/app/services.js

// this is our service module depending on "ngResource" module:

services_module = angular.module('searchServices', ['ngResource']);



// and here's the definition of "duckDuckGoService":

services_module.factory( // again the definitio resembles a controller definition - see controllers.js for detals

    'duckDuckGo',

    [

        '$resource',

        function($resource) {

            // we define a REST resource:

            return $resource(

                'http://api.duckduckgo.com/?format=json&q=:q', // this is a URL; please note the "q" parameter!

                { callback: 'JSON_CALLBACK' }, // this is configuration only

                { ask: { method: 'JSONP' } } // we define only one method here named "ask"

                // there's way more to that - to understand in detail please check AngularJS docs.

            );

        }

    ]

);



// we could use low-level $http in controller instead but using services has its advantages, primarily:

// - they're separate - you can change them without any knowledge how controllers work

// - they can provide a full set of REST methods - we're defining only one here but it is just a simple example.