news-model.js

function getQueryStringParameter(paramToRetrieve) {
  var params =
      document.URL.split('?')[1].split('&');
  var strParams = '';
  for (var i = 0; i < params.length; i = i + 1) {
    var singleParam = params[i].split('=');
    if (singleParam[0] == paramToRetrieve)
      return singleParam[1];
  }
}

App.News = Em.Object.extend({});
App.News.reopenClass({
  siteGroups: null,

  findAll: function () {
    var hostWebUrl = decodeURIComponent(getQueryStringParameter("SPHostUrl")),
        appWebUrl = decodeURIComponent(getQueryStringParameter("SPAppWebUrl")),
        hashIndex = appWebUrl ? appWebUrl.indexOf('#') : -1;

    // cut hash part of the url, otherwise RequestExecutor throws error
    if (hashIndex >= 0) {
      appWebUrl = appWebUrl.substring(0, hashIndex);
    }

    var context = new SP.ClientContext(appWebUrl);
    var factory = new SP.ProxyWebRequestExecutorFactory(appWebUrl);
    context.set_webRequestExecutorFactory(factory);
    var appContextSite = new SP.AppContextSite(context, hostWebUrl);

    var query = new SP.CamlQuery();
    var newsQuery = appContextSite.get_web().get_lists().getByTitle('News').getItems(query);
    var news = context.loadQuery(newsQuery, 'Include(Id, Title, Body)');

    var deferred = new Em.RSVP.Promise(function (resolve, reject) {
      context.executeQueryAsync(
          Function.createDelegate(this, function () {
            var mappedNews = news.map(function (n) {
              return App.News.create({ title: n.get_item('Title'), body: n.get_item('Body') });
            });
            resolve(mappedNews);
          }),
          function (ctx, args) {
            reject(args.get_message());
          }
        );
    });

    return deferred;
  }

});