Angular Service Restangular Caching

问题:

Are there scenarios where an angular service will cache Restangular/$http calls without being explicitly told to do so? For example I have a service doing something like this:

    function getSomeThings(){
        return Restangular.one('things').get().then(function (thing) {
            return thing;
        });
    }

This service gets called every time a page refreshes (it's in the UI-router route resolve). Is there any chance that this call WON'T be made every time, but will be cached by Angular somehow, without explicitly being told to do so?

I am familiar with caching explicitly like so:

RestangularProvider.setDefaultHttpFields({cache: true});

This is NOT the intent. My question is whether angular services have some innate caching logic, and if so, how to override it.

回答1:

By default Restangular doesn't implement any caching strategies or scenarios, you will need to build your owns. As far as i know, those are what you can do with cache when working with Restangular :

1. You can cache everything as you said but you might find yourself working with stale data, so be careful with that :

   RestangularProvider.setDefaultHttpFields({cache: true});
   

2. You can cache response for single requests like :

   function getSomeThings(){
       Restangular.one('thing', 123).withHttpConfig({ cache: true}).get().then(function (thing) {
           return thing;
       });
   }
   

3. You can involve a custom $cacheFactory instance to expire or invalidate cached responses when necessary by invoking this : $cacheFactory.get('$http').removeAll()

4. You can roll in your own cache interface instead of setting true to the cache. This is a factory example that I'm using to remove all cached data whenever I'm sending a create, update or delete request :

       .factory('HTTPCache', ['Restangular', '$cacheFactory', 
         function(Restangular, $cacheFactory) {
          var service = {};
          var cache;
   
          // Creates the cache
          service.init = function() {
              cache = $cacheFactory('http');
              Restangular.setDefaultHttpFields({cache: cache});
   
              Restangular.setResponseInterceptor(function(response, operation) {
                  if (operation === 'put' || operation === 'post' || operation === 'remove') {
                      cache.removeAll();
                  }
                  return response;
              })
          }
   
          return service;
   
       }])