Using localStorage as an $http cache

[Marc Cawood]

Sometimes it would be nice to cache all $htto calls to localStorage. This could make sense for very static data sources or to reduce the cost of using paid http services (like Google APIs).

I've taken a stab at implementing a cache by overriding the get() and put() methods of the $cacheFactory here:

http://embed.plnkr.co/CaZAVeC90qxQP1E4Z5Fb/preview

To use, just include the 'Cacher' service in your code (and as a dependency of your module/application). Next inject and pass CacheLocal as the cache option to all your $http calls.

$http.get(url, {cache: CacheLocal});

The first time the URL is requested it will be fetched via HTTP, thereafter fetched from localStorage.

Feedback welcome as well as better ways of doing this - perhaps via http interceptors?

[Marc Cawood]

PS: It seems AngularJS does not support the cache option for $http.jsonp() - Where can one submit suggestions?

[Michael Bielski]

I see methods for clearing individual items and the cache as a whole, but how are you determining when to call them? What caching rules are you using? LocalStorage is limited to somewhere 5mb per domain in the browser, and a busy page could reach that pretty easily. Once the cache is full, how would you then determine what gets flushed and replaced?

I'm just having a hard time wrapping my head around caching data in a RESTful environment. I think I can see a use for it (enabling an offline mode) but I still just can't get it to settle into my head.

[Marc J. Cawood]

On 3 January 2013 16:43, Michael Bielski <michael...@yahoo.com> wrote:

I see methods for clearing individual items and the cache as a whole, but how are you determining when to call them? What caching rules are you using?

The scenario is that the application caches certain $http calls with no expiration rules. The user can click a button/link which clears the entire cache or a refresh button to clear and reload a specific item. It's mainly for development actually where it does not always make sense to do 10+ AJAX requests each time the developer refreshes the page.

[Michael Bielski]

Hmm... interesting... I think I can get behind that.