Using Shared Service(with $resource) to share data between controllers, but how to define callback functions?

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Using Shared Service(with $resource) to share data between controllers, but how to define callback functions? Shaun Lim 10/7/12 12:42 PM
Hi All,

I'm building my first AngularJS app and am not very familiar with Javascript to begin with so any guidance will be much appreciated :)

My App has two controllers, ClientController and CountryController. In CountryController, I'm retrieving a list of countries from a CountryService that uses the $resource object. This works fine, but I want to be able to share the list of countries with the ClientController. After some research, I read that I should use the CountryService to store the data and inject that service into both controllers.

This was the code I had before:

CountryService:

services.factory('CountryService', function($resource) {
return $resource('http://localhost:port/restwrapper/client.json', {port: ':8080'});
});

CountryController:

//Get list of countries
//inherently async query using deferred promise
$scope.countries = CountryService.query(function(result){
        //preselected first entry as default
$scope.selected.country = $scope.countries[0];
});

And after my changes, they look like this:

CountryService:

services.factory('CountryService', function($resource) {
var countryService = {};

var data;
var resource = $resource('http://localhost:port/restwrapper/country.json', {port: ':8080'});

var countries = function() {
data = resource.query();
return data;
}

  return {
  getCountries: function() {
  if(data) {
  console.log("returning cached data");
  return data;
  } else {
  console.log("getting countries from server");
  return countries();
  }
 
  }
  };
  });

CountryController:

$scope.countries = CountryService.getCountries(function(result){
console.log("i need a callback function here...");
});

---

The problem is that I used to be able to use the callback function in $resource.query() to preselect a default selection, but now that I've moved the query() call to within my CountryService, I seemed to have lost what.

What's the best way to go about solving this problem?

Thanks for your help,
Shaun
Re: Using Shared Service(with $resource) to share data between controllers, but how to define callback functions? Shaun Lim 10/7/12 1:22 PM
Ok..so looks like I solved the problem by passing a callback function all the way up to the resource.query() call. Still not sure if this is the best way to do this.

For reference, this is what I did:

CountryController:

$scope.countries = CountryService.getCountries(function(){
//preselected default
$scope.selected.country = $scope.countries[0];
});

CountryService:

//Country Service. Will contain all relevant rest methods here
services.factory('CountryService', function($resource) {
var countryService = {};

var data;
var resource = $resource('http://localhost:port/restwrapper/country.json', {port: ':8080'});

var countries = function(callback) {
data = resource.query(callback);
return data;
}


  return {
  getCountries: function(callback) {
  if(data) {
  console.log("returning cached data");
  return data;
  } else {
  console.log("getting countries from server");
  return countries(callback);
  }
 
  }
  };
  });