Node

How to use Redis and/or memory cache with node-cache-manager

Paul Wellner Bou

• 1 min read

Upgrading legacy libraries of a (server-side, running on Node) legacy JavaScript application, I had to upgrade  (and replace) following libraries:

As there is missing documentation (node-cache-manager-redis-yet does not have any at all) and there is no current example using a memory cache and Redis at the same time, I spend some time finding the solution. So it might be a useful shortcut for you, if you need to do the same task.

TL;DR

The code I eventually came up with (in short, for more details read further):

The problems and my solutions

  • cache-manager's API changed. It changed for better, so this is a good thing, just a bit of work and restructuring of code, as it relies on Promises now and the application I am working on is already relying on a working cache object on startup.
    So I created a wrapper object taking care of the awaits.
  • While the memory cache accepts null and undefined as result values of a wrapped function, cache-manager-redis-yet does not, and instead of omitting it, it throws an error. If you don't want this error to pop up in your application, you have to catch it (see line 24).
  • cache-manager-redis is not maintained any more, so I removed it completely.
  • cache-manager-redis-store is not "officially" supported by cache-manager, so I used the recommend one: node-cache-manager-redis-yet, which unfortunately has absolutely no documentation and no example.
    It is a fork of cache-manager-redis-store, so we can use their example to create a Redis cache. Keep in mind, we need the full Redis URL here, including the schme redis://, just the host won't work.
  • Inconsistencies in the API using cache-managers multiCache: While creating a cache with caching(...), which returns a Promise<MemoryCache>, multiCache(...) is only accepting Cache objects as parameters, no promises. So we either have to wait until the caches are created, or wrapping it into Promise.all(...)