Strapi LRU Caching middleware

A cache middleware for the headless CMS strapi.io

How it works

This middleware caches incoming GET requests on the strapi API, based on query params and model ID. The cache is automatically busted everytime a PUT, POST, or DELETE request comes in.

Supported storage engines

• Memory (default)
• Redis

Important: Caching must be explicitely enabled per model

Installing

Using npm

npm install --save strapi-middleware-cache

Using yarn

yarn add strapi-middleware-cache

Setup

For Strapi stable versions, add a middleware.js file within your config folder

e.g

touch config/middleware.js

To use different settings per environment, see the Strapi docs for environments.

You can parse environment variables for the config here as well if you wish to, please see the Strapi docs for environment variables.

Enable the cache middleware by adding the following snippet to an empty middleware file or simply add in the settings from the below example:

module.exports = ({ env }) => ({
  settings: {
    cache: {
      enabled: true,
    },
  },
});

Starting the CMS should now log the following

$ strapi develop
[2020-04-14T11:12:41.648Z] debug [Cache] Mounting LRU cache middleware
[2020-04-14T11:12:41.648Z] debug [Cache] Storage engine: mem

Configure models

The middleware will only cache models which have been explicitely enabled. Add a list of models to enable to the module's configuration object.

e.g

// config/middleware.js
module.exports = ({ env }) => ({
  settings: {
    cache: {
      enabled: true,
      models: ['posts'],
    },
  },
});

Starting the CMS should now log the following

$ strapi develop
[2020-04-14T11:12:41.648Z] debug [Cache] Mounting LRU cache middleware
[2020-04-14T11:12:41.648Z] debug [Cache] Storage engine: mem
[2020-04-14T11:12:41.653Z] debug [Cache] Caching route /posts/:id* [maxAge=3600000]

Configure the storage engine

The module's configuration object supports the following properties

Property	Default	Description
type	mem	The type of storage engine to use (mem or redis)
max	500	Max number of entries in the cache
maxAge	3600000	Time in milliseconds after which a cache entry is invalidated
cacheTimeout	500	Time in milliseconds after which a cache request is timed out
logs	true	Setting it to false will disable any console output
redisConfig (redis only)	{}	The redis config object passed on to ioredis

Example

// config/middleware.js
module.exports = ({ env }) => ({
  settings: {
    cache: {
      enabled: true,
      type: 'redis',
      maxAge: 3600000,
      models: ['posts'],
      redisConfig: {
        sentinels: [
          { host: '192.168.10.41', port: 26379 },
          { host: '192.168.10.42', port: 26379 },
          { host: '192.168.10.43', port: 26379 },
        ],
        name: 'redis-primary',
      },
    },
  },
});

Running the CMS will output the following

$ strapi develop
[2020-04-14T11:31:05.751Z] debug [Cache] Mounting LRU cache middleware
[2020-04-14T11:31:05.752Z] debug [Cache] Storage engine: redis
[2020-04-14T11:31:05.784Z] debug [Cache] Caching route /listings/:id* [maxAge=3600000]
[2020-04-14T11:31:06.076Z] debug [Cache] Redis connection established

Per-Model Configuration

Each route can be configured with it's own unique maxAge. This can be done simply by replacing the model strings in the list by object.

e.g

// config/middleware.js
module.exports = ({ env }) => ({
  settings: {
    cache: {
      enabled: true,
      type: 'redis',
      maxAge: 3600000,
      models: [
        {
          model: 'listings',
          maxAge: 1000000,
        },
      ],
    },
  },
});

Running the CMS should now show the following

$ strapi develop
[2020-04-14T11:37:16.510Z] debug [Cache] Mounting LRU cache middleware
[2020-04-14T11:37:16.511Z] debug [Cache] Storage engine: redis
[2020-04-14T11:37:16.600Z] debug [Cache] Caching route /listings/:id* [maxAge=1000000]
[2020-04-14T11:37:16.946Z] debug [Cache] Redis connection established