express-output-cache

This middleware caches the output (headers and body) of an Express request using Redis. Only string-based responses sent using res.send() (including res.render()) with statusCode < 400 are cached. Also emits cache events.

Installation

npm i express-output-cache

Basic usage

var outputCache = require('express-output-cache');
// Cache the response for this request for 1 hour (default is 60 seconds)
app.get('/page-with-long-processing', outputCache(3600), handler);

outputCache(options)

Options can be the TTL for cache entries in seconds or an object with the following keys:

• prefix: Prefix to use inside Redis/cache. (default: 'outputcache')
• ttl: The TTL as an integer. (default: 60)
• cacheKey: Callback to generate the cache key for each entry. (default: options.prefix + ':' + req.originalUrl)
• skipCache: Either boolean true to skip the cache for all requests or a callback which will be passed Express' req as its only argument.
• cacheClient: Cache client; can be redis or any object that supports get(), set() and expire() like redis. (default: create a new Redis client)

Events

The module exports an event emitter which can directly be accessed at the outputCache function:

• hit(cacheKey, req)
• miss(cacheKey, req)
• save(cacheKey, req, cacheObj)
• cacheError(err)

License

MIT