Node Cache Manager store for Filesystem

Package to cache key-value pairs in JSON files.

Installation

1npm install cache-manager-fs-hash

Features

• Saves anything that is JSON.stringify-able to disk
• Buffers are saved as well (if they reach a certain size they will be stored to separate files)
• Works well with the cluster module

Usage example

Here is an example that demonstrates how to implement the Filesystem cache store.

1const {DiskStore} = require('cache-manager-fs-hash');
2
3const diskStore = new DiskStore({
4    path: 'diskcache', // path for cached files (default: cache)
5    ttl: 60 * 60 * 1000, // time to life in milliseconds 
6                         // (default: never expires)
7    zip: true, // zip files to save disk space (default: false)
8});
9
10(async () => {
11    await diskStore.set('key', 'value');
12    console.log(await diskStore.get('key')); // "value"
13
14    await diskStore.del('key');
15    console.log(await diskStore.get('key')); // undefined
16
17    await diskStore.set('key', 'value', 1000); // with custom TTL
18    console.log(await diskStore.ttl('key')); // 999 milliseconds
19
20    // delete stored files
21    await diskStore.reset();
22})();

Here is an example that demonstrates how to use the store with the node-cache-manager module.

1const cacheManager = require('cache-manager');
2const {DiskStore} = require('cache-manager-fs-hash');
3
4const diskCache = cacheManager.createCache(new DiskStore({
5    path: 'diskcache', // path for cached files
6    // ... other options
7}));
8
9
10(async () => {
11
12    await diskCache.set('key', 'value');
13    console.log(await diskCache.get('key')); // "value"
14
15    console.log(await getUserCached(5)); // {id: 5, name: '...'}
16    console.log(await getUserCached(5)); // {id: 5, name: '...'}
17
18    function getUserCached(userId) {
19        return diskCache.wrap(userId, function () {
20            return getUser(userId);
21        });
22    }
23
24    async function getUser(userId) {
25        await new Promise(r => setTimeout(r, 100)); // sleep 0.1 seconds
26        return {id: userId, name: '...' + Math.random()};
27    }
28
29})();

How it works

The filename is determined by the md5 hash of the key. (The key is also saved in the file to detect hash collisions. In this case it will just return a cache miss). Writing is performed with .lock files so that multiple instances of the library (e.g. using the cluster module) do not interfere with one another.

Tests

1npm test

License

cache-manager-fs-hash is licensed under the MIT license.