httpu.caches

Factory, api compatible with $cacheFactory, that creates LRU caches with support for:

Serialization to storage (storage) example: localStorage, sessionStorage
Entries expiration (maxAge) example: 60 seconds
Custom serialization/compression of values (serializer) example: lz-string compression
Limited number of entries in the cache (capacity) example: 10 entries

OR
Limited length of cache (maxLength) example: 2 Megabytes

The returned cache is again API compatible with angular $cacheFactory.Cache

Characteristics:

Items are not pro-actively pruned out as they age, but if you try to get an item that is too old, it'll drop it and return undefined instead of giving it to you. A convenience cache.prune() method is exported to allow you to prune the cache whenever you want
If you put more stuff in it than it can handle, then least used items items will fall out.
If you try to put an oversized thing in it, then it'll fall out right away.
Adaptation to change: serialized data is agnostic of the creation options, and you can update your code to use a cache with different options and still use the cached data in the storage (as long as you keep the same serializaration implementation)

Installation

Get it from bower or directly download it.

bower install --save angular-hu-caches

Add the dependencies to the HTML

<script type="text/javascript" src="bower_components/serialized-lru-cache/lib/lru-cache.js"></script>
<script type="text/javascript" src="bower_components/angular-hu-cacherp/caches.js"></script>

Add the httpu.caches dependency to your App Module

angular.module('MyApp', ['httpu.caches']);

The huCacheSerializableFactory dependency is now available

Usage

//Direct replacement of $cacheFactory, in localStorage
//Creates a cache of 50 entries saved to localStorage
var cache = huCacheSerializableFactory('myCache', {
  capacity: 50
});

//Cache whose 50 entries expire after 2 minutes, in sessionStorage
var cache = huCacheSerializableFactory('myCache', {
  capacity: 50,
  maxAge: 2 * 60 * 1000, //2 minutes in milliseconds
  storage: $window.sessionStorage
});

//2 MB cache whose entries expire after 10 minutes, in localStorage
var cache = huCacheSerializableFactory('myCache', {
  maxLength: 2 * 1024 * 1024, // 2MB of chars
  maxAge: 10 * 60 * 1000 //10 minutes in milliseconds
});

//1MB cache with compression in local storage
//You must create a dependency with the folling API
angular.module('myApp').factory('myCompressSerializer', function($window) {
  //add lz-string module to your included scripts
  //https://github.com/pieroxy/lz-string
  return {
     stringify: function(obj) {
       return $window.LZString.compress(JSON.stringify(obj));
     },
     parse: function(str) {
       return JSON.parse($window.LZString.decompress(str));
     }
  };
});

var cache = huCacheSerializableFactory('myCache', {
  maxLength: 1 * 1024 * 1024, // 1MB of compressed chars
  serializer: 'myCompressSerializer'
});

Live Example

Use cases

You want to save caches to a storage to allow returning users to read from them
You want to limit the amount of data stored instead of the number of requests
You want entries to expire after some time
You want to compress the data to allow more request to be cached in the 5MB storage that the browsers are giving
You want to resize your caches with new options for returning visitors

LICENSE

The MIT License (MIT)