's all magic! :)

Roadmap

• Add meta information about a cache entry, so it doesn't get warmed many times
• Add urlsFromFile option to config.warmer to support:
• APIFilepath: Swagger API filepath
• HARFilepath: Network filepath