oompa-cache

An Oompa middleware to cache task responses

It is based on the amazing lru-cache package.

Usage

const Oompa = require('oompa');
const cache = require('oompa-cache');
const db = require('./my-db');

const server = new Oompa({
  GET: ({key}) => db.get(key),
  SET: data => {
    data[cache.invalidate].GET(data.key);
    return db.set(data.key, data.value);
  },
});
server.use(cache('GET', 50, ({key}) => key));

server.listen(9000);

Why?

To cache common task responses.

require('oompa-cache')(type:String, cacheOptions:Either<Integer,Object>, hasher:(Object=>String))

• type is the task type you wish to cache.
• cacheOptions is passed to the LRU cache (see here).
• hasher will be called with the request payload and should produce a string key that will be used for the cache.

Side Effects

Every request will recieve a new payload property: require('oompa-cache').invalidate. The value of this property is an object with a method for each cached task type (so if we cache every FOO request, every request will have request.payload[cache.invalidate].FOO). This method accepts a key, and removes it from that task's cache.

Moreover, if there's a cache hit, no more middleware will be called, so it is advised to use this middleware as the last of the middleware chain (the last use call).