cache-ka

About

A Mongoose caching library based on redis engine.

Usage

Add .cache() method to query you want to cache. Works well with select, skip, limit ,lean, sort, and other query modifiers.

const mongoose = require('mongoose');
const cacheKa = require('cache-ka');
 
cacheKa(mongoose, {    
  host: '127.0.0.1',    // Redis host. Defaut value is 127.0.0.1.
  port: 6379            // Redis port. Default value is 6379.
});
 
Item
  .find({ yourQuery: true })
  .cache(20) // The number of seconds to cache the query. Defaults value is 60 seconds.
 
Item
  .aggregate()
  .group({ total: { $sum: '$yourField' } })
  .cache(0) // If ttl is set to 0 will store cache indefinetely.

Cache-ka allows you to store your cache with a custom prefix, that allows you to manage group of cached data.

 
const mongoose = require('mongoose');
const cacheKa = require('cache-ka');
 
cacheKa(mongoose, {    
  host: '127.0.0.1',   
  port: 6379        
});
 
Item
  .find({ yourQuery: true })
  .cache(40, 'cool_items') // Will create a redis entry with prefix cool_items.
                            
 
Item
  .find({yourOtherQuery: true})
  .sort('name')
  .cache(60, 'cool_items') // Creates one more entry with prefix cool_items.
 
 
//Clean cache for all queries with "cool_items" prefix.
cacheKa.clearCache('cool_items', null, function() {
//Your flow logic
});

Cache-ka also works with custom keys in your .cache() query that allows you to remove cache by key.

const mongoose = require('mongoose');
const cacheKa = require('cache-ka');
 
cacheKa(mongoose, {    
  host: '127.0.0.1',   
  port: 6379        
});
 
const parentID = '12052020';
 
Item
  .find({ parentID })
  .cache(0, null, userId + '_custom') // Will create a redis entry with key - 12052020_custom
 
 
 
ItemSchema.post('save', function(item) {
  // Clear the parent's cache when item is added/updated
  cacheKa.clearCache(null, item.parentID + '_custom', function() {
     //Your flow logic
  });
});

Clearing the cache

You can clean cache for a query with custom key, group of queries with a custom prefix and clean entire cache.

//For all queries related to prefix 
cacheKa.clearCache('prefix', null, function(){
    //Your flow logic
});
 
//For custom key. 
cacheKa.clearCache(null, 'key', function(){
    //Your flow logic
});
 
//Entire cache
cacheKa.clearCache(null, null, function(){
    //Your flow logic
});

Connecting to redis

Add you redis host and port as properties to options object of cache-ka initialisation. It will create new redis client and connect it to your redis.

const mongoose = require('mongoose');
const cacheKa = require('cache-ka');
 
cacheKa(mongoose, {    
  host: '127.0.0.1',    // Redis host. Defaut value is 127.0.0.1.
  port: 6379            // Redis port. Default value is 6379.
});

If you already has redis client you want to use you can pass it as redisClient property ot options object

const mongoose = require('mongoose');
const cacheKa = require('cache-ka');
 
const redis = require('redis');
 
const redisClient = redis.createClient({    
    host: '127.0.0.1', 
    port: 6379 
})
 
cacheKa(mongoose, { redisClient });

If you are using async-redis library use redisClientAsync property instead

const mongoose = require('mongoose');
const cacheKa = require('cache-ka');
 
const redis = require('async-redis');
 
const redisClientAsync = redis.createClient({    
    host: '127.0.0.1', 
    port: 6379 
})
 
cacheKa(mongoose, { redisClientAsync });

Caching populated documents

When a document returns from the cache, cache-ka hydrate it, which initializes its methods and virtuals. Hydrating a populated document will discard any populated fields (see Automattic/mongoose#4727). To cache populated documents without losing child items, use .lean(), but it returns a plain object, so you will not be able to use methods and virtuals.