Question

I want to be able to create a custom AngularJS service that makes an HTTP ‘Get’ request when its data object is empty and populates the data object on success.

The next time a call is made to this service, I would like to bypass the overhead of making the HTTP request again and instead return the cached data object.

Is this possible?

Answer 1

Angular’s $http has a cache built in. According to the docs:

cache – {boolean|Object} – A boolean value or object created with $cacheFactory to enable or disable caching of the HTTP response. See
$http Caching for more
information.

Boolean value

So you can set cache to true in its options:

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

or, if you prefer the config type of call:

$http({ cache: true, url: url, method: 'GET'}).success(...);

Cache Object

You can also use a cache factory:

var cache = $cacheFactory('myCache');

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

You can implement it yourself using $cacheFactory (especially handly when using $resource):

var cache = $cacheFactory('myCache');

var data = cache.get(someKey);

if (!data) {
   $http.get(url).success(function(result) {
      data = result;
      cache.put(someKey, data);
   });
}