Keep Object In Memory Between Requests with SailsJS/ Express

Question

I'm building a server using SailsJS (a framework built on top of Express) and I need to keep an object in memory between requests. I would like to do this because loading it to/ from a database is taking way too long. Any ideas how I could do this?

Here's my code:

var params = req.params.all();

Network.findOne({ id: params.id }, function(err, network) {
  if(network) {
    var synapticNetwork = synaptic.Network.fromJSON(network.jsonValue);
    if(synapticNetwork) { ...

Specifically, the fromJSON() function takes way too long and I would rather keep the synapticNetwork object in memory while the server is running (aka. load it when the server starts and just save periodically).

Answer 1

There are plenty libraries out there for caching purposes, one of which is node-cache as you've mentioned. All of them share similar api :

var cache = require('memory-cache');

// now just use the cache

cache.put('foo', 'bar');
console.log(cache.get('foo'))

You can also implement your own module and just require it wherever you need:

var cache = {};

module.exports = {
    put: function(key, item) {
        cache[key] = item;
    },
    get: function(key) {
        return cache[key];
    }
}

Answer 2

There are a lot of potential solutions. The first and most obvious one is using some session middleware for express. Most web frameworks should have some sort of session solution.

https://github.com/expressjs/session

---

The next option would be to use a caching utility like what Vsevolod suggested. It accomplishes pretty much the same thing as session, except if the data needs to be tied to a user/session then you'll have to store some kind of identifier in the session and use that to retrieve from the cache. Which I think is a bit redundant if that's your use-case.

There are also utilities that will expand your session middle-ware and persist objects in session to a database or other kinds of data stores, so that session information isn't lost even after server restarts. You still get the speed of an in-memory store, but backed by a database in case the in-memory store gets blown away.

---

Another option is to use Redis. You still have to serialize/deserialize your objects, but Redis is an in-memory data store and is super quick to write to and read from.