observer.js

function observer(){
	var observers = [];
	return {notify: notify, subscribe:subscribe}

	function subscribe(callback){
		observers.push(callback);
		var i = observers.length - 1;
		return function(){
			observers[i] = function(){}
		}
	}

	function notify(msg){
	    setTimeout(function(){
			for(var i=0; i < observers.length; i++){
				try{
					observers[i](msg);
				}catch(e){
					//
				}
			}
	    });
	}
}

function getService($http){
	var cache = {};

     return function(id){
     	return cache[id] = cache[id] || buildService(id);
     }

     function buildService(id){
     	var d,n,o = observer(), e = observer();
     	return {subscribe:subscribe, error:error, reload:reload};

     	function setup(){
     		p = p || $http.get("/data/"+id).then(function(r){
     			o.notify(r.data);
     			d = r.data;
     		}, e.notify);
     	}

     	function reload(){
     		d = p = null;
     		setup();
     	}

     	function subscribe(callback){
     		o.subscribe(callback);
     		if(d){
     			callback(d);
     		}
     		setup()
     	}

     	function error(callback){
     		o.subscribe(callback);
     	}
     }
}

function putService($http){
	return {put:put};

	function put(data){
		return $http.put("/data", data);
	}
}

function controller(getService, putService){
	var service = getService(1)
	var ctrl = {data:{}, errors:[]};

	ctrl.$onInit = function(){
		service.subscribe(function(d){
			ctrl.data = d;
		})
		service.error(function(e){
			ctrl.errors.push(e);
		})
	}

	ctrl.put = function(data){
		putService.put(data).then(function(){
			getService(data.Id).reload();			
		});
	}
	return ctrl;
}