gistfile1.js

   /**
   * Get list of resources
   */
   fetch: function(store, query) {
      store.loadQueryResults(query, SC.SparseArray.create({delegate: this, store: store, query: query, rangeWindowSize:20})); 
      return YES;
   },

   sparseArrayDidRequestLength: function(sparseArray) {
      this.sparseArrayDidRequestRange(sparseArray, { start: 0, length: 20 });
   },

   sparseArrayDidRequestRange: function(sparseArray, range) {
      var url = this._figureOutURL(sparseArray.query.recordType);

      var page = Math.ceil(range.start/range.length) + 1;
      var querystring = '?pagina='+ page +'&cuantos=' + range.length; 
      url = url+querystring;


      SC.Request.getUrl(url)
         .set('isJSON', YES)
         .notify(this, this._didFetch, { sparseArray:sparseArray })
         .send();
   },

   _didFetch: function(response, params){
      var sparseArray = params.sparseArray;

      if(response.status == 200){
         var count = response.get('body').cnt;
         var content = response.get('body').c;
         
         // id should not be a part of the data hash in sproutcore.
         var records = new Array();
         var ids = new Array();
         for(var i=0; i<content.length; i++) {
            var record = content[i];
            var id = record.id;
            delete(record.id);
            records.push(record);
            ids.push(id);
         };

         // Starting index for the sparseArray
         var address = response.address();
         var regex = new RegExp("[\\?&]pagina=([^&#]*)");
         var page = regex.exec(address);
         page = page[1];

         regex = new RegExp("[\\?&]cuantos=([^&#]*)");
         var howMany = regex.exec(address);
         howMany = howMany[1];

         var start = howMany * (page - 1);
         var range = {start:start, length:howMany};
         
         sparseArray.provideLength(count);
         var storeKeys = sparseArray.get('store').loadRecords(Core.Usuario, records, ids);
         sparseArray.provideObjectsInRange({ start: range.start, length: range.length }, storeKeys);
         sparseArray.rangeRequestCompleted(range.start);
      }

      return YES;
   },